bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Crystal Structure of the Iron Borate Fe2B2O5
Authors: Neumair Stephanie C. , Huppertz Hubert
Published: February 2015

Fe2B2O5, synthesized under mild high-pressure / high-temperature conditions of 3 GPa and 960 ◦C, possesses a structure isotypic to the triclinic pyroborates M2B2O5 with M = Mg, Mn, Co, and Cd. Although the parameter pressure is not essential to the synthesis of Fe2B2O5, the specific conditions enhance the crystallinity of the product. Therefore, the crystal structure of the iron pyroborate Fe2B2O5 could be determined via single crystal diffraction data [space group P1̄ (Z = 4) with the parameters a = 323.1(1), b = 615.7(2), c = 935.5(2) pm, α = 104.70(3), β = 90.82(3), γ = 91.70(3)◦, V = 0.1799(1) nm3, R1 = 0.0409, and wR2 = 0.0766 (all data)]. The structure is built up from layers of isolated pyroborate units ([B2O5]4−), which are composed of two corner-sharing BO3 triangles. These pyroborate layers serve to bridge 4×1 ribbons of edge-sharing FeO6 octahedra by both edgeand corner-sharing.
A New Type of 1-D Thioindates, [M(en)3]0.5[InS2] (M = Co, Ni), Synthesized by Solvothermal Reaction
Authors: Zhou Jian , Zhang Yong , Zhang Ming-Hui , Lei Zhi-Xin , Dai Jie
Published: February 2015

Two thioindates [M(en)3]0.5InS2 [en = ethylenediamine; M = Ni (1), Co (2)] were prepared by the reaction of In2S3, Ni (or Co) and S under solvothermal conditions, and their crystal structures have been determined. Both compounds are isostructural and crystallize in the orthorhombic space group Cmcm. The crystal structures consist of a new type of 1-D sinusoidal chain, which complements the reported I - III types of 1-D [InQ2
−]n (Q = S, Te) anions built from InQ4 tetrahedra. The band gaps of 3.47 eV for I and 3.31 eV for 2 have been derived from optical absorption spectra.
Acyclic and Cyclic Silylaminohydrazines
Authors: Klingebiel Uwe , Matthes Christoph , Ringe Arne , Magull Jörg
Published: February 2015

The reaction of H2N-NH2 with ClSiMe2N(SiMe3)2 in a molar ratio 1 : 2 gave the bis(silylamino) hydrazine [HNSiMe2-N(SiMe3)2]2 (1). Compound 1 forms a monomeric dilithium salt with BuLi. From n-hexane (Me3Si-NSiMe2-NLiSiMe3)2 (2) crystallizes while from THF [Me3Si-NSiMe2- NLi(THF)SiMe3]2 (3) precipitates. Compounds 2 and 3 are formed from 1 via a silyl group migration. In the rearranged salts, the silyl groups are bonded at the hydrazino nitrogen atoms. Hydrolysis of 2 led to the formation of (Me3Si-N-SiMe2-NHSiMe3)2 (4) which is a structural isomer of 1. Ring closure occurs in reactions of 2 or 3 with F3B ・ OEt2 or SiF4. The seven-membered rings (Me3Si- N-SiMe2-NSiMe3)2BF (5) and (Me3Si-NSiMe2-NSiMe3)2SiF2, (6) were isolated as the products. The crystal structures of 2, 3 and 5 have been determined.
The Molecular Structure of 1,3,5,7- Tetra(tert-butyl)-2,4,6,8-tetraazidoborazocine [1]
Authors: Nöth Heinrich
Published: February 2015

The tetra(tert-butyl)-tetraazido-borazocine, 1, has the expected tub shape as determined for (SCNB=NtBu)4. However, it crystallizes in the triclinic system and shows no symmetry element in contrast to the isothiocyanato derivate which has C2 symmetry. There are two kinds of BN bonds which alter from long to short (average 1.491 and 1.388 A° ). The BN bond lengths to the azido groups are, on average, 1.486 °A. All B and N atoms of the ring reside in a trigonal planar environment. The B-N-N bond angles are close to 120◦ showing that the central nitrogen atom can be considered as sp2-hybridized. The N-N-N bond angles are on average 173.6◦. The two sets of the opposite B2N2 planes include an angle of 114.8◦. The atoms of the azido groups are almost coplanar with the respective NBN planes. This together with the short BN(N2) bond lengths indicates that these azido groups are π-bonded to their corresponding boron atom.
Stereoselective Synthesis of α-Arylalkylamines by Glycosylation-induced Asymmetric Addition of Organometallic Compounds to Imines
Authors: Allef Petra , Kunz Horst
Published: February 2015

Activation of imines of aromatic aldehydes by N-glycosylation with O-pivaloyl-galactopyranosyl bromide (pivalobromogalactose) and subsequent addition of organotin, organolithium, Grignard, or organozinc reagents afforded α-arylalkylamines with moderate to high diastereoselectivity.
Unexpected Sodium Methoxide-catalyzed Rearrangement of 6-Amino-5-aroyl-1,3-dimethyluracils to Form Novel Cinnamoamides
Authors: Gerig Britta , Girreser Ulrich , Nather Christian , Heber Dieter
Published: February 2015

A synthetic access to novel cinnamoamides 6 was discovered by chance and explored following a two-step route. Compounds 3 were available from 6-amino-1,3-dimethyluracil (1) by acylation using benzoyl chlorides 2 and subsequently converted to 2-cyano-3-(N-methylamino)cinnamic acid methyl amides 6. This sodium methoxide-catalyzed reaction involves ring opening of the pyrimidine ring followed by elimination of CO to form dimethyl carbonate and rearrangement. The application of 6 as potential catecholamine-O-methyl transferase (COMT) inhibitors for the treatment of Parkinson’s disease is discussed.
A Simple Synthesis of 1-Substituted Diethyl Pyrrole-3,4-dicarboxylates
Authors: Škrlep Luka , Čerček-Hočevar Andreja , Jakše Renata , Stanovnik Branko , Svete Jurij
Published: February 2015

A series of 1-substituted diethyl 1H-pyrrole-3,4-dicarboxylates 4a - o were prepared in 14 - 93% yield by acid-catalysed treatment of diethyl 2,3-bis[(E,E)-(dimethylamino)-methylidene]succinate (2) with various aliphatic and (hetero)aromatic primary amines 3a - o. The configuration of the C=C double bonds in the bis-enaminone 2 was determined by 1H NMR and HMBC spectroscopy.
Synthesis of Bicyclic Salicylates by [3+3] Cyclization of 1,3-Bis(Silyl Enol Ethers) with Cyclic 3-(Silyloxy)alk-2-en-1-ones
Authors: Höttecke Nicole , Reinke Helmut , Fischer Christine , Langer Peter
Published: February 2015

