bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetric Transformation of N-Acetyl-Dl-leucine
Authors: Hongo Chikara , Yamada Shigeki , Chibata Ichiro 
Published: July 2006

Abstract
The asymmetric transformation of N-acetyl-Dl-leucine by a combination of preferential crystallization of a desired isomer and simultaneous racemization of the opposite isomer was studied. The reaction was analyzed in detail and a practical method for the asymmetric transformation was established. A supersaturated solution of N-Ac-Dl-Leu in acetic acid containing catalytic amounts of acetic anhydride was seeded with the crystals of N-Ac-l-Leu and cooled at a rate of 10 °C/h from 100 °C to 40 °C. As a result, almost optically pure N-Ac-l-Leu was obtained in a yield of 70%, based on the original weight of N-Ac-Dl-Leu.
Picosecond Laser Spectroscopy of Intramolecular Heteroexcimer Systems. Time-resolved Fluorescence Studies of p-(CH3)2NC6H4–(CH2)n–(9-Anthryl), p-(CH3)2NC6H4–(1-Pyrenyl) Systems and 9,9′-Bianthryl
Authors: Migita Masahito , Okada Tadashi , Mataga Noboru , Sakata Yoshiteru , Misumi Soichi , Nakashima Nobuaki , Yoshihara Keitaro 
Published: July 2006

Abstract
In order to elucidate the details of elementary processes of photochemical charge transfer and heteroexcimer formation processes, and also in order to compare the obtained results with those of transient absorption spectral measurements, we have examined the following intramolecular heteroexcimer systems by means of ps time-resolved fluorescence measurements with a mode-locked Nd3+: YAG laser and a streak camera: p-(CH3)2–NC6H4–(CH2)n–(9-anthryl) (n=0, 1, 2, 3), p-(CH3)2NC6H4–(CH2)n-(1-pyrenyl) (n=1, 2, 3) and 9,9′-bianthryl. Effects of methylene chain length, solvent polarity and viscosity upon the intramolecular charge transfer processes have been clearly demonstrated. It is concluded that molecules with sandwich configuration in the ground state are not recognized in both n=3 compounds, and it takes a few ns for the heteroexcimer formation in hexane because of an extensive conformation change necessary to take sandwich configuration. Both conformation change and solvent reorientation are involved in the heteroexcimer formation processes in polar solvents, and heteroexcimer formation becomes faster with increase of solvent polarity and decrease of its viscosity. Moreover, two step conformation changes are observed in the case of the heteroexcimer formation of n=3 compounds in polar solvents, i.e. a heteroexcimer with loose structure is formed first, and then follows a structural change to the one of sandwich type. In acetonitrile, a strongly polar solvent, formation of heteroexcimer is very fast, occurring within the time-resolution of the picosecond apparatus.
Transmission of Low-energy Electrons (0–15 eV) through Thin Films of Ethers, Ketones, Alcohols, and Ice. Determination of the Quasifree Electron State Energy
Authors: Hiraoka Kenzo , Nara Masaji 
Published: July 2006

Abstract
The transmission of low-energy electrons (0–15 eV) through 10–100 Å films of ethers, ketones, alcohols, and ice has been studied. Structures are indicated by electron current It transmitted through a thin film as a function of the incident electron energy Vi, displayed as dIt⁄dVi vs. Vi. With increasing the film thickness, a decrease of the height of the first peak (due to injection of electrons in the film) and an appearance of a second peak are observed for ethers and alcohols. The energies of quasifree electron state V0 are determined by measuring the energy of the second peak from the first peak for solid diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-nonanol. For acetone, diethyl ketone, dimethyl sulfoxide, and ice, neither a decrease of the first peak nor an appearance of a second peak is observed, indicating that these compounds have negative V0 values. From the energy of the onsets of broad negative peaks appeared at ≈14 eV for ethers and alcohols, the solid phase ionization energies IS and the polarization energies of cations P+ by the solid media are determined.
Metal Complexes Coordinating Pyridine Derivatives. II. Circular Dichroism and Magnetic Circular Dichroism Spectra of Chromium(III) Complexes in the Region of Pyridine Ring Absorption Band
Authors: Yamamoto Yukihiro , Shimura Yoichi 
Published: July 2006

