Synthesis and study of C -substituted methylthio derivatives of cobalt bis(dicarbollide).

The C -methylthio derivatives of cobalt bis(dicarbollide) were synthesized by reaction of anhydrous CoCl 2 with nido -carborane [7-MeS-7,8-C 2 B 9 H 11 ] - and isolated as a mixture of rac -[1,1'-(MeS) 2 -3,3'-Co(1,2-C 2 B 9 H 10 ) 2 ] - and meso -[1,2'-(MeS) 2 -3,3'-Co(1,2-C 2 B 9 H 10 ) 2 ] - isomers. The structures of both isomers were studied using DFT quantum chemical calculations. The most preferable geometry of rotamers and the stabilization energy of C -methylthio derivatives of cobalt bis(dicarbolide) were calculated. The (BEDT-TTF)[1,1'-(MeS) 2 -3,3'-Co(1,2-C 2 B 9 H 10 ) 2 ] salt was prepared and its structure was determined by single crystal X-ray diffraction. The cisoid conformation of the rac -[1,1'-(MeS) 2 -3,3'-Co(1,2-C 2 B 9 H 10 ) 2 ] - anion is stabilized by short intramolecular CH⋯S hydrogen and BH⋯S chalcogen bonds between the dicarbollide ligands, that is in good agreement with the data of quantum chemical calculations.