DFT theoretical studies of alkali metal acetylenic thiolates

It follows from DFT calculations of acetylenic thiolates and their structural isomers—thioketenes and thiirenes that only the acetylenic type is stable. Most of the negative charge is concentrated on the sulfur atom. The influence of the cation (Li, Na, K) and the acetylenic substituent on the electronic structure and geometry of the thiolates is investigated. DFT calculations of IR and ¹³C NMR spectra of phenylethynethiolate potassium are in agreement with experimental data.     

Synthesis of Sulfides by Reactions of 1,1-Dichloro-2-chloro-methylcyclopropane with S-Nucleophiles

1,1-Dichloro-2-chloromethylcyclopropane reacts with thiolates to give 2,2-dichlorocyclopropylmethyl sulfides via replacement of the side-chain chlorine atom. The resulting sulfides are readily oxidized to the corresponding sulfones.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 381–386.Original Russian Text Copyright © 2005 by Mikhed’kina, Nedel’ko, Prezhdo.     

Electronic structure of organylthiochloroacetylenes and their reactions with O-containing nucleophiles

Conclusions Reactivity of organylthiochloroacetylenes toward O-containing nucleophiles was studied. It was established that phenolate anions attack the acetylenic C atom bound to the Cl atom and alcoholate anions attack the carbon atom bound to the S atom, which corresponds with the data of quantum chemical calculations.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya No. 3, pp. 612–616, March, 1988.     

硫代双烯酮二聚反应机理的理论研究

利用HF／6－31G*及半经验分子轨道AM1法,研究了硫代双烯酮及双三氟甲基硫代双烯酮二聚反应的反应机理,采用Berny梯度法优化得到反应的过渡态,并进行了振动分析确认,计算结果表明：（1）所有的二聚反应均是按照非同步的协同途径,经过扭曲的四元环过渡态进行的;（2）硫代双烯酮的二聚反应,三种可能的二聚方式中,生成对称四元杂环产物的二聚反应的活化焓最高;（3）双三氟甲基硫代双烯酮的二聚反应,生成对称四元杂环产物的二聚方式其活化焓比另外两种二聚方式的活化焓要低得多,这与实验中只观察到生成对称四元杂环产物的结果是一致的。     

Novel P-Se anions and their copper complexes

Three reactions of Cu(i) thiolates and Woollins' reagent (W.R.) give rise to novel copper complexes with unusual P/Se anions.     

Acetylenic Selenides and Tellurides from 1-Bromo, 2-Phenyl Ethyne

Acetylenic selenides and tellurides were prepared in good yields by nucleophilic substitution at acetylenic carbon by reaction of selenolate and tellurolate anions with 1-bromo, 2-phenyl ethyne.     

Oxidative Polymerization of Silylthioketene Dimer

Summary: The first π‐conjugated poly(thioketene dimer) was synthesized via the homopolymerization of a silylthioketene dimer by a chemical oxidation‐reduction process. The polymerization of trimethylsilylthioketene dimer in the presence of FeCl₃ (in CHCl₃ at 70 °C for 24 h) gave the corresponding doped poly(thioketene dimer). After treatment of the doped polymer with an aqueous solution of ammonia, the neutral poly(thioketene dimer) was obtained with an incidental desilylation. The polymer obtained was soluble in DMF and DMSO. From gel permeation chromatographic analysis (DMF, polystyrene standards), the number‐average molecular weight of the polymer was found to be 7 460. The polymer showed low oxidation potentials derived from the thioketene dimer unit. An effective extension of the π‐conjugation was observed in the polymer.

Synthesis of π‐conjugated poly(thioketene dimer).     

Übergangsmetall-thioketen-komplexe: VII. Erzeugung eines vinyliden-liganden aus einem thioketen durch schwefelabspaltung

The thioketene iron cluster (CH₃)₄C₆H₆CS(PPh₃)₂(CO)₄Fe₂S (I) reacts with thioketene in excess quantitatively to a vinylidene complex, as confirmed by X-ray analysis.     

Reactions of Diorganyl Disulfides with Dihaloalkanes in Basic Reductive Media. Synthesis of Bis(organylthio)alkanes

A convenient preparative synthesis of bis(organylthio)alkanes was developed. It is based on alkylation with dihaloalkanes of solutions of diorganyl disulfides in the basic reductive system hydrazine hydrate-alkali. The generation of organylthiolate anions from disulfides and the subsequent reaction of the anions with dihaloalkanes are performed in one reaction vessel without isolation of intermediate alkali metal thiolates. At the same time, the reactions of diphenyl or dithienyl disulfides with dihaloalkanes result in substitution with the thiolate anions of only one halogen atom to give the corresponding unsymmetrical sulfides. In certain cases in the presence of excess alkali the latter sulfides are dehalogenated to form alkyl vinyl sulfides.     

A Convenient Procedure for the Synthesis of 4,6-Disubstituted 2-OXO-2H-Pyran-5-carboxylic Esters.

A simple procedure for the synthesis of 2H-pyran-2-ones 2a is described: The initial Michael addition product of β-ketoester anions with acetylenic esters readily cyclizes under the basic reaction conditions to give the α-pyrones 2a (Scheme 2).     

Intramolecular Cycloaddition of Geminal Dichloroazomethine Ylides to Multiple Carbon-Carbon Bonds

Geminal dichloroazomethine ylides generated by reaction of dichlorocarbene with Schiff bases derived from O-alkenyl- or O-alkynylsalicylaldehyde undergo intramolecular [3 + 2]-cycloaddition with participation of the olefinic or acetylenic dipolarophile to afford chromeno[4,3-b]pyrrole and chromeno[4,3-b]pyridine derivatives. The greatest yields of the intramolecular cycloaddition products were obtained from N-methyl-substituted dichloroazomethine ylides, whereas the main stabilization path of N-phenyl and N-tert-butyl derivatives was cyclization to geminal dichloroaziridines.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 571–577.Original Russian Text Copyright © 2005 by Khlebnikov, Voznyi, Novikov, Kostikov.     