Abstract
Dianionochromium(III) complexes coordinating (S)-N,N′-bis(2-pyridylmethyl)propylenediamine (abbrev. S-picpn) or (S)-1-(2-pyridyl)ethylamine (abbrev. S-pea) show CD spectra of a dispersion type in the region of pyridine ring absorption band. Utilizing the data of X-ray crystal structure analysis of Δ-cis-α-[CrCl2(S-picpn)]Cl, the difluoro complex shows the correct exciton CD sign pattern expected from a simple theory but the dichloro and dibromo complexes the inverse sign pattern. The latter fact is explained in terms of overlapping of the pyridine ring absorption band with the halogeno-to-chromium charge transfer band, referring to MCD spectra. The absorption and MCD bands appeared in the region 30–35×103 cm−1 for all the chromium(III) complexes are assigned to the spin-forbidden π→π* transition of the coordinated pyridine group.
Kinetics of Monomerization or Polymerization Reaction for Bis(N-phenylsalicylideneaminato)nickel(II) and Bis(N-methylsalicylidene-aminato)nickel(II) in Solid Phase
Authors: Miyokawa Kikuo , Hirashima Hidenori , Masuda Isao 
Published: July 2006

Abstract
A kinetic investigation was carried out by means of a thermomagnetic analysis on two structural transformation reactions in solid phase: monomeric square planar-to-polymeric octahedral for Ni(N-Me-salam)2 and polymeric octahedral-to-monomeric square planar for Ni(N-Ph-salam)2. The polymerization process followed the Avrami-Erofeev equation (n=2) with Ea=303 kJ/mol and the monomerization followed the first order equation with Ea=78 kJ/mol. The thermal pyridine liberating reaction of Ni(N-Ph-salam)2py2, involving an octahedral-to-square planar transformation, has been investigated isothermally and found to follow the first order equation with Ea=167 kJ/mol.
Syntheses and Properties of α-Ethyl-substituted Bisdehydro[15]annulenones
Authors: Ojima J\={u}ro , Murosawa Yoshiko 
Published: July 2006

Abstract
2-Ethyl-5,10-dimethyl- and 15-ethyl-5,10-dimethyl-6,8-bisdehydro[15]annulenone were synthesized. Influence of α-ethyl substitution upon the skeleton of the bisdehydro[15]annulenone ring system is discussed on the basis of 1H NMR and UV spectra of these annulenones and their α-methyl-substituted derivatives.
Intramolecular [2+2]Photocycloaddition of the 3-(3-Butenyloxy)-2-cyclohexenone System
Authors: Umehara Takashi , Inouye Yoshinobu , Kakisawa Hiroshi 
Published: July 2006

Abstract
The irradiation of 5,5-dimethyl-3-(4-methyl-3-pentenyloxy)-2-cyclohexenone gave regioselectively, 6,6,10,10-tetramethyl-2-oxatricyclo[5.4.0.01,5]undecan-8-one, while, that of 5,5-dimethyl-3-[(3-methylcyclohexenyl)methoxy]-2-cyclohexenone afforded, regio- and stereoselectively, 1,5,5-trimethyl-8-oxatetracyclo[8.3.1.02,7.01,5]tetradecan-3-one.
The Synthesis of Antigenic Glycopeptides, 2-Acetamido-N-(β-l-aspartyl)-2-deoxy-4-O-β-(d-galactopyranosyl)-β-d-glucopyranosylamine. (N-Acetyllactosaminyl-l-asparagine)
Authors: Shaban Mohammed Abd El-Monem , Jeanloz Roger W 
Published: July 2006

Abstract
The title compound, serving as intermediate in the chemical and biochemical synthesis of glycopeptides and as a reference substance in the structure elucidation of glycoproteins, was synthesized. 2-Acetamido-4-O-allyl-3,6-di-O-benzyl-2-deoxy-β-d-glucopyranosyl azide was reduced to the corresponding β-d-glucosylamine and coupled with 1-benzyl N-benzyloxycarbonyl-l-aspartate to give 2-acetamido-4-O-allyl-3,6-di-O-benzyl-N-[(S)-3-benzyloxycarbonyl-3-benzyloxycarbonylamino)propionyl]-2-deoxy-β-d-glucopyranosylamine. Removal of the allyl group of the latter followed by condensation with 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide gave the fully protected N-acetyllactosaminyl-l-asparagine. De-blocking of the O-acetyl, benzyl, and benzyloxycarbonyl groups gave the title compound.
Metal Complexes of Amino Acids. XIV. Carbon-13 NMR of Cobalt(III) Complexes Containing N-Substituted Glycines
Authors: Ama Tomoharu , Kawagughi Hiroshi , Yasui Takaji 
Published: July 2006

