Substituent effect on the cationic ring‐opening polymerization of acyloxymethyl five‐member cyclic dithiocarbonates

Five‐member cyclic dithiocarbonates were synthesized by the reactions of carbon disulfide with benzoic, p‐anisic, p‐chlorobenzoic, 1‐naphthalenecarboxylic, p‐nitrobenzoic, and p‐(tert‐butyl)benzoic glycidyl esters, and their cationic ring‐opening polymerizations were carried out with methyl trifluoromethane sulfonate and trifluoromethane sulfonic acid as initiators at room temperature to 80 °C. Polymers with number‐average molecular weights of 3400–24,900 were obtained in high yields, and their structures were estimated by NMR and IR spectroscopy. The monomers showed a clear difference in the polymerization rate according to the substituents. The rate of polymerization decreased in the order of p‐chlorobenzoic ≥ benzoic > 1‐naphthalenecarboxylic > p‐nitro‐benzoic > p‐tert‐butylbenzoic > p‐anisic. The data of the reaction kinetics, NMR studies, and molecular orbital calculations proved a plausible mechanism involving the participation of p‐substituted benzoyloxymethyl groups to stabilize the cationic propagating end. The polymers showed decomposition temperatures with 5% weight loss ranging from 200 to 260 °C. No glass‐transition temperatures for the polymers were observed below 200 °C by differential scanning calorimetry. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3967–3980, 2001     

The use of S,S-dialkyl dithiocarbonates in Li ion battery electrolytes

S,S-dialkyl dithiocarbonates such as S,S-dimethyl dithiocarbonate and S,S-diethyl dithiocarbonate were tested as solvents for rechargeable lithium ion batteries. Graphite electrodes can be successfully cycled at high reversible capacities in an S,S-dimethyl dithiocarbonate solution containing 1 M LiAsF₆, while lithium ions cannot intercalate into graphite in S,S-diethyl dithiocarbonate solutions. Fourier transform infrared spectroscopy, cyclic voltammetry and chronopotentiometric methods were used in order to monitor the reaction mechanism. Received: 23 April 1997 / Accepted: 5 June 1997     

Superoxide Ion–Promoted Facile One-Pot Synthesis of O-Alkyl-S-methyl Dithiocarbonates from Alcohol Under Mild Reaction Conditions

Abstract

A new, mild, and efficient protocol for the one-pot synthesis of O-alkyl-S-methyl dithiocarbonates (xanthates) has been described in reasonably good yields from a variety of alcohols employing carbon disulfide and methyl iodide using superoxide ion at room temperature.

GRAPHICAL ABSTRACT     

Reactions of O‐aryl S‐aryl dithiocarbonates with secondary alicyclic amines in aqueous ethanol. Kinetics and mechanism

The reactions of O‐(4‐methylphenyl) S‐(4‐nitrophenyl), O‐(4‐chlorophenyl) (4‐nitrophenyl), O‐(4‐chlorophenyl) S‐phenyl, and O‐(4‐methylphenyl) S‐phenyl dithiocarbonates ( 1 , 2 , 3 , and 4 , respectively) with a series of secondary alicyclic (SA) amines are subjected to a kinetic investigation in 44 wt% ethanol‐water, at 25.0 °C and an ionic strength of 0.2 M. The reactions are followed spectrophotometrically. Under amine excess, pseudo‐first‐order rate coefficients (k_obs) are found. For some of the reactions, plots of k_obs vs. free amine concentration at constant pH are linear but others are nonlinear upwards. This kinetic behavior is in accordance with a stepwise mechanism with two tetrahedral intermediates, one zwitterionic (T^±) and the other anionic (T^?). In some cases, there is a kinetically significant proton transfer from T^± to an amine to yield T^?. Values of the rate micro constants k₁ (amine attack to form T^±), k_?1 (its back step), k₂ (nucleofuge expulsion from T^±), and k₃ (proton transfer from T^± to the amine) are determined for some reactions. The Brønsted plots for k₁ are linear with slopes β₁ = 0.2–0.4 in accordance with the slope values found when T^± formation is the rate‐determining step. The sensitivity of log k₁ and log k_?1 to the pK_a of the amine, leaving and non‐leaving groups are determined by a multiparametric equation. For the reactions of 1 – 4 with 1‐formylpiperazine and those of 3 and 4 with morpholine the k₂ and k₃ steps are rate determining. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis and Tuberculostatic Activity of Methyl 3-Isonicotinoyldithiocarbazate and S,S'-Dimethyl Dithiocarbonate Isonicotinoylhydrazone, and Their Reactions with Amines and Hydrazines

Methyl 3-isonicotinoyldithiocarbazates and S,S'-dimethyl dithiocarbonate isonicotinoylhydrazone were prepared. Their reactions with primary and secondary amines, diamines, and hydrazines were studied. The newly obtained derivatives did not show tuberculostatic activity in vitro.     