Polymeric arrangements of P-Se anions and a first insight into their reactivity

The reactions of the P/Se-precursor Woollins' reagent [PhP(Se)mu-Se]2 with alkali-metal salts offer new perspectives for the synthesis of metal aggregates containing P-Se anions. Depending on the alkali-metal thiolates polymeric arrangements of [PhPSe3]2- or [PhPSe2Se-SeSe2PPh]2- dianions are observed and the mechanisms of their formation described.     

A simple one-pot synthesis of hydroxylated and carboxylated aryl alkyl sulfides from various bromobenzenes

A simple one-pot synthesis of aryl alkyl sulfides from various bromobenzenes containing a hydroxy, hydroxymethyl, hydroxyethyl, and carboxylic acid group at -o, -m, and -p positions is reported here. The reaction proceeds through, in sequence, in situ protection of the hydroxy or carboxylic acid group by reaction with a Grignard reagent, lithium-halogen exchange, the formation of lithium thiolates, and the nucleophilic attack of lithium thiolates on various electrophiles without isolation of the thiolates, in one vessel. This procedure required a very short reaction time (1-1.5 h) and gave the corresponding sulfides in 75-97% yields.     

Optimal Conditions for Masking of Sulfite Anions with Formaldehyde in Iodometric Titration of Photographic Fixing Solutions

The iodometric titration of photographic fixing solutions can be simplified by masking sulfite anions with 3% aqueous formaldehyde in a weakly acidic medium, instead of their standard masking with concentrated aqueous formaldehyde in weakly alkaline solutions.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 559–562.Original Russian Text Copyright © 2005 by Kiryushov, Skvortsova.     

Preparation d'homopolymeres du thietanne de masses moléculaires determinees

A study has been made of the polymerization of thietane by thiolates such as thia-3-pentane thiolate with sodium, potassium or tetraethylammonium as cation. The following solvents have been used: tetrahydrofurane, acetonitrile, hexamethylphosphorotriamide and dimethylsulphoxide. Such thiolates permit the preparation of homopolymers of thietane with specified molecular weights but it has not been possible to explain, in these reactions, the activity of sodium naphthalene at −78°. The relationship between number average molecular weight and intrinsic viscosity is given.     

Crystal Structure of Sodium Perchloratotriacetatoneptunate(V) Monohydrate Na<Subscript>3</Subscript>NpO<Subscript>2</Subscript>(OOCCH<Subscript>3</Subscript>)<Subscript>3</Subscript>ClO<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

The crystal structure of Na₃NpO₂(OOCCH₃)₃ClO₄ · H₂O was studied by single-crystal X-ray diffraction method. The structure is composed of the complex anions NpO₂(OOCCH₃)₃]²⁻, perchlorate anions, Na cations, and water molecules. The oxygen environment of Np(V) is a hexagonal bipyramid whose equatorial plane is formed by the oxygen atoms of three acetate ions. In addition to the acetate anions, the structure contains the perchlorate ion whose oxygen atoms, except for one, are included in the coordination environment of Na⁺ cations.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 636–640.Original Russian Text Copyright © 2005 by Charushnikova, Fedoseev, Starikova.     

Thioketene

Recent high-resolution FTIR studies of thioketene-H₂,-HD, and -D₂ have improved the precision with which a number of fundamental vibrations are determined and enabled accurate sets of rotation and distortion constants to be determined. These have been used, in conjunction with recent results for ketene, to determine the harmonic potential function for thioketene and the zero-point average molecular structure. A marked change in the methylene group geometry between thioketene and ketene is observed, such that a considerable increase in the CH bond length and concomitant decrease in the HCH angle occurs on sulfur substitution.     

Palladium-catalyzed Sonogashira coupling reaction followed by isomerization and cyclization

2-Iodoaniline reacts with terminal acetylenic carbinols in THF at 80 °C in the presence of a catalytic amount of PdCl₂(PPh₃)₂ and CuI along with aqueous tetrabutylammonium hydroxide to afford the corresponding 2-arylquinolines in good yields. The catalytic pathway seems to be proceeded via a sequence involving initial Sonogashira coupling between 2-iodoaniline and terminal acetylenic carbinols to form coupled acetylenic carbinols, isomerization of coupled acetylenic carbinols to α,β-unsaturated ketones, and cyclodehydration.     

Substitution of acetylenic groups for halogen in the quinonoid ring

The bromine or iodine atom in the quinonoid ring devoid of +M substituent in the position neighboring to the halogen is replaced by acetylenic groups on treatment with Cu^I acetylides, prepared either beforehand or in situ, in a mixture of DMSO and CHCl₃ in the presence of a Pd complex catalyst. A series of mono- and diacetylenic derivatives of 1,4-naphtho- and 1,4-benzoquinone were prepared. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1636–1639, July, 2005.     

Isomer structures of thioketene and its cyclic oligomers. <Emphasis Type="Italic">Ab initio</Emphasis> calculations

The thioketene molecule, as well as its isomer and dimer molecules, were calculated by the HF, MP2, and DFT (B3LYP) ab initio methods. The 6-31G (d) and 6-311G (2d, p) basis sets were used. The sequence of stable isomers is refined, and vibrational spectra are calculated for three most stable structures. The assignment of some absorption bands is changed. The most stable dimers and trimers of thioketene are calculated.