Experimental and theoretical studies on the platinum-mediated selective C(sp)-Si bond cleavage of alkynylsilanes

Yasuhiro Okuda, Yuya Ishiguro, Seiji Mori, Kiyohiko Nakajima, Yasushi Nishihara

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A series of cis-alkynyl(silyl)platinum(II) complexes was prepared via the chemoselective C(sp)-Si bond cleavage of alkynylsilanes by a platinum(0) complex ligated with the P-N hemilabile bidentate ligand. The coordination of the triple bond to the platinum center triggers selective C(sp)-Si bond cleavage. Hammett plots of the 31P{1H} NMR spectroscopic properties (δ and J values) reflect an electronic effect on platinum(II) complexes; trans substituents of arylethynyl groups are influenced, but cis-positioned silyl groups are not affected, as evidenced by 29Si{1H} NMR. In comparison, Hammett plots show that C(sp)-Si bond cleavage rates are accelerated by electron-rich alkynylsilanes, which is opposite to the ordinary oxidative addition of aryl halides to transition metals often observed in catalytic cross-coupling reactions. A DFT calculation reveals that intermediates and transition states are stabilized by electron-rich alkynylsilanes and that the five-membered hemilabile P-N ligand is essential, in which a reactive electron-deficient 14-electron platinum(0) species is produced via the dissociation of nitrogen, giving rise to a monodentate phosphine coordination. Electron-rich alkynylsilanes allow decreased π back-donation from the platinum center to the ligand, accelerating the dissociation of the more labile nitrogen. Steric congestion between diisopropylphosphino and silyl groups thermodynamically disfavors C(sp)-Si bond cleavage.

Original languageEnglish
Pages (from-to)1878-1889
Number of pages12
JournalOrganometallics
Volume33
Issue number7
DOIs
Publication statusPublished - Apr 14 2014

ASJC Scopus subject areas

  • Organic Chemistry
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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