Solvent effects on complexation of thallium(I) with guanosine 5′‐monophosphate in methanol–water mixtures

The interaction of guanosine 5′‐monophosphate, GMP, with the thallium(I) ion was studied by UV–vis and potentiometric titration methods and ³¹P NMR spectroscopy. Both NMR spectra and UV–vis titration data have shown that GMP coordinates via guanine to the thallium(I) ion in the pH range 1.5–10. Our study of the system Tl(I) + GMP was performed in water–methanol mixtures with different volume ratios of methanol. The complexation equilibrium in the pH range of study led to the following mononuclear species: TlH₂(GMP)⁺, TlH(GMP) and Tl(GMP)^?, where (GMP)^2? represents the fully dissociated ligand. The formation constants of the species were calculated in the various media at constant temperature (25 °C) and constant ionic strength of sodium perchlorate (0.1 mol dm^?3) using a suitable computer program. The formation constants were analyzed in terms of Kamlet and Taft's parameters. A single‐parameter correlation of the formation constants, β₁₂₁, β₁₁₁ and β₁₀₁ vs α (hydrogen‐bond donor acidity), β (hydrogen‐bond acceptor basicity) and for π* (dipolarity/polarizability) are relatively poor in all solutions, but multi‐parameter correlations represent significant improvements with regard to the single‐parameter model. In this work, we have also used the normalized polarity parameter, E_T^N, alone and in combination with some of the Kamlet–Taft parameters to find a better correlation of the formation constants in different methanol–water mixtures. Copyright © 2007 John Wiley & Sons, Ltd.     

Solvent effects on kinetics of the reaction between 2‐chloro‐3,5‐dinitropyridine and aniline in aqueous and alcoholic solutions of [bmim]BF4

Rate constants, k_A, for the aromatic nucleophilic substitution reaction of 2‐chloro‐3,5‐dinitropyridine with aniline were determined in different compositions of 1‐(1‐butyl)‐3‐methylimidazolium terafluoroborate ([bmim]BF₄) mixed with water, methanol, and ethanol at 25°C. The obtained rate constants of the reaction in pure solvents are in the following order: water > methanol > ethanol > [bmim]BF₄. In these solutions, rate constants of the reaction decrease with the mole fraction of the ionic liquid. Single‐parameter correlations of log k_A versus normalized polarity parameter (E), hydrogen bond acceptor basicity (β), hydrogen bond donor acidity (α), and dipolarity/polarizability (π*) do not give acceptable results in all solutions. Dual‐parameter correlations of log k_A versus E and β also α and β gave reasonable results (e.g., in solutions of water with [bmim]BF₄, the correlation coefficients are 0.994 and 0.996, respectively). The proposed dual‐parameter models demonstrate that the reaction rate constant increases with E, β, and α. The increase in the rate constant is attributed to hydrogen‐bonding interactions (donor and acceptor) of the media with an activated complex of the reaction that has the zwitterionic character. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 681–687, 2007     

Reactions of halogenated organic peroxyl radicals with various purine derivatives,tyrosine, and thymine: A pulse radiolysis study

Absolute rate constants for the one electron oxidation of guanine, guanosine, uric acid, xanthine, hypoxanthine, tyrosine, and thymine by various halogenated peroxyl radicals in aqueous solutions have been determined using the technique of pulse radiolysis. Roughly, linear correlations have been observed between the logarithm of these rate constants and Taft's inductive parameter (σ*) for the radicals. However, the rate constants for the radical CBr₃O are slightly higher than those for CCl₃O for most of these compounds. © John Wiley & Sons, Inc.     

Preferential solvational effects on the Cr(VI) oxidation of benzylamines in benzene/2‐methylpropan‐2‐ol mixtures

Imidazolium fluorochromate (IFC) oxidation of 11 meta‐ and para‐substituted benzylamines, in varying mole fractions of benzene/2‐methylpropan‐2‐ol binary mixtures, is first order in IFC and acid and zero order in substrate. The Hammett correlation yielded a U‐shaped curve, indicating a change in the relative importance of bond formation and bond fission in the transition state. The rate data failed to correlate with macroscopic solvent parameters such as ε_r and E. The correlation of k_obs with Kamlet–Taft solvatochromic parameters suggests that H‐bonding between the reacting species and the solvent plays a major role in governing the reactivity. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 159–167, 2010     

Factors affecting the complexation of polyacrylic acid with uranyl ions in aqueous solutions: A luminescence study