Bicyclic salicylates were prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with cyclic 3-(silyloxy)alk-2-en-1-ones.
Anthranicine, an Unusual Cyclic Hexapeptide from Acremonium sp. A29-2004
Authors: Liermann Johannes C. , Thines Eckhard , Anke Heidrun , Opatz Till
Published: February 2015

Anthranicine, a cyclic hexapeptide containing anthranilic acid and pipecolic acid, was isolated from a mycophilic Acremonium species. The structure and stereochemistry of the compound featuring two D-configurated amino acids are discussed.
Amphiphilic Long-chain Citric Acid Ethers
Authors: Meißner Daniel , Jutzi Peter
Published: February 2015

The etherification of the hydroxyl group of citric acid with saturated and unsaturated long-chain alkyl groups is described. This is a new approach to polydentate acids which may serve as ligands for metal or metal oxide nanoparticles. For this purpose we developed a synthetic route to long-chain ω-unsaturated alcohols and their triflate derivatives.
The Residual Volume Approach II: Simple Prediction of Ionic Conductivity of Ionic Liquids
Authors: Bogdanov Milen G. , Iliev Boyan , Kantlehner Willi
Published: February 2015

The Residual Volume Approach (RVA), a recently developed method for the prediction of fundamental physical properties of ionic liquids (ILs) is extended and now allows the estimation of ionic conductivity of unknown ILs, using a simple linear correlation between the ionic conductivity and previously defined substituent parameters - βx. The proposed method is applied to the conductivity correlations of 61 n-alkyl substituted imidazolium, tetraalkylammonium, pyrrolidinium, piperidinium, sulfonium and phosphonium homologous ILs, containing [BF4]−, [Tf2 N]−, [C2 F5PF]−, [CF3BF3]−, [C2H5BF3]−, [F(HF)2.3]−, [Br]−, [I]−, and [formate]− as anions. The influence of the ion type - both anion and cation - on the property changes is discussed. Moreover, it is shown that relatively rigid cations with C2 symmetry decrease the expected conductivity in the same manner as they increase the viscosity of the ILs.
An ONIOM Study of a Guanidinium Salt Ionic Liquid. Experimental and Computational Characterization of N,N,N`,N`,N``-Pentabutyl-N``-benzylguanidinium Bromide
Authors: Tanaka Masato , Siehl Hans-Ullrich , Viefhaus Tillmann , Frey Wolfgang , Kantlehner Willi
Published: February 2015

The guanidinium salt-based ionic liquid N,N,N`,N`,N``-pentabutyl-N``-benzyl-guanidinium bromide was synthesized and characterized by 1H and 13C NMR spectroscopy in solution and by single crystal X-ray structure analysis. The MO computational hybrid method of Morokuma and coworkers (ONIOM method) is applied to compare experimental and quantum chemical results. Four calculation models for two layer ONIOM calculations are defined based on differences of the area for the high-level layer region. Optimized geometries, interaction energies between the cation and the anion, and atomic charges are compared to data of full-QM calculations for the optimized geometry as well as of an experimental X-ray structure determination. The results indicate that it is mandatory for obtaining reasonable results that the parts of the substituent groups which are directly bound to the amino nitrogen atoms are included into the high-level layer. This least required ONIOM model for guanidinium-type ionic liquids can save computational cost of 90% compared to the full-QM SCF calculation.
Computational Chemistry Approaches for Understanding how Structure Determines Properties
Authors: Katritzky Alan R. , Slavov Svetoslav , Radzvilovits Maksim , Stoyanova-Slavova Iva , Karelson Mati
Published: February 2015

The establishment of quantitative relationships between numerous molecular properties and chemical structures is now of great importance to society in understanding and improving environmental, medicinal and technological aspects of life. Quantitative structure-activity (property) relationships (QSA(P)R) relate physical, chemical, physico-chemical, technological and biological properties of compounds to their structure. A major factor driving the widespread use of QSP(A)R models is the rational estimation of properties of new compounds, without first synthesizing and testing them. Some of our recent findings in the field are briefly discussed below.
An 18-Membered Hexanuclear Manganese (MnN2)6 Metalladiazamacrocycle
Authors: Liang Qi-Feng
Published: February 2015

The macrocyclic hexanuclear manganese(III) 18-metallacrown-6, [Mn6(pmshz)6(DMF)4(C2H5- OH)2]·4DMF (1), where pmshz3− is N-propionyl-N'-5-methylsalicylhydrazide, has been synthesized by self-assembly and structurally characterized. The ring is formed by the succession of six structural moieties of the type [Mn(III)-N-N] with hydrazide N-N groups bridging the ring Mn ions. The ligand enforces the metal ions to form the stereochemistry of a configuration with alternate. . .ΔΛΔΛ. . .- type enantiomeric chiral units. The peripheral core ring is ~18.6 in diameter and ~12.4 Å in thickness. The title metallacrown exhibits photoluminescent properties in the solid state and a weak antiferromagnetic exchange interaction.
Synthesis, Structure and Electrochemistry of [Ru2(S2CNMe2)3(μ3-S2CNMe2)2]2[Mo6O19] · 2CH3COCH3
Authors: Wu Fang-Hui , Liu Yang-Li , Lu Lude , Zhang Qian-Feng , Leung Wa-Hung
Published: February 2015

Reaction of MoO2(S2CNMe2)2 with RuCl3 ・χH2O in acetone at reflux afforded [Ru2(S2CNMe2)3- (μ3-S2CNMe2)2]2[Mo6O19]・2CH3COCH3 (1・2CH3COCH3) which was characterized by singlecrystal X-ray diffraction to show a dinuclear ruthenium-dithiocarbamate species as cation and hexamolybdate as counter anion. The [Ru2(S2CNMe2)3(μ3-S2CNMe2)2]+ cation may be considered as a combination of [Ru(S2CNMe2)3] with a cis-[Ru(S2CNMe2)2]+ species, and the Lindqvist anion [Mo6O19]2− is located on an inversion center between two cations. Spectroscopic properties along with the electrochemistry of compound 1・2CH3COCH3 are reported.
Cyanoacetylation of 5-Aminopyrazole: Synthesis of 2-(1-Aryl-4- substituted pyrazolo[3,4-d]pyrimidin-6-yl)acetonitrile Derivatives
Authors: Salaheldin Abdellatif M.
Published: February 2015

