Reactions of the complexes [Re2(CO)9(η 1-P-P)] (P-P = Ph2P(CH2)nPPh 2, n = 1-6) with Me3NO: Formation of close-bridged complexes [Re2(CO)8(μ-P-P)] and phosphine oxide complexes [Re2(CO)9{P-P(O)}]

Abstract

Reactions of [Re2(CO)10] with Me3NO and diphosphines [Ph2P(CH2)nPPh2, n=1-6] yield mixtures of the monodentate-coordinated diphosphine complexes [Re 2(CO)9(η1-P-P)] (P-P=Ph 2P(CH2)nPPh2, n=1-6) (yields 5-40%) and bridged dimers [{Re2(CO)9}2(μ-P-P)] (5-50%). These complexes were isolated as either equatorial or axial isomers, or a mixture of two isomers. Reactions of the monodentate complexes with Me 3NO yield close-bridged complexes [Re2(CO) 8(μ-P-P)] and phosphine oxide complexes [Re2(CO) 9{P-P(O)}]. The structures of the close-bridged complexes 1 (n=3) and 2 (n=4), were determined by X-ray crystallography. The Re-Re bond in the close-bridged complex with the longest phosphine chain (n=6) is readily cleaved in CDCl3 to give the complex [{cis-ReCl(CO)4} 2(μ-dpph)] (3) as the product, the structure of which was also determined by X-ray crystallography. © 2004 Elsevier B.V. All rights reserved.