# Chiral 1D Metal-Organic Materials Based on Cu(II) and Amino Acid Schiff Bases

Carlos Cruz, Carla Gonzalez, Francisco Rubio, Juan Erices, Kerry

Wrighton-Araneda, Diego Cortes-Arriagada, Diego Venegas-Yazigi, Nathalie

Audebrand, Veronica Paredes-Garcia

► To cite this version:

Carlos Cruz, Carla Gonzalez, Francisco Rubio, Juan Erices, Kerry Wrighton-Araneda, et al., Chiral 1D Metal-Organic Materials Based on Cu(II) and Amino Acid Schiff Bases. Crystal Growth & Design, 2022, 22 (1), pp.237-250. 10.1021/acs.cgd.1c00877. hal-03512497

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Chiral 1D metal-organic materials based on Cu(II) and amino acid Schiff-bases

<table><tr><td>Journal:</td><td>Crystal Growth & Design</td></tr><tr><td>Manuscript ID</td><td>cg-2021-008778.R1</td></tr><tr><td>Manuscript Type:</td><td>Article</td></tr><tr><td>Date Submitted by the Author:</td><td>06-Oct-2021</td></tr><tr><td>Complete List of Authors:</td><td>Cruz Herrera, Carlos; Universidad Andres Bello, Departamento de Química<br>Gonzales, Carla; Universidad Andres Bello<br>Rubio, Francisco; Universidad de Santiago de Chile<br>Erices, Juan; Universidad Andres Bello<br>Wrighton, Kerry; Universidad Tecnologica Metropolitana<br>Cortés-Arriagada, Diego; Universidad Tecnologica Metropolitana, Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación<br>Venegas-Yazigi, Diego; Universidad de Santiago de Chile, Chemistry of Materials<br>Audebrand, Nathalie; Universite de Rennes 1, Institut des Sciences Chimiques de Rennes<br>Paredes-García, Verónica; Universidad Andres Bello, Ciencias Quimicas</td></tr></table>

SCHOLARONE™
Manuscripts
# Chiral 1D metal-organic materials based on Cu(II) and amino acid Schiff-bases

Carlos Cruz,ª,ᵇ Carla Gonzalez,ª,ᵇ Francisco Rubio,ª,ᵇ Juan Erices,ª,ᵇ Kerry Wrighton-

Araneda,ᶜ Diego Cortés-Arriagada,ᶜ Diego Venegas-Yazigi,ᵇ,ᵈ Nathalie Audebrand,ᵉ Verónica

Paredes-García*ª,ᵇ

ª Universidad Andrés Bello, Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Santiago, Chile.

ᵇ CEDENNA, Santiago, Chile.

ᶜ Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Santiago, Chile.

ᵈ Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Ciencias de los Materiales, Santiago, Chile.
e Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-
35000 Rennes, France

KEYWORDS

Coordination polymers, amino acid, chirality, circular dichroism, DFT

Abstract

Four new chiral coordination polymers (CPs), {[Cu(HLⁿ)MeOH]·NO₃}ᵦ (n= 1-4), were obtained using a chiral building block synthesized from the condensation reaction of L or D-valine with an imidazole aldehyde. These CPs crystallize in a non-centrosymmetric space group P2₁2₁2₁, evidencing that the chirality of the α-amino acid **valine** is transferred to the structure of the coordination polymer. Moreover, the CPs present a 1D structure with Cu(II) cation in a square base pyramid geometry formed by two units of chiral ligand and a methanol molecule.

The magnetic measurement and theoretical calculations show that the Cu(II) spin carriers are magnetically communicated through the carboxylate bridge, presenting a 1D ferromagnetic chain behavior. Furthermore, four new stable molecular compounds [Cu(HLⁿ)DMSO]⁺ (n= 1-4), sharing the same chiral building block of CPs, were characterized by circular dichroism
(CD). The theoretical electronic excited states of the molecular compounds reproduce the CD experimental spectra showing that the intrinsic chiral activity of the α-amino acid Schiff base is transferred to the Cu(II) centers. Remarkably, using crystal engineering tools, a family of chiral coordination compounds was obtained and analyzed combining several experimental and theoretical approaches, leading to a robust understanding of its chemical and physical properties.

# 1. INTRODUCTION

One of the most intriguing chemical features in nature is chirality, being this characteristic defined as the geometric property of an object of being non-superposable to its mirror image.¹ Even more, for some reason, nature presents preferential selection for one enantiomer over other ones, like proteins and enzymes, which have favoritism for L-aminoacid and D-sugars, respectively.² Thus, chirality can be related to some relevant aspects of chemical reactions, physics phenomena, and biology. In this sense, inorganic chemists have to pay attention to this property to design new chiral metal-organic materials with potential applications in asymmetric catalysis,³ chemical separation,⁴ bio-inorganic⁵,⁶ and nonlinear optical materials.⁷,⁸ Despite the attractiveness of these compounds, controlling the synthetic condition to obtain chiral materials
is not an easy task. The main obstacle that must be overcome to get chiral materials is to obtain a pure enantiomorph since synthetic procedures tend to form mixtures of enantiomers, forming the racemic mixture and even excluding chiral agents in the final compound.⁹ Crystal engineering provides tools to design materials by selecting suitable building blocks to produce the target chiral compounds. In this sense, from all the synthetic strategies, the direct use of an enantiopure organic ligand capable of transferring the chirality can guaranty the obtention of the desired homochiral material.¹⁰ Mainly, amino acids have been used as molecular building blocks in this field.¹¹,¹²,¹³,¹⁴ The advantages of this family of ligands are: (i) the possibility of anchoring cations of different nature (ns, np, nd, and nf) in monodentate or chelating form by N-amino and O-carboxylate groups; (ii) the alpha position substituent can present different chemical functions, conferring additional donor centers or bulky template groups;¹⁵ (iii) the possibility to functionalize the molecular structure to obtain modified linkers with higher coordination capabilities conserving the chiral nature of the α-amino acid such as oxamate,¹⁶,¹⁷ amides,¹⁸ oxamides¹⁹,²⁰,²¹ or oxalyl retro-peptide.²² In this sense, the α-amino acid Schiff base ligand (*aa*-SB) is one of the most used strategies for the chemical obtention of chiral ligands.²³ Puntus *et al*. reported the synthesis of two Eu(III) mononuclear complexes [Eu(PL-
Asp)(H₂O)₄]·(H₂O) and [Eu(PL-His)₂(H₂O)₂]Cl·(H₂O)₄ based on two multidentate aa-SB starting from aspartic acid (L-Asp) or L-histidine (L-His) and pyridoxal (PL).²⁴ In both compounds, the ligand acts effectively as an antenna presenting an enhancement in Eu(III) characteristic emission, which, together with good solubility and stability in water, makes these compounds good candidates for luminescence materials for biological applications.²⁴ On the other hand, using L-glutamic acid and o-vanillin, Thio et al. reported a more complex Ni₁₅ polynuclear compound displaying a metallomacrocyclic wheel-shape.²⁵ Furthermore, Muche et al. deepened into the properties of this Ni₁₅ wheel, reporting the detailed magnetostructural analysis and low toxicity over living tissue.²⁶ Besides, chiral coordination polymers have emerged as a class of interesting materials for applications in heterogenous catalysis.²⁷,²⁸,²⁹,³⁰ Thus, using L-tert-Leucine and salicylaldehyde derivatives, Jammi et al. obtained three chiral copper(II) coordination polymers used as a catalyst in the asymmetric acylation of secondary alcohols.³¹

On the other hand, the computational studies can complement the experimental evidence obtained by spectroscopic and magnetic studies using electronic structure descriptions. For instance, theoretical-experimental magnetic studies on molecular copper complexes³² and 1D copper coordination polymers³³,³⁴,³⁵ have successfully rationalized the nature and the magnitude of magnetic coupling constants by density functional theory (DFT) methods.³²,³³,³⁵–
³⁸ With this in mind, DFT methods represent a powerful tool to rationalize the electronic structure of copper complexes.

Considering that the use of chiral organic linkers is a direct method to induce chirality into a structure, Schiff bases containing naturally occurring α-amino acids offer an excellent alternative to obtain chiral CPs.<sup>39,40,41,42,43</sup> Herein, we report the synthesis of four new chiral coordination polymers CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4 based on {[Cu(HL<sup>n</sup>)MeOH]·NO<sub>3</sub>}<sub>∞</sub> (n= 1-4) using aa-SB obtained from valine and imidazole derivatives. The four compounds present a 1D chiral structure with ferromagnetic interaction within the chain. Furthermore, mononuclear compounds M-Cu1, M-Cu2, M-Cu3 and M-Cu4, showing stability in solution and chiroptical activity were formed, dissolving each coordination polymers in DMSO.

## 2. EXPERIMENTAL AND COMPUTATIONAL METHODS

The precursors and solvents used to obtain the aa-SB ligands N-(1H-imidazol-4-ylmethylene)-L-valine (H<sub>2</sub>L<sup>1</sup>), N-(1H-imidazol-4-ylmethylene)-D-valine (H<sub>2</sub>L<sup>2</sup>), N-[(5-methyl-1H-imidazol-4-yl)methylene]-L-valine (H<sub>2</sub>L<sup>3</sup>) and N-[(5-methyl-1H-imidazol-4-yl)methylene]-D-valine (H<sub>2</sub>L<sup>4</sup>) were of p.a. quality (<span style="color:red;">Sigma-Aldrich-Merck</span>) and were used
without any previous purification. Also, the metallic salt used to obtain CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4 metal complexes were of p.a. quality (Merck).

## 2.1 Synthesis of ligands aa-SB.

The ligands H₂L¹, H₂L², H₂L³ and H₂L⁴ were obtained using the same synthetical procedure.

A mixture of 1 mmol of L-valine (Lval) or D-valine (Dval) and 1 mmol of imidazole-4-carbaldehyde (4carIm) or 4-methyl-imidazole-5-carbaldehyde (4m5carIm) was dissolved in 10 mL of methanol (MeOH). The transparent solution was refluxed in constant stirring for 10 minutes at 70 °C until it turned yellow. The yellow solution of H₂L¹, H₂L², H₂L³ or H₂L⁴ was kept to synthesize copper complexes in a second step.

## 2.2 Synthesis of coordination polymers {[Cu(HL¹)MeOH]·NO₃}∞ (CP-Cu1), {[Cu(HL²)MeOH]·NO₃}∞ (CP-Cu2), {[Cu(HL³)MeOH]·NO₃}∞ (CP-Cu3) and {[Cu(HL⁴)MeOH]NO₃}∞ (CP-Cu4).

Synthesis of CP-Cu1. A mixture of 1 mmol (0.117 g) of Lval and 1 mmol (0.096 g) of 4carIm in 10 mL of MeOH was refluxed with constant stirring at 70°C for 10 minutes until it turns into a yellow color. When the yellow solution was cold, 0.5 mmol (0.121 g) of Cu(NO₃)₂·6H₂O dissolved in 10 mL of MeOH was added with constant stirring. The solution turned immediately
into a deep blue color and was left undisturbed. After two days, blue prismatic crystals of CP-Cu1 appeared. The crystalline product was separated by filtration and washed with methanol. MW: 351.81 g/mol. Yield of 55%, based on copper salt. The same synthetical procedure was used to obtain CP-Cu2, CP-Cu3 and CP-Cu4 (Supporting information).

