bluuebunny/crossref_metadata_2025 huggingface dataset:
NMR Spectroscopic Studies on Complex Formation between Dimeric (R)-3-Hydroxybutanoic Acid and β-Cyclodextrin
Authors: Li Jun , Uzawa Jun , Doi Yoshiharu
Published: June 2006

Dimeric (R)-3-hydroxybutanoic acid (3HB) was found to form an inclusion complex selectively with β-cyclodextrin (β-CD) in aqueous solution. The complex formation was confirmed by the changes of 1H and 13C NMR spectra of both dimeric 3HB and β-CD in D2O solution. The continuous variation experiments showed the formation of a 1 : 1 inclusion complex. The dissociation constants at various temperatures between 15 and 47 °C were determined and the thermodynamic analysis of the complex formation was performed. The results indicated that the complex formation is enthalpically favorable but entropically unfavorable. We propose that the 3HB unit with carboxy end-group is located in the narrow side of the β-CD cavity.
Rearrangements of Tricyclo[5.3.1.01,7]undecatrienide Anion: Circumambulation and Cleavage of the Cyclopropane Ring
Authors: Oda Mitsunori , Masaki Yoshimi , Okazaki Yoshimi , Kajioka Takanori , Morita Yasufumi , Miyatake Ryuta , Kuroda Shigeyasu
Published: June 2006

Reaction of tricyclo[5.3.1.01,7]undeca-2,4,9-triene with butyllithium in tetrahydrofuran-hexamethylphosphoric triamide at −78 °C and subsequent quenching of the resulted dark red reaction mixture with water or methanol gave tricyclo[6.3.0.01,3]undeca-5,7,9-triene (4) as the sole isolable product. It was also found that quenching of the anion solution with deuterium oxide under the same conditions caused stereoselective incorporation of deuterium atom. On the other hand, quenching of the anion solution with water after it was warmed to 0 °C gave a mixture of dihydromethylazulenes. The cycloadduct of the rearranged hydrocarbon 4 with 4-phenyl-3H-1,2,4-triazoline-3,5(4H)-dione was obtained and its structure was confirmed by X-ray crystallographic analysis. A driving force of the circumambulation was thought to be the creation of conjugation between the cycloheptadienide part and the five-membered ring olefin in the product on the basis of the facts that a circumambulatory rearrangement in the opposite direction, which would lead to a different product via a less conjugated tricyclic anion, was not observed, and that the anion generated from tricyclo[5.3.1.01,7]undeca-2,4-diene was reluctant to undergo the rearrangement.
Novel Disaccharide Chiral Ligands Derived from α,α-Trehalose and Their Applications to Asymmetric Hydrogenation of Enamides
Authors: Yonehara Koji , Hashizume Tomohiro , Ohe Kouichi , Uemura Sakae
Published: June 2006

New chiral diphosphinite ligands such as 4,6 : 2′,3′ : 4′,6′-tri-O-cyclohexylidene-2,3-di-O-diphenylphosphino-α,α-trehalose (1), 3,3′-di-O-benzyl-4,6 : 4′,6′-di-O-benzylidene-2,2′-di-O-diphenylphosphino-α,α-trehalose (2), 4,6 : 4′,6′-di-O-benzylidene-2,2′-di-O-diphenylphosphino-3,3′-di-O-methyl-α,α-trehalose (3), and 2,2′-di-O-benzyl-4,6 : 4′,6′-di-O-benzylidene-3,3′-di-O-diphenylphosphino-α,α-trehalose (4) were prepared from α,α-trehalose which is an inexpensive natural reserve sugar. These ligands work as chiral ligands for Rh-catalyzed hydrogenation of α-acetamidoacrylic and cinnamic acid derivatives to afford both enantiomers of amino acids up to 84%ee (S) and 72%ee (R).
Solitons, Polarons, and Excitons in Quasi-One-Dimensional Halogen-Bridged Transition Metal Compounds
Authors: Okamoto Hiroshi , Yamashita Masahiro
Published: June 2006

We report the photogeneration of solitons and polarons in the quasi-one-dimensional (1-D) halogen (X)-bridged metal (M) compounds (simply abbreviated as the MX chain compounds). The most significant feature of this system is the remarkable tunability of the charge density wave (CDW) ground states. By substituting the metals (M = Pt, Pd, and Ni), the bridging halogens (X = Cl, Br, and I), the ligand molecules and the counter anions surrounding the 1-D chains, the amplitude of CDW, the optical gap energy, and the degeneracy of CDW can be widely controlled. On the basis of these controls, we have investigated the nature of photoexcited states. By comparing the results of photoinduced absorption (PA), ESR and photoinduced ESR measurements in the degenerate CDW states with those in the non-degenerate CDW states, we clearly characterized the photoinduced gap states as solitons and polarons. In the compounds having relatively large optical gap energies (ECT), spin-solitons and polarons are photogenerated. From a comparison of the excitation profiles of the PA signals with those of the luminescence of the self-trapped exciton (STE), it was demonstrated that the luminescence process strongly competes with the dissociation to spin–soliton pairs. An analysis of the temperature dependence of the luminescence decay time revealed that the conversion from an STE to a solitonic state occurs through a finite potential barrier, the magnitude of which depends on degeneracy of CDW. With decrease of ECT, the nature of the photoexcited states changes considerably; photogenerations of charged-solitons are observed instead of spin–solitons and the STE luminescence is remarkably quenched. While referring to the theoretical expectations based upon the Peierls–Hubbard model, we will discuss the overall view of the relaxation process of the photoexcited states related to solitons, polarons, and excitons in the MX compounds.
Theoretical Study of the Potential Energy Curves for the Ca–Ar and Sr–Ar Systems
Authors: Zhu Rong-Shun , Han Ke-Li , Huang Jian-Hua , Zhan Ji-Ping , He Guo-Zhong
Published: June 2006

The X1Σ ground state and the low-lying 1,3Σ, 1,3Π excited states of the Ca–Ar and Sr–Ar systems have been studied using pseudopotentials at MCSCF(CASSCF)-SDCI level. The results indicate that the 1,3Σ excited states are essentially repulsive, but the X1Σ ground state and the 1,3Π excited states have shallow potential minima at large equilibrium distance (Re) values. Spectroscopic constants of the X1Σ ground state and the 1,3Π excited states have been calculated and compared to those obtained by experiment.
Viscometric Behavior of Some Symmetrical Tetraalkylammonium Bromides in Acetonitrile + Water Mixtures at 303.15 K
Authors: Nikam Pandharinath S , Sawant Arun B
Published: June 2006