Abstract
The down-field shifts of α-carbons in N-alkylglycines, which were caused by the chelation to cobalt(III), were larger than those in C-alkylglycines. The down-field shifts of N-(carboxymethyl)glycine (ida) and N-(2-aminoethyl)glycine (enma) in fac complexes were also larger than those of ida and enma in mer complexes, respectively, and those of the C-alkylglycines.
The Aromatization Observed on the Reaction of Terpinolene with Tetrahydrogeraniol in the Presence of Boron Trifluoride Etherate
Authors: Nagai Kimiko , Nakayama Mitsuru 
Published: July 2006

Abstract
The reaction of terpinolene with tetrahydrogeraniol in the presence of boron trifluoride etherate gave an aromatic ether in addition to the corresponding aliphatic ether, along with p-cymene, p-cymen-8-ol, and the monoterpene hydrocarbons formed by double-bond migration. The aromatic ether was proved to form upon the treatment of the aliphatic ether with boron trifluoride etherate.
Synthetic Photochemistry. XXIII. The Photoreduction of Dioxetanes to cis-1,2-Glycols: 18O-Labellingr Experiments
Authors: Takeshita Hitoshi , Hatsui Toshihide 
Published: July 2006

Abstract
The Rose Bengal-sensitized photooxidation of some dioxetane-forming olefins, the Diels-Alder dimer of spiroheptadiene, indene, acenaphthylene, and thujopsene, under an 18O2-atmosphere yielded the labelled analogs of the previously characterized cis-1,2-glycols. According to the mass-spectral analysis, both oxygens of the glycols were derived from the oxygen molecule.
Ultrasonic Absorption in Solutions of Sodium Iodide in Isopropyl Alcohol and Isopropyl Alcohol–Water Mixtures
Authors: Okuwa Tsunemichi , Ohno Kozo 
Published: July 2006

Abstract
Ultrasonic relaxational absorption was observed in solutions of NaI in i-PrOH. Assuming the excess ultrasonic absorption to be caused by the relaxation of the dissociation equilibrium of NaI in the solutions, the dissociation and recombination rates of NaI, the Arrhenius activation energy, and the enthalpy and volume changes due to dissociation were calculated; these were compared with the values estimated from other methods. An increase of the dissociation constant of NaI was observed with an increase in the concentration of H2O in i-PrOH–H2O mixtures.
Studies on the Electronic Structures of Hydrocarbon Diradicals by the Unrestricted Hartree-Fock Theory
Authors: Hashimoto Katsufumi , Fukutome Hideo 
Published: July 2006

Abstract
Electronic structures of low-lying states of cyclobutadiene, trimethylenemethane (2), and tetramethyleneethane (3) are studied by the unrestricted Hartree-Fock (UHF) theory. Characteristics of electronic correlations, called dynamical spin polarization effect, in these molecules are well described by corresponding orbitals and spin density structures of low-lying UHF solutions. The spin polarization of σ electrons is found to be relatively small but not negligible for quantitative discussion. The two low-lying singlet states of 2 are described by two UHF solutions with different spin density structures. The fact that the singlet UHF state of 3 lies a little below the triplet UHF state is explained by the difference in the spin polarization of the bonding π electrons between the singlet and triplet states. Two rules are given which predict the spin structure of low-lying UHF states and the spin multiplicity of ground states of hydrocarbon diradicals. These rules are applied to 1,1,2,3,3-pentamethylenepropane and 1,3-dimethylenecyclobutadiene, which confirms their validity.
Kinetics and Mechanism of Acylhydrazine Hydrolysis in Sulfuric Acid–Water Mixtures
Authors: Mashima Mitsuo , Ikeda Fujiko , Doi Takako , Nishikawa Sadakatsu 
Published: July 2006

