Rhenium complexes with weakly coordinating solvent ligands, cis-[Re(PR3)(CO)(4)-(L)][BArF], L = CH2Cl2, Et2O, NC5F5: Decomposition to chloride-bridged dimers in CH2Cl2 solution

The solvent-coordinated complexes [cis-Re(CO)(4)(PR3)(S)][BArF] (R = Ph, Pr -i, Cy BArF = [B(3,5-(CF3)(2)C6H3)(4)](-)) for S = Et2O. CH(2)Chl(2) and NC 5F5 have been prepared from reaction of the neutral methyl precursors, cis- Re-(CO)(4)(PR3)(Me), with either [H(OEt2)(2)][BArF] or [Ph3C][BArF] in the appropriate solvent. A crystal structure of the complex [cis-Re(CO)(4)((PPr 3)-Pr-i)(ClCH2Cl)][BArF] shows that the dichloromethane ligand is coordinat ed through one chlorine, with an Re-Cl distance of 2.554(2) Angstrom. The f irst example of a structurally characterized pentafluoropyridine complex of rhenium was also determined, [cis-Re(CO)(4)((PPr3)-Pr-i)(NC5F5)][BArF], wi th an Re-N distance of 2.319(5) Angstrom. Activation of C-CI bonds in the d ichloromethane complexes result in the formation of the chloride-bridged di mers, {[Cis-Re(CO)(4)(PR3)](2)(mu-Cl)}{BArF}, and the X-ray structures of t he Ph and Cy derivatives were determined.