The viscosity measurements for some symmetrical tetraalkyl ammonium bromide (R4NBr, R = CH3 to C5H11) KCl, and KBr solutions in acetonitrile (ACN) + water mixtures containing 0, 10, 30, 50, 70, 90, and 100 mass% of ACN at 303.15 K have been performed. The Jones–Dole equation was used for the analysis of viscosity data of these salts. The viscosity B-coefficients in the entire range of ACN+water mixtures were obtained from the computerized least-squares method. The experimental criterion B(K+) = B(Cl−) = (1/2)B(KCl) was applied in order to obtain the ionic B-coefficients. The B± coefficients are interpreted in terms of solvent structure and ion-solvent interactions in the solvents.
Heat Treatment of Hydrogen Molybdenum Bronze in an Oxygen-Free Atmosphere. Formation of a Defect Structure and Attempt to Carry Out a Catalytic Reaction
Authors: Nakamura Kentaro , Eda Kazuo , Sotani Noriyuki
Published: June 2006

Hydrogen molybdenum bronze, HxMoO3 (x = 0.25), was treated in vacuo, which was changed by four steps to form MoO3 and MoO2 through the Type-I and the MoO3-like structure with defects, such as an oxygen vacancy. The structural changes were studied by TG-DTA, XRD, ESR, and XANES. Type-I with a defect structure was effective for the isomerization of 1-butene.
Second-Order Perturbational Effect on the Interlayer Interactions in Graphite and Graphite Intercalation Compounds
Authors: Yoshizawa Kazunari , Kato Takashi , Yamabe Tokio
Published: June 2006

The role of second-order perturbations in interlayer interactions of two-dimensional electronic systems is examined from simple two-layer models. The preferred nuclear motions are discussed specifically for the preferred stacking of layers in graphite on the basis of transition-density analyses for extended systems. The well-known ABAB stacking of layers in neutral graphite and the AAAA stacking of layers in graphite intercalation compounds (GICs) such as C6Li and C8K complexes are proposed to be consequences of orbital interactions (near the Fermi level) between nearest neighbor layers. This paper raises doubts about a widely accepted belief that the interlayer interaction between graphite layers is of the van der Waals type.
X-Ray Analyses of Complexes Formed between Surfactants and Aromatic Compounds. I. A Common Structural Pattern of the Complexes
Authors: Sawada Keiju , Kitamura Tatsuo , Ohashi Yuji , Iimura Nahoko , Hirata Hirotaka
Published: June 2006

The cationic surfactants such as hexadecyl-, tetradecyl-, dodecyl-, and decyltrimethylammonium bromides form complexes with a variety of aromatic compounds in aqueous solutions. Well-defined crystals were obtained if the aromatic compounds had hydrogen donor moieties. The structures of ten kinds of the complex crystals were analyzed by X-rays. All the crystal structures had a common pattern of complex formation, in which the aromatic compounds are sandwiched by the two alkyl chains of the surfactant molecules. There are two modes of stacking when the complexes with the common pattern are piled up to form the crystalline lattice. The common pattern of complex formation is responsible for the high viscoelasticity of the aqueous solutions containing cationic surfactants and aromatic compounds.
Extraction and Stripping of Copper(I) as a Neocuproine Complex in a Surfactant System and Determination of Copper in Steel
Authors: Tagashira Shoji , Murakami Yoshiko , Yano Mituya , Sasaki Yoshiaki
Published: June 2006

An aqueous solution containing surfactants exhibits the property of being separated into two phases due to a temperature change or an addition of salts. The extraction and stripping of copper(I) as a neocuproine complex were investigated between the anionic surfactant of sodium dodecylsulfate (SDS) and aqueous phases. When the surfactant was separated by the addition of NaCl, the copper complex was extracted into the SDS phase. The stripping of copper(I) into the aqueous phase was maintained by phase separation, which was achieved by cooling the solution. Since neocuproine is a highly specific chromogen for copper(I), iron(II) could not form a complex with neocuproine, and was scarcely extracted into the SDS phase. This selective extraction was applied to the separation of copper from iron and the determination of copper in steel samples by a spectrophotometric method and/or an atomic-absorption spectrometric method (AAS).
Synthesis and Structural Characterization of Thiolato-Bridged Zinc(II) Complexes with NNS-Tridentate Thiolic Ligands
Authors: Mikuriya Masahiro , Jian Xiao , Ikemi Shin-ichiro , Kawahashi Takako , Tsutsumi Hideyuki
Published: June 2006

Zinc(II) complexes with 2-[(2-aminoethyl)amino]ethanethiol (HL1), 2-[(3-aminopropyl)amino]ethanethiol (HL2), 2-[(2-pyridylmethyl)amino]ethanethiol (HL3), and 2-{[2-(2-pyridyl)ethyl]amino}ethanethiol (HL4), [Zn(L1)](ClO4) (1), [Zn{Zn(L1)2}2](ClO4)2 (2), [Zn(L2)](ClO4) (3), [Zn{Zn(L3)2}2](ClO4)2 (4), and [Zn3(L4)3](ClO4)3 (5), have been synthesized and characterized by measurements of the infrared and electronic spectra. The molecular structures of these complexes were determined by the single-crystal X-ray structure analysis. Complex 1 has a thiolato-bridged polymeric chain structure, in which each metal atom is essentially four-coordinated in a distorted tetrahedron. Complexes 2 and 4 have a thiolato-bridged trinuclear complex with a linear arrangement of three metal atoms. Complex 5 is a thiolato-bridged trinuclear complex displaying a six-membered ring of Zn3S3.
Experimental and Theoretical Studies of the Possible and Preferred Site of Protonation in Polyfunctional N1,N1-Dimethyl-N2-benzoylformamidine in the Gas Phase
Authors: Raczynska Ewa D , Mishima Masaaki , Mustanir
Published: June 2006

Proton-transfer reactions for N1,N1-dimethyl-N2-benzoylformamidine containing three basic sites, the carbonyl-O, imino-N, and amino-N atoms, have been studied by experimental (FT-ICR) and theoretical (ab initio) methods. The ICR study gave a GB of 225.5 kcal mol−1 for this compound. The empirical structure-basicity relationships predicted GB values of 224.8 and 212.8 kcal mol−1 for protonation at the imino-N and carbonyl-O atoms, respectively. The observed GB values is close to the value for the imino-N atom. Theoretical calculations (B3LYP/6-311+G(2d,p)//HF/6-31G(d)) also showed that protonation at the imino-N atom is preferred by 7 kcal mol−1 compared to protonation at the carbonyl-O atom.
Conformational Effect (Induced-Fit) on Catalytic Activity of α-Chymotrypsin
Authors: Kawai Yasushi , Matsuo Takashi , Ohno Atsuyoshi
Published: June 2006