Abstract
The rates of acid-catalyzed hydrolysis of formylhydrazine, acetylhydrazine, chloroacetylhydrazine, propionylhydrazine, butyrylhydrazine, and octanoylhydrazine in sulfuric acid–water mixtures have been investigated over a wide range of acidities (about 1–18 M H2SO4) by means of spectrophotometric methods. First-order kinetics were obtained in all cases, and the pseudo-first-order rate constants showed one of two types of acidity dependences: (i) a rate maximum at intermediate acidities, followed by slow hydrolysis in highly concentrated acids; (ii) a rate maximum at intermediate acidities, followed by a sharp increase in rate at high acidities. This result was treated as a function of the Hammett acidity function, the water activity, and the total concentration of hydrogen ion to yield reaction parameters which are explicable in terms of a change in mechanism at a high acidity from A-2 to A-1. The mechanism change also was deduced from a criterion based on the values of activation entropies.
Solid-Liquid and Liquid-Liquid Phase Equilibria in the Symmetrical Tetraalkylammonium Halide–Water Systems
Authors: Nakayama Haruo 
Published: July 2006

Abstract
Solid-liquid and liquid-liquid phase diagrams of the binary R4NX–water (R=n-C3H7–n-C6H13 and i-C5H11; X=F, Cl, Br, and I) systems were determined in the temperature range between −20 °C and +80 °C. These diagrams showed (1) the formation of a clathrate-like hydrate for four salts (n-C5H11)4NF, (n-C5H11)4NCl, (i-C5H11)4NBr, and (i-C5H11)4NI; (2) a phase separation into two liquid phases in the systems of (n-C5H11)4NBr, (i-C5H11)4NBr, (n-C6H13)4NCl, and (n-C6H13)4NBr; (3) that the solubility (in water at a definite temperature) of a series of the salts did not show a systematic change with respect to either the alkyl-chain length or the kind of anion; and (4) that the salt which gave the maximum solubility in water at 25 °C was (n-C5H11)4NCl for chloride, (n-C4H9)4NBr for bromide, and (C2H5)4NI for iodide, respectively. The effect of anions on the solubilities of a series of salts having the same cation was examined. It was found that the ratio mcl⁄mI at 25 °C became as high as 22800 for the tetrapentylammonium salts. Phase diagrams for the bolaform salt [(n-C4H9)3N(CH2)6N(nC4H9)3]X2–water systems are also presented.
Solubility Diagrams of Cobalt(III) Complexes Containing Amino Acid. I. Spontaneous Resolution of Tetraammine-(valinato or leueinato)cobalt(III) Salts
Authors: Yamanari Kazuaki , Naito Shigeru , Shimura Yoichi 
Published: July 2006

Abstract
The binary and ternary solubility phase diagrams of the racemic and optically active complexes, [Co(val)(NH3)4]X2 and [Co(leu)(NH3)4]X2 (X=(1/2)SO42−, Cl−, Br−, and I−), were determined in water. Spontaneous resolution was found for [Co(Dl-val)(NH3)4]X2 (X=Cl− and Br−) at 5–55 °C and for [Co(Dl-leu)(NH3)4]SO4 at 30–55 °C, the latter of which has been shown to crystallize as both a racemic compound (below 30 °C) and a conglomerate (above 30 °C).
The Interaction between α-Helical Poly-l-lysine and Thyroxine as Measured by Circular Dichroism
Authors: Okabe Nobuo , Okamura Mariko , Tokuoka Ryoji , Tomita Ken-ichi 
Published: July 2006

Abstract
The interaction between α-helical poly-l-lysine (poly(l-Lys)) and the thyroid hormone, l-thyroxine (l-T4), was investigated at pH 11 by means of circular dichroism (CD) measurements in the wavelength region of 200–380 nm. At least four CD bands were induced near 235, 250, 290, and 343 nm. This indicates that these induced Cotton effects occurred as the result of the binding of l-T4 to poly(l-Lys), probably due to the electrostatic interaction. The wavelengths of the induced GD bands corresponded to those of the UV absorption bands of l-T4 in the poly(l-Lys) : l-T4 mixture, although small red-shifts of the CD bands were observed at the shortest and the longest wavelengths (235 nm and 343 nm). These CD bands might be interpreted by the fixed intramolecular orientation around an asymmetric α-carbon atom of the bound l-T4 or by the intermolecular interaction between the peptide backbone of poly(l-Lys) and the bound l-T4.
Syntheses of Recyclized Macrolide Antibiotics and Related Derivatives from Mycaminosyltylonolide
Authors: Tanaka Akihiro , Watanabe Azuma , Kobayashi Reiko , Tsuchiya Tsutomu , Umezawa Sumio 
Published: July 2006

