Complexes In Toluene Research Articles

Electroinitiated polymerization of bis(tribromophenoxo)-N,N,N′,N′-tetramethylethylenediamine copper(II) complex

Tribromophenol copper(II) complexes with ligands such as pyridine and ethylenediamine are known to polymerize thermally. Generally, high temperature is required for thermal polymerization of such complexes. Thermal polymerization of trihalophenol copper(II) complexes in toluene has an induction period of c. 30 min. Electroinitiated polymerization of trihalophenol copper(II) complexes has also been accomplished recently using pyridine or ethylenediamine as ligands. However, the above mentioned copper(II) complexes cannot be polymerized electro-chemically in acetonitrile. When pyridine and ethylenediamine are used as ligands, such complexes rapidly polymerize in acetonitrile without the passage of any current even at room temperature. Therefore, the electrochemical polymerization of trihalophenol copper(II) complexes with pyridine and ethylenediamine ligands must be carried out in dimethylformamide. In the present work, electroinitiated polymerization of bis(2,4,6-tribromo-phenoxo)-N,N,N′,N′-tetramethylethylenediamine copper(II) complex (TBPTD) was accomplished for the first time in acetonitrile. When N,N,N′,N′-tetramethylethylene diamine is used as the ligand in the preparation of tribromophenol copper(II) complex it is found that acetonitrile can be used as solvent. This complex does not polymerize in acetonitrile without the application of potential. Electroinitiated polymerization of TBPTD was carried out by constant potential electrolysis, at each anodic peak potential of the complex. These potentials of TBPTD were measured, in advance, by cyclic voltammetry in acetonitrile. Electrolysis of TBPTD yielded polymers in the anode compartment only. Electroinitated polymerization of this monomer exhibited no induction period in contrast to the case of thermal polymerization. The reacted monomer concentration was simultaneously followed by cyclic voltammetry, in the same electrolysis cell. This process was accomplished by a specially designed H-type cell equipped with six electrodes. Use of cyclic voltammetry for simultaneous in-situ monitoring of reacted monomer concentrations was found to be more accurate, quicker and more reproducible than gas chromatography or spectroscopy. Polymers were characterized by FTIR, 1HNMR, and 13CNMR spectral analyses as well as measurement of molecular weight by the isopiestic method.

Organo- f-element thermochemistry. Actinide-ligand bond disruption enthalpies in tris(indenyl)actinide hydrocarbyls

Thorium- and uranium-ligand bond disruption enthalpies ( D(AnR)) have been obtained for the series of complexes Ind 3AnR, where Ind  C 9H 7 or 1-C 2H 5C 9H 6, An  Th or U, R = an alkyl group. All the new compounds have been characterised by microanalysis and spectroscopy. The thermodynamic data were determined by oxygen-free batch-titration, solution calorimetry from the enthalpies of solution of the organo- f-element complexes in toluene and from the subsequent enthalpies of alcoholysis with 2,2,2-trifluoroethanol. D(An) gas values obtained (95% of confidence) were as follows: (C 9H 7) 3ThCH 2Si(CH 3) 3, (397 ± 7) kJ mol −1; (C 9H 7) 3ThCH 3, (371 ± 6) kJ mol −1; (1-C 2H 5C 9H 6) 3ThCH 3, (365 ± 5) kJ mol −1; (C 9H 7) 3ThCH(CH 3) 2, (357 ± 8) kJ mol −1; (C 9H 7) 3UCH 3, (351 ± 2) kJ mol −1; (1-C 2H 5C 9H 6) 3UCH 3, (350 ± 4) kJ mol −1 and (C 9H 7) 3ThCH 2C 6H 5, (342 ± 9) kJ mol −1. These bond disruption enthalpies parallel, but are significantly larger than, those for the identical R functionalities in the (C 5H 5) 3ThR series. For corresponding Th/U pairs, the differénce { D(ThR) − D(UR)} is ca. 20 kJ mol −1.

ChemInform Abstract: Reaction of Certain Nitrogen Oxides with Iron(III) Porphyrin μ‐Oxo Complexes.

AbstractThe nitrogen oxides NO, N2O4, and N2O3 are reacted with the title complexes (I) in toluene in the absence of O2, (Ib) also in the more polar medium DMA.