## 2.3 X-ray Data Collection and Structure Determination.
Single crystals of CP-Cu1, CP-Cu2 and CP-Cu3 were directly picked up from reaction media, immediately immersed in a drop of Paratone® oil and mounted with a cryo-loop on a four-circle D8 VENTURE Bruker AXS diffractometer using Mo-Kα radiation (λ = 0.71073 Å). The intensities were measured at 150 K. Frame integration and data reduction were carried out with the program SAINT,44 and SADABS program was employed for multiscan-type absorption corrections.45

Using the Olex2⁴⁶ package, the crystal structures were solved with the ShelXT⁴⁷ structure solution program using Dual Methods and refined with the ShelXL⁴⁸ package using least-squares minimization based on F². Crystallographic data details on data collections and refinement parameters of the crystal structure are summarized in Table 1 and Table S1, S2 and S3. Structure drawings have been made with TOPOS software.⁴⁹ Additional data concerning the crystals and the refinement parameters are detailed in the supporting information.
The X-ray powder diffraction data were collected at room temperature on a Bruker D8 Advance diffractometer with Cu Kα₁,₂ radiation equipped with a LynxEye detector in the range of 4° < 2θ< 70°2θ. The experimental X-ray powder diffraction patterns of ground crystals agree with the theoretical patterns generated from the crystal structures. Indexing of the powder patterns has been recorded with the program Dicvol14 through the PreDICT interface.⁵⁰ The whole powder pattern fittings (pattern-matching with the Le Bail fit) were done employing the FULLPROF program⁵¹ available in the software package WinPLOTR⁵² (Figure S1). The crystal size of CP-Cu4 (0.30 × 0.07 × 0.02 mm for CP-Cu3) difficult the collection of single-crystal diffraction data. Nevertheless, X-ray powder diffraction data and chemical and physical analysis herein presented support the fact that the structure of CP-Cu4 corresponds to that of the isomer of compound CP-Cu3.

## 2.4 Spectroscopic and Spectrometry Measurement.

(a) Infrared spectroscopy. Fourier transform infrared spectra were recorded on a PerkinElmer BX-II spectrophotometer in the 4000–400 cm⁻¹ range, using KBr pellets.

(b) UV-Vis-NIR spectroscopy. UV-Vis-NIR spectra were performed on a PerkinElmer Lambda 1050 spectrophotometer UV-Vis/NIR, equipped with a PerkinElmer 150 mm InGaAs
Integrating sphere. The measurements were carried out in the 200–1200 nm range using the solid sample without any support.

(c) *Circular Dichroism spectroscopy*. The circular dichroism spectra of the copper compounds were recorded in a JASCO-500 spectrometer. The measurements were carried out in a 300–800 nm range using dimethylsulfoxide (DMSO) solutions at 0.01 M of each compound using cells of 1 cm.

(d) *Mass Spectrometry*. In a typical experiment, the compounds CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4 were dissolved in dimethylsulfoxide (DMSO) and diluted in acetonitrile. The measurements of mass spectrometry were performed in positive scanning in a Linear Ion Trap LTQ-XL Thermo Scientific spectrometer and were further analyzed comparing theoretical isotopic pattern using the code MMass5.5.0.<sup>53,54,55</sup>

2.5 *Electronic Paramagnetic Resonance*. EPR spectra were collected on a Bruker EMX-1572 spectrometer working at 9.39 GHz (X-band) using polycrystalline samples at 298 K.

2.6 *Magnetic Measurement*. Magnetic measurements were carried out using a Quantum Design Dynacool Physical Properties Measurement System (PPMS), equipped with a Vibrating Sample Magnetometer (VSM). The *dc* data were collected under an externally applied field of
1 kOe in the 1.8–300 K temperature range. Isothermal magnetization measurements were performed between 0 and ±90 kOe at temperatures varying from 1.8 to 8 K. Diamagnetic corrections (estimated from Pascal constants) were considered.⁵⁶

## 2.7 Thermogravimetric analysis

Thermogravimetric analyses were performed on a Mettler Toledo TGA/DSC-II system. The samples were introduced in an alumina holder and heated under an air atmosphere from room temperature to 900 °C with a heating rate of 5 °C/min.

### 2.8 Quantum-chemical studies.
UV-vis spectra and circular dichroism data were analyzed by the time-dependent DFT calculations⁵⁷,⁵⁸ using the M06/TZVP method.⁵⁹,⁶⁰ Dimethyl sulfoxide solvation effects [ε(DMSO)= 46.8] were considered using the universal solvent model(SMD).⁶¹ The lowest energy structures were validated by vibrational analysis. For spectroscopic modeling, 150 excitations were considered to achieve a good match between experimental and theoretical spectra. Hole-electron densities were computed in the Multiwfn3.6 program⁶² as:

$$ \rho^{\text{hole}}(r) = \sum_{i \to a} (w_i^a)^2 \phi_i(r) \phi_i(r) + \sum_{i \to a} \sum_{j \neq i \to a} w_i^a w_j^a \phi_i(r) \phi_j(r) \quad (1) $$

$$ \rho^{\text{ele}}(r) = \sum_{i \to a} (w_i^a)^2 \phi_a(r) \phi_a(r) + \sum_{i \to a} \sum_{i \to b \neq a} w_i^a w_j^b \phi_a(r) \phi_b(r) \quad (2) $$

Where $\rho^{\text{hole}}$ and $\rho^{\text{electron}}$ are the density of holes and electrons in each excited state wavefunction, including the contribution of each single-transition ($w_i$) and the molecular orbitals ($\phi$) involved in the excitation. $w_i$ is the weighting coefficient of each “monoexcitation” due to the promotion of one electron from the occupied orbital $i$ to the virtual orbital $j$; in this
way φ stands for the occupied (or virtual) molecular orbital. Moreover, Mulliken's population scheme⁶³ was employed for the partitioning of ρhole and ρelectron in different fragments.

The magnetic modeling used a simplified model of the copper dimmer based on crystal structures. The magnetic coupling constants were calculated using B3LYP functional⁶⁴⁻⁶⁶ at the broken-symmetry formalism.⁶⁷,⁶⁸ The Heisenberg-Dirac-Van Vleck⁶⁹ spin Hamiltonian describes the exchange coupling in the copper dimmer as follows:

$$ \mathcal{H} = - \sum_{1>2} J_{12} \mathcal{S}_1^\uparrow \cdot \mathcal{S}_2^\uparrow \quad (3) $$

Where $S_1$ and $S_2$ are the spin operators of the paramagnetic centers 1 and 2 of the dimmer. $J_{12}$ exchange magnetic coupling constant was obtained from the non-projected approach of broken symmetry as discussed by Ruiz et al.⁷⁰⁻⁷⁹

$$ E_{HS} - E_{BS} = -(2S_1S_2 + S_2)J_{12} \quad (4) $$

$E_{HS}$ and $E_{BS}$ correspond to the total energy of high-spin and broken-symmetry states, representing the antiferromagnetic (AFM) and ferromagnetic (FM) states. The terms $S_1$ and $S_2$ are the total spins of the involved paramagnetic centers considering that $S_1 \ge S_2$, being $S_1 = S_2 = 1/2$ for copper centers. The exchange pathway and orbital overlap between the magnetic orbitals of the magnetic copper dimers was analyzed using the unrestricted corresponding orbitals (UCOs).⁷⁰,⁷⁹⁻⁸¹

### 3. RESULTS AND DISCUSSION

#### 3.1 Coordination Polymers CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4

##### 3.1.1 Structural characterization.
Herein, enantiomer aa-SB pairs of ligands, H₂L¹/H₂L², and H₂L³/H₂L⁴ have been successfully synthesized by condensing the α-amino acid valine with
two carbaldehyde-imidazoles (Figure 1a). H₂L¹ and H₂L³ contain L-valine, while H₂L² and H₂L⁴ contain D-valine using the same carbaldehyde-imidazoles in each case, which means that H₂L¹/H₂L² and H₂L³/H₂L⁴ are L/R stereoisomers. The difference between H₂L¹/H₂L² and H₂L³/H₂L⁴ is that the last two have a methyl group in the 5-position of the imidazole group. As established in the experimental section, H₂L³/H₂L⁴ was synthesized using 4-methyl-imidazole-5-carbaldehyde (4m5carIm) as starting reagent. Then, it should be expected that N-[(4-methyl-1H-imidazol-5-yl)methylene]-L/D-valine were formed. Nevertheless, N-[(5-methyl-1H-imidazol-4-yl)methylene]-L/D-valine was observed in the coordination polymers CP-Cu3 and CP-Cu4 (as it will be further explained). Looking closely, the characteristic tautomerization of the imidazole ring, which consists of the internal movement of one hydrogen between the two annular nitrogen atoms, seems to be responsible for this result (Figure 1b). In imidazole-based coordination compounds, this hydrogen transfer occurs to satisfy specific coordination requirements of the metal cations. The tautomerization changes one H atom from 1 to 3 position on the imidazole ring, leading the ligand with the imine in the 4-position, observed in CP-Cu3 and CP-Cu4.⁸²
FTIR spectra of CP-Cu1/CP-Cu2 and CP-Cu3/CP-Cu4 present the same patterns (Figure S2).

The four compounds present a strong absorption at 1640 cm⁻¹ associated with the C=N vibration of the imine group of the ligand, which confirms the formation of the Schiff base. Additionally, the characteristic asymmetrical and symmetrical vibrations of carboxylate groups belonging to the valine fragment can be observed at 1567 cm⁻¹ and 1428 cm⁻¹, respectively. Furthermore, the magnitude of the Δ value between the v_asym and v_sym vibrations is consistent with a 1,3-carboxylate type of bridge.⁸³

Solid-state electronic UV–Vis–NIR spectra of CP-Cu1/CP-Cu2 and CP-Cu3/CP-Cu4 are shown in Figure S3. The spectra show a strong absorption below 350 nm with a shoulder near 400 nm assigned to the intraligand π–π* and n–π* transitions, respectively.⁸⁴ On the other hand, a broad absorption centered near 700 nm can be associated with the *d–d* absorption corresponding to transition characteristic of Cu(II) cations.⁸⁵

Moreover, the thermograms for CP-Cu1/CP-Cu2 and CP-Cu3/CP-Cu4 (Figure S4), exhibit similar thermal stability with onset decompositions temperatures above 200 °C. A gradual mass decrease of around 6.0 wt % (CP-Cu1/CP-Cu2 ) and 6.3% (CP-Cu3/CP-Cu4 ) between 33 and 80 °C can be associated with the release of methanol molecules. After that, the samples
gradually decompose in multistep mass loss into unidentified products. An experimental loss of ca. 72 wt % was found for CP-Cu1/CP-Cu2 and 74% for CP-Cu3/CP-Cu4. From 370 °C a plateau is reached without further weight loss until 900 °C, giving a residual mass of 21.97 wt %, 22.31 wt %, 19.63 and 20.22 wt % for CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4, respectively. These values correlate well with copper oxide (CuO) as the final product, whose calculated values are 22.61 wt % for CP-Cu1/CP-Cu2 and 21.74 wt % for CP-Cu3/CP-Cu4.

Single crystal analysis CP-Cu1, CP-Cu2 and CP-Cu3 show that the compounds share the same crystalline $P2_12_12_1$ orthorhombic space group, presenting similar unit-cell parameters (Table 1) and skeleton structure. Taking CP-Cu1 as an example, the asymmetric unit consists of one Cu(II) cation, one monoprotonated $[HL^1]^-$ ligand, one $NO_3^-$ counter anion, and one methanol molecule. As shown in figure 2a, the Cu(II) cation presents a $CuN_2O_3$ square pyramid geometry composed by a monoprotonated $\kappa N,N',O'[HL^1]$- anion coordinating in a tridentate fashion through the N-imidazole, N-imine and one O-carboxylate atom forming two adjacent five-member chelate rings. These three $\kappa N,N',O'[HL^1]$-donor atoms occupy the in-plane coordination along with a second $\kappa O'-[HL^1]$- anion coordinating in a monodentate fashion through the carboxylate group. A MeOH molecule is bonded in one axial position with a Cu-
$O_{MeOH}$ =2.2724(19) Å bond length, which is larger than the equatorial bond distances (Cu1-O1=1.940(2) Å, Cu1-O2=1.999(2) Å) around Cu(II) cations (Table S1), then, a (4+1) square pyramid describes the geometry around Cu(II) centers (inset figure 3a). Furthermore, one $NO_3^-$ anion weakly interacts with Cu(II) cations in the other axial position with an $Cu-O_{nitrate}$ distance of 2.717(2) Å. Brewer *et al.*⁸⁶ reported a copper(II) mononuclear compound $[Cu(L₁)(5Me4Im)(ClO₄)]$ ($ClO₄^−$ = perchlorate) in which L₁ is *aa*-SB formed by 5-methyl-4-imidazolecarboxaldehyde and valine. In this compound, copper cations present a $CuN₂O₄$ octahedron environment in which L₁ coordinates in κ*N*,*N*′,O chelating fashion, same as $HL^n$ (n= 1-4) ligands.

