Charge-transfer complexes of chloranil in solution: A conductometric study

The formation of charge-transfer complexes has been studied by conductometric measurements, in the systems aniline—chloranil and pyridine—chloranil in methyl alcohol. The stoichiometry of charge-transfer complexes formed in solution has been determined from the position of the conductivity maximum obtained during the titration of donor solution with acceptor solution. The stoichiometry of the aniline—chloranil complex is 1:1 and that of the pyridine—chloranil complex is 2:3.     

A study of some charge transfer complexes as electrodes in solid-state cells

The electrical and electrochemical properties of charge transfer complexes of iodine with o-tolidine, phenothiazine and N-methylphenothiazine have been investigated with a view to determining their suitability as electrodes in cells based on solid electrolytes. Discharge and polarization studies have shown that iodine electrodes based on phenothiazine and N-methylphenothiazine offer excellent prospects as practical cathodes.     

Intramolecular charge transfer complexes

Summary Radical copolymerization of N-(2-hydroxyethyl)carbazolyl methacrylate (HECM, M₁) with 2-ethylacryl-(ETNFA) and 2-ethylmethacryl-(ETNFM)-4,5,7-trinitro-9-fluorenon-2-carboxylate (M₂), respectively, can be approximated by the simple terminal model having the parameters : HECM-ETNFM r₁ = 0.66 r₂ = 0.40 HECM-ETNFA r₁ = 0.84 r₂ = 0.10Two intramolecular charge transfer complexes copolymers are obtained. Analysis of intramolecular complexation suggests a more complicated copolymerization mechanism, especially in the case of HECM-ETNFA system. Also, the complexation aeems to be independent on the acrylate or methacrylate type of the comonomers.Dedicated to Prof. G. B. Butler on the occasion of his 65th anniversary     

Intramolecular charge transfer complexes

Summary Radical copolymerization of N-ethyl-3-hydroxymethyl cartbazolyl methacrylate (EHMCM) with methacryloyl--hydroxyethyl-3,5-dinitrobenzoate (DNBM) and acryloyl--hydroxyethyl-3,5-dinitrobenzoate (DNBA), respectively, lead to intramolecular charge transfer complexes (CTC). In the case of EHMCM-DNBA copolymerization, a mechanism involving intermonomeric CTC participation is evidenced.Dedicated to Professor B. Vollmert's 60th anniversary     

Intramolecular charge transfer complexes

Summary A new acceptor monomer (methacryloyl -hydroxyethyl-3,5-dinitrobenzoate), having an increased distance between the acceptor group and the double bond, was copolymerized with N-(2-hydroxyethyl)carbazolyl methacrylate and acrylate, respectively. The copolymers are strong intramolecular charge transfer complexes, even at high temperatures. Because the increased distance between the acceptor group and the main chain permits a favourable steric arrangement of the donor and acceptor groups, the intramolecular complexation is independent on copolymer configuration.     

Intramolecular charge transfer complexes

Summary Radical copolymerization of 2,4-dinitrophenyl methacrylate (DNPM, M₂) with N-(2-hydroxyethyl)-3,6-dichlorocarbazolyl methacrylate (HECl₂CM, m₁) and N-(2-hydroxyethyl)-3,6-dichloro-carbazolyl acrylate (HEC1₂CA, M₁) takes place by the simple terminal mechanism having the parameters: r₁=0.13 r₂=1.65 (M₁=HECl₂CM) r₁=0.13 r₂=1.20 (M₁=HECl₂CA) Intramolecular complexation differences for the two obtained systems are explained by configurational differences.Dedicated to our Prof. C.I. Simionescu in occasion of his 60th anniversary6th part in this series: reference (6) Abbrevuiations The monomer mixture is indicated by the initials of the two monomers (for example HECA-PM) and their copolymer by the initials separated by -co- (for example HECA-co-PM).     

Intramolecular charge transfer complexes

Summary In chloroform solutions, 2-naphtyl methacrylate (M₁) and picryl methacrylate (M₂) give a charge transfer complex (CTC) having a 11 composition. The CTC plays a decisive part in the radical copolymerization of these monomers. The reactivity ratio values for this system are : r₁₂=30; r_1C= 0.14; r_1C1=0.19; and r_1C2=0.53.The obtained copolymers are intramolecular CTC, and their charge transfer interactions depend on copolymer composition and conformation.     

Intramolecular charge transfer complexes

Summary Radical copolymerization of acryloyl (PtA)- and methacryloyl (PtM)-2-hydroxyethyl-2-(N-phenothiazinyl)propionate with methacryloyl-2-hydroxyethyl-3,5-dinitrobenzoate proceeds through a mechanism which implies intermonomeric complex participation. There are indirect proofs that the intramolecular charge transfer complexes obtained present a total electron transfer phenomenon at high temperatures.     

Intramolecular charge transfer complexes 6

Summary By modifying the copolymerization temperature for the system N-(2-hydroxyethyl) carbazolyl mathacrylate and picryl methacrylate in dioxane, the reactivity ratio values were shown to be determined mainly through the entropic factor. The obtained intramolecular charge transfer complexes copolymers presented a different intramolecular complexation degree.     

Intramolecular charge transfer complexes 5

Summary Copolymerization of N-(2-hydroxyethyl) carbazolyl mathacrylate (M₁) with 2,4-dinitrophenyl methacrylate (M₂) takes place through the simple terminal mechanism having the parameters r₁=0.35 and r₂=0.53. Intramolecular charge transfer complexes with different donor/acceptor ratios are obtained. The intramolecular complexation is correlated with the alternating diad fraction and with the copolymer conformation through the ¹H-NMR spectra registration temperature.     