The co-ordination of small molecules by manganese(II) phosphine complexes. Part 11. The co-ordination of dioxygen by manganese(II) complexes containing long-chain phosphine ligands

Manganese(II) complexes of long-chain phosphines, [MnX2(phosphine)][X = Cl, Br, or I; phosphine = P(C12H25)3, P(C14H29)3, P(C16H33)3, PPh(C12H25)2, PPh(C14H29)2, or PPh(C16H33)2], have been prepared. They form highly coloured 1 : 1 adducts with dioxygen, [MnX2(phosphine)(O2)], in both toluene and tetrahydrofuran (thf) solution. Infrared and e.s.r. spectra strongly suggest that these [MnX2(phosphine)] complexes are pseudotetrahedral dimers in the solid state and in toluene, contrasting vividly with the previously reported structure of [Mnl2(PPhMe2)]. Some molecular weight data indicate the product of dioxygenation in toluene to be the monomeric [MnX2(phosphine)(O2)] species. Dioxygen-binding curves for toluene and thf solutions have been obtained and equilibrium constants, KO1, for the dioxygenation reaction have been deduced. The general observation that KO2 increases and P50, the partial pressure when 50% of sites are deoxygenated, decreases for changes in halide ligand from Cl to Br to I in both solvents mirrors earlier observations with complexes of short-chain phosphines. The affinity of the complexes for O2 in thf is in the order phenyldialkylphosphines < trialkylphosphines. Hill coefficients, n, are approximately 1 for thf solutions of the chloride and bromide complexes, but for the iodides in thf and all of the complexes in toluene n lies in the range 1.10–1.64 indicating co-operativity for O2 binding, which may be related to the dimeric structure proposed for the complexes in toluene.

Synthesis, Methanolysis, and Asymmetric Polymerization of meta- and para-substituted Triphenylmethyl Methacrylates

Five novel meta- and para-substituted triphenylmethyl methacrylates, diphenyl-m-fluorophenylmethyl methacrylate (m-F1TrMA), m-chlorophenyldiphenylmethyl methacrylate (m-Cl1TrMA), tris(m-chlorophenyl)methyl methacrylate (m-Cl3TrMA), tris(p-chlorophenyl)methyl methacrylate(p-Cl3TrMA), and tris(m-tolyl)methyl methacrylate (m-Me3TrMA), were synthesized: Their solvolysis rates were measured in CDCl3-CD3OD (1:1) by 1H NMR spectroscopy at 35°C. The rates were greatly affected by the substituents. Chlorine and fluorine substituents decreased the rates of the methanolysis and the methyl group accelerated it. These methacrylates were polymerized with chiral anionic initiators, such as (+)-(2S,3S)- or (−)-(2R,3R)-dimethoxy-1,4-bis(dimethylamino)butane (DDB)-N,N′-diphenylethylenediamine monolithium amide (DPEDA-Li) and (−)-sparteine-fluorenyllithium (Sp-FlLi) complexes in toluene at −78°C. DDB-DPEDA-Li complex was more reactive than the Sp-FlLi complex and gave quantitatively optically active, isotactic polymers with one-handed helicity except for p-Cl3TrMA. p-Cl3TrMA did not form a high polymer probably because of the bulkiness of the ester group. The CD spectra of the optically active polymers were different from each other. The copolymerization of p-Cl3TrMA with TrMA by (+)-DDB-DPEDA-Li complex gave a low-molecular-weight copolymer of low optical activity which decreased slowly with time probably because of uncoiling of the helix.

ChemInform Abstract: Organo‐f‐Element Thermochemistry. Thorium vs. Uranium and Ancillary Ligand Effects on Metal‐Ligand Bond Disruption Enthalpies in Bis(pentamethylcyclopentadienyl)actinoid Bis(hydrocarbyls) and Bis(pentamethylcyclopentadienyl)alkoxyactinoid Hydrides and Hydrocarbyls.

AbstractThe thermodynamic data are obtained by anaerobic, batch‐titration, solution‐calorimetry from the enthalpies of solution of the organoactinoid complexes (I) in toluene and from the subsequent enthalpies of alcoholysis with tBuOH or MeOH.

Ethylene–propylene copolymerization initiated with solubilized Ziegler–Natta macromolecular complexes. I. Determination of kinetic parameters

AbstractCopolymerization of ethylene with propylene (E–P) was initiated with soluble polystyrene –butadiene–Li/TiCl4 complexes in toluene leading to vinylic‐olefinic based block copolymers. The activity of the system was measured at a constant ratio r = Li/Ti for different feed compositions. From measurements of the amount of copolymers produced, a direct determination of the efficiency of the catalytic system was made. This efficiency was found to be close to that obtained for homopolymerizations of C2H4 and C3H6 initiated with the same catalytic complex (≃ 80% with respect to the concentration of “carbon‐titanium” bonds).Both the measured values of the efficiency and the determination of the molar masses of the polyolefinic block are consistent with a living character of the system involved in the E–P copolymerization. In such conditions well‐defined linear [styrene]‐b‐[ethylene‐co‐propylene] copolymers were obtained. Furthermore, 13C NMR analyses allowed determination of the comonomer reactivity ratios, the values of which indicate an E–P random copolymerization.From both these values and those of the absolute rate constants of propagation determined for the homopolymerization of C2H4 and C3H6 initiated with the same catalytic system, the absolute rate constants of cross‐propagation were deduced.