The kinetics for the hydrolyses of p-nitrophenyl esters of acetic acid and certain amino acid derivatives mediated by α-chymotrypsin have been studied. The kinetics are a function of the medium viscosity, which indicate that the enzyme must change its conformation during the reaction. Detailed analysis of the dependence of kinetic rate constants on the medium viscosity has revealed that (1) the reaction is associated with the induced-fit conformational adjustment of the enzyme: When the enzyme-substrate (ES) complex is converted into the corresponding acyl enzyme, the conformation of the enzyme is changed in order to accommodate the acyl group in the pocket of the enzyme at an appropriate position. (2) The conformationally distorted α-chymotrypsin recovers its conformation when it releases the acid part of the substrate ester. (3) The formation of an ES complex is independent of any induced-fit movement. The induced-fit conformational adjustment of the enzyme plays a crucial role in its catalytic activity.
Single-Stranded DNA Recognition of a 24-mer Peptide Derived from RecA Protein
Authors: Nakano Shu-ichi , Sugimoto Naoki
Published: June 2006

A 24-mer peptide with L2 and helix G amino acids of E. coli RecA protein (Ac–Ile–Arg–Met–Lys–Ile–Gly–Val–Met–Phe–Gly–Asn–Pro–Glu–Thr–Thr–Thr–Gly–Gly–Asn–Ala–Leu–Lys–Phe–Tyr–NH2) showed a single-stranded DNA (ssDNA) binding property with a more than 1000 times affinity difference than for a double-stranded DNA. However, a truncated 15-mer peptide (sequence) showed no ssDNA binding activity. In the ssDNA binding, the 24-mer peptide changed its conformation with the perturbation of an α-helix structure. The ssDNA binding and the DNA discrimination property of this peptide were due to almost all L2 and helix G amino acids, respectively. This result useful to design synthetic peptides as functional materials for DNA recognition.
Reaction of Benzanthrone (7H-Benz[d,e]anthracen-7-one) with Nitrogen Dioxide Alone or in Admixture with Ozone. Implications for the Atmospheric Formation of Genotoxic 3-Nitrobenzanthrone
Authors: Enya Takeji , Suzuki Hitomi , Hisamatsu Yoshiharu
Published: June 2006

The reaction of benzanthrone (7H-benz[d,e]anthracen-7-one, 1) with nitrogen dioxide alone or in admixture with ozonized oxygen has been investigated in polar and nonpolar organic solvents at different temperatures. A remarkable change of product distribution was observed depending on the solvent employed; 3-nitrobenzanthrone (4) was the main product from the reaction in dichloromethane, while 2-nitrobenzanthrone was obtained as the major product in tetrachloromethane. Addition of protonic acid or inorganic solid support was found to promote the reaction, favoring the formation of the former nitro compound at the expense of the latter. All major products were identified. The variation of isomer distribution depending on the conditions employed has been discussed in terms of the competition between the homolytic and heterolytic mechanisms involved in the nitration of ketone 1. On the basis of the results obtained, the atmospheric formation of the genotoxic nitro ketone 4 has been briefly discussed.
Synthesis and Properties of Europium Complexes with β-Diketone Ligands for Organic Electroluminescent Devices
Authors: Uekawa Masahiro , Miyamoto Yasuo , Ikeda Hitoshi , Kaifu Katsuaki , Nakaya Tadao
Published: June 2006

Europium complexes with new β-diketone ligands with fluorene for organic electroluminescent (EL) devices have been synthesized and their properties examined. The absorption spectra of the complexes were varied by changing the conjugated system of the β-diketone; also, the energy transfer from the host material to the europium complexes and the intramolecular energy transfer have been improved. Concerning the volatility, the thermal properties of the europium complexes were improved by using phenanthroline derivatives. We fabricated organic EL devices using the synthesized complexes, and investigated the luminance of the devices.
Thermodynamic Study on Dioxygen Binding of Diiron(II) and Dicobalt(II) Complexes Containing Various Dinucleating Ligands
Authors: Sugimoto Hideki , Nagayama Toshihiko , Maruyama Sachihito , Fujinami Shuhei , Yasuda Yuichi , Suzuki Masatatsu , Uehara Akira
Published: June 2006

A new dinucleating ligand containing a sterically bulky imidazolyl group, Ph-Htidp (N,N,N′,N′-tetrakis[(1-methyl-4,5-diphenyl-2-imidazolyl)methyl]-1,3-diamino-2-propanol), and its μ-alkoxo-diiron(II) complexes [Fe2(Ph-tidp)(RCO2)](ClO4)2, (RCO2 = C6H5CO2 (1), C6F5CO2 (2), CF3CO2 (3), and C2H5CO2 (4)), were synthesized. The structure of complex 1 was determined by X-ray crystallography. Complex 1 crystallizes in the monoclinic space group P21/c with a = 13.464(2), b = 19.223(4), c = 31.358(4) Å, β = 92.84(2)°, and Z = 4. The complex has a doubly-bridged structure with μ-alkoxo of Ph-tidp and μ-benzoate; the two iron centers have a distorted five-coordinate structure with N3O2 donor set. All the complexes showed fairly good reversible oxygenation below −30 °C in CH2Cl2, which was monitored by UV-vis and NMR spectroscopies, and dioxygen up-take measurements. Introduction of 4,5-diphenyl substituents into 2-imidazolyl group stabilized the μ-peroxo diiron species against irreversible oxidation, just as introduction of 6-methyl substituent into 2-pyridyl group did. Phenyl substituents appear to weaken the electron donor ability of a dinucleating ligand to stabilize divalent oxidation state of iron and to form a hydrophobic cavity for a O2 binding site, which would suppress the irreversible oxidation and facilitate the reversible oxygenation. Dioxygen affinities of the Ph-tidp and Me4-tpdp diiron(II), and the tpdp and bpmp dicobalt(II) complexes were measured, [Fe2(Me4-tpdp)(RCO2)]2+ (RCO2 = C6H5CO2 and RCO2 = CF3CO2) and [Co2(L)(RCO2)]2+ (L = tpdp, RCO2 = CH3CO2, and L = bpmp, RCO2 = C6F5CO2, and CF3CO2), where Me4-tpdp, tpdp, and bpmp are N,N,N′,N′-tetrakis[(6-methyl-2-pyridyl)methyl]-1,3-diamino-2-propanolate, N,N,N′,N′-tetrakis(2-pyridylmethyl)-1,3-diamino-2-propanolate, and 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenolate, respectively. Within a series of the Ph-tidp diiron(II) complexes, dioxygen affinity is well correlated with electron donor ability of bridging carboxylates (1 (C6H5CO2) > 2 (C6F5CO2) > 3 (CF3CO2)). In contrast to the above trend, dioxygen affinities of the Ph-tidp complexes are lower than those of the Me4-tpdp complexes, although electron donor abilities of the Me4-tpdp complexes are weaker than those of the Ph-tidp complexes. Significant enhancement of dioxygen affinity was observed for both iron and cobalt complexes with 2,6-bis(aminomethyl)phenolate bridging skeleton compared to the complexes with a 1,3-diamino-2-propanolate bridging one. Thermodynamic study suggested that the observed enhancement is mainly attributable to a favorable entropy effect along with a steric effect.
Cooperative Ligand Binding to Globular Protein(I). Binding of Monoanionic Azo Dyes to Hen Egg White Lysozyme
Authors: Murakami Kiyofumi
Published: June 2006

