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

Abstract

Sulfur and oxygen functionalized cyclopentandienyl half-sandwich cobalt dichalcogenolate carborane complexes, [η 5 -C 5 H 4 (CH 2 ) 2 SCH 2 CH 3 ]Co(E 2 C 2 B 10 H 10 ) and {[η 5 -C 5 H 4 (CH 2 ) 2 OCH 3 ]Co(E 2 C 2 B 10 H 10 )} 2 (E=S, Se), have been synthesized and characterized. X-ray structure analysis of [η 5 -C 5 H 4 (CH 2 ) 2 SCH 2 CH 3 ]Co(S 2 C 2 B 10 H 10 ) shows that the sulfur atom of the appended side-chain was bonded to the metal via an intramolecular coordination. Sulfur and oxygen functionalized cyclopentandienyl half-sandwich cobalt dicarbonyl complexes [η 5 -C 5 H 4 (CH 2 ) 2 SCH 2 CH 3 ]Co(CO) 2 ( 3 ) and [η 5 -C 5 H 4 (CH 2 ) 2 OCH 3 ]Co(CO) 2 ( 7 ) were prepared. Oxidation of 3 or 7 with I 2 led to formation of 18-electron complexes [η 5 -C 5 H 4 (CH 2 ) 2 SCH 2 CH 3 ]CoI 2 ( 4 ) and [η 5 -C 5 H 4 (CH 2 ) 2 OCH 3 ]Co(CO)I 2 ( 8 ). The reactions of diiodide complex ( 4 ) with dilithium 1,2-dicarba- closo -dodecaborane(12)-1,2-dichalcogenolates [(THF) 3 LiE 2 C 2 B 10 H 10 Li(THF)] 2 [E=S ( 1a ), Se ( 1b )] afforded 18-electron mononuclear complexes [η 5 -C 5 H 4 (CH 2 ) 2 SCH 2 CH 3 ]Co(E 2 C 2 B 10 H 10 ) [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 {[η 5 -C 5 H 4 (CH 2 ) 2 OCH 3 ]Co(E 2 C 2 B 10 H 10 )} 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 Co 2 Se 2 four-membered ring is planar, and the direct metal–metal interaction is absent.