N1-Substituted-5-amino-4-cyanopyrazoles were cyanoacetylated with a mixture of cyanoacetic acid and acetic anhydride. Cyclization with POCl3 gave 4-chloro-pyrazolo[3,4-d]pyrimidine derivatives. From the reaction with hydrazine and arylhydrazines, the hydrazinyls and their oxidized forms, the azo products, were obtained. The structure of the compounds obtained has been confirmed by 1H and 13C NMR spectroscopy.
Equilibrium between Hydroxycycloalkanones and Oxabicycloalkanols
Authors: Kräme Guido , Oehlhof Annette , Meier Herbert
Published: February 2015

Hydroxycycloalkanones 1 of medium ring size (8 -10) exist in a transannular tautomeric equilibrium with the corresponding oxabicycloalkan-1-ols 2, which represent hemiacetals. Normally, the bicyclic structures 2 predominate in solution although their portion decreases with increasing solvent polarity. A correlation of the Gibbs reaction enthalpies ΔG (1→2) with the solvent parameters ET (30) is presented.
Crystal Structure of the New Phosphate AgMnPO4
Authors: Yahia Hamdi Ben , Gaudin Etienne , Darriet Jacques
Published: February 2015

The new compound AgMnPO4 has been synthesized by a solid-state reaction route. Its crystal structure was determined from single-crystal X-ray diffraction data. AgMnPO4 crystallizes with triclinic symmetry, space group P1̄, a = 9.6710(6), b = 5.695(2), c = 6.629(3) Å , α = 102.55(3), β = 105.85(2), γ = 80.70(2)◦, and Z = 4. Its structure is built up from MnO6, MnO5 and PO4 polyhedra forming tunnels filled with silver atoms.
Synthesis and Crystal Structure of the High-pressure Iron Borate β-FeB2O4
Authors: Neumair Stephanie C. , Glaum Robert , Huppertz Hubert
Published: February 2015

The iron borate β -FeB2O4 was synthesized under high-pressure / high-temperature conditions of 8 GPa and 1030 ◦C. The structure of β -FeB2O4 is isotypic to HP-NiB2O4, representing the second example of a borate in which every BO4 tetrahedron shares a common edge with a second one. β - FeB2O4 crystallizes in the space group C2/c (Z = 4) with the parameters a = 950.0(2), b = 562.9(2), c = 443.7(1) pm, β = 108.50(3)◦, V = 0.22495(8) nm3, R1 = 0.0293, and wR2 = 0.0647 (all data). The structure consists of layers of BO4 tetrahedra, connected via strings of edge-sharing FeO6 octahedra. A ligand field splitting of Δo ≈8860 cm−1 is estimated from polarized single-crystal electronic absorption spectra of β -FeB2O4. The tetragonal distortion of the ligand field in the [FeIIO6] chromophore amounts to −(8/3)dσ ≈2900 cm−1. In the range of 16000 cm−1 ≤ṽ ≤24000 cm−1, rather strong spin-forbidden transitions within the [FeIIO6] chromophore are observed
Unusually Short Ce–Ru Distances in CeRuAl and Related Compounds
Authors: Hermes Wilfried , Matar Samir F. , Pöttgen Rainer
Published: February 2015

The aluminide CeRuAl with orthorhombic LaNiAl-type structure contains two crystallographically independent cerium sites which both exhibit relatively short Ce-Ru distances, i. e. 280 - 302 pm for Ce1 and 286 - 310 pm for Ce2. Susceptibility measurements show intermediate valence behavior of the cerium atoms (1.19(1) μB per formula unit) and no magnetic ordering down to 2 K. Chemical bonding analysis reveals a non-magnetic ground state and strong Ce-Ru bonding. The Ce-Ru bonding peculiarities of CeRuAl are discussed in line with those of other binary and ternary cerium- ruthenium compounds
Low-temperature Crystal Structures and Magnetic Properties of the V4-Cluster Compounds Ga1-xGexV4S8
Authors: Bichler Daniel , Slavik Herta , Johrendt Dirk
Published: February 2015

Solid solutions Ga1−xGexV4S8 (x = 0−1) were synthesized by solid-state reactions and characterized by temperature-dependent X-ray powder diffraction and static magnetic susceptibility measurements. The compounds crystallize in the cubic GaMo4S8-type structure (space group F43m), built up by heterocubane-like [V4S4](5−x)+ cubes and [Ga1−xGexS4](5−x)− tetrahedra arranged in a NaCllike manner. The successive substitution of Ga3+ by Ge4+ increases the electron count in the molecular orbitals (MO’s) of the V4-cluster gradually from seven to eight. We observe an almost linear increase of the magnetic moments, connected with a transition from ferromagnetic to antiferromagnetic ordering around x ≈ 0.5. Remarkably, low-temperature structural phase transitions as known from the ternary compounds were also detected in the solid solutions. The gallium-rich compounds (0 ≤ x < 0.5) undergo rhombohedral distortions like GaV4S8 (space group R3m), whereas distortions to orthorhombic symmetry (space group Imm2) as known from GeV4S8 occur in the germanium-rich part of the solid solutions (0.5 ≤ x ≤ 1)
The Starting Members of the Series Pr4n+2(C2)nBr5n+5 (n = 1, 2, 3)
Authors: Schaloske Manuel Christian , Mattausch Hansjürgen , Duppel Viola , Kienle Lorenz , Simon Arndt
Published: February 2015

The compounds Pr6(C2)Br10, Pr10(C2)2Br15 and Pr14(C2)3Br20 were prepared from PrBr3 and the appropriate amounts of Pr and C and characterized by X-ray structure analyses of single crystals. All three compounds crystallize in space group P1 with lattice parameters a = 7.571(2), b = 9.004(2), c = 9.062(2) Å ,α = 108.57(3), β = 97.77(3), γ = 106.28(3)◦ for Pr6(C2)Br10; a = 9.098(2), b = 10.127(2), c = 10.965(2) A° , α = 70.38(3), β = 66.31(3), γ = 70.84(3)◦ for Pr10(C2)2Br15; a = 9.054(2), b = 10.935(2), c = 13.352(3) Å , α = 86.27(3), β = 72.57(3), γ = 66.88(3)◦ for Pr14(C2)3Br20. They are members of a general series Ln4n+2(C2)nBr5n+5 and isostructural with the corresponding iodides known for Ln = La, Ce, Pr. Pr6(C2)Br10 was further characterized via transmission electron microscopy techniques
Structure and Magnetic Properties of a Two-dimensional Metal-Organic Framework: [Cu3(bpdc)4/2(pdon)2(H2O)6] · 2ClO4
Authors: Wang Xian-Wen , Liu Ming-Xing , Jiang Wen-Jun , Cai Tie-Jun , Deng Qian
Published: February 2015