Binding of sodium 4-(2- or 4-hydroxy-1-naphthylazo)benzenesulfonate and sodium 4-[4-(amino or dialkylamino)phenylazo]benzenesulfonate (alkyl: methyl, ethyl, or butyl) to hen egg white lysozyme has been studied by an equilibrium dialysis method at pH = 7.0 (0.1 mol dm−3 phosphate buffer) and 25 °C. In the case of the (2- or 4-hydroxy-1-naphthylazo)benzenesulfonate system, a single cooperative binding stage has been observed with a maximum binding number of 10. In the case of the 4-[4-(dialkylamino)phenylazo]benzenesulfonate systems, two cooperative binding stages have been observed for the dyes having alkyl groups longer than a methyl group. The maximum binding numbers of the first stage are 14 and 13 for 4-[4-(diethylamino)phenylazo]benzenesulfonate and 4-[4-(dibutylamino)phenylazo]benzenesulfonate, respectively, and those of the second stage were the same as those for the first one. The binding isotherms have been well interpreted by the stepwise binding model, which takes account of the free energy decrease due to interactions between bound ligands and of its reduction as the binding step proceeds, and binding constants have been evaluated. On the basis of the binding constants and the free energy changes of binding, the detailed binding mechanism is discussed.
Molecular Recognition in Ternary Complexes of γ-Cyclodextrin with Naphthalenedicarboxylate Ions and a Space-Regulator Ion
Authors: Tan Wei Hua , Ishikura Takahiro , Maruta Aya , Yamamoto Tatsuyuki , Matsui Yoshihisa
Published: June 2006

Complexation of γ-cyclodextrin (γ-CD) with the 2,6-naphthalenedicarboxylate ion (2,6-NDC) in alkaline D2O was greatly enhanced by the addition of 2,6-bis(1-pyridiniomethyl)naphthalene dibromide (2,6-PMN) as a space-regulator. Formation of a ternary 1 : 1 : 1 complex between γ-CD, 2,6-NDC, and 2,6-PMN was confirmed by means of 1H NMR spectroscopy, together with the measurements of induced circular dichroism spectra and UV absorption spectra. Changes in chemical shifts (δ) of the γ-CD protons in the presence of an excess amount of 2,6-PMN with the addition of NDC regioisomers were analyzed by a curve-fitting procedure to give binding constants (K6) for complexation of NDC’s with a γ-CD–2,6-PMN binary complex. The K6 values increased in the order of 1,5-NDC < 1,4-NDC < 1,8-NDC < 1,3-NDC < 1,6-NDC < 2,3-NDC < 2,7-NDC < 2,6-NDC, indicating that a binary complex of γ-CD with 2,6-PMN is able to recognize the molecular structures of NDC’s. The open space between the γ-CD cavity and 2,6-PMN will be favorable for the accommodation of a slender molecule such as 2,6-NDC, but unfavorable for the accommodation of a bulky molecule such as 1,5-NDC.
Chemistry of o-Mercaptophenolate: Syntheses, Structures, and Characterization of Titanium(IV) Complexes
Authors: Wen Ting-Bin , Kang Bei-Sheng , Su Cheng-Yong , Wu Da-Xu , Wang Li-Ge , Liao Sen , Liu Han-Qin
Published: June 2006

The reaction of Cp2TiCl2 with o-mercaptophenolate in the presence of a base (Et3N or NaOMe) afforded the complex (BnMe3N)2[Ti(o-SC6H4O)3] or (Et4N)2[Ti2(o-SC6H4O)4(OMe)2]·2H2O under slightly varied conditions. Single-crystal X-ray diffraction studies showed that the Ti(IV) geometry in both complexes is a severely distorted octahedron with average trans-angles of 162.2° and 159.1(2)°, respectively. Crystallographic data for (BnMe3N)2[Ti(o-SC6H4O)3]: a = 9.884(3), b = 16.501(7), c = 23.028(7) Å; β = 99.89(3)°, V = 3700.2(22) Å3, Z = 4, final R = 0.050 for 3134 observed reflections; for (Et4N)2[Ti2(o-SC6H4O)4(OMe)2]·2H2O: a = 8.953(4), b = 10.148(3), c = 14.527(3) Å; α = 73.16(2)°, β = 73.00(3)°, γ = 83.56(4)°, V = 1207.4(9) Å3, Z = 1, final R = 0.082 for 2233 observed reflections. The isolation of (BnMe3N)2[Ti(o-SC6H4O)3] provides strong evidence for the synthon character of [Ti(mp)3]2−, which was previously predicted to be present in the complex (Et4N)2[Ti(mp)3Na(MeOH)2]2. Both electronic and 1H NMR spectra showed a similar rigidity of the mp chelate rings to Ti(IV) in the complexes.
Kinetics and Mechanism of the Copper(II)-Catalyzed Oxidation of the Iodide Ion to Iodine by the Vanadium(V) Ion in an Aqueous Solution
Authors: Kimura Masaru , Shiga Yuko , Tsukahara Keiichi
Published: June 2006