Abstract
Mycaminosyltylonolide diethyl acetal was, after reduction of the 9-keto group, hydrolyzed, and the seco-acids obtained were recyclized to give new 16-membered (9R)- and (9S)-hydroxy macrolide derivatives, in which the 23-hydroxyl group of the starting substance was incorporated into the macrolactone ring. Selective oxidation of the (9S)-hydroxy derivative (15) with DDQ gave the keto compound (18). Removal of the acetal-protecting groups gave a new macrolide (19), which is antibacterial. Several other O-acetyl derivatives were also prepared and their antibacterial activities were measured. By the 1H- and 13C-NMR spectroscopies of 3,23-di-O-acetylmycaminosyltylonolide diethyl acetal by varying the temperature, the presence of two rotamers was clarified.
Studies on the Behavior of Natural Surfactant at the Oil-Water Interface. II. Behavior of Natural Surfactant at the Oil-Water Interface
Authors: Ogino Keizo , Yamauchi Hitoshi , Ueno Yoshinori 
Published: July 2006

Abstract
The behavior of natural surfactants was studied at an oil-water interface by measurement of the interfacial tension and the observation of the oil-water interface. Lecithin was used as an oil-soluble substance and sodium cholate was used as a water-soluble substance; n-paraffin, corn oil, unsaturated fatty acid and fatty alcohol were used as an oil phase. The reduction of interfacial tension was greatest in a dodecane-sodium cholate solution system, but the minimum interfacial tension was observed in an oleic acid-sodium cholate solution system. Spontaneous emulsification occurred in the oil phase when oleic acid was left in contact with sodium cholate solution. The most remarkable change was found in the system of oleic acid in contact with sodium cholate solution, in which crystal of cholic acid were formed at the interface.
An Optical Absorption Study of Trapped Electrons in γ-Irradiated 3-Methylhexane-2,2,4-Trimethylpentane-2,2-Dimethylbutane Mixture Glasses at 77 K
Authors: Kimura Toyoaki , Ogawa Naoyuki , Fueki Kenji 
Published: July 2006

Abstract
An optical absorption study was made on trapped electrons in γ-irradiated 3-methylhexane-2,2,4-trimethylpentane-2,2-dimethylbutane glasses at 77 K. The absorption maximum of trapped electron spectra shifts to longer wavelengths and the trapped electron yield decreases with decreasing 3-methylhexane concentration. The observed spectral shifts were interpreted through a semicontinuum model calculation.
Metachromatic Absorption Spectra of Spin-labeled Mono- and Diamino-acridine Dyes Bound to Synthetic Polyelectrolytes
Authors: Yamaoka Kiwamu , Matsuda Takumi , Murakami Tsuyoshi 
Published: July 2006

Abstract
Interactions between nitroxide spin-labeled dyes (Acridine Orange, Proflavine, and 9-aminoacridinium chloride) and poly(p-styrenesulfonate), polyphosphate, and polyacrylate were studied by measuring visible absorption spectra in aqueous solutions. The bound-dye spectra and equilibrium constants were determined by the principal-component-analysis method. The metachromatic behavior of dye-polymer complexes was clarified.
Acid-induced Ring-opening of 2′-Substituted Spiro[anthracene-9(10H), 1′-cyclopropan]-10-ones
Authors: Hirakawa Kiyoichi , Sato Hajime 
Published: July 2006

Abstract
The title compounds (1) reacted under acidic conditions to give cyclopropane ring-opened products. In these reactions of 1 bearing methyl-, phenyl-, chloro-, bromo-, and acetoxy-substituents, the cyclopropane ring opened from the more substituted side.
The Formation of a Propellane by the Oxidation of Biphenylene with Manganese(III) Acetate
Authors: Kurosawa Kazu , McOmie John F W 
Published: July 2006

