Dichalcogenide Cleavage and Carbonyl Insertion Reactions on a Dirhodium Bond

The reaction of the binuclear rhodium complex [(eta-C5H5)(2)Rh-2(mu-CO)(mu-eta(1):eta(1)-C-2(CF3)(2))] with a series of dichalcogenides, R2E2 (E = S, Se, Te; R = Me, Et, i-Pr, Ph, Fc; not all combinations) has provided mixtures of complexes, the majority of which have been characterized by standard spectroscopic techniques. These complexes arise as a consequence of carbonyl substitution followed by chalcogen-chalcogen bond cleavage giving [(eta-C5H5)(2)Rh-2(mu-ER)(2)(mu-eta(1):eta(1)-C-2(CF3)(2))], possibly concomitant with CO insertion into a Rh-C-2(CF3)(2) bond of the product in some cases, giving [(eta-C5H5)(2)Rh-2(CO)(mu-ER)(2)(mu-eta(1):eta(1)-C-2(CF3)(2)C(O))] (E = Se, Te; R = Me, Et, i-Pr, Ph, Fc; not all combinations). In the case of Te2R2 the dichalcogenide products have been structurally characterized for the carbonyl insertion product (for R = Et) and the simple cleavage case (for R = i-Pr). In both, the putative m-symmetry is broken by substituent dispositions and, in the R = Et adduct, torsion in the fluorocarbon skeleton.