A unique 2D sheet metal-organic framework, [Cu3(bpdc)4/2(pdon)2(H2O)6]·2ClO4 (2), has been synthesized by the hydrothermal reaction of pdon with Cu(ClO4)2 (bpdc = 2,2´-bipyridyl-3,3´- dicarboxylate, pdon = 1,10-phenanthroline-5,6-dione). Compound 2 crystallizes in the orthorhombic chiral space group P21212, with the cell parameters: a = 12.3596(11), b = 25.978(2), c = 7.9585(7) Å , V = 2555.3(4) Å3 [R1 = 0.068 and wR2 = 0.172]. It represents a novel metal-organic framework comprising of the mixed ligands of pdon and bpdc, where the cupric atoms are bridged by alternating the μ2- and μ4-bpdc groups into two-dimensional positively charged layers. The bpdc ligand has resulted from the in situ oxidative carbon-carbon bond cleavage of the pdon ligand. Compound 2 displays antiferromagnetic interactions. Above 40 K, χm −1 obeys the Curie-Weiss law with C = 1.37 cm3 Kmol−1 and Θ = −13.95 K.
A New Chlorine-containing Glucosyl-fused Compound from Curculigo glabrescens
Authors: Zhu Cui-Cui , Wang Tian-Ming , Wang Kai-Jin , Li Ning
Published: February 2015

A new chlorine-containing glucosyl-fused compound, crassifoside H (1), was isolated from the EtOH extract of the rhizomes of Curculigo glabrescens. The structure was established on the basis of MS, IR, 1D and 2D NMR experiments. In addition, seven known compounds (2 - 8) were isolated and identified by spectroscopic analysis and comparison of their spectral data with those reported previously. All the compounds were isolated from this plant for the first time. The free radical scavenging activity of the isolated compounds was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 1 and 2 showed strong radical scavenging activities. The primary structure-activity relationship is also discussed.
The Molecular Structure of 1,3,5,7- Tetra(tert-butyl)-2,4,6,8-tetra(chloro)- borazocine [1]
Authors: Nöth Heinrich
Published: February 2015

The borazocine (ClB=NCMe3)4 crystallizes in the monoclinic system, space group C2/c with Z = 6, i. e. there are two independent molecules in the unit cell. The first molecule has no crystallographic symmetry, while the second molecule is characterized by a twofold axis which generates the (ClB= NCMe3)4 molecule from the fragment (ClB=NCMe3)2. The molecules are tub-shaped showing alternating longer and shorter B-N bonds. Compared with the borazocine (N3B= NCM3)4 the BN bonds of (ClB=NCMe3)4 are on average shorter than those of the azide derivative. Although B-N bond lengths and N-B-N and B-N-B bond angles in both molecules of (ClB=NCMe3)4 are identical within the limits of the standard deviation, the opposite B2N2 planes differ significantly for the two independent molecules.
Siloles Bearing Si-Vinyl and Si-Allyl Functions. 1,1-Organoboration and Protodeborylation
Authors: Khan Ezzat , Wrackmeyer Bernd
Published: February 2015

1,1-Organoboration of dialkyn-1-yl(divinyl)silanes, dialkyn-1-yl(organo)(vinyl)silanes and dialkyn- 1-yl(allyl)(methyl)silane using triethylborane, BEt3, or 9-ethyl-9-borabicyclo[3.3.1]nonane, Et-9- BBN, afforded selectively silole derivatives with Si-vinyl and Si-allyl functions, respectively, bearing the dialkylboryl group in 3-position. The siloles are formed via intermolecular 1,1-alkylboration, followed by intramolecular 1,1-vinylboration. In the cases of several 3-diethylboryl-substituted siloles, smooth and essentially quantitative protodeborylation could be achieved by the reaction of the siloles with an excess of acetic acid at ambient temperature. All new siloles were characterized in solution by multinuclear magnetic resonance spectroscopy (1H, 13C, 11B and 29Si NMR).
CaAgxZn1– x: Zwischen CrB- und FeB-Strukturtyp – Eine Studie zu elektronischen Einflüssen auf die Stapelung von Zick-Zack-Ketten in polaren Erdalkalimetall-Monometalliden / CaAgxZn1−x: Between CrB and FeB Structure Type – A Study on Electronic Factors Influencing the Stacking of Zig-zag Chains in Polar Alkaline Earth Monometallides
Authors: Harms Wiebke , Mihajlov Viktoria , Wendorff Marco , Röhr Caroline
Published: February 2015

Depending on both electronic (valence electron numbers) and geometric (atom size ratios) characteristics of the contributing elements, the 1 : 1 compounds AIIM of the heavier alkaline earth elements A and electron-rich transition metals M form the well known CrB or FeB structure types. Both structure types exhibit M zig-zag chains, which are stacked in different orientations. In systematic studies of the pseudo-binary section CaAgxZn1−x four new ternary phases with different stacking variants between the CrB (cubic stacking, c) and the FeB (hexagonal stacking, h2) structure type have been prepared and characterized on the basis of single crystal X-ray data. Starting from CaAg (CrB type, orthorhombic, space group Cmcm, a = 405.22(7), b = 1144.7(2), c = 464.43(11) pm, Z = 4, R1 = 0.0197), up to 24% of Ag (CaAg0.76Zn0.24: a = 408.6(2), b = 1144.3(5), c = 460.7(2) pm, R1 = 0.0208) can be substituted by zinc without a change in the structure type. Close to the 1 : 1 ratio of Ag and Zn, the HT-TbNi structure type with the stacking sequence (hc2)2, i. e. 33% hexagonality (CaAg0.52Zn0.48: orthorhombic, space group Pnma, a = 2345.47(6), b = 454.370(10), c = 609.950(10) pm, Z = 12, R1 = 0.0298) is formed, followed by the SrAg type with 50% hexagonality (CaAg0.48Zn0.52: orthorhombic, space group Pnma, a = 1571.0(2), b = 451.50(7), c = 609.80(9) pm, Z = 8, R1 = 0.0733). The amount of hexagonal stacking is further increased with increasing Zn content in CaAg0.33Zn0.67 (Gd0.7Y0.3 structure type, h2c stacking, 67% hexagonality, monoclinic, space group P21/m, a = 610.39(9), b = 448.53(5), c = 1195.7(2) pm, β = 96.829(14)◦, Z = 3, R1 = 0.0221). Finally, a pure hexagonal stacking sequence, i. e. the FeB structure type (orthorhombic, space group Pnma, Z = 4) is observed from CaAg0.14Zn0.86 (a = 804.57(2), b = 443.050(10), c = 611.350(10) pm, R1 = 0.0131) to CaAg0.06Zn0.94 (a = 806.1(3), b = 441.0(2), c = 610.4(3) pm, R1 = 0.0255). Intriguingly, the series ends with the binary compound CaZn, which again crystallizes with the CrB structure type exhibiting cubic stacking of the zig-zag chains only (0% hexagonality). In an accompanying computational study, the chemical bonding in the series Ca(Ge/Ga/Zn/Ag) of isotypic binary metallides with variable valence electron numbers has been analyzed using FP-LAPW band structure methods. The electronic structures of the two border stacking variants are compared using the crystal data of CaZn (CrB type) and CaAg0.06Zn0.94 (FeB type). Geometrical and electronic criteria are used to compare and discuss the stability ranges of the different stacking variants inbetween the CrB and the FeB structure type found in polar intermetallic 1 : 1 phases.
Elution Behavior and Structural Characterization of N- and C-functionalized DOTA Complexes for the Labelling of Biomolecules
Authors: Weißhoff Hardy , Janek Katharina , Henklein Peter , Schumann Herbert , Mügge Clemens
Published: February 2015

