Metal Centered Commo-Bis(metallaselenaborane): Heterotrimetallic Systems Bearing a Zn(II) Center

Thermolysis of an in situ generated intermediate, obtained from the reaction of [Cp*MCl2](2) (M = Rh, Ir) and LiBH4 center dot thf, with Se powder and [Zn(BH4)(2)] afforded the two unusual heterotrimetallic complexes [(Cp*MB2H3Se2)(2) (mu(4)-Zn)] (1, M = Ir; 2, M = Rh), along with [(Cp*M)(2)B2H2Se2] (M = Rh, Ir; Cp* = eta(5)-C5Me5). Clusters 1 and 2 are distinct due to the presence of a tetracoordinated Zn(II) in the Se-4 pocket molded by the Se atoms of two {Cp*MB2H3Se2} units. These clusters belong to a rare class of metal-centered commo-bis(metallaheteroborane) species. The molecular structures of 1 and 2 can be viewed as two arachno-metallaheteroborane subclusters conjoined at the common zinc atom that obey Mingos' fusion formalism. Both 1 and 2 have been comprehensively characterized by multinuclear NMR, IR, and UV-vis spectroscopy, mass spectrometry, and single-crystal X-ray diffraction techniques. All experimental results are well supported by theoretical studies.