The vanadium(V) ion, which is described as VV herein, could hardly oxidize the iodide ion to iodine at pH ≥ 2.8; however, the oxidation reaction occurred catalytically upon adding traces of copper(II) ion. When a copper(II) solution of 10−8—10−5 M (M = mol dm−3) was mixed with an iodide solution, after a rapid formation of iodine, the iodine concentration remained constant. After such iodine formation had occurred, if a VV solution was added into the reacting mixture, the iodine began to form again in accordance with a rate law of 2(d[I2]/dt) = −d[VV]/dt = k[CuI][VV], in which [CuI] is a steady-states’ concentration in a chain cycle CuI+/CuI. The reaction rate was independent of the time to add the VV ion, and the formation of iodine I2 (or triiodide ion I3−) stopped at the time when all of the VV was consumed, indicating the stoichiometry to be 2I− + 2VV → I2 + 2VIV. The initial rate (Vi) after VV addition was proportional to the concentrations of not only the added VV over the range 10−6—10−5 M, but also the added copper(II) ion. Although a self-inhibiting effect did not appear over the pH range 2.8—3.6, it occurred at pH > 3.6. It was found that such a retarding effect was caused by the vanadium(IV) ion (denoted as VIV herein), which was the reduced product of VV; the VIV inhibiting effect was extremely dependent on the pH in the reacting solution. The mechanisms for the retardation reaction as well as iodine formation are discussed in terms of accounting for the obtained results.
Difference in the Reactions of N-Methylhydroxylamine and N-Phenylhydroxylamine with Nitrosobenzene
Authors: Magro Jacir Dal , Yunes Rosendo Augusto
Published: June 2006

The reaction of nitrosobenzene with N-methylhydroxylamine was studied. The pH-rate profile exhibits a negative break at between pH 0.5 and 3.0, which is considered to be caused by a change in the rate-determining step of the reaction from an attack of the amine on nitrosobenzene at low pH, to the dehydration of an addition intermediate previously formed between the reagents at higher pH. This behavior is different from that of the reaction between N-phenylhydroxylamine and nitrosobenzene where, over the entire pH range, the only rate-determining step is dehydration of the addition intermediate. This fact confirms the special behavior of phenylhydroxylamine as a nucleophile, as was observed in its reactions with aromatic aldehydes.
An Easy Direct Conversion of Pyridine- and Pyrimidine-Thiones into Multi-Fused Heterocyclic Compounds
Authors: Erian Ayman Wahba , Abu-Shanab Fathi Ali
Published: June 2006

The reaction of azine-thiones with ethyl chlorofluoroacetate afforded 2-fluorothienoazines. The latter underwent self-condensation and gave multi-fused heterocyclic compounds. A wide range of unique heterocycles could be obtained on treatment of 2-fluorothienoazines with nitrogen nucleophilic reagents. The reactivity of the pyrimidine-thiones towards a variety of electrophilic reagents was studied. Chemical and spectroscopic evidence of the newly synthesized compounds are described.
A Facile Preparation and Cyclopropanation of 1-Alkenylsilanols
Authors: Hirabayashi Kazunori , Takahisa Eisuke , Nishihara Yasushi , Mori Atsunori , Hiyama Tamejiro
Published: June 2006

Alkenylsilanols are prepared by the reaction of hexamethyltrisiloxane (D3) with alkenyllithiums or alternatively by the reaction of cyclic siloxanes substituted by an alkenyl group with organolithiums and transformed to the corresponding cyclopropylsilanols using diiodomethane and diethylzinc. Lithium alkenylsilanolates, primary products of the preparation, also undergo cyclopropanation. As in the case of allylic alcohols, the silanol functionality is found to enhance the rate of cyclopropanation compared with that of alkenyltrialkylsilane or alkoxydialkylsilane. The obtained cyclopropylsilanols are further converted into the corresponding cyclopropanols by the Tamao oxidation.
Specific Deuterium Labeling of Archaeal 36-Membered Macrocyclic Diether Lipid
Authors: Arakawa Kenji , Eguchi Tadashi , Kakinuma Katsumi
Published: June 2006

Described in this paper is a practical synthesis of the specifically deuterated 36-membered macrocyclic diether lipid 4 and its acyclic deuterated counterpart 5, both of which are essential to the detailed biophysical studies of the conformational order of phospholipids in vesicles. The synthesis of 4 was principally composed of the preparation of deuterated diether 15, subsequent macrocyclization of the crucial dialdehyde 21 by McMurry coupling, and final transformation into the phosphocholine derivative. The acyclic deuterated counterpart 5 was also synthesized from the common intermediary tosylate 16.
Theoretical Study on Carbocation Formation Reactions. Resonance Demands and Transition Structures
Authors: Mishima Masaaki , Yamataka Hiroshi
Published: June 2006

Ab initio molecular-orbital calculations were carried out for two carbocation-generating reactions, the SN1 reaction of protonated 1-phenylethyl alcohol (H2O leaving group) and the acid-catalyzed hydration of styrene. Separated reactants, reactant complexes, transition states (TSs), product complex, and separated products were optimized at MP2/6-31G* and the vibrational frequencies were analyzed. The SN1 TS lies halfway between the reactant and the product with respect to the bond lengths, charge distribution, and secondary deuterium isotope effects. The degree of the π-orbital overlap between the benzylic carbon and the phenyl ring is almost the same in the SN1 TS and the 1-phenylethyl cation. The proton-transfer TS of the hydration, on the other hand, reaches earlier, and the π-orbital overlap in the TS is less effective. These differences are responsible for the difference in the experimental substituent effect reported in the literature for the two reactions.
Synthetic Study on a 26-Membered Macrolide, Amphidinolide B: Synthesis of the C1—C13 Fragment
Authors: Ohi Katsuhide , Shima Kyoko , Hamada Kozue , Saito Yoshio , Yamada Naoki , Ohba Shigeru , Nishiyama Shigeru
Published: June 2006

The C1—C13 fragment of amphidinolide B (1) was synthesized from D-erythrose (3). The Evans alkylation reaction protocol allowed the introduction of the stereogenic center at the C11 position, which was unambiguously confirmed by a single X-ray crystallographic analysis.
1,2,3-Triphenyl-1,2,3-trithexylcyclotrisilanes: Synthesis and Ring-Opening by Halogens
Authors: Unno Masafumi , Masuda Hiroyuki , Matsumoto Hideyuki
Published: June 2006