A study was carried out in aqueous solutions using luminescence technique to investigate the effects of pH, salt concentration, and temperature on the polyacrylic acid/uranyl ion (PAA/UO) complex formation as well as competitive phenomena of enhancement and quenching effects on photoexcited state of uranyl ions. It was found that excess of H⁺ and OH^? is not favorable for complexation between uranyl ions and polymer. Added nitrate salts of Na⁺ and K⁺ had significant enhancement effect on emission spectra of PAA/UO complex. These results indicated that the metal ion/polymer chain complex collapsed by addition of salts and then complex became more compact with consequent phase separation. No significant effect of temperature on the PAA/UO complex stability has been observed between 25–50 °C. The quenching rate constants obtained from Stern–Volmer plots were found to be in the order of k_q(H⁺) >> k_q(K⁺) > k_q(Na⁺). © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2737–2744, 2005     

Kinetic study of the interaction of adenosine 5′‐monophosphate with diaqua (2‐hydrazinopyridine) palladium(II) in aqueous medium

The interaction of the palladium(II) complex [Pd(hzpy)(H₂O)₂]²⁺, where hzpy is 2‐hydrazinopyridine, with purine nucleoside adenosine 5′‐monophosphate (5′‐AMP) was studied kinetically under pseudo‐first‐order conditions, using stopped‐flow techniques. The reaction was found to take place in two consecutive reaction steps, which are both dependent on the actual 5′‐AMP concentration. The activation parameters for the two reaction steps, i.e. ΔH = 32 ±2 kJ mol^?1, ΔS = ?168 ±7 J K^?1 mol^?1, and ΔH = 28 ± 1 kJ mol^?1, ΔS = ?126 ± 5 J K^?1 mol^?1, respectively, were evaluated and suggested an associative mode of activation for both substitution processes. The stability constants and the associated speciation diagram of the complexes were also determined potentiometrically. The isolated solid complex was characterized by C, H, and N elemental analyses, IR, magnetic, and molar conductance measurements. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 132–142, 2010     

Solvent Effects on Complexation of Molybdenum（Ⅵ） with Nitrilotriacetic Acid in Different Aqueous Solutions of Propanol

By using spectrophotometric and potentiometric techniques the formation constants of the species formed in the systems H^＋＋ Mo（Ⅵ）＋nitrilotriacetic acid and H^＋ ＋ nitrilotriacetic acid have been determined in aqueous solutions of propanol at 25 ℃ and constant ionic strength 0.1 molodm^-3 sodium perchlorate. The composition of the complex was determined by the continuous variation method. It was shown that molybdenum（Ⅵ） forms a mononuclear 1 ： 1 complex with nitrilotriacetic acid of the type MoO3L^-3 at -lg[H^＋] =5.8. The formation constants in various media were analyzed in terms of Kamlet and Taft＇s parameters. Linear relationships were observed when lg Ks was plotted versusp. Finally, the results were discussed in terms of the effect of solvent on complexation.     

Effects of CH3OH‐H2O and CH3OH solvents on rate of reaction of phthalimide with piperidine

Pseudo‐first‐order rate constants (k_obs) for the cleavage of phthalimide in the presence of piperidine (Pip) vary linearly with the total concentration of Pip ([Pip]_T) at a constant content of methanol in mixed aqueous solvents containing 2% v/v acetonitrile. Such linear variation of k_obs against [Pip]_T exists within the methanol content range 10%–∼80% v/v. The change in k_obs with the change in [Pip]_T at 98% v/v CH₃OH in mixed methanol‐acetonitrile solvent shows the relationship: k_obs = k[Pip]_T + k[Pip], where respective k and k represent apparent second‐order and third‐order rate constants for nucleophilic and general base‐catalyzed piperidinolysis of phthalimide. The values of k_obs, obtained within [Pip]_T range 0.02–0.40 M at 0.03 M NaOH and 20 as well as 50% v/v CH₃OH reveal the relationship: k_obs = k₀/(1 + {k_n[Pip]/k_OX[⁻OX]_T}), where k₀ is the pseudo‐first‐order rate constant for hydrolysis of phthalimide, k_n and k_OX represent nucleophilic second‐order rate constants for the reaction of Pip with phthalimide and for the XO⁻‐catalyzed cyclization of N‐piperidinylphthalamide to phthalimide, respectively, and [⁻OX]_T = [NaOH] + [⁻OX_re], where [⁻OX_re] = [⁻OH_re] + [CH₃O_re⁻]. The reversible reactions of Pip with H₂O and CH₃OH produce ⁻OH_re and CH₃O_re⁻ ions. The effects of mixed methanol‐water solvents on the rates of piperidinolysis of PTH reveal a nonlinear decrease in k with the increase in the content of methanol. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 33: 29–40, 2001     