Moreover, the metal cations are connected by *syn*-anti carboxylate bridge belonging to the valine fragment of the $[HL^1]^-$ ligand in equatorial-equatorial position (Figure 2b), forming a zigzag chain growing through the *a* axis with a $Cu1···Cu1^{2#}$ intrachain distance of 5.1867(2) Å ($2#=1/2+x, 1/2-y, 1-z$). Furthermore, two hydrogen bonds are observed in the crystal packing, between the $NO_3^-$ anions and both H-N protons belonging to imidazole ring ($d_{(D-A)}$=2.819(3) Å) and H-O of MeOH coordination molecule ($d_{(D-A)}$ of 2.792(3) Å, Figure 2c, Table S1). Thereby, the pseudo-coordination of nitrate to copper cations is the key to the growth of the crystal 3D
packing of CP-Cu1/CP-Cu4 compounds, which can be considered a 1D cationic chain associated supra-molecularly with $NO_3^-$ as a counter-anion (Figure S5a). Finally, in the supramolecular H-bond 3D packing, the nearest interchain $Cu1···Cu1^{1#}$ distance is 7.721(4) Å ($1#=1/2-x, -y, -1/2+z$).

Comparing CP-Cu1 and CP-Cu2, the stereogenic center of valine is conserved in forming the copper compounds. Thus, the L and D conformation of valine is transferred to the formed aa-SB ligands. In figure 3a, the valine fragment in $[HL^1]^-$ and $[HL^2]^-$ maintains the L- or D- configuration of the chiral precursor, then giving the L- and D- aa-SB ligands. Likewise, comparing the $[Cu(HL^n)MeOH]^+$ ($HL^n= [HL^1]^-$ and $[HL^2]^-$) building block of the 1D structure, in CP-Cu1 and CP-Cu2, it is clear that $[Cu(HL^1)MeOH]^+$ and $[Cu(HL^2)MeOH]^+$ are mirror images between each other (Figure 3b). This means that chirality is also transferred to the coordination compound, explaining that the Cu(II) compounds crystallized in the same Sohncke space group with similar cell parameters.⁸⁷

Furthermore, although the aa-SB ligand in compound CP-Cu3/CP-Cu4 presents a methyl group in 5-position of the imidazole ring, the structure is essentially the same as that of CP-Cu1 and CP-Cu2 complexes. Thus, comparing both $[HL^3]^-$ and $[HL^2]^-$, both ligands present opposite
absolute configurations (Figure S5b). Also, comparing the [Cu(HLⁿ)MeOH]⁻ (HLⁿ=[HL³]⁻ and
[HL²]⁻) building block of the compound CP-Cu3 and CP-Cu2, it is also clear that they are mirror
images one to each other, confirming that CP-Cu3 is an L-enantiomer (Figure S5c).

Copper compounds based on *aa*-SB ligand can be found in the literature.⁸⁸,⁸⁹,⁹⁰,⁹¹ Meanwhile,
a compound having *aa*-SB containing valine are more scarce. For example, Nakagame et al.
reported a chiral Cu(II)-chain with an *aa*-SB based on 2-hydroxy-1-naphthaldehyde and L-
valine in which the metal cations are doubly connected by two oxocarboxylate groups
presenting an equatorial-axial *syn*-*anti* coordination mode.⁹² Furthermore, Zehra et al. reported
the structure the same compounds using both *aa*-SB enantiomers.⁹³

### 3.1.2 Electronic Paramagnetic Resonance and Magnetic Measurement.
The X-band EPR spectra of polycrystalline samples of CP-Cu1/CP-Cu2 and CP-Cu3/CP-Cu4 at room temperature are shown in figure S6. As expected, a broad signal characteristic for square-based-pyramidal coordination of the copper(II) ions is observed, with a resonant field between 3215-3227 G giving a *g* value around 2.08-2.09.⁹⁴

Figure 4a and S7 show $\chi_m$T vs T plots for CP-Cu1, CP-Cu2, CP-Cu3, CP-Cu4 between 300-1.8 K at 1 kOe. The four compounds present a $\chi_m$T value at 300 K near 0.40 emu K mol⁻¹, close to the expected value for non-interacting Cu(II) paramagnetic center, 0.41 emu K mol⁻¹, considering a $S_{Cu(II)}$=1/2 and $g_{Cu}$ obtained for de EPR measurements. The four compounds show the same behavior in all the temperature range. In the first stage, a constant $\chi_m$T value is
observed as the temperature is down till 50 K, indicating that a paramagnetic behavior is predominant in this temperature range. Below 50 K, ferromagnetic interactions become dominant in the four compounds, evidenced by an abrupt increase in χ<sub>m</sub>T, reaching a value between 0.9-1.0 emu K mol<sup>-1</sup> at 1.8 K.

Additionally, the field dependence of magnetization at 1.8, 3, 5, and 8 K represented as reduced magnetization N<sub>b</sub> against applied field HT<sup>-1</sup> are shown in Figure 4b and S8 for CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4. In the four cases, the magnetization increases rapidly, reaching a saturation value of 1 N<sub>b</sub> near 40 kOe, which is consistent with the value expected for a single unpaired electron belonging to Cu(II) cations present in CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4. Moreover, in the four plots, the magnetization curves at different temperatures cannot be superimposed due to a small orbital contribution present in the (1+4) CuN<sub>2</sub>O<sub>3</sub> square pyramid geometry present in CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4. This fact explains the little higher value of χ<sub>m</sub>T and g factor obtained experimentally.

As shown in the structural section, CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4 presents a structure consisting of an infinite arrangement of cationic building blocks [Cu(HL)MeOH]<sub>n</sub>⁺ (HL= HL¹⁻, HL², HL³⁻ and HL⁴⁻) connected by equatorial-equatorial syn-anti carboxylate bridge forming a 1D covalent structure with Cu1···Cu1²# intrachain distance of 5.1867(2) Å (2#=1/2+x,
1/2-y, 1-z). Due to the Cu1···Cu1¹# interchain distance (Cu1···Cu1¹#= 7.7207(4) Å; 1#=1/2-x, -y,-1/2+z) is higher than intrachain distances, the magnetic structure of CP-Cu1, CP-Cu2, CP-Cu3 and CP-Cu4 can be considered as isolated chains. Based on quantitative studies in Heisenberg 1-D antiferromagnets, H=-JΣSᵢSᵢ+₁,⁹⁵,⁹⁶ an analytical expression (equation 5)⁹⁷ for the temperature dependence of the susceptibility in Heisenberg 1-D ferromagnet has been reported to describe the ferromagnetic interactions in an infinite arrangement of S=1/2 spin carriers⁹⁸,⁹⁹

$$ \chi_M T = C \frac{\sum_{i=1}^{5} N_i x^i}{\sum_{i=1}^{6} D_i x^i} ; \quad C = \frac{N^2 g^2 \beta^2}{4k_B} \quad \text{and} \quad x = \frac{J}{k_B T} \qquad (5) $$

where N is the Avogadro number, g is the Lande factor, β is the Bohr magneton, k_B is the Boltzmann constant, J is the magnetic coupling constant and the coefficients Nᵢ, Dᵢ which are given in Table S4. The fit parameters are shown in Table S5. Maintaining the g factor fixed using the experimental value obtained by EPR, a good agreement factor (R=Σ(χ_mTobs)-(χ_mTexp))²/Σ(χ_mTobs)²) corroborates the fits of the data with the used model. The magnetic coupling constants are near in the order of magnitude, being 3.0 cm⁻¹ for CP-Cu1 and CP-Cu2 and near 5.0 cm⁻¹ for CP-Cu3, CP-Cu4, which is in accordance with the equatorial-equatorial interaction of Cu(II) through syn-anti carboxylate bridge reported for similar compounds.¹⁰⁰
### 3.1.3 Modeling of Magnetic properties.
The magnetic properties were analyzed based on a binuclear model constructed using the crystal structures to obtain the magnetic coupling constant *J*. The hydrogen atoms, methanol, and nitrate are optimized for the correct evaluation of *J* constants. Values with significant deviation were obtained for the magnetic interaction when $NO_3^-$ was not considered, showing values near ~+100 cm⁻¹. This overestimation of the coupling constant is explained by the participation of axial molecules in the ligand field around the Cu(II) paramagnetic center, perturbing the $d_{z^2}$ orbitals. The equatorial perturbation produced by $N_2O_2$ is compensated by the presence of the axial molecules, $NO_3^-$ ion and methanol molecules, causing a decrease in the energy difference between magnetic states. On the other hand, the calculated magnetic coupling constants *J* considering the whole surrounding environment, including axial ligands, corroborate the ferromagnetic nature of the interactions of the copper centers through the carboxylate bridge, showing values of +4.82 and +4.31 cm⁻¹ for compounds CP-Cu1 and CP-Cu3, respectively. These ferromagnetic interactions are consistent with the values obtained experimentally from magnetic measurements with *J* values of 3-5 cm⁻¹.
Finally, figure 5 presents the unrestricted corresponding orbitals (UCOs) surfaces that describe the magnetic orbitals involved in the magnetic exchange. The exchange pathway (Cu-O-C-O-Cu) shows a very low overlap ($S$) between $\alpha$ and $\beta$ UCOs, allocated on the $O$ atom of the carboxylate group in the ligand. The overlap surface integration displays lower $S$ values in the range of 0.023-0.025 a.u., corroborating that the magnetic interaction of copper cations is ferromagnetic. The spin density distribution is delocalized on the first coordination sphere of each Cu(II) center. Also, there is no significant difference between CP-Cu1 and CP-Cu3, and the effect of the methyl group seems to be non-appreciable. The spin density for Cu(II) centers reach values up to 0.6 unpaired electrons, consistent with the reported values in related systems.<sup>71,101</sup> On the other hand, the delocalized spin density distribution quench the magnetic coupling between unpaired electrons, and the nuclear spin of copper centers, explaining the non-well resolved hyperfine structure of the EPR spectrum.

## 3.2 Molecular Compounds M-Cu1, M-Cu2, M-Cu3, and M-Cu4

### 3.2.1 Mass spectrometry.
Compounds CP-Cu1, CP-Cu2, CP-Cu3, and CP-Cu4 are insoluble in typical organic solvents such as alcohols, acetonitrile and DMF. Nevertheless, all the coordination polymers were completely dissolved using DMSO, forming a new group of
compounds named M-Cu1, M-Cu2, M-Cu3 and M-Cu4. ESI mass spectrometry was used to identify the chemical species of DMSO solutions, recording the spectra between 200 and 2000 m/z (Figures 6a and S9). In positive scanning, a molecular ion peak at 335 m/z was detected for M-Cu1/M-Cu2 and 349 m/z for M-Cu3/M-Cu4, with c.a 100% of abundance in each case. Each signal correlates with the moiety $[Cu(HL^n)DMSO]^+$ (n=1-4), where $[Cu(HL^n)]^+$ is the same chiral building block present in the CPs. The presence of DMSO in the molecular compounds is not surprising if the high coordination ability of DMSO is considered.¹⁰² The fact that the isotopic pattern was solved for all the compounds (Figures 6a and S9) and that the other signals only reach 5% of abundance is evidence that M-Cu1, M-Cu2, M-Cu3, and M-Cu4 are the predominant species in DMSO solutions, being also stable in the media.