Reaction of dichlorophenylthexylsilane (thexyl = 1,1,2-trimethylpropyl) with lithium naphthalenide in tetrahydrofuran at −65 °C gave cis,cis- and cis,trans-1,2,3-triphenyl-1,2,3-trithexylcyclotrisilane 1 (cis,cis-1 and cis,trans-1) in yields of 19 and 52%, respectively. The structures of both isomers were determined by X-ray crystallography. The ring-opening reaction of each isomer with bromine leads to the formation of 1,3-dibromo-1,2,3-triphenyl-1,2,3-trithexyltrisilane (2); cis,cis-1 gave only (1R,3R)/(1S,3S)-1,3-dibromo-1,2,3-triphenyl-1,2,3-trithexyltrisilane ((1R,3R)/(1S,3S)-2) (87% yield). While cis,trans-1 formed (1R,2s,3S)- and (1R,2r,3S)-1,3-dibromo-1,2,3-triphenyl-1,2,3-trithexyltrisilane ((1R,2s,3S)-2 and (1R,2r,3S)-2, in 13 and 31% yields) as well as (1R,3R)/(1S/3S)-2 (44% yield). The structures of (1R,3R)/(1S,3S)-2 and (1R,2r,3S)-2 were confirmed by X-ray crystallography. From the stereochemical results observed in the ring-opening reactions, it is concluded that the cleavage of the Si–Si bonds occurs with retention–inversion of the configuration of the silicon atoms. In the chlorination, cis,cis-1 gave (1R,3R)/(1S,3S)-1,3-dichloro-1,2,3-triphenyl-1,2,3-trithexyltrisilane ((1R,3R)/(1S,3S)-3, 40% yield) and (1R,2r,3S)-1,3-dichloro-1,2,3-triphenyl-1,2,3-trithexyltrisilane ((1R,2r,3S)-3, 30% yield); cis,trans-1 gave (1R,3R)/(1S,3S)-3 (33% yield), (1R,2r,3S)-3 (14% yield), and (1R,2s,3S)-1,3-dichloro-1,2,3-triphenyl-1,2,3-trithexyltrisilane in 40% yield. The structure of (1R,2r,3S)-3 was confirmed by X-ray crystallography. The result indicates that stereoselectivity was lower in the ring-opening by chlorine than in that by bromine.
Irradiation Effects of Excimer Laser Light on Vinylidene Chloride–Vinyl Chloride (Saran®) Copolymer Film
Authors: Izumi Yoshinobu , Kawanishi Shunichi , Takagi Noriaki , Honda Shigeo , Yamamoto Tadashi
Published: June 2006

Vinylidene chloride–vinyl chloride copolymer (Saran® copolymer) film was irradiated with ArF and KrF excimer laser light in a vacuum at ambient temperature. The irradiation of ArF and KrF excimer laser light mainly caused the formation of diene and triene structures, respectively. From the dependence on the laser intensity it was concluded that diene and triene were formed via single-photon and multi-photon processes, respectively. The wavelength dependence was explained by photochemical and photothermal effects for the ArF and KrF lasers, respectively.
Micellar Electrokinetic Chromatography
Authors: Otsuka Koji , Terabe Shigeru
Published: June 2006

A review of the research on micellar electrokinetic chromatography (MEKC), carried out mainly in our laboratory, is described from the viewpoints of (1) fundamental characteristics of MEKC, such as the separation principle, chromatographic parameters, selectivity and resolution, thermodynamic parameters, retention index, and band broadening; (2) selectivity manipulation, including effects of surfactants, temperature, pH, and various additives; (3) on-line coupling of MEKC with mass spectrometry; (4) applications, such as the separation of closely related compounds and enantiomer separations; and (5) on-line neutral sample concentration techniques.
Structural Genealogy of BEDT-TTF-Based Organic Conductors I. Parallel Molecules: β and β″ Phases
Authors: Mori Takehiko
Published: June 2006

A method is proposed to systematize a number of structural modifications of BEDT-TTF (bis(ethylenedithio)tetrathiafulvalene)-based organic conductors and related materials. Analysis of actual crystal structures indicates that most crystal structures are constructed of two essential building blocks: “ring-over-bond” (RB) and “ring-over-atom” (RA) overlap modes. Several different ways to pile up these elements lead to various structures which are conventionally designated as β,β′,β″,θ,α, and α″-phases. In the β- and β″-phases, introduction of “dislocations” along the stacking axis generates a number of modifications. Here dislocations mean interactions of two donor molecules which have larger displacements along the molecular long axis than the standard RB and RA modes. Systematic nomenclature to distinguish these modifications is proposed. Transfer integrals are, however, not very sensitive to the existence of dislocations, so that the Fermi surfaces of these multiple phases are derived from the fundamental structure by folding the first Brillouin zone.
Ferromagnetic and Antiferromagnetic Phases of 4-(4-Iodobenzylideneamino)-2,2,6,6-tetramethylpiperidin-1-yloxyl
Authors: Ishida Takayuki , Togashi Kensuke , Imachi Ron , Yamamoto Hajime , Yasui Masanori , Iwasaki Fujiko , Nogami Takashi
Published: June 2006

Temperature dependences of d.c. magnetic susceptibilities and magnetizations were measured for two different crystallographic phases of 4-(4-iodobenzylideneamino)-2,2,6,6-tetramethylpiperidin-1-yloxyl. Intermolecular ferromagnetic (Weiss temperature θ = +0.71 K) and antiferromagnetic (θ = −0.23 K) interactions were found for α- and β-phases, respectively, in the magnetic measurements above 1.8 K; the former phase showed a bulk ferromagnetic transition at 0.28 K. Based on the X-ray crystallographic data, intermolecular magnetic interactions are discussed. In the α-phase crystal, NO-radical sites form two-dimensional zigzag sheets. The ferromagnetic interaction within the sheet can be interpreted in terms of a β-hydrogen mechanism, ON(↑)–Cα(↓)–Cβ(↑)–Hβ(↓)···(↑)ON<, in which the magnetic interaction is transmitted by β-hydrogens. A dimer structure was found in the β-phase crystal, and direct exchange and/or dipole interactions between N–O radicals seem to be the main origin of the antiferromagnetic interaction.
Transient Membrane Potential in Response to a Bitter Substance in a Membrane Filter Impregnated with Phospholipid and 1-Octanol
Authors: Yata Terumasa , Nomura Kazuo
Published: June 2006

