| Abstract
| - The products obtained in the reaction of cobalt atoms in neat benzene or in a benzene/argon mixture at lowtemperature have been reinvestigated. At least three cobalt-containing species were detected by IR, namely,Co(C6H6), Co(C6H6)2, and Cox(C6H6), x> 1. The IR bands were assigned to these complexes by monitoringtheir behavior as a function of (a) Co and C6H6 concentration, (b) isotopic substitution, and (c) photoirradiation.We were able to analyze the sample in neat benzene by both electron paramagnetic resonance (EPR) and IRspectroscopy and to determine the magnetic parameters (g tensor and Co hyperfine interaction) for the Co(C6H6)2 sandwich compound. The large number of fundamental bands observed in the IR spectrum of Co(C6H6)2, the absorption pattern observed in the Co-ring stretching region of the IR spectrum of the mixedcomplex, Co(C6H6)(C6D6) and the orthorhombic g-values extracted from the EPR spectrum are most consistentwith nonequivalent benzene ligands in Co(C6H6)2, i.e., Cs symmetry. A bonding scheme consistent with boththe EPR and IR data for Co(C6H6)2 is discussed.
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