Two types of lanthanide complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for the labelling of biomolecules were investigated by HPLC, MS and NMR spectroscopy. The elution behavior of lanthanide complexes of N-functionalized DOTA [1,4,7,10-tetraazacyclododecane- 1,4,7-triacetic acid-10-maleimidoethylacetamide (nDOTA-Mal) and 1-{2-[4-(maleimido- N-propylacetamidobutyl)amino]-2-oxoethyl}-1,4,7,10-tetraazacyclododecane-4,7,10-triacetic acid (nDOTA-Bu-Mal)] and C-functionalized DOTA [2-{4-(maleimido-N-propylacetamido)benzyl}-1,4, 7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (cDOTA-Bnz-Mal) and 2-(4-isothiocyanatobenzyl)- 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (cDOTA-Bnz-NCS)] was compared. N-functionalized lanthanide DOTA complexes coelute as required for their use as ICAT-analogous reagents. The complexation of the C-functionalized DOTA with lanthanides results in two fractions separable by HPLC. Coelution is observed for the main fractions of the lanthanide complexes. The retention times of the minor fractions show a dependence on the ionic radii of the metal ions. MALDI spectra of lanthanide-DOTA-peptide conjugates including different monoisotopic lanthanides demonstrate the advantage of the mass variations for extensive peptide and protein investigations.
Three New Unsaturated Fatty Acids from the Marine Green Alga Ulva fasciata Delile
Authors: Abou-ElWafa Ghada S. E. , Shaaban Mohamed , Shaaban Khaled A. , El-Naggar Mohamed E. E. , Laatsch Hartmut
Published: February 2015

From the dichloromethane extract of the marine green alga Ulva fasciata Delile, collected from the Mediterranean coast of Egypt, three new fatty acids, namely, (E)-11-oxo-octadeca-12-enoic acid (1a), (E)-11-hydroxy-octadeca-12-enoic acid (2a) and 6-hydroxy-oct-7-enoic acid (3a) together with cholesterol were isolated. Analysis of the unpolar part of the extract using GC-MS detected the existence of further ten compounds, namely, dimethylsulfoxide, dimethylsulfone, phenylacetamide, 6,10,14-trimethyl-pentadecan-2-one, 8-heptadecene, dodecane, tridecane, 4-oxo-pentanoic acid, hexadecanoic acid, and the naturally new 1,1ʹ-bicyclohexyl. Structures of the isolated compounds 1a - 3a were confirmed by spectroscopic analyses including mass spectra (EI-MS, HR/ESIMS), 1D and 2D NMR experiments, and by the synthetic conversion into their corresponding methyl esters 1b - 3b. The algal extract and its components were comparatively examined against several pathogenic microorganisms, and brine shrimps for cytotoxicity.
Electronic and Geometric Structure of the Cluster Compound Au55[P(C6H5)3]12Cl6. A Computational Study
Authors: Genest Alexander , Krüger Sven , Rösch Notker
Published: February 2015

Relativistic density functional calculations have been carried out on the model cluster Au55(PH3)12Cl6 assuming a cuboctahedral or an icosahedral Au55 metal core to model the experimentally suggested cluster compound assigned as Au55[P(C6H5)3]12Cl6. Besides the overall shape of the metal core, the study focused on the unresolved issue at which sites the chlorine ligands are attached. The calculations reproduce characteristic interatomic distances within ∼ 2 pm, with the exception of the Au-Cl bonds. Chlorine ligands were calculated to prefer higher coordinated sites whereas the previously postulated on-top coordination at the center of the Au (100) facets of a cuboctahedron was found to be unstable. In fact, the present model results suggest an ensemble of several higher coordinated sites. The often assumed cuboctahedral shape of the metal cluster core was determined to be slightly less stable than an approximately icosahedral shape. The calculations allow a rationalization of the difficulties faced in experiments that attempted to discriminate cluster isomers
An Improved Gas Electron Diffractometer – The Instrument, Data Collection, Reduction and Structure Refinement Procedures
Authors: Berger Raphael J. F. , Hoffmann Manfred , Hayes Stuart A. , Mitzel Norbert W.
Published: February 2015

Graphical Abstract

An Improved Gas Electron Diffractometer – The Instrument, Data Collection, Reduction and Structure Refinement Procedures
,, ... und ehrt mir ihre Kunst!“ – Evaluierung historischer und neuer Synthesewege zu 1,5-Dihydroxy-6-oxo-1,6-dihydropyridin-2-carbonsäure und 1,3-Dihydroxy-2-oxo-3-pyrrolin-4-carbonsäure / “. . . and honour their art!” – Evaluation of Historical and New Routes to 1,5-Dihydroxy-6-oxo-1,6- dihydropyridine-2-carboxylic Acid and 1,3-Dihydroxy-2-oxo-3-pyrroline-4-carboxylic Acid
Authors: Wiedemann Dennis , Grohmann Andreas
Published: February 2015

Graphical Abstract

,, ... und ehrt mir ihre Kunst!“ – Evaluierung historischer und neuer Synthesewege zu 1,5-Dihydroxy-6-oxo-1,6-dihydropyridin-2-carbonsäure und 1,3-Dihydroxy-2-oxo-3-pyrrolin-4-carbonsäure / “. . . and honour their art!” – Evaluation of Historical and New Routes to 1,5-Dihydroxy-6-oxo-1,6- dihydropyridine-2-carboxylic Acid and 1,3-Dihydroxy-2-oxo-3-pyrroline-4-carboxylic Acid
Ethylene-bridged Mesoporous Organosilicas with Hexagonal and Cubic Symmetry
Authors: Liang Yucang , Erichsen Egil Sev. , Hanzlik Marianne , Anwander Reiner
Published: February 2015