Transient and steady membrane potentials in response to a bitter substance have been measured in a membrane filter impregnated with phospholipid and 1-octanol. Quinine, which is one of the alkaloids, was used as the bitter substance. The internal and external solutions both contained 0.1 mol dm−3 KCl. A cation exchange liquid membrane was formed in a Teflon filter by impregnating it with a 1-octanol solution of dihexadecyl hydrogenphosphate (DCP). After the injection of the solution of quinine hydrochloride into the external solution, the membrane potential rapidly increased to reach a peak and gradually decreased to relax to a level of another steady potential. The time course curve of membrane potential was resolved in the early portion and the other portion after the peak to obtain the Donnan potential at the interface and the diffusion potential within the membrane at steady state, respectively. In comparison with the case of the response to HCl, even a small amount of aqueous quinine hydrochloride induced a great magnitude of change both in the Donnan potential and in the diffusion potential within the membrane. The amount of quinine transported across the membrane was measured by UV spectrophotometry. From the time dependence of the UV spectrum, we determined the time lag for the membrane diffusion to obtain the diffusion coefficient of quinine in the membrane. According to the theoretical expressions of the Donnan potential at the interface for the charged membrane and the intramembrane diffusion potential derived by solving the Nernst–Planck equations taking into account the Donnan equilibrium at the interface, these two constituents of the total membrane potential were estimated using the diffusion coefficient. By fitting the theoretical curves to the experimental results, large values of the partition coefficient and the equilibrium constant of the complex formation with DCP for monoprotonated quinine ion relative to potassium ion were obtained.
Synthesis and Characterization of the Water-Soluble, All-Inorganic Composition, Keggin-Type Triniobium(V)-Substituted SiW9Nb3O407− Heteropolyoxoanions with Alkali Metal Countercations (Li+, Na+, K+, and Cs+)
Authors: Nomiya Kenji , Ohsawa Katsunori , Taguchi Takayuki , Kaneko Masahiko , Takayama Toshio
Published: June 2006

The Keggin-type triniobium(V)-substituted tungstoheteropolyanion, A-β-SiW9Nb3O407−, was synthesized as its hepta alkali-metal salts of Li+, Na+, K+, and Cs+countercations. These alkali-metal salts were useful for allowing the crystallization of SiW9Nb3O407−, itself, and/or the SiW9Nb3O407−-supported organometallic complexes, as well as controlling the water solubility of these complexes. The analytically pure compounds, obtained as homogeneous colorless solids via a stoichiometric reaction of the (Bu4N)6H2Si2W18Nb6O77, (Nb–O–Nb)3-bridged anhydride with the corresponding alkali tetrafluoroborates, and then with the alkali hydroxides, were compositionally characterized by complete elemental analyses, TG/DTA and FABMS spectra. They were structurally characterized by FT-IR and solution 183W NMR measurements, as well as solid-state CP/MAS and GHD/MAS 29Si NMR and solution 29Si NMR measurements. The cation-dependent properties of these heteropolytungstates in the solid state were observed in the thermal stabilities, the amounts of hydrated water and adsorbed water, the solubilities in water and in organic solvents, and in the ease of crystallization.
Synthesis, Structure, and Properties of Di-μ-phenoxo-bridged Dinuclear CuIINiII and CuIICoII Complexes and Cyclic Di-μ-phenoxo-μ-amido-bridged Tetranuclear Cu2IIZn2II and Cu4IIComplexes Derived from the 1,2-Bis(2-oxidobenzamidato)benzenecuprate(II) Dianionic Ligand-Complex
Authors: Sunatsuki Yukinari , Matsuo Toshihiro , Nakamura Masaaki , Kai Fumiaki , Matsumoto Naohide , Tuchagues Jean-Pierre
Published: June 2006

Dipotassium N,N′-1,2-phenylenebis(2-carbamoyl-κN-phenolato-κO]cuprate(II)), K2[CuL], reacts with nickel(II), cobalt(II), and zinc(II) acetates, and 2,2′-bipyridine in a 1 : 1 : 2 molar ratio in methanol to yield the hetero-metal dinuclear complexes [CuLNi(bpy)2]·3MeOH (1·3MeOH), [CuLCo(bpy)2]·2DMF (2·2DMF), and [CuLZn(bpy)2]·1.5H2O (3), respectively. Crystal data for 1 : P1 (No. 2) with a = 15.969(2), b = 23.494(3), c = 12.705(2) Å, α = 92.15(1), β = 91.652(10), γ = 101.521(9)°, V = 4663(1) Å3, and Z = 4; 2, P21/c (No. 14) with a = 12.604(3), b = 24.364(5), c = 13.823(2) Å, β = 94.49(1)°, V = 4231(1) Å3, and Z = 4. 1 and 2 have a similar discrete di-μ-phenoxo-bridged dinuclear structure, in which the Cu(II) ion assumes a square-planar geometry with the N2O2 donors atoms consisting of two amido nitrogen and two phenoxo oxygen atoms of the tetradentate ligand, and the Ni(II) or Co(II) ion assumes an octahedral geometry with the two phenoxo oxygens of the tetradentate ligand and four nitrogen atoms from two bpy. The magnetic-susceptibility data were reproduced based on the isotropic spin Hamiltonian H = −2JS1·S2 with J = −118.0 cm−1, (S1, S2) = (1/2, 1) for 1 and J = −11.0 cm−1, (S1, S2) = (1/2, 3/2) for 2, respectively. When 3 was recrystallized from DMF/2-propanol, [CuLZn(bpy)]2·2DMF (3′) was obtained. The 1 : 1 : 1 reaction of K2[CuL′], copper(II) acetate monohydrate, and 2,2′-bipyridine in methanol yielded [CuL′Cu(bpy)]2·2MeOH (4), (H4L′ = 1,2-bis(hydroxybenzamido)ethane). Crystal data for 3′: Pbca (No. 61) with a = 19.143(2), b = 18.195(2), c = 16.832(3) Å, and Z = 4; 4, P21/n (No. 14) with a = 13.407(1), b = 13.172(4), c = 13.764(2) Å, β = 94.11(1)°, V = 2424.4(8) Å3, and Z = 4. 3′ and 4 have a similar cyclic di-μ-phenoxo-μ-amido-bridged tetranuclear structure, which can be described as two di-μ-phenoxo-bridged dinuclear units bridged together by the coordination of one amido oxygen atom from each dinuclear unit to the zinc(II) or copper(II) ion of the other dinuclear unit, with Zn(1)–O(3)* = 2.004(3) and Cu(2)–O(4)* = 1.924(4) Å bond distances, respectively. In the tetranuclear structure, the copper(II) ion coordinated by the tetradentate ligand assumes a square-planar geometry and the zinc(II) or the other copper(II) ion assumes a square-pyramidal coordination geometry with two phenoxo-oxygen atoms, two nitrogen atoms of bpy, and one amido oxygen atom. The magnetic susceptibility of 4 was reproduced by an equation derived from the H = −2J(S1·S2 + S3·S4) − 2J′(S2·S3 + S4·S1) spin Hamiltonian with J = −14.6 cm−1 and J′ = −4.0 cm−1.
Solvatochromism and Structure of Acetylacetonatocopper(II) Complexes with N,N′-Dipropyl-, N,N,N′,N′-Tetrapropyl-, and N,N- and N,N′-Diisopropylethylenediamines
Authors: Miyamae Hiroshi , Kudo Hideyuki , Hihara Goro , Sone Kozo
Published: June 2006

