Reactivity of silyl-substituted heterobimetallic iron-platinum hydride complexes: Part III. Alkyne insertions into the platinum-hydride bond and competition between mu-vinylidene and dimetallacyclopentenone formation
Résumé
nsertion of aliphatic 1-alkynes such as tert-butylacetylene, 1-hexyne or 1,6-heptadiyne into the Pt-H bond of the heterobimetallic hydride Complex [(OC)(3)Fe{Si(OMe)(3)}(mu-dppm)Pt(H)(PPh3)] (1) (dppm = Ph2PCH2PPh2) leads to the formation of an isomeric mixture of p-vinylidene complexes [(OC)(3)Fe{mu-C=C(H)R}(mu-dppm)Pt(PPh3)](2a: R = tert-Bu, 2b: R = n-Bu, 2c: R = (CH2)(3)-C&3bond; CH) and dimetallacyclopenteriones [(OC)(2)Fe{mu-C(=O)CR=CH}(mu-dppm)Pt(PPh3)] (3a: R = tert-Bu, 3b: R = n-Bu. 3e: R = (CH2)(3)-C&3bond; CH). The molecular structures of 2a and 3c have been determined by single-crystal X-ray diffraction. (c) 2005 Elsevier B.V. All rights reserved