Thiolate-Bridged Heterodinuclear Manganese-Cobalt Complexes with Bridging Hydride Ligands

Synthesis and structural elucidation of a series of thiolate-bridged heterobimetallic MnCo complexes are described. Irradiation of [Mn2(CO)10] in the presence of Li[BH3SPh] followed by room-temperature reaction with [Cp*CoCl]2 (Cp* = 15-C5Me5) afforded dithiolateand hydride-bridged dinuclear heterobimetallic MnCo complex [{(Mn(CO)3}(mu-SPh)2(mu-H){CoCp*}] (1). The solid-state structure of 1 established that the two metal fragments, {Mn(CO)3} and {Cp*Co}, are linked by a Mn-Co bond. In addition to 1, the reaction also yielded half-sandwiched trithiolate-bridged dinuclear MnCo complex [{Mn(CO)3}(mu-SPh)3(CoCp*)] (2) and a dinuclear heterometal-coordinated diborane analogue [{Mn(CO)3}(mu-12:12-SBH3)-(mu-H)(CoCp*)] (3). To isolate the Se analogues of 1-3, a similar reaction was carried out in the presence of Li[BH3SePh] that led to the formation of complexes [{(Mn(CO)3}(mu-SePh)2(mu-H)(CoCp*)] (4), [{Mn(CO)3}(mu-SePh)3(CoCp*)] (5), and [{Mn(CO)3}(mu-12:12-SeBH3)(mu-H)(CoCp*)] (6). All of the complexes were characterized by employing multinuclear nuclear magnetic resonance and infrared spectroscopies as well as mass spectrometric techniques. Single-crystal X-ray diffraction analyses of complexes 1, 2, and 4 helped to establish the molecular formulations and structural integrity of these complexes. The bonding interactions present in these di-or trichalcogenate-bridged dinuclear heterobimetallic complexes were explicated computationally by density functional theory calculations that supported the {Mn-H-Co} and Mn-Co bonding interactions in 1 and 4. The inherent electronic properties of all of the complexes were demonstrated by ultraviolet-visible spectroscopy. Furthermore, the critical involvement of the bridging chalcogenato functionalities was probed via cyclic voltammetry and complementary spectroelectrochemical studies.