A series of ordered periodic mesoporous organosilicas (PMOs) with cubic and hexagonal symmetries were fabricated by using divalent surfactants [CH3(CH2)15NMe2(CH2)3NMe3]2+ 2Br− (C16-3-1) or binary surfactant mixtures [CH3(CH2)15NMe3]+ Br− (C16TABr) and C16-3-1 as structure-directing agents (SDAs) and 1,2-bis(triethoxysilyl)ethane (BTEE) as an organosilica source under various basic conditions. The shape/structure of surfactant, molar ratio of binary surfactant mixtures, and base concentration crucially affect the formation of distinct mesophases. Face-centered cubic Fm3̄̅m mesoporous organosilicas can be obtained by using various concentrations of divalent surfactant C16-3-1 or equimolar mixtures of divalent and monocationic surfactants as SDAs under basic conditions. Cubic Pm3̄̅n or 2D hexagonal p6mm mesophases can be synthesized by changing the molar ratio of the binary surfactant mixtures or the amount of the base NaOH. Use of monocationic C16TABr instead of C16-3-1 as template produced the hexagonal p6mm mesophase exclusively independent of the amount of the surfactant and the base. In addition, use of trimethylbenzene as expander molecule in the aforementioned binary surfactant template system caused a mesophase transformation from cubic Pm3̄̅n to p6mm symmetry. All samples were characterized by powder X-ray diffraction (PXRD) analysis and N2 physisorption. The formation of face-centered cubic Fm¯3m, primary cubic Pm3̄̅n, and hexagonal p6mm PMOs was also confirmed by transmission electron microscopy (TEM), revealing a good long-range ordering with regular arrays.Moreover, variation of the synthesis parameters resulted in a variety of different PMO morphologies, as ascertained by scanning electron microscopy (SEM). FT-IR and solid-state 13C and 29Si NMR spectroscopy further revealed that the organic groups were uniformly incorporated into the framework. The various BET surface areas of the PMOs range from 470 to 780 m2 g−1, while the pore diameters lie within a 26 to 30 °A range, as derived from N2 physisorption
New Organogallium Peroxides
Authors: Uhl Werner , Halvagar Mohammad R. , Bock Henrik R. , Jasper-Peter Beate , Layh Marcus
Published: February 2015

Treatment of (Me3C)2Ga-CH(SiMe3)2 (1) with oxygen gave the oxidation of both quaternary carbon atoms of the tert-butyl groups, while the bis(trimethylsilyl)methyl substituent was not affected. One tert-butyl group was transferred to an alkoxide which in the dimeric formula unit of the product 2 occupies the bridging position between both gallium atoms. The second one afforded a terminally arranged tert-butylperoxo ligand by the insertion of a complete oxygen molecule into the respective Ga-C bond. Another organogallium peroxide (5) was obtained by the reaction of Li(OEt2)[H3GaCH(SiMe3)2] (3) with H-O-O-CMe2OMe (4). Two hydrido ligands of the trihydridogallanate were replaced by peroxo groups, while the third Ga-H bond gave a hydroxide (Ga-OH) by insertion of a single oxygen atom. The product, Li[Ga(OH)(OOCMe2OMe)2R] [5, R=CH(SiMe3)2], forms a singular dimeric formula unit with a complicated oligocyclic structure in which all peroxo groups are in bridging positions between lithium and gallium atoms
Solid-state and Solution Studies on a β-Diketiminate Zinc Hydride Complex
Authors: Schulz Stephan , Eisenmann Tamara , Schuchmann Daniella , Bolte Michael , Kirchner Michael , Boese Roland , Spielmann Jan , Harder Sjoerd
Published: February 2015

[MesnacnacZn(μ-H)]2 (1) was synthesized by reaction of MesnacnacZnI with either an equimolar amount of KNH(iPr)BH3 or an excess of NaH and characterized by multinuclear NMR and IR spectroscopy as well as X-ray diffraction. Two polymorphs of 1 were found and their structures determined on single crystals
Hexaphosphaferrocene [Fe(η5-P3C2tBu2)2] as a Connecting Moiety in Oligomeric and Polymeric Compounds
Authors: Schindler Andrea , Zabel Manfred , Nixon John F. , Scheer Manfred
Published: February 2015

The hexaphosphaferrocene complex [Fe(η5-P3C2tBu2)2] (1) derived from the corresponding 1,2,4-triphosphospholyl anion reacts with CuX (X = Cl, Br, I) in a 1 : 1 stoichiometry to give the isostructural, one-dimensional polymeric compounds [{Cu(μ3-X)}4{Fe(μ,η5:η1-P3C2tBu2)2}2]n (X = Cl (2), Br (3), I (4)), which display a unique sinusoidal (CuX)n ladder structure. In the reaction with CuI a second one-dimensional polymeric compound [{Cu3(μ-I)(μ3-I)2}(CH3CN){Fe(μ,η5:η1- P3C2tBu2)(μ3,η5:η1-P3C2tBu2)}]n (5) is formed. The reaction of 1 with CuX (X= Cl, Br, I) in a 1 : 2 stoichiometric ratio leads only in the case of CuCl to the formation of the new, oligomeric compound [{Cu(μ3-Cl)}4(CH3CN)2{Fe(μ,η5:η1-P3C2tBu2)2}2] (6), whereas in the case of CuBr and CuI the polymeric compounds 3 and 5 were isolated. The reaction of 1 with Ag[Al{OC(CF3)3}4] in a 1:1 stoichiometric ratio results in the formation of [Ag{Fe(μ,η5:η1-P3C2tBu2)2}2][Al{OC(CF3)3}4] (7), which shows dynamic behaviour in solution
Construction of Luminescent Gold(I) Aryl Thiolates via Isonitrilegold(I) Complexes: Influence of Synthetic Methodology and the Thiolate Ligand on Structure and Properties
Authors: Bachman Robert E. , . Bodolosky-Bettis Sheri A.
Published: February 2015

