THE 1ST STRUCTURALLY CHARACTERIZED CHIRAL RHENIUM COMPLEX CONTAINING A METAL METAL QUADRUPLE BOND - SYNTHESES, STRUCTURE, AND SPECTRA OF BETA-RE2CL6[(S,S)-ISODIOP] - AN UNPRECEDENTED REARRANGEMENT OF THE DIOP LIGAND

By reaction of Re2(O2CCH3)2Cl4, (CH3)3SiCl, and (S,S)-diop in THF at room temperature, a yellow-green product can be prepared. The pink-red complex beta-Re2Cl6[(S,S)-isodiop] was obtained by recrystallizing the yellow-green solid from CH2Cl2 solvent. The UV-vis, IR, and CD spectra of beta-Re2Cl6[(S,S)-isodiop] have been recorded and the structure has been determined. The crystals of this compound are arranged in the space group P2(1)2(1)2(1) with four molecules per unit cell. Crystallographic data: a = 15.039 (6) angstrom, b = 21.056 (7) angstrom, c = 12.299 (9) angstrom, V = 3895 (6) angstrom3. Final residuals: R = 0.0556, R(w) = 0.0673. The structure of this complex has a twist angle of approximately 0-degrees, and the Re-Re distance is 2.236 angstrom. It is found in this structure that the diop ligand has been rearranged to give isodiop through a pathway similar to the acid-catalyzed rearrangements of acetals. Isodiop is Ph2PCH2CH(O)R; R = CHOCMe2PPh2CH2. Isodiop is a zwitter ion with R'O- and PR''4+ (R' and R'' represent alkyl or phenyl groups) components, which coordinates as a bridging ligand through P to one Re atom and O to the other.