Studies on the composition and kinetics of chromium(III)-alanine system

Kinetics of the complex formation of chromium(III) with alanine in aqueous medium has been studied at 45, 50, and 55°C, pH 3.3–4.4, and μ = 1 M (KNO₃). Under pseudo first-order conditions the observed rate constant (k_obs) was found to follow the rate equation: Values of the rate parameters (k_an, k, K_IP, and K) were calculated. Activation parameters for anation rate constants, ΔH^≠(k_an) = 25 ± 1 kJ mol^?1, ΔH^≠(k) = 91 ± 3 kJ mol^?1, and ΔS^≠(k_an) = ?244 ± 3 JK^?1 mol^?1, ΔS^≠(k) = ?30 ± 10 JK^?1 mol^?1 are indicative of an (I_a) mechanism for k_an and (I_d) mechanism for k routes (‥substrate Cr(H₂O) is involved in the k route whereas Cr(H₂O)₅OH²⁺ is involved in k′ route). Thermodynamic parameters for ion-pair formation constants are found to be ΔH°(K_IP) = 12 ± 1 kJ mol^?1, ΔH°(K) = ?13 ± 3 kJ mol^?1 and ΔS°(K_IP) = 47 ± 2 JK^?1 mol^?1, and ΔS°(K) = 20 ± 9 JK^?1 mol^?1.     

Kinetics and mechanism of the cationic polymerization of trioxane. I. Crystallization during polymerization

Cationic polymerizations of trioxane in 1,2‐ethylene dichloride and benzene were heterogeneous and reversible. Phase separation accompanying with crystallization occurred during the polymerization. Three morphological changes were found in the course of the polymerization as were investigated by dilatometry and precipitation method. Based on the findings of morphological changes and three reversible processes for the polymerization, a rate equation was proposed to describe the polymerization. The proposed rate equation was fairly good in describing the experimental data, and kinetics constants including K_p, K_d, K_p′, K_d′, M, M, and K_dis/K_cr for the polymerization at 30, 40, and 50°C in 1,2‐ethylene dichloride and benzene were obtained. Factors that affected the kinetics constants were discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 483–492, 1999     

Kinetics of the simultaneous oxidation of nickel(II) and sulfur(IV) by oxygen in alkaline medium in Ni(II)–sulfur(IV)–O2 system

In the Ni(II)–S(IV)–O₂ system in the region of pH > 8.4, both Ni(II) and S(IV) are simultaneously autoxidized, and when sulfur is consumed fully NiOOH precipitates. At pH > 8.4, ethanol has no effect on the rate, whereas ammonia strongly inhibits the reaction when pH > 7.0. The kinetics of the reaction, in both the presence and the absence of ethanol, is defined by the rate law where k is the rate constant, K_O is the equilibrium constant for the adsorption of O₂ on ? Ni(OH)₂ particle surface. In ammonia buffer, the factor F is defined by where K, K_OH, K₁, K₂, K₃, and K₄ are the stability constants of NiSO₃, NiOH⁺, Ni(NH₃)²⁺, Ni(NH₃), Ni(NH₃), and Ni(NH₃), respectively. In unbuffered medium, the factor F reduces to The values of k and K^sp were found to be (1.3 ± 0.08) × 10^?1 s^?1 and (4.2 ± 3.5) × 10^?16, respectively, at 30°C. A nonradical mechanism that assumes the adsorption of both SO₃^2? and O₂ on the ? Ni(OH)₂ particle surface has been proposed. At pH ≤ 8.2, Ni(II) displays no catalytic activity for sulfur(IV)‐autoxidation and it is also not oxidized to NiOOH. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 464–478, 2010     

Mass spectrometric evidence for collisionally induced removal of H2 from monoanions of 10B nido‐carborane derivatives investigated by electrospray ionization quadrupole linear ion trap and Fourier transform ion cyclotron resonance mass spectrometry