Organo-f-element thermochemistry. Thorium vs. uranium and ancillary ligand effects on metal-ligand bond disruption enthalpies in bis(pentamethylcyclopentadienyl)actinide bis(hydrocarbyls) and bis(pentamethylcyclopentadienyl) alkoxy actinide hydrides and hydrocarbyls

Thorium and uranium-ligand bond disruption enthalpies (D(M-R)) have been determined for a series of complexes of the type Cp'/sub 2/M(R)X, where M = Th, or U, Cp' = eta/sup 5/-(CH/sub 3/)/sub 5/C/sub 5/, R = alkyl, aryl, or hydride, and X = alkyl, chloride, or alkoxide. The thermodynamic data were obtained by anaerobic, batch-titration, solution calorimetry from the enthalpies of solution of the organic-f-element complexes in toluene and from the subsequent enthalpies of alcoholysis with tert-butyl alcohol or methanol.

ChemInform Abstract: Axial Ligation Constants of [5,10,15,20‐Tetraphenylporphyrinato(2‐)]cobalt.

AbstractThe constants are determined for Py, 4‐cyanopyridine, 3,5‐dichloropyridine, 4‐methylpyridine, 4‐dimethylaminopyridine, isoquinoline, quinoline, and piperidine in five‐coordinated tetraphenylporphyrinatocob‐alt(II) complexes in toluene.

Hydrogenation of α,β-unsaturated aldehydes and ketones to the unsaturated alcohols catalysed by hydridoiridium phosphine complexes

Unusual selective hydrogenation of cinnamaldehyde and benzylideneacetone to the corresponding unsaturated alcohols is catalysed by [H2Ir(phosphine)4]+ complexes in toluene; use of a chiral phosphine gives a 7.4% enantiomeric excess of (S)-(–)-1-phenylbut-1-en-3-ol.

Intrinsic reactivity of active species in Ziegler–Natta polymerization of ethylene initiated with Li/Ti‐based macromolecular complexes

AbstractPolymerization of ethylene was initiated with soluble polystyrene100‐butadiene3‐Li/TiCI4 complexes in toluene leading to block copolymers. The activity of the system was measured at a constant ratio r = [Li]/[Ti] and for different concentrations in active centers and in monomer. Measurement of the amount of the block copolymers formed led to the direct determination of the efficiency of the catalytic system. This efficiency is defined with respect to the number of potentially active centers and is close to 90%. From both measured values of activity of the catalytic system and of its efficiency, the rate constants of propagation were deduced. The kinetic behavior of the system is fully consistent with that of a living system. The rate is first order towards both ethylene and active centers concentrations. So, the rate constant of propagation is an absolute rate constant, measuring the intrinsic reactivity of active sites. Determination of the absolute rate constant at different temperatures, led to thermodynamic parameters of the propagation reaction. The chemical composition of the complex and the absence of polymeric aggregation, leads to propose a structure of the active species: a bioctahedral binuclear structure is consistent with kinetic, thermodynamic results, and structural determinations.

PREPARATION OF 1-ALKENYL PHENYL SULFIDES BY THE NICKEL(II)-COMPLEXES CATALYZED COUPLING REACTION OF 3-METHOXY-1-PHENYLTHIO-1-PROPENE WITH GRIGNARD REAGENTS

Abstract The reaction of 3-methoxy-1-phenylthio-1-propene with aryl and primary alkyl Grignard reagents in the presence of nickel(II)–phosphine complexes in benzene or toluene proceeded chemo- and regioselectively to give 1-alkenyl phenyl sulfides in high yields.

