Sulfur and oxygen functionalized cyclopentadienyl half-sandwich cobalt complexes with 1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolato ligands

Sulfur and oxygen functionalized cyclopentandienyl half-sandwich cobalt dicarbonyl complexes [η5-C5H4(CH2)2SCH2CH3]Co(CO)2 (3) and [η5-C5H4(CH2)2OCH3]Co(CO)2 (7) were prepared. Oxidation of 3 or 7 with I2 led to formation of 18-electron complexes [η5-C5H4(CH2)2SCH2CH3]CoI2 (4) and [η5-C5H4(CH2)2OCH3]Co(CO)I2 (8). The reactions of diiodide complex (4) with dilithium 1,2-dicarba-closo-dodecaborane(12)-1,2-dichalcogenolates [(THF)3LiE2C2B10H10Li(THF)]2 [E=S (1a), Se (1b)] afforded 18-electron mononuclear complexes [η5-C5H4(CH2)2SCH2CH3]Co(E2C2B10H10) [E=S (5a), Se (5b)] in which sulfur atoms of side-chain were attached via an intramolecular coordination. Complex 7 reacted with 1a and 1b to give the binuclear complexes {[η5-C5H4(CH2)2OCH3]Co(E2C2B10H10)}2 [E=S (10a), Se (10b)]. The molecular structures of 5a and 10b were determined by X-ray crystallographic analysis. According to the X-ray structure analyses, 10b contains two o-carborane diselenolate bridges, and each Cp′Co fragment is attached to one terminal and two bridging selenolato ligands. The central Co2Se2 four-membered ring is planar, and the direct metal–metal interaction is absent.