Gold thiolate polymers ([ArSAu]n) were prepared via two synthetic routes - the direct reaction of an aromatic thiolate (ArSH) with HAuCl4, or the reaction of an isonitrilegold(I) chloride complex with a thiolate anion. The former route, which is general to almost all thiols, yields an amorphous and non-luminescent material. The latter route, which is more limited in scope, proceeds via an isonitrilegold( I) thiolate complex and typically yields a crystalline and luminescent material. Addition of electron-donating groups to the thiol aromatic ring leads to more rapid polymer formation and loss of luminescence while addition of electron-withdrawing groups slows or stops polymer formation and leads to a red-shift of the luminescence of the final polymeric materials. Two isonitrilegold(I) thiolate complexes with varying numbers of fluorine substituents on the thiolate aromatic ring were characterized crystallographically - C8H17NCAu(p-FC6H4S) and C12H25NCAu(2,4-F2C6H3S). As the fluorination of the aromatic ring increases, no significant changes were observed in the bond lengths of the complexes; however, the intermolecular Au-S distances lengthen while the aurophilic interaction distances decrease. These results suggest clear relationships between the molecular structure and both the supramolecular structure and photophysical properties in these materials
Cleavage of an Iron-Silicon Bond by Hexamethylphosphoric Triamide: Synthesis and Characterization of [SiCl3(HMPA)3]+[Fe(CO)4SiCl3]–
Authors: Du Van An , Baumann Stefan O. , Stipicic Gregor N. , Schubert Ulrich
Published: February 2015

Addition of excess hexamethylphosphoric triamide (HMPA) to cis-Fe(CO)4(SiCl3)2 led to the exclusive formation of the new complex [SiCl3(HMPA)3]+ [Fe(CO)4SiCl3]− by cleavage of an ironsilicon bond. A reaction mechanism is presented, based on density functional theory calculations
Molecular Structure and UV Absorption Spectra of OH and NH2 Derivatives of Dodecamethylcyclohexasilane: A Combined Experimental and Computational Study
Authors: Stueger Harald , Fuerpass Gottfried , Baumgartner Judith , Mitterfellner Thomas , Flock Michaela
Published: February 2015

The monofunctionalized cyclohexasilanes XSi6Me11 [X = -OH (2); -NH2 (3)] are easily accessible from XSi6Me11 and H2O/Et3N or NH3, respectively. The crystal structure of 2 as determined by single crystal X-ray crystallography exhibits the cyclohexasilane ring in chair conformation with the OH group in an unusual equatorial position due to intermolecular hydrogen bonding. Full geometry optimization (B3LYP/6-31+G∗) of the gas-phase structures of 2 and 3 affords six minima on the potential energy surface for chair, twist and boat conformers with the heterosubstituents either in axial or equatorial positions all being very close in energy. According to time-dependent DFT B3LYP/TZVP calculations contributions of several conformers to the observed solution UV absorption spectra of dodecamethylcyclohexasilane (1), 2 and 3 need to be considered in order to achieve satisfactory agreement of calculated and experimental data
Stereoselective Synthesis of Bromopiperidinones and their Conversion to Annulated Heterocycles
Authors: Knauer Stefan , Weymann Markus , Kunz Horst
Published: February 2015

N-Galactopyranosyl- and N-glucopyranosyl imines of aliphatic, aromatic and heteroaromatic aldehydes react with 1-methoxy-3-trimethylsilyloxy-1,3-butadiene in a domino Mannich-Michael reaction cascade to give 2-substituted 5,6-dehydro-piperidin-4-ones with high diastereoselectivity. Treatment of these cyclic enaminones with N-bromo-succinimide yields the corresponding 2-substituted 5-bromo-5,6-dehydropiperidinones which react with L-SelectrideⓇ or methylcuprate to afford the saturated bromo-piperidinones with high diastereoselectivity. Condensation reactions of these products with thioamides afford thiazolopiperidines
Sc2(MoO4)3 and Sc2(WO4)3: Halide Flux Growth of Single Crystals and 45Sc Solid-state NMR
Authors: Balamurugan Sarkarainadar , Rodewald Ute Ch. , Harmening Thomas , van Wüllen Leo , Mohr Daniel , Eckert Hellmut , Pöttgen Rainer
Published: February 2015

Single crystals of Sc2(TO4)3 with T = Mo and W were synthesized from Sc2O3, MoO3, and WO3 at 1223 K in NaCl / KCl as solvent. Both structures were refined from X-ray diffractometer data: Pbcn, a = 1325.1(1), b = 954.9(1), c = 964.4(1) pm, wR2 = 0.0425, 2097 F2, 79 variables for Sc2(MoO4)3 and a = 1332.9(9), b = 959.4(7), c = 967.9(2) pm, wR2 = 0.0384, 1971 F2, 79 variables for Sc2(WO4)3. The structures consist of a three-dimensional network of corner-sharing ScO6/2 octahedra and two crystallographically independent TO4/2 tetrahedra. 45Sc MAS NMR spectra show sharp single resonances in accordance with the crystallographic data. The quadrupolar interaction parameters obtained from a simulation of the full 45Sc MAS NMR spectra are found to be in good agreement with those obtained from DFT calculations of the electric field gradient
Effect of the Analytic Regions on the Quality Trend of Diamond-like/Graphitic Carbon Ratios in Raman Spectra
Authors: Shen Ai-Lin , Weng Yu-Ching , Chou Tse-Chuan
Published: February 2015

Raman spectroscopy is a useful and non-destructive tool for the structural characterization of diamond-like carbon (DLC) films. Even though Raman spectroscopy is not a quantitative technique, the area integral intensity ratio of D and G peaks (ID/IG) derived by the fitting of separate Gaussian curves usually serves as an indicator of the quality trend of diamond-like material. However, conflicting reports still exist on the diamond-like films analyzed by the fitting method of Raman spectra. In this work we show that the quality trend of the diamond-like/graphitic carbon ratio is critically dependent upon the boundary conditions of the analytic regions. We also examine the possibility of directly applying the peak height ratio HD/HG as an alternative method to analyze Raman spectra. The method based on peak height ratios (HD/HG), and an established method using ID/IG ratios can give similar results depending on the choice, in the latter method, of the boundary conditions used for integration. However, the method based on the determination of peak heights avoids the arbitrary assignment of integral boundary conditions while additionally generating a data set that shows statistically smaller standard deviations than the commonly used integration method
151Eu Mössbauer Spectroscopic Characterization of EuRu4B4 and the New Boride EuRuB4
Authors: Harmening Thomas , Pöttgen Rainer
Published: February 2015