The ‘pocket’ porphyrins: Hemoprotein models with lowered CO affinities

A new series of hemoprotein models, the iron(II) ‘pocket’ porphyrins [1], have been synthesized (Fig.1). This series of congruent models has been designed so as to incorporate varying degrees of steric encumbrance at the gaseous ligand binding site. Throughout the series, the pockets are expected to accommodate the formation of unhindered, bent FeO 2 units, while providing, in differing degrees, steric hindrance sufficient to interfere with the binding of CO in a normal linear fashion. Dilute solutions of several iron(II) ‘pocket’ porphyrin complexes in toluene are five-coordinate in the presence of excess axial ligands (1-methylimidazole and 1,2-dimethylimidazole) and are sufficiently stable with respect to oxidation so as to allow determination of ▪ and ▪ at room temperature under equilibrium conditions. Whereas the oxygenaffinities of the ferrous ‘pocket’ systems are comparable to those of the ‘picket fence’ [2] compounds, the carbon monoxide affinities are significantly lowered and approach that of myoglobin (Table I). Kinetic data indicate that the lowered CO affinities in the ‘pocket’ complexes are primarily reflected in decreased association rates. By contrast, the ‘pocket’ models show both decreased O 2 dissociation and association rates as compared to the ‘picket fence’ analogues, FeTpivP(1,2-Me 2Im), I, and FePiv 35CIm, II. These results indicate that steric hindrance can selectively discriminate against CO binding in model compounds and support the hypothesis that the intrinsic CO affinities of hemes may be reduced by steric interaction with the binding pocket in hemoproteins [3]. A full account of this work is to be published elsewhere [1]. ▪ t001 O 2 and CO Binding to Iron Porphyrins and Hemoproteins a,b . k CO B ( M −1 s −1) P CO 1 2 (torr) k O 2 B ( M −1 s −1) P O 2 1 2 (torr) Mb c [0.1 M KPi] 3–5 × 10 5 0.014 –0.025 1–2 × 10 7 0.37–1 HbA, R state c [0.05–0.1 M KPi] 4.6 × 10 6 0.0014 3.3 × 10 7 0.22 d , 0.36 e 2.9 × 10 6 d HbA, T state c [0.1 M KPi] 2.2 × 10 5 0.30 1.2 × 10 7 e 40 d , 140 e FePiv 35Clm( II) f 3.6 × 10 7 2.2 × 10 −5 4.3 × 10 8 0.58 FeMedPoc(1-Melm) ( IVa) f 1.5 × 10 6 6.5 × 10 −4 1.7 × 10 7 0.36 g FePocPiv(1-MeIm) ( IIIa) f 5.8 × 10 5 1.5 × 10 −3 2.2 × 10 6 0.36 FeTpivP(1,2-Me 2Im) ( I) f 1.4 × 10 6 8.9 × 10 −3 1.1 × 10 8 38 FeTalPoc(1,2-Me 2Im) ( V) f 1.1 × 10 −3 7.4 × 10 8 4 FeMedPoc(1,2-Me 2Im) ( IVb) f 2.1 × 10 5 0.026 5.2 × 10 6 12.4 FePocPiv(1,2-Me 2Im) ( IIIb) f 9.8 × 10 4 0.067 1.9 × 10 6 12.6 a Errors ⩽ 15%, unless otherwise indicated. b For original literature citations see references 1a and 1c. c Aqueous, pH 7.0–7.4, 20°C. d Value for α chain. e Value of β chain. f Toluene, 25°C. g −+20% error.

Equilibrium studies on Schiff base complexes of copper(II) and nickel(II): Ligand substitution and formation of mixed ligand complexes

Vis spectrophotometry has been used to study various ligand substitution equilibria (1) and (2) involving four-coordinate copper(II) and nickel(II) his chelate complexes in methanol, propan-2-ol and toluene. MA2 + HB ⇋ MAB+HA, K1 (1) MAB + HB ⇋ MB2 + HA, K2 (2) The Schiff base ligands, HA and HB, which are monobasic and bidentate, represent salicylaldimine type N,O-ligands (≙ HSA=NR) (1) or pyrrole-2-aldimine type N,N-ligands (≙ HPA=NR) (2) with different branching at the α- or (3-carbon of the organic group R. For both types of ligand the relative thermodynamic stability of their copper and nickel complexes is governed mainly by the steric demands of R, which determine the degree of tetrahedral distortion. The order of stability as given by β = K1 K2 is: t-Bu < neo-Pent < i-Pr < i-Bu < Et < n-Pr. The K1/K2 ratio is strongly solvent dependent in the sense that the mixed ligand species MAB is stabilised in toluene relative to methanol. Such a solvent effect is not observed for β. The MAB complexes could not be isolated. The vis spectrum of the mixed ligand species Ni(SA=NiPr, SA=NEt) was calculated by computer fitting of the experimental data.

