Synthesis and crystal structure of [Re(CO)(3)(mu-CH3CO2)(THF)](4)

A tetrameric complex [Re(CO)(3)(mu-CH3CO2)(THF)](4) (1) is formed in high y ield when the reaction product of Re(CO)(5)Cl with acetic acid in refluxing 1,2-dichlorobenzene is dissolved in THF. The use of Re-2(CO)(10) instead o f rhenium pentacarbonyl chloride also affords 1. The characterization of 1. 3THF.0.5C(6)H(14), has been accomplished by X-ray crystallography. The stru cture of the tetrameric molecule 1 consists of four rhenium(I) atoms bridge d by four acetate ligands. The coordination of each metal center is fulfill ed by three CO groups and one THE molecule in a way that all carbonyls are trans to oxygen atoms. The geometry of each acetate bridge is anti-syn prov iding a Re to Re separation of 5.40 Angstrom. This bonding mode is seen her e for the first time in rhenium carboxylates. Different coordination types for Re-RCO2 interaction are also discussed in the paper. (C) 1999 Elsevier Science S.A. All rights reserved.