Seven copper(II) complexes of the general formula [Cu(acac)(diam)]X were prepared, where acac and diam stand for acetylacetonate and one of the diamines in the title, and X− for a bulky univalent anion, respectively. Their solvatochromism was compared with that of the corresponding complexes with N,N,N′,N′-tetramethylethylenediamine and related diamines, to see the effect of their bulky N-alkyl groups. X-ray crystal analyses showed that the perchlorates of N,N′- and N,N-diisopropyl complexes are apparently 6- and 5-coordinated, respectively, in their crystals, although their ClO4− ions are held extremely weakly and are easily driven out by solvent molecules in solution, leading to their solvatochromism. The Cu–N and Cu–O(acac) bond distances in the former, 199.5(4)/202.4(5) and 190.6(4)/190.1(4) pm, respectively, are similar to each other, while the Cu–N(isopropyl)2 distance, 206.4(9) pm, in the latter is notably longer than the Cu–NH2 distance, 196(1) pm.
Steric Effects of Axial Methyl Substituents on Axial Coordination of Macrocyclic Nickel(II) and Cobalt(III) Complexes
Authors: Mochizuki Katsura , Ikeuchi Kouki , Kondo Takeshi
Published: June 2006

The nickel(II) complex with L1 (5,5,7-trimethylcyclam: 5,5,7-trimethyl-1,4,8,11-tetrazacyclotetradecane), trans-[NiL1(H2O)2]Cl2·H2O, was isolated. An X-ray structural analysis gave strong evidence for the presence of steric interaction between the axial methyl substituent at the 5-position and the water molecule coordinating to the nickel(II) ion. The bimacrocyclic cobalt(III) complex with L3 (6,6′-bi[5R(S),7S(R)-dimethyl-1,4,8,11-tetraazacyclotetradecane], trans-[Co2L3Cl4]Cl2, was synthesized and its structure was analyzed by X-ray crystallography, as well as the monomacrocyclic trans- and cis- dichlorocobalt(III) complexes with L2 (5R(S),7S(R)-dimethyl-1,4,8,11-tetraazacyclotetradecane). The structure of trans-[Co2L3Cl4]2+ was quite different from that of [Ni2L3]4+. In trans-[Co2L3Cl4]2+, the bridged six-membered chelate rings adopted an approximately twist-boat conformation. The steric interaction between the coordinated chloride anions on the cobalt(III) ion and the methyl substituents introduced at the 5- and 7-positions in the six-membered chelate ring was discussed.
Sulfenato and Sulfinato Complex Formation via Oxidation of OC-6-3′2-Bis{2-[(2-pyridylmethyl)amino]ethanethiolato}cobalt(III) (1+) Complex by Molecular Dioxygen
Authors: Yamanari Kazuaki , Kawamoto Tatsuya , Kushi Yoshihiko , Komorita Takashi , Fuyuhiro Akira
Published: June 2006

The first ligand oxidation of sulfur donors of OC-6-3′2-[Co(pyet)2]+ [pyet = 2-[(2-pyridylmethyl)amino]ethanethiolate (1−)] by molecular dioxygen is attained in the presence of active charcoal. The oxidation products are characterized as one (thiolato)(sulfinato) complex OC-6-3′2-[Co(pyet)(pyesi)]+ (b; 82%), one (thiolato)(sulfenato) complex OC-6-3′2-[Co(pyet)(pyese)]+ (d; 14%) and a mixture of four bis(sulfenato) complexes OC-6-3′2-[Co(pyese)2]+ (h, i, j, and k; 4%), [pyese = 2-[(2-pyridylmethyl)amino]ethanesulfenate (1−); pyesi = 2-[(2-pyridylmethyl)amino]ethanesulfinate (1−)]. It is apparent that the route producing the monosulfinato complex is dominant in the dithiolatocobalt(III) complex as well as in the dithionickel(II) complexes. The isolation of OC-6-3′2-[Co(pyet)(pyese)]+, however, is extremely interesting because this complex is the first example of an oxidation product free from an O2.
The Study of π–π Interaction in Layered [3.3]Orthocyclophanes. Charge-Transfer Complexes of [3.3]Orthocyclophanes with Tetracyanoethylene
Authors: Taniguchi Masahiko , Mataka Shuntaro , Thiemann Thies , Sawada Tsuyoshi , Mimura Keisuke , Mitoma Yoshiharu
Published: June 2006

Dibenzo[3.3]orthocyclophanes ([3.3]OCPs) with a bicyclo[4.4.1]undecane substructure form charge-transfer (C-T) complexes with tetracyanoethylene (TCNE). 3,4 : 8,9-Dibenzobicyclo[4.4.1]undecane (9) and its 11-methylene derivative 8 are flexible molecules and take a chair-boat conformation. Complexes 8- and 9-TCNE exhibit the absorption maximum at ca. 420 nm, which coincides with the value for the TCNE complex of o-xylene. On the other hand, acetal 5, methylcarbinol 6, and dimethylmethylene derivative 7 are rigid, layered [3.3]OCPs with stacked benzene rings. Compounds 5, 6, and 7 form a 1 : 1 complex with TCNE in solution. The absorption maxima of the complexes at ca. 500 nm suggest an enhanced C-T complexation due to a π–π through-space interaction in 5, 6, and 7. A 2 : 1 complex of rigid [3.3]OCP 7 with TCNE crystallized from dichloromethane, while OCP 8 gave a red crystalline 2 : 3 complex with TCNE. X-ray crystallographic analyses of these two complexes is given.