### 3.2.2 Electronic structure of M-Cu1, M-Cu2, M-Cu3, and M-Cu4.
The structure of the molecular compounds M-Cu1, M-Cu2, M-Cu3, and M-Cu4 were calculated, taking as reference the crystalline structure of the CPs that produce each molecular moiety $[Cu(HL^n)DMSO]^+$ (n=1,2,3 and 4) obtained in the mass spectra. Calculated geometry and Cu-N and Cu-O bond lengths are in the range of 1.97-2.02 Å and 1.95 Å, respectively, similar to those reported for the crystalline structures of CPs (section 3.1.1). Considering the similar structures of the
molecular compounds, M-Cu1 was taken to describe the electronic structures (Figure 6b). Since the system presents an open-shell electronic structure, both α and β electrons occupying α and β molecular orbitals are considered, respectively. The α and β frontier molecular orbitals show a HOMO-LUMO energy gap of 5.18 eV (~240 nm) and 4.10 eV (~301 nm), respectively (Figure 6c). The fragmental composition of the molecular orbitals was divided into three fragments: (i) copper center, (ii) [HL¹]⁻ ligand, and (iii) DMSO molecule (Figure 6d). α-HOMO is composed mainly of ligand fragment reaching up to ~78% (~9 and ~13 % for (i) and (iii), respectively). In contrast, for α-LUMO the contribution of ligand increases up to ~97% (~2, and ~1% for (i) and (iii), respectively), demonstrating the dominance of ligand participation in both α frontier molecular orbitals. On the other hand, ligand contribution to β-HOMO is almost complete (98%), while for β-LUMO, the main contributions belong to the mixture of Cu(II) and the ligand fragments reaching 61 and 31%, respectively. Under this perspective, the fragmental analysis demonstrates that [HL¹]⁻ ligand contributes strongly to α and β frontier molecular orbitals, while only β-LUMO presents a dominant influence of Cu(II).

The unpaired electron should be allocated on Cu(II) center (3d⁹, external electronic configuration) from a crystal field theory viewpoint. Nevertheless, the first coordination sphere
around the copper cation fully participates in the spin density distribution since [HL¹]- ligand and DMSO molecule provide 29% and 7% of the spin density, respectively, overcoming the third part the total spin density (Figure 6d). Considering the shape of the surface, clearly copper contributes with the unpaired electron occupying the 3dₓ² - y² orbital, characteristic of Cu(II) complexes in a square planar ligand field.³⁷,¹⁰³⁻¹⁰⁷ Likewise, in the first coordination sphere the *N* (imine and imidazole) and *O* (carboxylate and DMSO molecule) atoms display spin density with shapes that resemble 2pₓ,ᵧ orbital shape that is in line with 3dₓ² - y² copper orbital. In this regard, the spin density would be delocalized in the CuN₂O₂ moiety, including atoms of the three fragments (Cu(II), organic ligand and DMSO molecule). A similar spin density distribution has also been observed for complexes with similar square plane coordination environment,³⁷,¹⁰⁴⁻¹⁰⁷ verifying the proposed electronic structure.

### 3.2.3 Circular Dichroism of M-Cu1, M-Cu2, M-Cu3, and M-Cu4.
Coordination compounds based on α-amino acid should be optically active.¹⁰⁸ Considering that compounds M-Cu1 and M-Cu2 or M-Cu3 and M-Cu4 should be optical isomers, CD spectra between 300 and 800 nm were performed to study the chiroptical activity of the molecular compounds (Figure 7a and S10). The CD spectrum of M-Cu1/M-Cu2 and M-Cu3/M-Cu4 compounds show two bands (i)
a strong and sharp absorption in the UV-vis zone (360 nm) associated with intra-ligand
transitions (IL), and (ii) broadband in the visible region (660 nm) associated with transitions
involving Cu(II) cations.¹⁰⁹ Also, each enantiomeric pair (M-Cu1/M-Cu2 or M-Cu3/M-Cu4)
shows a CD profile as an exact mirror image.¹¹⁰ Moreover, the Cotton effect centered at 360
nm in M-Cu1, M-Cu2, M-Cu3 and M-Cu4 should belong to the chiral aa-SB base fragment;
being not surprising that the dichroic signals present opposite signs for each enantiomeric pair
(positive in the case of M-Cu1 and M-Cu3 and negative for M-Cu2 and M-Cu4),¹¹¹ as has also
been reported for other enantiomeric coordination compounds using pure isomers like proline¹⁴
and tartaric acid.¹¹² The absorption at 660 nm centered on Cu(II) metal cation presents a
negative Cotton effect in M-Cu1/M-Cu3 and a positive Cotton effect in M-Cu2/M-Cu4.
Considering the first coordination sphere of the copper cation (CuN₂O₂) a silent dichroic
response should be expected in the *d-d* transitions zone.¹¹³ Therefore, the chiroptical activity
observed in the visible zone indicates that the organic ligand should be contributing to the
Cotton effect observed 660 nm.¹¹⁴,¹¹⁵,¹¹⁶

**3.2.4 Electronic excitation analysis.** Considering the structural and electronic similarities of
the enantiomeric pairs M-Cu1/M-Cu2 and M-Cu3/M-Cu4, the analysis of theoretical electronic
excitation was performed only for the M-Cu1/M-Cu2 pair. The dichroic behavior was evaluated by the rotatory velocity parameter ($R_{vel}$), because it represents the rotatory effect and the intensity of an absorption band in the CD spectra simultaneously (Table 2), in the same way that oscillator strength represents the intensity of an absorption band in the UV-Vis. The simulated spectra correlate well with experimental Cotton effect tendencies observed for M-Cu1/M-Cu2 (Figure 7), where two main excitations appear at (i) 369/370 nm and (ii) 677/680 nm. For M-Cu1, $R_{vel}$ presents a positive value for the bands at 369 nm, and a negative value for the band at 677 nm correlates with the two Cotton effects observed experimentally. Conversely, for M-Cu2 the $R_{vel}$ displays an opposite behavior for the excitations at 370 and 680 nm. The main orbital contributions for the observed behavior come from β molecular orbitals (Figure 8a), where the electron is promoted from several low-lying orbitals up the β-LUMO. For instance, the excitation at 677/680 nm comes mainly from β-HOMO-14 (Table 2 and Figure 8b); while the β-HOMO-1 dominates in the transition at 369/370 nm. A remarkable distinction between β-HOMO-14 and β-HOMO-1 molecular orbitals reside in the copper contribution since the former presents a notable occupation on this metal center. Contrarily, the β-HOMO-1 is dominated for the ligand fragment. The hole-electron functions scheme that characterizes
the electron density transferred during the vertical excitation has been successfully exploited to evaluate a complete set of the molecular orbitals involved in the representative excitations, including a whole range of occupied and virtual molecular orbitals (Eqs. (1) and (2)). The hole-electron density was divided into the fragment contributions, offering a local and non-local landscape for each transition (Figure 8c). For the transition at 369 nm, the hole surface is distributed on the imidazole ring and the carboxylate group of the [HL¹]⁻ fragment, while the electron surface is displayed on the entire first coordination sphere of Cu(II) cation (CuN₂O₂ moiety). Thus, this band at 369 nm presents two main contributions; the first one belongs to the electron promotion from imidazole and carboxylate groups to the *N* and *O* atoms directly linked to Cu(II) center, suggesting an intra-ligand charge transfer (ILCT) transition. The second type of electronic excitation is the electron promotion from [HL¹]⁻ surface to 3dₓ²⁻ᵧ² orbital of Cu(II), leading to a ligand-to-metal charge transfer (LMCT) transition with a non-local character demonstrated by the lower overlapping (c.a 10%, Table 2). In these two cases, the allowed ILCT and LMCT transitions explain the high intensity of the bands in the experimental and theoretical spectra.
On the other hand, the transition at 677 nm locates the hole density mainly into the Cu(II) cation (88%) with an orbital shape that resembles a $d_z^2$ orbital; while the electron surface is a combination of $d_{x^2-y^2}$ and $p_{x,y}$-orbital belonging to the first coordination sphere (N₂O₂). In this sense, this transition is also a mixture of two different contributions (i) a local copper *d*-*d* transition ($d_z^2 \rightarrow d_{x^2-y^2}$) that reaches 61 % and (ii) a metal to ligand charge transfer (MLCT) with a fragmental contribution of ~31%. Despite the *d*-*d* character of the latter excitation (forbidden by Laporte's rule), the MLCT contribution enhances the electron mobility associated with the higher R<sub>vel</sub> value (R<sub>vel</sub>, 369 nm=+14.73 vs. R<sub>vel</sub>, 677 nm=-8.52). Moreover, since the band at 677 nm is truly a mixture of two transitions in which the MLCT involves ligand orbitals, it demonstrates the induced chiroptical activity caused by the participation of the chiral aa-SB in the intrinsic Cu(II) electronic transitions. A comparison of the results with literature data shows that only a few examples were achieved to rationalise the CD spectrum of transition metal complexes based on copper and Schiff bases.<sup>117,118</sup> Enamillah *et al*.<sup>118</sup> informed the rationalization of the experimental CD data in the visible range, showing similar band assignment for Cu(II) complexes formed by naphtaldiminato Schiff bases, with “*d*-*d”* transitions at ~690 nm. The authors reported a higher deviation in the UV region (about 60 nm)
in the assignment of the LMCT band. In this sense, the results obtained in our work display a better match with the experimental data in all the measured spectrum range.

## 4. CONCLUSIONS

A novel family of 1D chiral coordination polymers based on copper(II) cation was obtained using an α-amino acid Schiff base as a chiral building block. These coordination polymers crystalize in a non-centrosymmetric space group, proving that the amino acid chirality is conserved in the Schiff base ligand and transferred to the extended crystal structure. As expected, the Cu(II) spin carriers are magnetically communicated through the carboxylate bridge, presenting a 1D ferromagnetic chain behavior in all cases. Theoretical calculations give insight into the super-exchange mechanism and the role of the axial perturbation on the Cu(II) cation in the observed magnetic properties.

Furthermore, the four molecular compounds derived from the coordination polymers share the same chiral motif. The theoretical simulated excited states reproduce the CD spectra, showing that intrinsic chiral activity of α-amino acid Schiff base is transferred to the Cu(II) centers. Finally, the experimental and theoretical approaches lead to a robust understanding of the chemical and physical properties of these chiral materials.
TABLES

Table 1. Crystal data and structure refinement for CP-Cu1, CP-Cu2 and CP-Cu3

Table 2. Theoretical spectroscopic parameters λ for CP-Cu1 and CP-Cu2 enantiomers. Orbital and fragmental contribution to the main transitions.