Some newly synthesized ¹⁰B nido‐carborane derivatives, i.e., 7,8‐dicarba‐nido‐undecaborane monoanions ([7‐Me‐8‐R‐C₂B₉H₁₀]^‐K⁺, R = H, butyl, hexyl, octyl and decyl), have been fully characterised and examined by electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry with liquid chromatographic separation (LC/ESI‐FTICR‐MS). These boron‐containing compounds exhibit abundant molecular ions ([M]^?) at m/z 140.22631 [CB₉H₁₄]^?, m/z 196.28883 [CB₉H₂₂]^?, m/z 224.32032 [CB₉H₂₆]^?, m/z 252.35133 [CB₉H₃₀]^? and m/z 280.38354 [CB₉H₃₄]^? at the normal tube lens voltage setting of ?90 V, which was an instrumental parameter value selected in the tuning operation. Additional [M–nH₂]^? (n = 1?4) ions were observed in the mass spectra when higher tube lens voltages were applied, i.e., ?140 V. High‐resolution FTICR‐MS data revealed the accurate masses of fragment ions, bearing either an even or an odd number of electrons. Collision‐induced dissociation of the [M–nH₂]^? ions (n = 0–4) in the quadrupole linear ion trap (LTQ) analyzer confirmed the loss of hydrogen molecules from the molecular ions. It is suggested that the loss of H₂ molecules from the alkyl chain is a consequence of the stabilization effect of the nido‐carborane charged polyhedral skeleton. Copyright © 2009 John Wiley & Sons, Ltd.     

Spectroscopic studies on the dynamics of charge‐transfer interaction of pantoprazole drug with DDQ and iodine

Spectrophotometric method was used to study the kinetics of charge‐transfer (CT) complexes of pantoprazole with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and iodine. The reactions of DDQ and iodine with pantoprazole have been investigated in different solvents at three different temperatures. The products of the interactions have been isolated and characterized using UV–vis, GC‐MS, FT‐IR, and far‐IR spectral techniques. The rate of formation of the product has been measured and discussed as a function of solvents and temperature. The iodine complex indicates the formation of the tri‐iodide CT complex with a general formula [(PTZ)I]⁺I. The characteristic strong absorptions of I are observed around 360 and 290 nm in the electronic spectra, and the far‐IR spectrum exhibits three characteristic vibrations of I unit at 156, 112, and 69 cm^?1 assigned to ν_as(I‐I), ν_s(I‐I), and δ(I), respectively. The activation parameters (ΔG^#, ΔS^#, and ΔH^#) were obtained from the temperature dependence of the rate constants. The influence of relative permittivity of the medium on the rate indicated that the intermediate is more polar than the reactants, and this observation was further well supported by spectral studies. Based on the spectrokinetic results, plausible mechanisms for the interaction of the drug with the chosen acceptors, which proceed via the formation of CT complexes and its transformation into final products, have been proposed. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 787–799, 2009     

Hydroxylation of 4‐Amino‐5‐hydroxynaphthalene‐2,7‐disulfonic Acid Monosodium Salt Catalysed by Horseradish Peroxidase and Hydrogen Peroxide: Computation of Kinetic Parameters Including Its Application to Crude Plant Extracts

The new spectrophotometric assay method for the quantification of peroxidase activity uses 4‐amino‐5‐hydroxynaphthalene‐2,7‐disulfonicacid monosodium salt (AHNDSA) as chromogenic co‐substrate. The method is based on hydroxylation of AHNDSA in presence of H₂O₂/peroxidase forming quinone, having λ_max = 460 nm in the acetate buffer (pH = 4.0) at 30 °C. The linearity of H₂O₂ by kinetic method was 10–332 µM and for peroxidase by kinetic and fixed time methods were 1.18–18.92 and 1.18–9.46 nM, respectively. Catalytic efficiency and catalytic power for peroxidase assay were 7.965 × 10⁴ M^?1min^?1 and 3.76 × 10^?4 min^?1, respectively. From the plot of d(1/A_o) vs d(1/V_o) and d(1/H_o) vs d(1/V_o), the apparent Michaelis‐Menten constants for H₂O₂ and AHNDSA were K = 68 and K = 275 µM, respectively. The method was tested with some plant extracts and also compared with guaiacol/peroxidase system. Except Boerhavia diffusa, all other tested plant samples showed highest peroxidase activity. The proposed method is a rapid and convenient method to determine peroxidase activity by spectrophotometer. This method for the first time reports peroxidase activity in Lantana camara and Oplismenus compositus plants. Kinetic results showed that AHNDSA/peroxidase system can be better hydrogen donor for peroxidase assay than guaiacol system.     

