14180-55-3Relevant articles and documents
A new series of bis(ene-1,2-dithiolato)tungsten(iv), -(v), -(vi) complexes as reaction centre models of tungsten enzymes: Preparation, crystal structures and spectroscopic properties
Sugimoto, Hideki,Hatakeda, Kohei,Toyota, Kazuo,Tatemoto, Susumu,Kubo, Minoru,Ogura, Takashi,Itoh, Shinobu
, p. 3059 - 3070 (2013)
The carbomethoxy substituted dithiolene ligand (LCOOMe) enabled us to develop a series of new bis(ene-1,2-dithiolato)tungsten complexes including WIVO, WIV(OSiBuPh2), W VIO2, WVIO(OSiBuPh2) and W VIO(S) core structures. By using these tungsten complexes, a systematic study of the terminal monodentate ligand effects has been performed on the structural, spectroscopic properties and reactivity. The structure and spectroscopic properties of the tungsten complexes have also been compared to those of the molybdenum complexes coordinated by the same ligand to investigate the effects of the metal ion (W vs. Mo). X-ray crystallographic analyses of the tungsten(iv) complexes have revealed that the tungsten centres adopt a distorted square pyramidal geometry with a dithiolene ligand having an ene-1,2-dithiolate form. On the other hand, the dioxotungsten(vi) complex exhibits an octahedral structure consisting of the bidentate LCOOMe and two oxo groups, in which π-delocalization was observed between the WVIO2 and ene-1,2-dithiolate units. The tungsten(iv) and dioxotungsten(vi) complexes are isostructural with the molybdenum counter parts. DFT calculation study of the WVIO(S) complex has indicated that the WS bond of 2.2 A? is close to the bond length between the tungsten centre and ambiguously assigned terminal monodentate atom in aldehyde oxidoreductase of the tungsten enzyme. Resonance Raman (rR) spectrum of the WVIO(S) complex has shown the two inequivalent LCOOMe ligands with respect to their bonding interactions with the tungsten centre, reproducing the appearance of two ν(CC) stretches in the rR spectrum of aldehyde oxidoreductase. Sulfur atom transfer reaction from the WVIO(S) complex to triphenylphosphines has also been studied kinetically to demonstrate that the tungsten complex has a lower reactivity by about one-order of magnitude, when compared with its molybdenum counterpart.
Mechanism of sulfur transfer from 1,2,4-dithiazolidine-3,5-diones to triphenylphosphines
Ponomarov, Oleksandr,Padelkova, Zdenka,Hanusek, Jiri
supporting information, p. 560 - 564 (2013/07/26)
The mechanism of sulfurization of substituted triphenylphosphines with 4-(3- and 4-substituted)-1,2,4-dithiazolidine-3,5-diones in acetonitrile, dichloromethane, tetrahydrofuran and toluene at 25°C was studied. The reaction pathway involves rate-limiting initial nucleophilic attack of the phosphorus at sulfur followed by fast decomposition of the phosphonium intermediate to the corresponding phosphine sulfide, phenylisocyanate and carbonylsulfide. From the Hammett correlations and from the solvent dependency, it was concluded that the transition-state structure is very polar and resembles the zwitter-ionic intermediate. The extent of P-S bond formation and S-S bond cleavage is very similar in the solvents series, but the latter gradually decreases with the decreasing polarity of the solvent. Copyright 2013 John Wiley & Sons, Ltd. The mechanism of sulfurization of substituted triphenylphosphines with 4-(3- and 4-substituted)-1,2,4-dithiazolidine-3,5- diones in acetonitrile, dichloromethane, tetrahydrofuran and toluene at 25°C was studied. The reaction pathway involves rate-limiting initial nucleophilic attack of the phosphorus at sulfur followed by fast decomposition of the phosphonium intermediate to the corresponding phosphine sulfide, phenylisocyanate and carbonylsulfide. The transition-state structure is very polar and resembles the zwitter-ionic phosphonium intermediate. Copyright
Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride)
Hanusek, Jiri,Russell, Mark A.,Laws, Andrew P.,Jansa, Petr,Atherton, John H.,Fettes, Kevin,Page, Michael I.
, p. 478 - 484 (2008/03/27)
Contrary to a previous report, the sulfurisation of phosphorus(iii) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett ρ-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are ～ -1.0. The entropies of activation are very negative (-114 ± 15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of ΔS ≠ and ρ values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations. The Royal Society of Chemistry 2007.
