- Properties and Reactivities of Zwitterionic Platinum(II)-ate Complexes Generated by Transforming Coordination of an Alkyne-Bisphosphine Ligand
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Coordination of an alkyne-bisphosphine ligand with platinum(II) precursors produced a structural reorganization in the ligand backbone to form stable zwitterionic platinum(II) complexes bearing an anionic platinum center. The structural properties and reactivities of these complexes were investigated using X-ray crystallographic analyses, computational studies, and stoichiometric reactions involving oxidative addition and reductive elimination. These studies have shown that the enhanced nucleophilicity of the platinum center to alkyl halides promotes smooth oxidative addition and that the charge rebalance accelerates the dissociation of the halide anion from the platinum(IV) intermediate, which is essential in the carbon-carbon bond-forming step.
- Okamoto, Kazuhiro,Sasakura, Kohei,Funasaka, Satoshi,Watanabe, Hiiro,Suezaki, Masahiro,Ohe, Kouichi
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supporting information
p. 848 - 856
(2021/05/04)
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- Kinetics and mechanism of gas-phase pyrolysis of ylides. Part 3. 1 Thermal reactivity of α-carbonyl- and thiocarbonyl-stabilized methylenetriphenylphosphoranes
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Fourteen ketone/thione-stabilized triphenylphosphonium methylides were subjected to conventional gas-phase and flash vacuum pyrolysis (FVP). The kinetics of the first-order thermal gas-phase reactions of all these compounds were investigated over 360-653K temperature range. The values of the Arrhenius logA and energy of activation of these ylides averaged 11.52±0.34s -1 and 133.20±3.14kJmol-1, respectively. The products of sealed-tube (static) and FVP were analyzed and compared. A mechanism is proposed to account for the products of reaction. The rate constants [k (s-1)] of the substrates at 500K were calculated and used to substantiate the proposed mechanism of pyrolysis, and to rationalize the thermal gas-phase reactivities of the ylides under study.
- Al-Bashir, Rasha F.,Al-Awadi, Nouria A.,El-Dusouqui, Osman M. E.
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scheme or table
p. 311 - 319
(2012/04/17)
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- Thermal rearrangement of thiocarbonyl-stabilised triphenylphosphonium ylides leading to (Z)-1-diphenylphosphino-2-phenylsulfenylalkenes
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While thermolysis of thiocarbonyl-stabilised phosphonium ylides generally results in extrusion of Ph3PS to give alkynes, those with a PCH function instead undergo a novel P to S transfer of a phenyl group to give (Z)-configured 1-phosphino-2-su
- Alan Aitken,Dawson, Graham,Keddie, Neil S.,Kraus, Helmut,Slawin, Alexandra M. Z.,Wheatley, Joanne,Woollins, J. Derek
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body text
p. 7381 - 7383
(2010/06/13)
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- Wittig-like reactions of tungsten alkylidyne complexes
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W(C-t-Bu)(DIPP)3 (DIPP = 2,6-diisopropylphenoxide) reacts rapidly with acetonitrile to give [W(N)(DIPP)3]x and t-BuC≡CMe. It reacts with acetone, benzaldehyde, paraformaldehyde, ethyl formate, and N,N-dimethylformamide to give oxo vinyl complexes of the type W(O)(t-BuC=CR1R2)(DIPP)3. The tungstenacyclobutadiene complex W(C3Et3)(DIPP)3 reacts similarly with acetone, benzaldehyde, ethyl formate and N,N-dimethylformamide to give complexes of the type W(O)(EtC=CR1R2)(DIPP)3. The oxo vinyl complexes can be hydrolyzed by base to yield the expected olefinic product in good to excellent yield. The olefin product is mainly the cis isomer in most cases.
- Freudenberger, John H.,Schrock, Richard R.
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p. 398 - 400
(2008/10/08)
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