A fourier-transform infrared spectroscopic study of the surface hydrolysis of polythiazyl

The hydrolysis of (SN)_x, in air at room temperature and 90% relative humidity has been studied using the attenuated total reflectance (ATR) method. Decomposition gave rise to strong bands at 3210 and 3150 cm^–1 [v₃ and v₁ (NH)], 1420 cm^–1 (v_b NH), 1220 cm^–1 (S?O), 1089 and 610 cm^–1 [v₁ and v₃ (SO)]. For the first 3 days, the decay of the 808 and 690 cm^–1 bands of (SN)_x was first order, with a half life of about 30 h. The spectroscopic data were consistent with the rapid formation of ? SO₂? NH₂ and ?S?NH chain end groups with subsequent relatively slow hydrolysis to (NH₄)₂SO₄, sulfur, and fresh hydrolysable chain ends.     

Thermochemistry of the Ternary Complex Nd（Et2dtc）3（phen）

Introduction A series of lanthanide sulfide complexes have beenlargely used for ceramics and thin film materials1 andthese complexes could be prepared from the precursorswhich are the compounds containing lanthanide-sulfurbonds.2-4 For instance, the compounds synthesized with[(alkyl)2dtc]-, phen?H2O and lanthanide salts were usedas the volatile precursors for preparing lanthanide sul-fide, its friction properties in lubricant was investigatedin literature 5 and the preparation and propertie…     

Peculiar kinetics of the complex formation in the iron(III)–sulfate system

The results of comprehensive equilibrium and kinetic studies of the iron(III)–sulfate system in aqueous solutions at I = 1.0 M (NaClO₄), in the concentration ranges of T = 0.15–0.3 mM, and at pH 0.7–2.5 are presented. The iron(III)–containing species detected are FeOH²⁺ (=FeH_?1), (FeOH) (=Fe₂H_?2), FeSO, and Fe(SO₄) with formation constants of log β = ?2.84, log β = ?2.88, log β = 2.32, and log β = 3.83. The formation rate constants of the stepwise formation of the sulfate complexes are k_1a = 4.4 × 10³ M^?1 s^?1 for the ${\rm Fe}^{3+} + {\rm SO}_4^{2-}\,\stackrel{k_{1a}}{\rightleftharpoons}\, {\rm FeSO}_4^+The results of comprehensive equilibrium and kinetic studies of the iron(III)–sulfate system in aqueous solutions at I = 1.0 M (NaClO₄), in the concentration ranges of T = 0.15–0.3 mM, and at pH 0.7–2.5 are presented. The iron(III)–containing species detected are FeOH²⁺ (=FeH_?1), (FeOH) (=Fe₂H_?2), FeSO, and Fe(SO₄) with formation constants of log β = ?2.84, log β = ?2.88, log β = 2.32, and log β = 3.83. The formation rate constants of the stepwise formation of the sulfate complexes are k_1a = 4.4 × 10³ M^?1 s^?1 for the ${\rm Fe}^{3+} + {\rm SO}_4^{2-}\,\stackrel{k_{1a}}{\rightleftharpoons}\, {\rm FeSO}_4^+$ step and k₂ = 1.1 × 10³ M^?1 s^?1 for the ${\rm FeSO}_4^+ + {\rm SO}_4^{2-} \stackrel{k_2}{\rightleftharpoons}\, {\rm Fe}({\rm SO}_4)_2^-$ step. The mono‐sulfate complex is also formed in the ${\rm Fe}({\rm OH})^{2+} + {\rm SO}_4^{2-} \stackrel{k_{1b}}{\longrightarrow} {\rm FeSO}_4^+$ reaction with the k_1b = 2.7 × 10⁵ M^?1 s^?1 rate constant. The most surprising result is, however, that the 2 FeSO? Fe³⁺ + Fe(SO₄) equilibrium is established well before the system as a whole reaches its equilibrium state, and the main path of the formation of Fe(SO₄) is the above fast (on the stopped flow scale) equilibrium process. The use and advantages of our recently elaborated programs for the evaluation of equilibrium and kinetic experiments are briefly outlined. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 114–124, 2008     

One‐ to Three‐Dimensional CuI and CuCN Based Coordination Polymers containing the Alkali Cation Ligating Thiacrown Ether 1, 10‐Dithia‐18‐Crown‐6