Reactions of O‐aryl S‐aryl dithiocarbonates with pyridines in aqueous ethanol: kinetics and mechanism

The reactions of O‐(4‐methylphenyl) S‐(4‐nitrophenyl) dithiocarbonate ( 1 ), O‐(4‐chlorophenyl) S‐(4‐nitrophenyl) dithiocarbonate ( 2 ), and O‐(4‐chlorophenyl) S‐phenyl) dithiocarbonate ( 3 ) with a series of pyridines were subjected to a kinetic investigation in 44 wt% ethanol–water, at 25.0 °C and an ionic strength of 0.2 M. The reactions were followed spectrophotometrically. Under amine excess, pseudo‐first‐order rate coefficients (k_obs) were determined. For the studied reactions, plots of k_obs versus free pyridine concentration at constant pH were linear, with the slope (k_N) independent of pH. The Brønsted‐type plots for ( 1 ) and ( 2 ) were biphasic, suggesting a stepwise mechanism with a change in the rate‐determining step, from breakdown to the formation of a tetrahedral intermediate (T^±), as the basicity of the pyridines increases. For the reactions of ( 3 ), at the pK_a range of the pyridines studied, only the breakdown to products of T^± was observed. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of newly synthesized disulfides of aryldithiocarbonates and vanadium(V) and niobium(V) complexes of aryldithiocarbonates based on spectroscopic,thermogravimetric, SEM and DFT studies

ABSTRACT

Oxidation of the sodium salt of 2-methyl, 3-methyl, 4-methyl and 4-chloro-3-methylphenyldithiocarbonic acid by I₂ affords the disulfides of respective dithiocarbonates [(ArOCS₂)₂] (Ar?=?2-CH₃C₆H₄, 3-CH₃C₆H₄, 4-CH₃C₆H₄ and 4-Cl-3-CH₃C₆H₃. Vanadium(V) and Niobium(V) complexes of 2-methyl, 3-methyl, 4-methyl and 4-chloro-3-methylphenyldithiocarbonates have also been synthesised by one-step synthetic route. The metal salt (VOCl₃ and NbCl₅) were reacted with 2-CH₃C₆H₄, 3-CH₃C₆H₄, 4-CH₃C₆H₄ and 4-Cl-3-CH₃C₆H₃OCS₂Na in 1:2 stoichiometric molar ratio yielding the complexes corresponding to the molecular formula [(ArOCS₂)₂VO(Cl)] and [(ArOCS₂)₂NbCl₃] [Ar?=?2-CH₃C₆H₄, 3-CH₃C₆H₄, 4-CH₃C₆H₄ and 4-Cl-3-CH₃C₆H₃OCS₂)]. The compounds were characterised by elemental analyses, infrared, mass and heteronuclear NMR (¹H and ¹³C) spectroscopic studies. Thermogravimetric analysis and scanning electron microscopic analyses were also carried out for deeper investigation of the structural features. Comprehensive theoretical investigation was performed by applying density functional theory (DFT) calculations on vanadium and niobium complexes by the DFT/B3LYP/LANL2DZ method to obtain the optimised molecular geometry, vibrational frequencies, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), thermodynamic properties and various other quantum-mechanical parameters.     

A novel one-pot oxidation polymerization of dithiols obtained from bifunctional five-membered cyclic dithiocarbonates with amines

One-pot oxidation polymerization of dithiols, obtained from bifunctional five-membered cyclic dithiocarbonates ( 4a and 4b ) with two equivalents of amines, was studied. The monomers 4a and 4b were synthesized by the reactions of bisphenol A diglycidyl ether and neopentyl glycol diglycidyl ether with carbon disulfide, respectively. Polydisulfides with M̄_ns 4600–20,200 were obtained quantitatively in the oxidation polymerization of the dithiols obtained in situ by the reactions of 4a with benzylamine, n-butylamine, and piperidine. On the other hand, dithiols obtained from 4b with benzylamine, afforded cyclic disulfides as well as the polydisulfide under similar conditions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 79–84, 1998     

O-Tolyldithiocarbonate Complexes of Iron(II) and Iron(III)

Abstract

Reactions of O-tolyldithiocarbonate ligands, (o-, m-, and p-CH₃C₆H₄O)CS₂Na, with anhydrous FeCl₂ (1:2 molar ratio) and with FeCl₃ (1:1 and 1:3 molar ratio) yielded the complexes [{(CreO)CS₂}₂Fe] and [{(CreO)CS₂}_nFeCl_3–n] (Cre = o-, m-, and p-CH₃C₆H₄; n = 1 and 3), respectively. These complexes were reacted with nitrogen and phosphorus donor ligands in dichloromethane, which afforded the adducts corresponded to [{(CreO)CS₂}₂Fe.xL] and [(CreO)CS₂FeCl₂.xL] {x = 1, L = N₂C₁₂H₈; x = 2, L = NC₅H₅, P(C₆H₅)₃}. Elemental analyses and IR, UV-visible, and mass spectroscopic and magnetic studies indicated bidentate mode of bonding by dithiocarbonate ligands leading to sixcoordination around the iron atom as a consequence of Fe…Fe interaction in the complexes [{(CreO)CS₂}₂Fe] and [(CreO)CS₂FeCl₂]. The complexes exhibited antifungal activity. The fungicidal activity of the complexes has been tested by poisoned food technique using fungi Fusarium sp.

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