<table><caption>Table 1. Crystal data and structure refinement for CP-Cu1, CP-Cu2 and CP-Cu3</caption><thead><tr><th>Identification code</th><th>CP-Cu1</th><th>CP-Cu2</th><th>CP-Cu3</th></tr></thead><tbody><tr><td>Empirical formula</td><td>C<sub>10</sub>H<sub>16</sub>CuN<sub>4</sub>O<sub>6</sub></td><td>C<sub>10</sub>H<sub>16</sub>CuN<sub>4</sub>O<sub>6</sub></td><td>C<sub>11</sub>H<sub>18</sub>CuN<sub>4</sub>O<sub>6</sub></td></tr><tr><td>Formula weight</td><td>351.81</td><td>351.81</td><td>365.83</td></tr><tr><td>Temperature/K</td><td>150</td><td>150</td><td>150</td></tr><tr><td>Crystal system</td><td>orthorhombic</td><td>orthorhombic</td><td>orthorhombic</td></tr><tr><td>Space group</td><td>P2<sub>1</sub>2<sub>1</sub>2<sub>1</sub></td><td>P2<sub>1</sub>2<sub>1</sub>2<sub>1</sub></td><td>P2<sub>1</sub>2<sub>1</sub>2<sub>1</sub></td></tr><tr><td>a/Å</td><td>9.3535(2)</td><td>9.3488(9)</td><td>9.3530(19)</td></tr><tr><td>b/Å</td><td>11.1729(2)</td><td>11.18060(10)</td><td>11.202(2)</td></tr><tr><td>c/Å</td><td>13.7040(3)</td><td>13.7032(16)</td><td>14.326(3)</td></tr><tr><td>α/°</td><td>90</td><td>90</td><td>90</td></tr><tr><td>β/°</td><td>90</td><td>90</td><td>90</td></tr><tr><td>γ/°</td><td>90</td><td>90</td><td>90</td></tr><tr><td>V/Å<sup>3</sup></td><td>1432.15(5)</td><td>1432.3(2)</td><td>1500.9(5)</td></tr></tbody></table>
<table><tr><td>Z</td><td>4</td><td>4</td><td>4</td></tr><tr><td>ρcalc /g.cm<sup>-3</sup></td><td>1.632</td><td>1.631</td><td>1.619</td></tr><tr><td>μ/mm<sup>-1</sup></td><td>1.558</td><td>1.558</td><td>1.490</td></tr><tr><td>F(000)</td><td>724.0</td><td>724.0</td><td>756.0</td></tr><tr><td>Crystal size/mm<sup>3</sup></td><td>0.3 × 0.22 × 0.12</td><td>0.430 × 0.350 × 0.320</td><td>0.30 × 0.07 × 0.02</td></tr><tr><td>Radiation</td><td>MoKα (λ = 0.71073)</td><td>MoKα (λ = 0.71073)</td><td>MoKα (λ = 0.71073)</td></tr><tr><td>2Θ range for data collection/°</td><td>4.704 to 54.964</td><td>4.702 to 55.068</td><td>5.202 to 54.97</td></tr><tr><td>Index ranges</td><td>-12 ≤ h ≤ 12, -14 ≤ k ≤ -12 ≤ h ≤ 11, -14 ≤ k ≤ -12 ≤ h ≤ 10, -14 ≤ k ≤ 14, 0 ≤ 1 ≤ 17</td><td>-12 ≤ h ≤ 12, -14 ≤ k ≤ -12 ≤ h ≤ 11, -14 ≤ k ≤ -12 ≤ h ≤ 10, -14 ≤ k ≤ 14, -18 ≤ 1 ≤ 18</td><td>-12 ≤ h ≤ 12, -14 ≤ k ≤ -12 ≤ h ≤ 11, -14 ≤ k ≤ -12 ≤ h ≤ 10, -14 ≤ k ≤ 14, -18 ≤ 1 ≤ 18</td></tr><tr><td>Collected reflections</td><td>6360</td><td>14586</td><td>9379</td></tr><tr><td>Independent reflections</td><td>3265 [R<sub>int</sub> = 0.0206, 3287 [R<sub>int</sub> = 0.0271, 3416 [R<sub>int</sub> = 0.0259, R<sub>sigma</sub> = 0.0420]</td><td>R<sub>sigma</sub> = 0.0238]</td><td>R<sub>sigma</sub> = 0.0300]</td></tr><tr><td>Data/restraints/refined parameters</td><td>3265/3/202</td><td>3287/0/255</td><td>3416/3/207</td></tr><tr><td>Goodness-of-fit on F<sup>2</sup></td><td>1.029</td><td>1.094</td><td>1.044</td></tr><tr><td>Final R indexes [I>=2σ (I)]</td><td>R<sub>1</sub> = 0.0223, wR<sub>2</sub> = R<sub>1</sub> = 0.0188, wR<sub>2</sub> = R<sub>1</sub> = 0.0196, wR<sub>2</sub> = 0.0483</td><td>R<sub>1</sub> = 0.0223, wR<sub>2</sub> = R<sub>1</sub> = 0.0188, wR<sub>2</sub> = R<sub>1</sub> = 0.0196, wR<sub>2</sub> = 0.0483</td><td>R<sub>1</sub> = 0.0223, wR<sub>2</sub> = R<sub>1</sub> = 0.0188, wR<sub>2</sub> = R<sub>1</sub> = 0.0196, wR<sub>2</sub> = 0.0483</td></tr><tr><td>Final R indexes [all data]</td><td>R<sub>1</sub> = 0.0241, wR<sub>2</sub> = R<sub>1</sub> = 0.0195, wR<sub>2</sub> = R<sub>1</sub> = 0.0216, wR<sub>2</sub> = 0.0488</td><td>R<sub>1</sub> = 0.0241, wR<sub>2</sub> = R<sub>1</sub> = 0.0195, wR<sub>2</sub> = R<sub>1</sub> = 0.0216, wR<sub>2</sub> = 0.0488</td><td>R<sub>1</sub> = 0.0241, wR<sub>2</sub> = R<sub>1</sub> = 0.0195, wR<sub>2</sub> = R<sub>1</sub> = 0.0216, wR<sub>2</sub> = 0.0476</td></tr><tr><td>Largest diff. peak/hole / e Å<sup>-3</sup></td><td>0.30/-0.27</td><td>0.28/-0.23</td><td>0.23/-0.25</td></tr><tr><td>Flack parameter</td><td>0.268(15)</td><td>-0.004(5)</td><td>-0.011(5)</td></tr></table>
<table><caption>Table 2. Theoretical spectroscopic parameters λ for CP-Cu1 and CP-Cu2 enantiomers. Orbital and fragmental contribution to the main transitions.</caption><thead><tr><th>λ (nm)</th><th>R<sub>vel</sub>*</th><th>CP-Cu1 orbital contribution</th><th>Fragment</th><th>%hole</th><th>%electron</th><th>%overlap</th></tr></thead><tbody><tr><td rowspan="3">677</td><td rowspan="3">-8.52</td><td>HOMO-14(β)-&gt;LUMO(β) (24%)</td><td>Cu</td><td>88.3</td><td>60.8</td><td>70.3</td></tr><tr><td>HOMO-7(β)-&gt;LUMO(β) (24%)</td><td>L</td><td>9.4</td><td>31.2</td><td>17.2</td></tr><tr><td>HOMO-3(β)-&gt;LUMO(β) (11%)</td><td>DMSO</td><td>2.2</td><td>8.0</td><td>4.3</td></tr><tr><td rowspan="3">369</td><td rowspan="3">+14.73</td><td>HOMO-1(β)-&gt;LUMO(β) (82%)</td><td>Cu</td><td>1.7</td><td>59.4</td><td>10.0</td></tr><tr><td>HOMO-2(B)-&gt;LUMO(β) (6%)</td><td>L</td><td>89.7</td><td>32.8</td><td>54.3</td></tr><tr><td>HOMO-5(β)-&gt;LUMO(β) (3%)</td><td>DMSO</td><td>8.6</td><td>7.8</td><td>8.2</td></tr><tr><th>λ</th><th>R<sub>vel</sub>*</th><th>CP-Cu2 orbital contribution</th><th>Fragment</th><th>%hole</th><th>%electron</th><th>%overlap</th></tr><tr><td>680</td><td>+6.58</td><td>HOMO-14(β)-&gt;LUMO(β) (28%)</td><td>Cu</td><td>88.0</td><td>60.6</td><td>73.0</td></tr><tr><td rowspan="3">370</td><td rowspan="3">-19.68</td><td>HOMO-7(β)-&gt;LUMO(β) (16%)</td><td>L</td><td>7.1</td><td>31.4</td><td>14.9</td></tr><tr><td>HOMO-5(β)-&gt;LUMO(β) (10%)</td><td>DMSO</td><td>4.9</td><td>8.1</td><td>6.3</td></tr><tr><td>HOMO-1(β)-&gt;LUMO(β) (76%)</td><td>Cu</td><td>1.2</td><td>56.9</td><td>8.4</td></tr><tr><td></td><td></td><td>HOMO-2(β)-&gt;LUMO(β) (6%)</td><td>L</td><td>89.4</td><td>35.5</td><td>56.4</td></tr><tr><td></td><td></td><td>HOMO-5(β)-&gt;LUMO(β) (3%)</td><td>DMSO</td><td>9.4</td><td>7.6</td><td>8.4</td></tr></tbody></table>

FIGURES CAPTIONS

Figure 1. (a) Summary of the synthesized ligands H<sub>2</sub>L<sup>1</sup>, H<sub>2</sub>L<sup>2</sup>, H<sub>2</sub>L<sup>3</sup> and H<sub>2</sub>L<sup>4</sup> starting from Lval/Dval with 4carIm/4m5carIm. (b) Tautomerization reaction between N-[(4-methyl-1H-imidazol-5-yl)methylene]-L-valine and N-[(5-methyl-1H-imidazol-4-yl)methylene]-L-valine.

Figure 2. (a) Coordination environment around copper centers in CP-Cu1; CuN<sub>2</sub>O<sub>3</sub> is shown in the inset copper polyhedron. (b) Chain growth along a axis and (c) hydrogen bonding present in CP-Cu1.

<footnote>* R<sub>vel</sub> = 10<sup>-40</sup> erg esu cm/Gauss</footnote>
Figure 3. Mirror images between (a) [HL¹]⁻ (L-isomer) and [HL²]⁻ (D-isomer) and (b) CP-Cu1 (L-isomer) and CP-Cu2 (D-isomer) (axial coordinated MeOH molecule was not considered for clarity of the figure).

Figure 4. (a) $\chi_mT$ vs T and (b) $M_{red}$ vs H plots for CP-Cu1.

Figure 5. Magnetic corresponding orbital of CP-Cu1 and CP-Cu2, spin density surface and overlap between magnetic corresponding orbitals.

Figure 6. (a) Mass spectra of M-Cu1 and M-Cu2, (b) optimized molecular structure, (c) frontier molecular orbitals, (d) fragmental composition of frontier molecular orbitals and spin density surface for M-Cu1. Bond lengths are in Å; orbital and spin-density surfaces isovalue of 0.05 and 0.005 a.u., respectively.

Figure 7. (a) Experimental and (b) simulated CD spectra of M-Cu1 and M-Cu2.

Figure 8. (a) Molecular orbital energy diagram for the electronic transitions, (b) most relevant molecular orbital related to the electronic transition and (c) hole-electron surface for the relevant electronic transitions for M-Cu1. The isovalues for molecular orbital and hole-electron surfaces are 0.05 and 0.002 a.u.
<figure><img src="image_2.png" /><figcaption>Figure 1</figcaption></figure>
<figure><img src="image_3.png" /><figcaption>b</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>c</figcaption></figure>

<figure><img src="image_5.png" /><figcaption>Figure 2</figcaption></figure>

<figure><img src="image_6.png" /><figcaption>b</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Figure 3</figcaption></figure>
<figure><img src="image_8.png" /></figure>

<figure><img src="image_9.png" /><figcaption>Figure 4</figcaption></figure>

<figure><img src="image_10.png" /><figcaption>Figure 5</figcaption></figure>
<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

<figure><img src="image_14.png" /></figure>

<table><caption>Figure 6</caption><thead><tr><th>Fragment</th><th>% α-HOMO</th><th>%α-LUMO</th><th>%β-HOMO</th><th>%β-LUMO</th><th>ρ<sub>s</sub></th></tr></thead><tbody><tr><td>Cu(II)</td><td>9.1</td><td>2.5</td><td>1.5</td><td>60.8</td><td>64.4</td></tr><tr><td>L</td><td>77.7</td><td>97.3</td><td>98.0</td><td>31.2</td><td>28.7</td></tr><tr><td>DMSO</td><td>13.2</td><td>0.2</td><td>0.5</td><td>8.0</td><td>6.9</td></tr></tbody></table>

<figure><img src="image_15.png" /></figure>

<figure><img src="image_16.png" /></figure>
<caption>Figure 7</caption>

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<figure><img src="image_17.png" /><figcaption>Figure 8</figcaption></figure>

ASSOCIATED CONTENT

Supporting Information.
The following files are available free of charge.

X-ray powder diffraction patterns, FTIR, UV-Vis-NIR, ESI-mass, CD and EPR spectra, additional $\chi_m T$ vs T and $M_{red}$ vs H plots, supplementary figures of structural drawings and complete crystal data and structure refinement for coordination polymers.

