- 作者: 陳文徵 ; Espenson, James H. ; Bakac, Andreja
- 作者服務機構: Ames Laboratory and Dept. of Chemistry, Iowa State Univ., Ames, Iowa, U.S.A.
- 中文摘要: The reaction between certain platinum(II) complexes and alkyl radicals produces an unstable organoplatinum(III) intermediate, .lbrace.Pt/sup III/-R.rbrace.. The kinetics of this step were evaluated by laser flash photolysis with ABTS/sup 2-/ (2,2'- azinobis(3-ethylbenzothiazoline-6- sulfonate) ion) and TMPD (tetramethylphenylenediamine) as kinetic probes. The rate constants for PtCl/sub 4//sup 2-/ are: k/sub Pt//10/sup 8/L/mol-s=5.2, 2.8 and 0.27 for.bcdot.CH/sub 3/, .bcdot.C/sub 2/H/sub 5/ and .bcdot.CH/sub 2/Cl in aqueous solution at pH 1. Those with cis-Pt(NH/sub 3/)/sub 2/Cl/sub 2/ are somewhat smaller, and those for Pt(NH/sub 3/)/sub 4//sup 2+/ too small to measure with this technique. The product analysis indicates that the decomposition of organoplatinum takes place by hydrolysis and (for R=C/sub 2/H/sub 5/ only) by .beta.- elimination. The kinetic isotope effect on the .beta.- elimination of DCH/sub 2/CH/sub 2/PtCl/sub 4//sup 2-/ is k/sub H//k/sub D/=1.2. The .beta.- elimination step produces a Pt/sup III/-hydride that releases hydrogen gas and forms.lbrace.Pt/sup III/-OH.rbrace.. The short-lived Pt(III) intermediate may disproportionate or oxidize the Co/sup II/ complex that is produced in the radical-generating step.
- 英文摘要: --
- 中文關鍵字: Radical; Platinum; Kinetics; Radical Probe; Reaction Mechanism
- 英文關鍵字: 自由基;鉑;動力學;自由基探針;反應機構