M. Boom, Shyh-Yeon Liou, L. Shimon
May 14, 1996
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0
Influential Citations
15
Citations
Journal
Organometallics
Abstract
The mechanism of the selective formation of the new benzylic mono- and bicyclometalated platinum(II) complexes 2a,b and 3b has been studied. Monitoring the initial sp3 C−H activation of the ligand DIPPIDH (α2-(diisopropylphosphino)isodurene; 1) and (1,5-cyclooctadiene)dimethylplatinum(II) ((COD)PtMe2) at room temperature by 31P{1H} NMR reveals that, after displacement of 1,5-cyclooctadiene, the complex cis-(DIPPIDH)(DIPPID)PtMe (2a) is formed selectively by oxidative addition of a benzylic C−H bond and subsequent reductive elimination of CH4. This reaction is controlled by electronic factors. Heating of 2a results in isomerization to the thermodynamically more stable isomer trans-(DIPPIDH)(DIPPID)PtMe (2b) as well as the formation of the double-C−H activated complex trans-(DIPPID)2Pt (3b) with liberation of CH4 in parallel pathways. Continuous heating results in the quantitative formation of the thermally stable 3b. Mechanistically, the second C−H activation proceeds analogously to the first one. The mole...