Metal-Dependent Reactivity Differences for Transients Formed By Flash Photolysis of (PNP)M(CO), M = Co and Rh

Autor:	David C. Grills, Peter C. Ford, R. Dale Rimmer, Kenneth G. Caulton, Hongjun Fan
Rok vydání:	2007
Předmět:	Chemistry Photodissociation General Chemistry Rate equation Photochemistry Biochemistry Catalysis Metal Colloid and Surface Chemistry Reaction rate constant visual_art Reagent visual_art.visual_art_medium Flash photolysis Reactivity (chemistry) Singlet state
Zdroj:	Journal of the American Chemical Society. 129:15430-15431
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja076357l
Popis:	Spin triplet (PNP)Co adds one CO according to a rate law first-order in each reagent with k = 9.3 × 105 M-1 s-1. In contrast, the transient produced by photodissociation of CO from (PNP)Rh(CO) forms, within 10 ns, the Rh(III) species [η4-tBu2PCH2SiMe2NSiMe2CH2PtBu(CMe2CH2)]RhH, and this adds CO with a second-order rate constant of 6 × 106 M-1 s-1. The resulting monocarbonyl then slowly (k = 3 × 101 s-1) reductively eliminates H and C(sp3) to re-form (PNP)Rh(CO). The former two rate constants support the idea that a spin crossing between triplet (PNP)Co and singlet (PNP)Co(CO) causes a rate suppression.
Databáze:	OpenAIRE
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