A study of some alkali metal-furangraphite compounds and of their charge transfer characteristics

The reaction of furan on the 1st- to 6th-stage potassium-graphite compounds, as well as on some derivatives of other alkali metals, has been critically examined. The composition and the main structural features were determined and it is suggested that the formation of the ternary compound and the stage changes observed are intimately connected with a redistribution between the furan and the aromatic layers of the electron donated by the metal atom. The presence of the electron on the furan has two important consequences: an increase in the apparent volume of the molecules due to the fuzzy orbital occupied by the electron and to the repulsion between the charged species, and a long-term chemical instability of the ternary compound probably due to the presence of the electron on an antibonding orbital.     

Conductometric studies of charge transfer complexes in solution

Conductometric study for formation of charge-transfer complexes, in the systems napthtalene: picric acid and biphenyl: picric acid in acetonitrile; and p-phenylendiamine:choloranil in acetone, methanol and acetonitrile yielded the stoichiometry of the napthalene:picric acid complex as 1:1 and that of the biphenyl:picric acid and p-phenylendediamine:chloranil complexes as 2:1. On dilution with inert solvent CCl₄μ_ν = A + Bm^{$\text{sol1}\text{2}$}_DA is found applicable but with positive slope. The positive values of B obtained are attributed to decreased ionization or/and enchanced ion pair formation with decrease in dielectric constant of the solvent medium.     

Photo-oxidation stabilization of polystyrene by aromatic ultraviolet light absorbers forming charge transfer complexes

Summary The aim of this work was to investigate the influence of UV light absorbing additives on the rate of ultra violet light initiated degradation of polystyrene (PS) in solutions. Anthracene (ANT), chloranil (CA) nitrobenzene (TNB) which can form cnarge transfer complexes between each other were used. It was found for illuminated PS-solutions by light of =254 nm that independently of the screening efficiency of these compounds, tne formed CT complexes ANT-CA and ANT-TNB cause a decrease of tne rate constant of degradation and of the value of the number average of chain scission S. This effect is due to the energy transfer from the excited polymer chain segments to the low energy triplets of these CT-complexes thus hindering the rection of polymer chain segments with oxygen leading to slowing down of photodegradation.     

钌配合物催化苯乙酮的氢转移还原反应的研究

在空气气氛条件下,对钌配合物催化苯乙酮听氢转移还原反应作了详细的考察,取得了较好的结果,使反应更加方便快捷。考察了ＲｕＣｌ３、ＲｕＣｌ３／Ｌｎ〗Ｌｎ＝邻苯二胺（简称ＰＤＡ）、邻氨基酚（简称ＡＰＯ）、邻氨基苯甲酸（简称ＡＢＡ）、２,２＇－联吡啶（简称ＢＩＰＹ）〖及ＲｕＣｌ２（ＰＰＨ３）３这种催化剂对苯学原为苯乙醇的经效果。实验表明,在异丙醇作为溶剂及提供氢源的情况下,以少量Ｎａ#作为助催化剂,Ｒｃ／     

Comparison of intramolecular complexation in several charge transfer complexes copolymers

Summary Another representation of the chemical shift of the acceptor structural units' protons in the NMR spectra is proposed in order to make possible direct comparison between intramolecular complexation in intramolecular charge transfer complexes obtained by copolymerization. The influence of synthesis conditions and comonomer type on the intramolecular complexation is discussed.More experimental data are neededto elucidate these findings.     

Photoinitiation of multifunctional acrylates via ferrocene-alkyl chloride charge transfer complexes

The propensity for ferrocene-alkyl chloride charge transfer complexes (CTCs) to photoinitiate free-radical polymerization of multifunctional acrylates was determined using photodifferential scanning calorimetry. Also, the effects of varying ferrocene (ferrocene, methoxyferrocene, and cyanoferrocene) and alkyl chloride (dichloromethane and benzyl chloride) derivatives were evaluated with regard to the overall polymerization rate and conversion. Furthermore, relative polymerization rates of traditional free-radical Type I and Type II photoinitiators were compared to those of the ferrocene-alkyl chloride CTCs. Semi-empirical quantum mechanical analysis of the complexation reaction was performed using PM3, indicating a thermodynamic preference of complexations involving benzyl chloride, and corroborated the reported complexation mechanism. In order to explain the varying polymerization rates, the association constants for each complex were determined, whereupon complexation of each ferrocene derivative with dichloromethane was found to be more facile than similar complexation with benzyl chloride due to steric considerations. Substituent effects were more pronounced for the benzyl chloride complexes relative to those involving dichloromethane where steric constraints caused deviation from the expected effect. Thus, the cyanoferrocene-benzyl chloride CTC was determined to be the most effective photoinitiator examined with regard to semi-empirical analysis, complexation kinetics, and polymerization rate. Presented at e|5: UV and EB Technical Expo and Conference, sponsored by RadTech International North America, May 4, 2004, Charlotte, NC.     

On some dynamic peculiarities of the charge transfer with adsorption and attractive interactions

Complex electrode reactions with adsorption of intermediate product and with attractive interactions accounted for by Frumkin adsorption isotherm may show up a variety of unusual steady states (ss) characterized by ss adsorption isotherms. Under symmetry of kinetic equations the single peculiarity to be expected in electrochemical adsorption and desorption reactions is hysteresis responsible for current discontinuities in potential sweep experiments and similar discontinuity of immittance data recorded for potential or frequency sweeps. For asymmetry of partial reactions, as for charge transfer coefficients different then 0.5 or unequal charge numbers in partial reactions, the steady-state isotherms get unusual forms described in the chemical dynamics literature as “mushrooms” or “isolas”, this last term referring to disjoined branches of the ss isotherm. In potential scan experiments, these isotherms present double hystereses and irreversible switches between steady states’ branches at high and at low surface coverage.