Abstract
The reaction of biphenylene with manganese (III) acetate gave 2-acetoxybiphenylene, 2-formylbiphenylene, 2-(acetoxymethyl)biphenylene, and 7-oxa-10,11-benzotricyclo[4.3.2.0]undeca-2,4,10-trien-8-one. The reaction pathways are discussed.
Synthesis of Amphiphilic Porphyrins
Authors: Takagi Shigeru , Yamamura Takeshi , Nakajima Masayuki , Ishiguro Koji , Kawanishi Yuji , Nihojima Shigeru , Tsuchiya Hiroo , Saito Taro , Sasaki Yukiyoshi 
Published: July 2006

Abstract
A water soluble surfactant porphyrin 5,10,-15-tris (1-methylpyridinium-4-yl)-20-[4-(octadecyloxy)phenyl]21H, 23H-porphine triiodide and its metal complexes have been synthesized and characterized.
Ring-opening Polymerization of Tetrahydrofuran Initiated by the 2-Norbornyl Cation Generated from exo-2-Norbornyl Tosylate in the Presence of Lithium Perchlorate
Authors: Takeuchi Ken’ichi , Kato Yukari , Okamoto Kunio 
Published: July 2006

Abstract
exo-2-Norbornyl tosylate initiates ringopening polymerization of THF in the presence of lithium perchlorate. The deuterium scrambling of exo-2-norbornyl exo-3-d tosylate indicates the SNl nature of the initiation mechanism.
Sand Separated from Athabasca Tar Sand (Canada) by Solvent Extraction
Authors: Yoshida Ryoichi , Okutani Takeshi , Shimokawa Katsuyoshi , Ikawa Yasuko , Maekawa Yousuke , Kodaira Kohei , Yoshida Yuji 
Published: July 2006

Abstract
The nature of the sand separated from Athabasca tar sand (Canada) by solvent extraction was examined. The existence of α-SiO2 was confirmed by X-ray analysis. By DTA-TG determination, the occurrence of displacive transformation from low quartz to high quartz at 573±1 °C was proved, this coincides with the results obtained by means of X-ray analysis.
Liposomal Membranes. IX. Fluorescence Depolarization Studies on N-Dansylhexadecylamine in Liposomal Bilayers
Authors: Iwamoto Kiyoshi , Sunamoto Junzo 
Published: July 2006

Abstract
A fluorescent probe, N-dansylhexadecylamine (DSHA), was found to aggregate in aqueous media by monitoring the emission maximum, relative intensity, and polarization of fluorescence as functions of solvent polarity and probe concentration. In aqueous methanol, the critical solvent polarity for DSHA at a given concentration to form self-aggregates corresponded to 57% (v/v) aqueous methanol, while the critical aggregate concentration for the probe was 2.3×10−6 M in 50% aqueous methanol. In liposomal bilayers, the dansyl moiety seemed to be localized in a polar region close to the surface of membranes. Fluorescence characteristics of DSHA in liposomes as a function of incubation temperature revealed the phase transition of liposomal bilayers, which was almost consistent with those previously estimated by other methods. As the salt concentration was increased up to about 1.5 M, DSHA in liposomes underwent the phase separation and formed self-aggregates even in liposomal bilayers.
Studies on Mixed Chelates. XII. Formation and Electronic Spectra of 5-Coordinated Mixed Copper(II) Chelates Containing N-Alkylated Ethylenediamine, Acetylacetonate, and Pseudohalide Anions
Authors: Fukuda Yutaka , Sato Noriko , Hoshino Naomi , Sone Kozo 
Published: July 2006

Abstract
The visible absorption spectra of three new mixed chelates of copper (II), Cu(tmen)(acac)X(tmen=N,N,N′,N′-tetramethylethylenediamine, acac=acetylacetonate ion, X=NCS, N3, or NCO) were studied in various organic solvents. It was found that the \ ildeνmax values of their d-d bands depend strongly on the nature of the solvent, and shift in the opposite direction as compared with the case of [Cu(tmen)(acac)]ClO4 studied before, where \ ildeνmax shifted to red with the increase of the donor number (DN) of the solvent. Here the magnitude of the red shift is affected not only by the DN, but also by other parameters of the solvent polarity, such as Kosower’s Z or Reichardt’s ET. The obtained data can reasonably be explained, if an equilibrium
[Cu(tmen) (acac)X]\ightleftarrows[Cu(tmen)(acac)]++X−
(5−coordinated)(4−coordinated)
(with axial solvation)
is assumed to exist in such solutions.