- Synthesis of mononuclear and dinuclear palladium (II) complexes containing oxadithioether ligands and their catalytic activities in norbornene polymerization
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The Pd (II) complexes trans-[PdCl2(μ-L)]2 and [Pd(acac)(L)][BF4] (L = RS(CH2)2O(CH2)2SR, R = Me, Et, nPr, iPr, nBu, iBu, n-hexyl, benzyl) were obtained through the reaction of Pd(cod)Cl2 or [Pd(acac)(MeCN)2][BF4] with one equivalent of oxadithioether (L). The structural features of these complexes were analyzed by nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR), as well as electrospray ionisation mass spectrometry and density functional theory calculations. The complexes di-μ-(2,10-dimethyl-6-oxa-3,9-dithiaundecane-κ2S,S′)-bis[trans-dichloropalladium (II)] and (acetylacetonate-κ2O,O′)(2,10-dimethyl-6-oxa-3,9-dithiaundecane-κ2S,S′)palladium (II) tetrafluoroborate were characterized by X-ray diffractometry. The X-ray structures of each complex indicate an axial M–O interaction formed by the endodentate conformation of the oxadithioether ligand. Palladium (II) dichloride complexes with oxadithioethers were demonstrated to have a 16-membered dinuclear structure with a trans-configured S2PdCl2 fragment. In the case of cationic palladium acetylacetonate complexes, only mononuclear complexes with a cis configuration of the oxadithioether fragment were observed. Variable temperature 1H and 13C NMR studies of the complexes demonstrate dynamic bonding of the oxadithioether ligands consistent with the presence of diastereoisomers that differ in the orientation of the S-R groups along with both endodentate and exodentate bonding modes in solution. FTIR studies of the complexes indicate the presence of isomers in the solid state. The palladium catalyst precursors trans-[PdCl2(μ-L)]2 and [Pd (acac)(L)][BF4] were found to be active in the addition polymerization of norbornene. In the presence of cocatalysts, such as diisobutylaluminum chloride and boron trifluoride etherate, Pd (II) complexes exhibited activities in the range of 105 to 107 g of polymer (mol of Pd)?1?h?1. The catalyst systems showed good thermostability with a high activity of 1.43 × 107 g of polymer (mol of Pd)?1?h?1 at 75°C. These complexes are examples of Pd (II) complexes bearing thioether ligands, which are rarely observed in the field of olefin polymerization.
- Suslov, Dmitry S.,Abramov, Zorikto D.,Babenko, Ilya A.,Bezborodov, Viktor A.,Borodina, Tatyana N.,Bykov, Mikhail V.,Pakhomova, Marina V.,Smirnov, Vladimir I.,Suchkova, Anastasia V.,Ratovskii, Gennadii V.,Ushakov, Igor A.,Vilms, Alexey I.
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- Destruction of chemical warfare agent simulants by air and moisture stable metal NHC complexes
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The cooperative effect of both NHC and metal centre has been found to destroy chemical warfare agent (CWA) simulants. Choice of both the metal and NHC is key to these transformations as simple, monodentate N-heterocyclic carbenes in combination with silver or vanadium can promote stoichiometric destruction, whilst bidentate, aryloxide-tethered NHC complexes of silver and alkali metals promote breakdown under mild heating. Iron-NHC complexes generated in situ are competent catalysts for the destruction of each of the three targetted CWA simulants.
- Weetman, Catherine,Notman, Stuart,Arnold, Polly L.
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supporting information
p. 2568 - 2574
(2018/02/28)
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- Synthesis of polydentate chalcogen-containing ligands using the system hydrazine hydrate–base
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The reaction of dichlorodiethyl ether or dichlorodiethylamine hydrochloride with potassium or ethanolammonium dichalcogenides prepared in situ from elemental sulfur or selenium in the system hydrazine hydrate–alkali results in oligomeric dichalcogenides,
- Levanova,Vilms,Bezborodov,Babenko,Sosnovskaya,Istomina,Albanov,Russavskaya,Rozentsveig
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p. 396 - 401
(2017/05/01)
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- Replacing phosphorus with sulfur for the efficient hydrogenation of esters
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Catalyst tune-up: A readily available, air-stable amino-sulfide catalyst, [RuCl2(PPh3){HN(C2H4SEt) 2}], has been developed. This complex displays outstanding efficiency for the hydrogenation of a broad range of substrates with C-X bonds (esters, ketones, imines), as well as for the acceptorless dehydrogenative coupling of ethanol to ethyl acetate (see scheme). Copyright
- Spasyuk, Denis,Smith, Samantha,Gusev, Dmitry G.
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supporting information
p. 2538 - 2542
(2013/04/10)
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- Reactions of bielectrophiles (ClCH2CH2)2Y with sulfur in basic reducing systems
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A simple procedure was developed for preparing bis(β-mercaptoethyl) ether and bis(β-mecraptoethyl) sulfide from commercially available chemicals: elemental sulfur, alkali, and bis(β-chloroethyl) ether or sulfide, based on thiylation with elemental sulfur of these substrates in the aqueous system hydrazine hydrate-alkali, with initial formation of the corresponding polysulfide polymers (thiokols). Their reduction with the system hydrazine hydrate-alkali, followed by acidification of dithiolate anions, yields the corresponding dithiols. Thiokols based on bis(β-chloroethyl) ether are soluble in organic solvents; they were studied by 1H NMR.
- Korchevin,Russavskaya,Alekminskaya,Deryagina
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p. 240 - 243
(2007/10/03)
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- THE CHARACTERIZATION OF SULFONIUM CHLORIDES BY GAS CHROMATOGRAPHY/MASS SPCTROMETRY AND THE DEGRADATION OF 2-CHLOROETHYL SULFIDE DERIVATIVES
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Three aqueous samples containing sulfonium chloride salts of both mustard gas (2,2'-dichlorodiethylsulfide) and its simulant 2-chloroethyl ethyl sulfide have been characterized by gas chromatography/mass spectrometry (GC/MS).Theese salts decompose thermallly to the sorresponding 2-chloroethyl and 2-hydroxyethyl sulfides, therefore GC/MS analysis is not indicative of the true composition of these solutions.Small amounts of dithioethers characteristic of the decomposition of the dimeric salts were also detected.Electron Impact (EI) ionization produces a more intense molecular ion than methane chemical ionization (CI) for the dithioethers because of the ease of formation of sulfonium ions during chemical ionization.The composition products of four aged samples of 2-chloroethyl sulfides (RSCH2CH2Cl where R=methyl, ethyl, phenyl and benzyl groups) were also characterized by GC/MS, which indicated that decomposition of these compounds may proceed via dimeric sulfonium ions.Mustard gas was detected in all but one of the samples, providing evidence for secondary sulfonium cation formation in the degradation prcess.Keywords: Sulfonium chlorides; 2-chloroethyl sulfides; degradation; dimeric sulfonium cations; GC/MS characterization.
- Rourhbaugh, Dennis K.,Yang, Yu-Chu,Ward, J. Richard
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