### Accession Codes

CCDC 2099735, 2099736 and 2099737 contains the supplementary crystallographic data for this publication. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

### Acknowledgments

The authors acknowledge FONDECYT 1211394, CONICYT-FONDEQUIP/PPMS/EQM130086-UNAB, CONICYT-FONDEQUIP/EQM140060, Chilean-French International Associated Laboratory for Multifunctional Molecules and Materials-LIAM3-CNRS No.1027, Financiamiento Basal, AFB180001, CEDENNA and the support of
the Laboratory of Analyses of Solids (L.A.SUNAB). C.C. acknowledge the financial support
of CONICYT/FONDECYT Postdoctorado N° 3210314 and K.W-A acknowledges the financial
support of CONICYT/FONDECYT Postdoctorado N° 3200270. D.C-A thanks the financial
support of the CONICYT/FONDECYT project 11170289 and the computational resources
through the CONICYT/FONDEQUIP project EQM180180. Project supported by the Fund of
Scientific and Technological Equipment, 2018, code L318-04, Universidad Tecnológica
Metropolitana. Powered@NLHPC: This research was partially supported by the
supercomputing infrastructure of the NLHPC (ECM-02).

AUTHOR INFORMATION

Corresponding Author

*V.P-G.: e-mail, vparedes@unab.cl; tel, +56-2-2661 5756.

REFERENCES

(1) Moss, G. Basic Terminology of Stereochemistry (IUPAC Recommendations 1996).

*Pure Appl. Chem.* **1996**, *68*, 2193–2222.
(2) Liu, M.; Zhang, L.; Wang, T. Supramolecular Chirality in Self-Assembled Systems. *Chem. Rev.* **2015**, *115*, 7304–7397.

(3) Fritschi, H.; Leutenegger, U.; Pfaltz, A. Chiral Copper-Semicorrin Complexes as Enantioselective Catalysts for the Cyclopropanation of Olefins by Diazo Compounds. *Angew. Chemie Int. Ed. English* **1986**, *25*, 1005–1006.

(4) Galaverna, G.; Corradini, R.; de Munari, E.; Dossena, A.; Marchelli, R. Chiral Separation of Unmodified Amino Acids by Ligand-Exchange High-Performance Liquid Chromatography Using Copper(II) Complexes of L-Amino Acid Amides as Additives to the Eluent. *J. Chromatogr. A* **1993**, *657*, 43–54.

(5) Jing, B.; Li, L.; Dong, J.; Li, J.; Xu, T. Synthesis, Crystal Structure, and DNA Interaction Studies of a Mixed-Ligand Copper(II) Complex of 1,10-Phenanthroline and a Schiff Base Derived from Isoleucine. *Transit. Met. Chem. Commun.* **2011**, *36*, 565–571.

(6) Long, L.S.; Ding, K.Y.; Chen, X.M.; Ji, L.N. A Novel Dinuclear Zinc Complex Containing Both Imidazole and Carboxylate Groups as a Possible Model for Serine/Threonine Protein Phosphatase-1. *Inorg. Chem. Commun.* **2000**, *3*, 65–67.
(7) Wang, C.; Zhang, T.; Lin, W. Rational Synthesis of Noncentrosymmetric Metal-Organic Frameworks for Second-Order Nonlinear Optics. *Chem. Rev.* **2012**, *112*, 1084–1104.

(8) Iazzolino, A.; Ould Hamouda, A.; Naïm, A.; Stefánczyk, O.; Rosa, P.; Freysz, E. Nonlinear Optical Properties and Application of a Chiral and Photostimulable Iron(II) Compound. *Appl. Phys. Lett.* **2017**, *110*, 1–6.

(9) Lu, W. G.; Gu, J. Z.; Jiang, L.; Tan, M. Y.; Lu, T. B. Achiral and Chiral Coordination Polymers Containing Helical Chains: The Chirality Transfer between Helical Chains. *Cryst. Growth Des.* **2008**, *8*, 192–199.

(10) Hao, Z.; Song, S.; Su, S.; Song, X.; Zhu, M.; Zhao, S.; Meng, X.; Zhang, H. Design and Synthesis of Enantiomerically Pure Chiral Sandwichlike Lamellar Structure: New Explorations from Molecular Building Blocks to Three-Dimensional Morphology. *Cryst. Growth Des.* **2013**, *13*, 976–980.

(11) Aspinall, H. C. Chiral Lanthanide Complexes: Coordination Chemistry and Applications. *Chem. Rev.* **2002**, *102*, 1807–1850.
(12) Imaz, I.; Rubio-Martínez, M.; Saletra, W. J.; Amabilino, D. B.; Maspoch, D. Amino Acid Based Metal-Organic Nanofibers. *J. Am. Chem. Soc.* **2009**, *131*, 18222–18223.

(13) Vaidhyanathan, R.; Bradshaw, D.; Rebilly, J. N.; Barrio, J. P.; Gould, J. A.; Berry, N. G.; Rosseinsky, M. J. A Family of Nanoporous Materials Based on an Amino Acid Backbone. *Angew. Chemie - Int. Ed.* **2006**, *45*, 6495–6499.

(14) An, H.; Wang, E.; Xiao, D.; Li, Y.; Su, Z.; Xu, L. Chiral 3D Architectures with Helical Channels Constructed from Polyoxometalate Clusters and Copper–Amino Acid Complexes. *Angew. Chemie Int. Ed.* **2006**, *45*, 904–908.

(15) Farkas, E.; Buglyó, P. Lead(II) Complexes of Amino Acids, Peptides, and Other Related Ligands of Biological Interest. *Met. Ions Life Sci.* **2017**, *17*, 201–240.

(16) Grancha, T.; Ferrando-Soria, J.; Proserpio, D. M.; Armentano, D.; Pardo, E. Toward Engineering Chiral Rodlike Metal-Organic Frameworks with Rare Topologies. *Inorg. Chem.* **2018**, *57*, 12869–12875.
(17) Grancha, T.; Qu, X.; Julve, M.; Ferrando-Soria, J.; Armentano, D.; Pardo, E. Rational Synthesis of Chiral Metal-Organic Frameworks from Preformed Rodlike Secondary Building Units. *Inorg. Chem.* **2017**, *56*, 6551–6557.

(18) Liu, X.; Guo, W.; Hu, X.; Wang, Y.; Yue, Q.; Gao, E. Journal of Solid State Chemistry Chiral Coordination Frameworks Constructed by a Pyridine-Based Alanine Derivative with Semi-Rigid and Asymmetrical Con Fi Guration%: Structure , Photocatalysis and Selective Luminescent Sensing. *J. Solid State Chem.* **2019**, *273*, 53–61.

(19) Grancha, T.; Mon, M.; Ferrando-Soria, J.; Armentano, D.; Pardo, E. Structural Studies on a New Family of Chiral BioMOFs. *Cryst. Growth Des.* **2016**, *16*, 5571–5578.

(20) Grancha, T.; Ferrando-Soria, J.; Cano, J.; Amorós, P.; Seoane, B.; Gascon, J.; Bazaga-García, M.; Losilla, E. R.; Cabeza, A.; Armentano, D.; Pardo, E. Insights into the Dynamics of Grotthuss Mechanism in a Proton-Conducting Chiral BioMOF. *Chem. Mater.* **2016**, *28*, 4608–4615.
(21) Yu, R.; Yang, W.; Wu, X. Y.; Lu, C. Z. A Series of Chiral Metal-Organic Frameworks Based on Oxalyl Retro-Peptides: Synthesis, Characterization, Dichroism Spectra, and Gas Adsorption. *Cryst. Growth Des.* **2012**, *12*, 3304–3311.

(22) Servetas, J. G.; Kostakis, G. E.; Haukka, M.; Bakas, T.; Plakatouras, J. C. Synthesis, and Characterization of 1- and 2-D Coordination Polymers Derived from the Pseudopeptidic Ligand Oxamide-N,N'-Diacetate: Insights into the Supramolecular Architectures Constructed through H-Bonds. *Polyhedron* **2009**, *28*, 3322–3330.

(23) Maxim, C.; Muntean, D.; Andruh, M. On the Role Played by the Chirality of Ligands on the Aggregation of Heterometallic Cu<sup>II</sup>-Hg<sup>II</sup> Complexes. *Chirality* **2019**, *31*, 621–627.

(24) Puntus, L.; Zhuravlev, K.; Lyssenko, K.; Pekareva, I. Luminescence and Structural Properties of Lanthanide Complexes of Schiff Bases Derived from Pyridoxal and Amino Acids. *Dalt. Trans.* **2007**, 4079–4088.

(25) Thio, Y.; Toh, S. W.; Xue, F.; Vittal, J. J. Self-Assembly of a 15-Nickel Metallamacrocyclic Complex Derived from the L-Glutamic Acid Schiff Base Ligand. *Dalt. Trans.* **2014**, *43*, 5998–6001.
(26) Muche, S.; Levacheva, I.; Samsonova, O.; Pham, L.; Christou, G.; Bakowsky, U. A Chiral, Low-Cytotoxic [Ni<sub>15</sub>]-Wheel Complex. *Inorg. Chem.* **2014**, *53*, 7642–7649.

(27) Nguyen, K. D.; Kutzscher, C.; Drache, F.; Senkovska, I.; Kaskel, S. Chiral Functionalization of a Zirconium Metal-Organic Framework (DUT-67) as a Heterogeneous Catalyst in Asymmetric Michael Addition Reaction. *Inorg. Chem.* **2018**, *57*, 1483–1489.

(28) Xi, W.; Liu, Y.; Xia, Q.; Li, Z.; Cui, Y. Direct and Post-Synthesis Incorporation of Chiral Metallosalen Catalysts into Metal-Organic Frameworks for Asymmetric Organic Transformations. *Chem. - A Eur. J.* **2015**, *21*, 12581–12585.

(29) Bhattacharya, B.; Maity, D. K.; Pachfule, P.; Colacio, E.; Ghoshal, D. Syntheses, X-Ray Structures, Catalytic Activity and Magnetic Properties of Two New Coordination Polymers of Co(II) and Ni(II) Based on Benzenedicarboxylate and Linear N,N'-Donor Schiff Base Linkers. *Inorg. Chem. Front.* **2014**, *1*, 414–425.

(30) Dong, X. W.; Yang, Y.; Che, J. X.; Zuo, J.; Li, X. H.; Gao, L.; Hu, Y. Z.; Liu, X. Y. Heterogenization of Homogeneous Chiral Polymers in Metal-Organic Frameworks with
Enhanced Catalytic Performance for Asymmetric Catalysis. *Green Chem.* **2018**, *20*, 4085–4093.

(31) Jammi, S.; Rout, L.; Saha, P.; Akkilagunta, V. K.; Sanyasi, S.; Punniyamurthy, T. *Synthesis, Structure and Application of Chiral Copper(II) Coordination Polymers for Asymmetric Acylation*. *Inorg. Chem.* **2008**, *47*, 5093–5098.

(32) Seguin, A. K.; Wrighton-Araneda, K.; Cortés-Arriagada, D.; Cruz, C.; Venegas-Yazigi, D.; Paredes-García, V. A New Cu<sup>II</sup>-Dinuclear Paddlewheel Complex. *Structural and Electronic Properties*. *J. Mol. Struct.* **2021**, *1224*, 129172.

(33) Wojciechowska, A.; Janczak, J.; Zierkiewicz, W.; Rytlewski, P.; Rojek, T.; Duczmal, M. Copper(II) Complex with L-Arginine – Crystal Structure, DFT Calculations, Spectroscopic, Thermal and Magnetic Properties. *Mater. Chem. Phys.* **2019**, *228*, 272–284.