Treatment of an acetonitrile solution of CuI with 1, 10‐dithia‐18‐crown‐6 (1, 10DT18C6) in the presence of Rb₂CO₃ leads to formation of the lamellar coordination polymer [Rb{Cu₄I₅(1, 10DT18C6)₂}] ( 1 ).The anionic network of 1 is composed of parallel [(Cu₄I₅)^—] chains linked by bridging thiacrown ether ligands, pairs of which coordinate the Rb⁺ counter cations. [Cs{Cu₅I₆(1, 10DT18C6)₂}] ( 2 ) can be prepared under similar conditions but contains separated helical anionic chains. In this case 1, 10DT18C6 ligands bridge copper atoms of individual chains in an intrastrand manner. In contrast the coordination networks in [(CuCN)₂(1, 10DT18C6)] ( 3 ) and [K₂{Cu₁₂(CN)₁₄(1, 10DT18C6)₃} · CH₃CN] ( 4 ) are both three‐dimensional and based on CuCN‐containing sheets bridged by 1, 10DT18C6 ligands. In the latter compound pairs of K⁺ cations are coordinated by groups of three thiacrown ether molecules. The neutral network of 3 can imbibe up to 31 % KNO₃ per 1, 10DT18C6 pair without loss of lattice integrity.     

Zur Stabilität der Metallkomplexe von Methantriessigsäure und cis,cis-1,3,5-Cyclohexantricarbonsäure

The stabilities of the Mn²⁺-, Co²⁺-, Ni²⁺-, Cu²⁺- and Zn²⁺-complexes with 2-(carboxymethyl)glutaric acid ( 2 ) and cis,cis-1,3,5-cyclohexanetricarboxylic acid ( 3 ) were measured potentiometrically at 25° and I = 0.5 (KNO₃). Beside the complexes ML^? protonated species MLH and MLH are also formed. Their stability constants are given in Table 1. A comparison between the stabilities of 2 or 3 and those of acetate, as a model for a monocarboxylate, or succinate and glutarate, as examples for dicarboxylates, indicates that in all species only one carboxylate is strongly bound whereas the second and third ones are probably not. The observation that Δlog K₁ = log K ? log K as well as Δlog K₂ = log K ? log K are practically constants with values of 0.34 ± 0.05 and 0.49 ± 0.07, respectively, for both ligands and the five metal ions studied is also in line with the proposed monodentate structures of the complexes ML^?, MLH and MLH.     

Depolymerization kinetics of di(4‐tert‐butyl cyclohexyl) itaconate and Mark‐Houwink‐Kuhn‐Sakurada parameters of di(4‐tert‐butyl cyclohexyl) itaconate and di‐n‐butyl itaconate

Multipulse pulsed laser polymerization coupled with size exclusion chromatography (MP‐PLP‐SEC) has been employed to study the depropagation kinetics of the sterically demanding 1,1‐disubstituted monomer di(4‐tert‐butylcyclohexyl) itaconate (DBCHI). The effective rate coefficient of propagation, k, was determined for a solution of monomer in anisole at concentrations, c, 0.72 and 0.88 mol L^?1 in the temperature range 0 ≤ T ≤ 70 °C. The resulting Arrhenius plot (i.e., ln k vs. 1/RT) displayed a subtle curvature in the higher temperature regime and was analyzed in the linear part to yield the activation parameters of the forward reaction. In the temperature region where no depropagation was observed (0 ≤ T ≤ 50 °C), the following Arrhenius parameters for k_p were obtained (DBCHI, E_p = 35.5 ± 1.2 kJ mol^?1, ln A_p = 14.8 ± 0.5 L mol^?1 s^?1). In addition, the k data was analyzed in the depropagatation regime for DBCHI, resulting in estimates for the associated entropy (?ΔS = 150 J mol^?1 K^?1) of polymerization. With decreasing monomer concentration and increasing temperature, it is increasingly more difficult to obtain well structured molecular weight distributions. The Mark Houwink Kuhn Sakurada (MHKS) parameters for di‐n‐butyl itaconate (DBI) and DBCHI were determined using a triple detection GPC system incorporating online viscometry and multi‐angle laser light scattering in THF at 40 °C. The MHKS for poly‐DBI and poly‐DBCHI in the molecular weight range 35–256 kDa and 36.5–250 kDa, respectively, were determined to be K_DBI = 24.9 (10³ mL g^?1), α_DBI = 0.58, K_DBCHI = 12.8 (10³ mL g^?1), and α_DBCHI = 0.63. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1931–1943, 2007