Reactions of the complexes [Re2(CO)9(η1-P-P)] (P-P = Ph2P(CH2)nPPh2, 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)}]

Reactions of [Re-2(CO)(10)] with Me3NO and diphosphines [Ph2P(CH2)(n)PPh2, n = 1-6] yield mixtures of the monodentate-coordinated diphosphine complexes [Re-2(CO)(9)(eta(1)-P-P)] (P-P = Ph2P(CH2)(n)PPh2, n = 1-6) (yields 5-40%) and bridged dimers [{Re2CO)(9)}(2)(mu-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 Me3NO yield close-bridged complexes [Re-2(CO)(8)(mu-P P)] and phosphine oxide complexes [Re-2(CO)(9){P-P(O)}]. The structures of the close-bridged complexes 1 (n = 3) and 2 (n = 4), were determined by Xray 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)}(mu-dpph)] (3) as the product, the structure of which was also determined by X-ray crystallography. (C) 2004 Elsevier B.V. All rights reserved.