(34) Ma, X.; Wu, Y.; Cen, P.; Ma, S.; Zhang, C.; Luo, S.; Zhou, H.; Song, W.; Liu, X. Ferromagnetic Ordering and Slow Magnetic Relaxation Observed in a Triple-Bridged Azido-Cu(II) chain Compound with Mixed Carboxylate/Ethanol Linkers. *New J. Chem.* **2017**, *41*, 9631–9638.
(35) Kamaal, S.; Usman, M.; Afzal, M.; Alarifi, A.; Ali, A.; Das, R.; Lama, P.; Ahmad, M. *A New Copper(II)-Based Layered Coordination Polymer: Crystal Structure, Topology, QTAIM Analysis, Experimental and Theoretical Magnetic Properties Based on DFT Combined with Broken-Symmetry Formalism (BS-DFT).* *Polyhedron* **2021**, *193*, 114881.

(36) Peng, X.; Cui, G. H.; Li, D. J.; Wu, S. Z.; Yu, Y. M. *Structure, Spectroscopy, and Theory Calculations of Mononuclear Mixed-Ligand Copper(II) Complex with Malonate and 2-Propylimidazole*, [Cu(Mal)(PIM)₂(H₂O)]. *J. Mol. Struct.* **2010**, *971*, 47–52.

(37) De Bellefeuille, D.; Orio, M.; Barra, A. L.; Aukauloo, A.; Journaux, Y.; Philouze, C.; Ottenwaelder, X.; Thomas, F. *Redox Noninnocence of the Bridge in Copper(II) Salophen and Bis(Oxamato) Complexes*. *Inorg. Chem.* **2015**, *54*, 9013–9026.

(38) Kumar, M.; Kishor, S.; Kumar, A.; Bhagi, A. K.; John, R. P. *Structural Characterisation and Theoretical Study of a Dinuclear Copper(II) Complex Bridged by Meta-Phenylenediiminophenolate Moiety*. *J. Mol. Struct.* **2020**, *1199*, 126996.

(39) Han, Z.; Shi, W.; Cheng, P. *Synthetic Strategies for Chiral Metal-Organic Frameworks*. *Chin. Chem. Lett.* **2018**, *29*, 819-822.
(40) Xu, Z. X.; Tan, Y. X.; Fu, H. R.; Liu, J.; Zhang, J. Homochiral Metal-Organic Frameworks with Enantiopure Proline Units for the Catalytic Synthesis of β-Lactams. *Inorg. Chem.* **2014**, *53*, 12199–12204.

(41) Rebilly, J. N.; Bacsa, J.; Rosseinsky, M. J. 1D Tubular and 2D Metal-Organic Frameworks Based on a Flexible Amino Acid Derived Organic Spacer. *Chem. - An Asian J.* **2009**, *4*, 892–903.

(42) Tay, H. M.; Hua, C. Chiral Cd(II) Coordination Polymers Based on Amino Acid Derivatives: The Effect of Side Chain on Structure. *Cryst. Growth Des.* **2020**, *20*, 5843–5853.

(43) Guan, G. X.; Liu, X.; Yue, Q.; Gao, E. Q. Homochiral Metal-Organic Frameworks Embedding Helicity Based on a Semirigid Alanine Derivative. *Cryst. Growth Des.* **2018**, *18*, 364–372.

(44) SAINT V6.22. SAINT V6.22 Bruker AXS Inc.: Madison, WI, USA 2000.

(45) SADABS V2.05. SADABS V2.05 Bruker AXS Inc.: Madison, WI, USA 2001.
(46) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. OLEX2: A Complete Structure Solution, Refinement and Analysis Program. *J. Appl. Crystallogr.* **2009**, *42*, 339–341.

(47) Sheldrick, G. M. SHELXT - Integrated Space-Group and Crystal-Structure Determination. *Acta Crystallogr. Sect. A Found. Adv.* **2015**, *A71*, 3–8.

(48) Sheldrick, G. M. Crystal Structure Refinement with SHELXL. *Acta Crystallogr. Sect. C Struct. Chem.* **2015**, *C71*, 3–8.

(49) Blatov, V.; Shevchenko, A. ToposPro, Program Package for Multipurpose Crystallochemical Analysis. ToposPro V5.0, program package for multipurpose crystallochemical analysis 2014.

(50) Blanton, J. R.; Papoular, R. J.; Louër, D. PreDICT%: A Graphical User Interface to the DICVOL14 Indexing Software Program for Powder Diffraction Data. *Powder Diffr.* **2019**, *34*, 233–241.

(51) Rodríguez-Carvajal, J.; Roisnel, T. Line Broadening Analysis Using Fullprof: Determination of Microestructural Properties. *Mater. Sci. Forum* **2004**, **443–444**, 123–126.
(52) Roisnel, T.; Rodríguez-Carvajal, J. WinPLOT: A Windows Tool for Powder Diffraction Pattern Analysis. *Mater. Sci. Forum* **2001**, *378–381*, 118–123.

(53) Strohalm, M.; Hassman, M.; Košata, B.; Kodíček, M. MMass Data Miner: An Open Source Alternative for Mass Spectrometric Data Analysis. *Rapid Commun. Mass Spectrom.* **2008**, *22*, 119–130.

(54) Strohalm, M.; Kavan, D.; Novák, P.; Volný, M.; Havlíček, V. MMass 3: A Cross-Platform Software Environment for Precise Analysis of Mass Spectrometric Data. *Anal. Chem.* **2010**, *82*, 4648–4651.

(55) Niedermeyer, T.; Strohalm, M. MMass as a Software Tool for the Annotation of Cyclic Peptide Tandem Mass Spectra. *PLoS One* **2012**, *7*, e44913–e44913.

(56) Bain, G. A.; Berry, J. F. Diamagnetic Corrections and Pascal’s Constants. *J. Chem. Educ.* **2008**, *85*, 532–536.

(57) Runge, E.; Gross, E. K. U. Density-Functional Theory for Time-Dependent Systems. *Phys. Rev. Lett.* **1984**, *52*, 997–1000.
(58) Ullrich, C. A. *Theory, Time-Dependent Density-Functional Concepts and Applications*; Oxford University Press: Oxford, 2012.

(59) Zhao, Y.; Truhlar, D. G. The M06 Suite of Density Functionals for Main Group Thermochemistry, Thermochemical Kinetics, Noncovalent Interactions, Excited States, and Transition Elements: Two New Functionals and Systematic Testing of Four M06-Class Functionals and 12 Other Function. *Theor. Chem. Acc.* **2008**, *120*(1-3), 215-241.

(60) Schäfer, A.; Huber, C.; Ahlrichs, R. Fully Optimized Contracted Gaussian Basis Sets of Triple Zeta Valence Quality for Atoms Li to Kr. *J. Chem. Phys.* **1994**, *100*, 5829-5835.

(61) Marenich, A. V.; Cramer, C. J.; Truhlar, D. G. Universal Solvation Model Based on Solute Electron Density and on a Continuum Model of the Solvent Defined by the Bulk Dielectric Constant and Atomic Surface Tensions. *J. Phys. Chem. B* **2009**, *113*, 6378-6396.

(62) Lu, T.; Chen, F. Multiwfn: A Multifunctional Wavefunction Analyzer. *J. Comput. Chem.* **2012**, *33*, 580-592.

(63) Mulliken, R. S. Electronic Population Analysis on LCAO-MO Molecular Wave Functions. *I. J. Chem. Phys.* **1955**, *23*, 1833-1840.
(64) Becke, A. D. Density-Functional Exchange-Energy Approximation with Correct Asymptotic Behavior. *Phys. Rev. A* **1988**, *38*, 3098–3100.

(65) Lee, C.; Yang, W.; Parr, R. G. Development of the Colle-Salvetti Correlation-Energy Formula into a Functional of the Electron Density. *Phys. Rev. B* **1988**, *37*, 785–789.

(66) Becke, A. D. Density-Functional Thermochemistry. III. The Role of Exact Exchange. *J. Chem. Phys.* **1993**, *98*, 5648–5652.

(67) Noodleman, L. Valence Bond Description of Antiferromagnetic Coupling in Transition Metal Dimers. *J. Chem. Phys.* **1981**, *74*, 5737–5743.

(68) Noodleman, L.; Davidson, E. R. Ligand Spin Polarization and Antiferromagnetic Coupling in Transition Metal Dimers. *Chem. Phys.* **1986**, *109*, 131–143.

(69) Van Vleck, J. H. Quantum Mechanics: The Key to Understanding Magnetism. *Science* **1978**, *201*, 113–120.

(70) Rodríguez-Fortea, A.; Alemany, P.; Alvarez, S.; Ruiz, E. Exchange Coupling in Carboxylato-Bridged Dinuclear Copper(II) Compounds: A Density Functional Study. *Chem. - A Eur. J.* **2001**, *7*, 627–637.
(71) Ruiz, E.; Alemany, P.; Alvarez, S.; Cano, J. Toward the Prediction of Magnetic Coupling in Molecular Systems: Hydroxo- and Alkoxo-Bridged Cu(II) Binuclear Complexes. *J. Am. Chem. Soc.* **1997**, *119*, 1297–1303.

(72) Ruiz, E.; Rodríguez-Fortea, A.; Tercero, J.; Cauchy, T.; Massobrio, C. Exchange Coupling in Transition-Metal Complexes via Density-Functional Theory: Comparison and Reliability of Different Basis Set Approaches. *J. Chem. Phys.* **2005**, *123*.

(73) Ruiz, E.; Cano, J.; Alvarez, S.; Alemany, P. Broken Symmetry Approach to Calculation of Exchange Coupling Constants for Homobinuclear and Heterobinuclear Transition Metal Complexes. *J. Comput. Chem.* **1999**, *20*, 1391–1400.

(74) Ruiz, E.; Rodríguez-Fortea, A.; Cano, J.; Alvarez, S.; Alemany, P. About the Calculation of Exchange Coupling Constants in Polynuclear Transition Metal Complexes. *J. Comput. Chem.* **2003**, *24*, 982–989.

(75) Desplanches, C.; Ruiz, E.; Alvarez, S. Exchange Coupling in Metal Complexes of the Second Transition Series: A Theoretical Exploration. *Eur. J. Inorg. Chem.* **2003**, 1756–1760.
(76) Ruiz, E.; Alvarez, S.; Cano, J.; Polo, V. About the Calculation of Exchange Coupling Constants Using Density-Functional Theory: The Role of the Self-Interaction Error. *J. Chem. Phys.* **2005**, *123*, 1-7.

(77) Rodríguez-Fortea, A.; Alemany, P.; Alvarez, S.; Ruiz, E. A Theoretical Study of the Exchange Coupling in Hydroxo- and Alkoxo-Bridged Dinuclear Oxovanadium(IV) Compounds. *Eur. J. Inorg. Chem.* **2004**, 143-153.

(78) Cauchy, T.; Ruiz, E.; Alvarez, S. Magnetostructural Correlations in Polynuclear Complexes: The Fe₄ Butterflies. *J. Am. Chem. Soc.* **2006**, *128*, 15722-15727.

(79) Muñoz-Becerra, K.; Aravena, D.; Ruiz, E.; Spodine, E.; Soto-Donoso, N.; Paredes-Garcia, V.; Venegas-Yazigi, D. Models to Predict the Magnetic Properties of Single- and Multiple-Bridged Phosphate Cu II Systems: A Theoretical DFT Insight. *Inorg. Chem. Front.* **2017**, 509-520.

(80) Hopmann, K. H.; Noodleman, L.; Ghosh, A. Spin Coupling in Roussin's Red and Black Salts. *Chem. - A Eur. J.* **2010**, *16*, 10397-10408.
(81) Cui, S. X.; Wang, H. Y.; Xu, J.; Zhang, J. P. Theoretical Studies on Magnetic Properties of a Binuclear Paddle Wheel Cu(II) Complex {Cu₂(µ₂-O₂CCH₃)₄}(OCNH₂CH₃)₂. *Russ. J. Phys. Chem. A* **2017**, *91*, 1070–1075.