The Lewis-acidity of square-planar nickel(II) complexes. III. A kinetic study of the effects of substituents on the addition of 1,10-Phenanthroline to Bis(monothioacetylacetonato)nickel(II) and Bis(dithiophosphato)nickel(II) complexes in toluene

The second-order rate constants and activation parameters for the addition of 1,10-phenanthroline to bis(dialkyldithiophosphato)nickel(II) complexes and substituted bis(monothioacetylacetonato)-nickel(II) complexes in toluene have been measured. Rate constants are in the range 102-108 1. mol-1 s-1 at 25°C, while ΔH‡ is in the range 10-50 kJ mol-1 and ΔS‡ is in the range from -30 to -110 J mol-1 K-1. The higher rate constants, smaller ΔH‡ and more negative ΔS‡ values are associated with complexes with electron- withdrawing substituents. The results are related to the thermo- dynamics of adduct formation, the inductive effects of the substituents and the pKa of the ligands.

The solubility of water in low-dielectric solvents

The solubility of water has been measured in several low-dielectric solvents at 25 °C, and the values in the nonpolar solvents are treated by using a modification of the Scatchard–Hildebrand equation. The water–solvent interaction parameter in this equation is represented by a new relationship involving the separate contributions due to dispersion and polar interactions. A new method is given for calculation of the dispersion component of the solubility parameter of a polar species. Formation constants are reported for 1:1 water–solvent complexes in carbon tetrachloride, benzene, toluene, and p-xylene.

ESR and Optical Absorption Studies of Various Bis(N-salicylidenealkylaminato)copper(II) Complexes with Tetrahedrallydistorted Coordination Geometry

Abstract The ESR and visible absorption spectra of a number of bis(N-salicylidenealkylaminato)copper(II) complexes with different kinds of alkyl groups were measured in toluene. The coordinations of these complexes in toluene are distorted towards a tetrahedral geometry to varying extents; the relationship between the degree of the distortion and the ESR and visible absorption parameters was systematically investigated. Especially, the experimental fact that the absolute values of the hyperfine coupling constant with the copper nucleus decrease with an increase in the degree of distortion was discussed. A configurational equilibrium between two species with different degrees of the distortion was found to exist for the complexes with R=isopropyl and cyclohexyl in toluene.

Rapid colorimetric micromethod for free fatty acids

Free fatty acids (FFA), the uranyl ion, and the basic dye Rhodamine B form colored complexes, which are extractable into toluene or benzene. Fatty acids of different chain lengths above C(10) and different degrees of unsaturation gave constant molar yield. Complexes in toluene alone are unstable, especially in the light, but a small amount of aqueous uranyl acetate stabilizes them sufficiently for determination. At constant uranyl and Rhodamine B concentrations, a plot of optical density vs. FFA concentration yields two straight lines of different slope, i.e., a biphasic standard curve. Phospholipids interfere, and must be removed with zeolite during FFA extraction. Recovery of FFA added to rat plasma was very similar to that with titration. Assay of rat and dog plasma samples under fasting and fed conditions gave good agreement with the titration method. Values of human plasma samples tended to be higher by the colorimetric procedure; a few samples gave significant disagreement. The method compares well with previous methods in sensitivity and accuracy, and offers advantages in speed, simplicity, and possibly specificity.

Inorganic polarography in organic solvents—III: Analytical applications of metal-acetylacetonate complexes in toluene

Indium and palladium are determined polarographically with a dropping mercury electrode in a toluene phase, following extraction as the acetylacetonates from aqueous solutions containing 2–10 ppm of the metals (or 0.1–0.5 ppm with a greater ratio of sample volume to solvent volume). Of 31 elements examined, only Co(III), Cr(III), Cu(II), Fe(III), In, Mo(VI), Pd and Ti(IV) gave extractable complexes with reduction waves in the available potential range. Specificity for palladium is obtained by extraction at pH 0.5, and for indium at pH 9 m the presence of cyanide and ascorbic acid as masking agents.

Inorganic polarography in organic solvents—I: Some metal-pyridine-thiocyanate complexes in toluene

Results are reported for the direct application of polarography to the examination of organic phases following solvent extraction. Experimental factors such as suitable solvents, supporting electrolytes and electrode parameters have been studied and the method is tested for the extraction of the Cd, Co(II), Cu(II), Fe(II), Mn(II), Ni and Zn pyridine/thiocyanate complexes into toluene. The results show that the sensitivity is increased by the concentrating effect of the extraction system and better selectivity is achieved without searching for a suitable supporting electrolyte.