Halogen oxidation reactions of (C5Ph5)Cr(CO)(3) and Lewis base addition to[(C5Ph5)Cr(mu-X)X](2): Electrochemical, magnetic, and Raman spectroscopic characterization of [(C5Ph5)CrX2](2) and (C5Ph5)CrX2(THF) (X = Cl, Br, I) and X-ray crystal structure of [(C5Ph5)Cr(mu -Cl)Cl](2)

The 17-electron complex (C5Ph5)Cr(CO)(3) reacts with halogens (C6H5I . Cl-2 , Br-2, and I-2) in C6H6 to yield the dimeric oxidation products [(C5Ph5)Cr (mu -X)X](2) as thermally stable solids. Reactions with other chlorinating agents similarly yield [(C5Ph5)CrCl2](2). An X-ray crystal structure of [(C 5Ph5)Cr(mu -Cl)Cl](2) was obtained. The magnetic properties of the Cia-brid ged dimer have been determined and modeled using the usual isotropic Hamilt onian H = -2J (S) over cap (1). (S) over cap (2), which yields J/k = -30 K. Low-temperature (77 K) Raman spectra of solid [(C5Ph5)-CrX2](2) (X = Cl, I ) allow assignments to be made for the metal-ring and metal halogen stretch ing modes in the low-frequency region (<600 cm(-1)). Tetrahydrofuran (THF) cleaves these dimers to yield complexes of the form (C5Ph5)CrX2(THF).