(82) Zou, R. Q.; Zhong, R. Q.; Jiang, L.; Yamada, Y.; Kuriyama, N.; Xu, Q. Tuning the Formation of Cadmium(II) Urocanate Frameworks by Control of Reaction Conditions: Crystal Structure, Properties, and Theoretical Investigation. *Chem. - An Asian J.* **2006**, *1*, 536–543.

(83) Nakamoto, K. *Infrared and Raman Spectra of Inorganic and Coordination Compounds*. Part B: Applications in Coordination, Organometallic, and Bioinorganic Chemistry, John Wiley & Sons, 2002; Vol. 326.

(84) Ünver, H.; Hayvali, Z. Synthesis, Spectroscopic Studies and Structures of Square-Planar Nickel(II) and Copper(II) Complexes Derived from 2-{(Z)-[furan-2-ylmethyl]imino}methyl}-6-methoxyphenol. *Spectrochim. Acta - Part A Mol. Biomol. Spectrosc.* **2010**, *75*, 782–788.

(85) Choi, K. Y.; Kim, M. J.; Kim, D. S.; Kim, Y. S.; Kim, J. H.; Ryu, H.; Lim, Y. M.; Kang, S. G.; Shin, U. S.; Lee, K. C.; Hong, C. P. Preparation and Characterization of Nickel(II) and
Copper(II) Tetraaza Macrocyclic Complexes with Isonicotinate Ligands. *Bull. Korean Chem. Soc.* **2002**, *23*, 1062–1066.

(86) Brewer, G.; Brewer, C.; Butcher, R. J.; Zemba, M. Structural Evidence of a Ketimine as the Product of an Amino Acid with an Aldehyde. An Intermediate in the Racemization and Transamination of Amino Acids. *Inorg. Chem. Commun.* **2016**, *64*, 35–38.

(87) Sohncke, L.; Teubner, B. G. *Entwicklung Einer Theorie Der Kristallstruktur*, 1874.

(88) Langer, V.; Gyepesova, D. (1-Methylimidazole)(N-Salicylidene-Rac-Glutamato)Copper(II). *Acta Crystallogr. Sect. A* **2003**, *E59*, m1181–m1183.

(89) Langer, V.; Gyepesová, D.; Kohútova, M.; Valent, A. Dimeric (Isoquinoline)(N-Salicylidene-D,L-Glutamato)Copper(II) Ethanol Solvate. *Acta Crystallogr. Sect. C* **2009**, *C65*, m208–m210.

(90) Lou, B.; Yuan, D. M-4,4-Bipyridine-Bis[Aqua(N-Salicylidene-Aspartato)Copper(II)]. *Acta Crystallogr. Sect. E* **2004**, *E60*, m1976–m1977.
(91) Jin, L.; Zhang, S.; Liu, Z.; Li, G. Aqua[3-carboxy-2-(3,5-Dibromo-2-oxidobenzylamino-κ₂N,O)propanoato-κO1](dimethylformamide-κO)Copper(II) dimethylformamide solvate monohydrate. *Acta Crystallogr. Sect. E* **2007**, *E63*, m2631–m2632.

(92) Nakagame, R.; Tsaturyan, A.; Haraguchi, T.; Pimonova, Y.; Lastovina, T.; Akitsu, T.; Shcherbakov, I. Photochemical Reaction of Amino Acid Schiff Base Derived Cu Complexes with Extended π-System and Their Titanium Oxide Composites. *Inorganica Chim. Acta* **2019**, *486*, 221–231.

(93) Zehra, S.; Roisnel, T.; Arjmand, F. Enantiomeric Amino Acid Schiff Base Copper(II) Complexes as a New Class of RNA-Targeted Metallo-Intercalators: Single X-Ray Crystal Structural Details, Comparative in Vitro DNA/RNA Binding Profile, Cleavage, and Cytotoxicity. *ACS Omega* **2019**, *4*(4), 7691–7705.

(94) Garribba, E.; Micera, G. The Determination of the Geometry of Cu(II) Complexes. An EPR Spectroscopy Experiment. *J. Chem. Educ.* **2006**, *83*(8), 1229–1232.

(95) Johnston, D.; Kremer, R.; Troyer, M. Thermodynamics of Spin Antiferromagnetic Uniform and Alternating-Exchange Heisenberg Chains. *Phys. Rev. B* **2000**, *61*, 9558–9606.
(96) Bonner, J. I. C.; Fisher, M. E. Linear Magnetic Chains with Anisotropy Coupling. *Phys. Rev. 1964*, *205*, A640-A658.

(97) Landee, C.; Turnbull, M. Review: A Gentle Introduction to Magnetism: Units, Fields, Theory, and Experiment. *J. Coord. Chem.* **2014**, *67*, 375-439.

(98) Takahashi, M. Few-Dimensional Heisenberg Ferromagnets at Low Temperature. *Phys. Rev. Lett.* **1987**, *58*, 168-170.

(99) Oitmaa, J.; Bornilla, E. High-Temperature-Series Study of the Spin-½ Heisenberg Ferromagnet. *Phys. Rev. B* **1996**, *53*, 14228-14235.

(100) Colacio, E.; Ghazi, M.; Kivekäs, R.; Moreno, J. M. Helical-Chain Copper(II) Complexes and a Cyclic Tetranuclear Copper(II) Complex with Single Syn-Anti Carboxylate Bridges and Ferromagnetic Exchange Interactions. *Inorg. Chem.* **2000**, *39*, 2882-2890.

(101) Borisova, N. E.; Kostin, A.; Magdesieva, T. V.; Reshetova, M. D.; Nikitin, O.; Paredes-García, V.; Garland, M. T.; Hermosilla-Ibáñez, P.; Cañon-Mancisidor, W.; Rodionov, A.; Venegas-Yazigi, D.; Spodine, E. Solvent Switchable CuII Complexes. *New J. Chem.* **2014**, *38*, 709.
(102) Díaz-Torres, R.; Alvarez, S. Coordinating Ability of Anions and Solvents towards Transition Metals and Lanthanides. *Dalt. Trans.* **2011**, *40*, 10742.

(103) Ruiz, E.; Cirera, J.; Alvarez, S. Spin Density Distribution in Transition Metal Complexes. *Coord. Chem. Rev.* **2005**, *249*, 2649–2660.

(104) Rudra, I.; Wu, Q.; Van Voorhis, T. Accurate Magnetic Exchange Couplings in Transition-Metal Complexes from Constrained Density-Functional Theory. *J. Chem. Phys.* **2006**, *124*, 1–9.

(105) Bencini, A.; Totti, F.; Daul, C. A.; Doclo, K.; Fantucci, P.; Barone, V. Density Functional Calculations of Magnetic Exchange Interactions in Polynuclear Transition Metal Complexes. *Inorg. Chem.* **1997**, *36*, 5022–5030.

(106) Neese, F. Theoretical Study of Ligand Superhyperfine Structure. Application to Cu(II) Complexes. *J. Phys. Chem. A* **2001**, *105*(17), 4290–4299.

(107) Jorgensen, K. *Inorganic Complexes*, Elsevier, 1963.
(108) Liu, C. T.; Douglas, B. E.; Chong, B.; Liu, T. A. N. Circular Dichroism of Coordination Compounds III. Cobalt(III) Complexes of Optically Active Amino Acids. *Inorg. Chem.* **1964**, *3*, 1356–1361.

(109) Manch, W.; Fernelius, W. C. The Structure and Spectra of Nickel(II) and Copper(II) Complexes. *J. Chem. Educ.* **1961**, *38*, 192–201.

(110) Li, X.; Liu, T.; Hu, B.; Li, G.; Zhang, H.; Cao, R. Homochiral Supramolecular Compounds Constructed from Amino Acid Derivatives: Syntheses, Structures, Chiroptical, and Photoluminescence Properties. *Cryst. Growth Des.* **2010**, *10*, 3051–3059.

(111) Liu, M.; Yu, H.; Wang, Y.; Liu, Z. A Pair of Enantiomeric Trinuclear Nickel(II) Clusters Based on Chiral Schiff-Base: Synthesis, Structures, Circular Dichroism and Magnetic Properties. *Inorg. Chem. Commun.* **2017**, *86*, 281–284.

(112) Hu, G.; Zhang, H.; Miao, H.; Wang, J.; Xu, Y. Journal of Solid State Chemistry Synthesis, Structures and Properties of Two New Chiral Rare Earth-or- Ganic Frameworks Constructed by L/D-Tartaric Acid. *J. Solid State Chem.* **2015**, *229*, 208–212.
(113) Pessoa, J. C.; Correia, I.; Gameiro, A.; Felix, V.; Fiuza, E. Enantioselectivity in Ni(II) Schiff-Base Complexes Derived from Amino-Acids and (S)-o-N-(N-Benzylprolyl)Aminobenzophenone. Molecular Structure of Several Chiral Ni(II) Schiff-Base Complexes, Circular Dichroism and Molecular Mechanics Studies. *Dalt. Trans.* **2005**, *2312–2321*.

(114) Mayans, J.; Martin, A.; Escuer, A. Chiral Tetranuclear NiII Clusters Derived from Schiff Bases and Azido Co-Ligands. *Polyhedron* **2018**, *150*, 10–14.

(115) Wang, S.; Zheng, F.; Zhang, M.; Liu, Z.; Chen, J.; Xiao, Y.; Wu, A.; Guo, G.; Huang, J. Homochiral Zinc(II) Coordination Compounds Based on In-Situ-Generated Chiral Amino Acid–Tetrazole Ligands: Circular Dichroism, Excitation Light-Induced Tunable Photoluminescence, and Energetic Performance. *Inorg. Chem.* **2013**, *52*, 10096–10104.

(116) Ene, C. D.; Maxim, C.; Rouzières, M.; Clérac, R.; Avarvari, N.; Andruh, M. Enantiopure versus Racemic Mixture in Reversible, Two-Step, Single-Crystal-to-Single-Crystal Transformations of Copper(II) Complexes. *Chem. - A Eur. J.* **2018**, *24*, 8569–8576.
(117) Yamazaki, A.; Akitsu, T. Polarized Spectroscopy and Polarized UV Light-Induced Molecular Orientation of Chiral Diphenyl Schiff Base Ni(II) and Cu(II) Complexes and Azobenzene in a PMMA Film. *RSC Adv.* **2012**, *2*, 2975–2980.

(118) Enamullah, M.; Uddin, A. K. M. R.; Pescitelli, G.; Berardozzi, R.; Makhloufi, G.; Vasylyeva, V.; Chamayou, A. C.; Janiak, C. Induced Chirality-at-Metal and Diastereoselectivity at Δ/Λ- Configured Distorted Square-Planar Copper Complexes by Enantiopure Schiff Base Ligands: Combined Circular Dichroism, DFT and X-Ray Structural Studies. *Dalt. Trans.* **2014**, *43* (8), 3313–3329.

For Table of Contents Use Only
Chiral 1D metal-organic materials based on Cu(II)

and amino acid Schiff-bases

Carlos Cruz,ª,ᵇ Carla Gonzalez,ª,ᵇ Francisco Rubio,ª,ᵇ Juan Erices,ª,ᵇ Kerry Wrighton-Araneda,ᶜ

Diego Cortés-Arriagada,ᶜ Diego Venegas-Yazigi,ᵇ,ᵈ Nathalie Audebrand,ᵉ Verónica Paredes-García*ª,ᵇ

a Universidad Andrés Bello, Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Santiago, Chile.

b CEDENNA, Santiago, Chile.

c Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Santiago, Chile.

d Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Ciencias de los Materiales, Santiago, Chile.

e Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France
<figure><img src="image_18.png" /></figure>

Four new coordination polymers, {[Cu(HLⁿ)MeOH]·NO₃}⁻ and four new stable molecular compounds [Cu(HLⁿ)DMSO]⁺ were synthesized using an α-amino acid Schiff base as a chiral building block. Both families of compounds share the same building block, in which the chirality of the α-amino is transferred to the structure of the coordination compounds.