Samples of EuRu4B4 and of the new boride EuRuB4 were prepared from europium, RuB, and RuB4 precursor alloys, respectively, in sealed tantalum tubes in an induction furnace. EuRu4B4 crystallizes with the LuRu4B4 structure, a = 748.1(1), c = 1502.3(4) pm. The structure of EuRuB4 was refined on the basis of X-ray diffractometer data: Pbam, a = 599.7(1), b = 1160.7(3), c = 358.06(7) pm, wR2 = 0.0691, 474 F2 values, and 38 variables. The four crystallographically independent boron sites build up layers which consist of almost regular pentagons and heptagons which sandwich the ruthenium and europium atoms, respectively. Within the two-dimensional [B4] networks each boron atom has a slightly distorted trigonal-planar boron coordination with B-B distances in the range 172 - 186 pm. Temperature-dependent 151Eu Mössbauer spectra show stable trivalent europium for EuRu4B4 and EuRuB4
TaRhGe with TiNiSi-type Structure
Authors: Dinges Tim , Eul Matthias , Pöttgen Rainer
Published: February 2015

The new germanide TaRhGe was prepared from the elements by arc-melting and subsequent annealing at 1020 K for 10 days. TaRhGe crystallizes with the TiNiSi-type structure, space group Pnma, Z = 4, oP12, a = 640.2(2), b = 383.2(2), c = 741.7(2) pm, wR2 = 0.0550, 432 F2 values, 20 parameters. The structure consists of a three-dimensional [RhGe] network of distorted RhGe4/4 tetrahedra with Rh-Ge distances ranging from 244 to 250 pm. The tantalum atoms are coordinated within this network by two folded and mutually tilted Rh3Ge3 hexagons. TaRhGe is Pauli-paramagnetic and shows no superconducting transition down to 3 K
Self-assembly of a Novel Three-dimensional Silver(I) Supramolecular Framework from Cationic Chains and Anionic Sheets
Authors: Sun Di , Yang Cheng-Feng , Wei Zhan-Hua , Luo Geng-Geng , Zhang Na , Xu Qin-Juan , Huang Rong-Bin , Zheng Lan-Sun
Published: February 2015

A new three-dimensional (3D) supramolecular framework, [Ag2(bipy)2(bdc)·4H2O]n 1, has been synthesized by the ultrasonic reaction of Ag2O, bipy and H2bdc (H2bdc = 1,4-benzenedicarboxylic acid; bipy = 4,4’-bipyridine) at room temperature. It exhibits a new 3D supramolecular framework which is built from cationic Ag-bipy chains and anionic bdc-H2O sheets through hydrogen bonds, π · · ·π stacking and C-H· · ·π interactions. Additionally, the photoluminescent and thermal properties of 1 were investigated.
High-Pressure Study of Oxo-bridged Mixed-Valent MnIII/MnIV Dimers High-Pressure Study of Oxo-bridged Mixed-Valent MnIII/MnIV Dimers
Authors: Prescimone Alessandro , Sanchez-Benitez Javier , Kamenev Konstantin V. , Warren John E. , Lennie Alistair R. , Murrie Mark , Parsons Simon , Brechin Euan K.
Published: February 2015

A combination of high-pressure single crystal X-ray diffraction and high-pressure SQUID magnetometry has been used to study two oxo-bridged mixed-valent MnIII/MnIV dimers. [Mn2O2(bpy)4](ClO4)3·3CH3CN, (1·3CH3CN; bpy = 2,2ʹ-bipyridine) has been compressed to 2.0 GPa whilst [Mn2O2(bpy)4](PF6)3·2CH3CN·1H2O, (2·2CH3CN·1H2O) could be measured crystallographically up to 4.55 GPa. The PF6 salt of [Mn2O2(bpy)4]3+ has never been reported before while 1 has been reported as a hydrate and in a different crystallographic space group. The application of hydrostatic pressure imposes significant distortions and modifications in the structures of both complexes. In particular, in complex 1·3CH3CN the Mn-Mn separation is reduced by the contraction of some of the Mn-O bond lengths, whilst in 2·2CH3CN·1H2O the Mn-O-Mn bridging angles and the Mn-O bond lengths are substantially unchanged. Interestingly 2·2CH3CN·1H2O also shows a constant contraction in nearly all the Mn-N bonds. The magnetic behaviour of the complexes has been measured up to 0.87 GPa for 1·3CH3CN and 0.84 GPa for 2·2CH3CN·1H2O.
Disruption of the La(III)[15-Metallacrown-5] Cavity through Bithiophene Dicarboxylate Inclusion
Authors: Jankolovits Joseph , Lim Choong-Sun , Kampf Jeff W. , Pecoraro Vincent L.
Published: February 2015

The inclusion of bithiophenedicarboxylate (btDC) in La(III)[15-MCCu,N,L-phenylalaninehydroximate-5] hosts (LaMC) unexpectedly results in a clathratocomplex with a completely disrupted hydrophobic cavity. Structures best formulated as {(LaMC)2(μ2-O)} are formed that dimerize across the hydrophilic parts. This dimer appears stabilized by 5 phenyl-DMF-phenyl interactions and 10 DMFamine hydrogen bonds. Electrospray ionization mass spectrometry reveals the presence of 2 : 2 LaMC-btDC complexes in solution. In the solid state, both cis- and trans-bithiophene dicarboxylate guests bridge the > 17 Å distance between LaMC hydrophobic faces. The resulting solid has over 50% void space, suggesting guest-length and solvent considerations can predictably lead to the formation of open LaMC coordination frameworks or close-packed molecular compartments.
A Promising New Schiff Base-like Ligand for the Synthesis of Octahedral Iron(II) Spin Crossover Complexes
Authors: Bauer Wolfgang , Ossiander Tanja , Weber Birgit
Published: February 2015

A new tetradentate Schiff base-like ligand H2L (1) ((E,E)-dimethyl-2,2´-[1,2-phenylenebis(aminomethylidyne)] bis[3-oxobutanoate]) was synthesised and structurally characterised. Its reaction with iron(II) acetate leads to the formation of the octahedral N2O4-coordinated complex [FeL(MeOH)2] (2). The complex is a pure high-spin (HS) compound as is evident from magnetic measurements and X-ray crystallography.
Catalysis of the Quadricyclane to Norbornadiene Rearrangement by SnCl2 and CuSO4
Authors: Shubina Tatyana E , Clark Timothy
Published: February 2015

Ab initio and density-functional theory (DFT) calculations have been used to investigate the model rearrangements of quadricyclane to norbornadiene catalysed by single CuSO4 and SnCl2 molecules. The isolated reactions with the two molecular catalysts proceed via electron-transfer catalysis in which the hydrocarbon is oxidised, in contrast to systems investigated previously in which the substrate was reduced. The even-electron SnCl2-catalysed reaction shows singlet-triplet two-state reactivity. Solvation by a single methanol molecule changes the mechanism of the rearrangement to a classical Lewis acid-base process.