Synthesis and molecular structures of novel hydrotris (3,5-dimethyl-1-pyrazolyl)borate molybdenum complexes containing 1,2-dicarba-closo-dodecaborane-1,2-dichalcogenolato ligands

Reactions of tridentate mononuclear hydrotris (3,5-dimethyl-1-pyrazolyl) borate molybdenum(V) complex Tp*Mo(O)Cl-2 (1) (Tp*=hydrido-tris 3,5-dimethyl-1-pyrazolyl-borate, HB(C3H(Me-2)N-2)(3)) with dilithium dichalcogenolate carboranes [(THF)(3)LiE2C2B10H10(THF)](2) [E=S(2a), Se(2b), Te(2c)] afforded mononuclear complexes Tp*Mo(O) E2C2B10H10 [E=S(3a), Se(3b), Te(3c)] in moderate yields. Complexes 3a similar to 3c have been characterized by IR and elemental analysis. The molecular structure of 3b was determined by X-ray crystallographic analysis. In the air 3a can convert into a novel binuclear oxo molybdenum complex [HMe(2)Pz][Tp*Mo(O)(mu(2)-O)(2)Mo(O)S2C2B10H10] 4a. The molecular geometry of 4a has been determined by a single crystal X-ray structure analysis. According to the short Mo-Mo distance (0.25483(12) nm), direct metal-metal interaction exists. CCDC: 263618, 3b; 263619, 4a.