Thiaborane clusters with an exoskeletal B–H group

Abstract

The thiaboranes closo-1-SB₁₁H₁₁ (1a) and 12-I-closo-1-SB₁₁H₁₀ (1b) react with 4-(dimethylamino)pyridine under inert conditions upon the formation of the nido-type thiaboranes 9-B{(4-Me₂N)C₅NH₄}₂(H)-7-SB₁₀H₁₁ and 9-B{(4-Me₂N)C₅NH₄}₂(H)-5-I-7-SB₁₀H₁₀ containing an exoskeletal B–H group. The same type of B–H moiety is also stabilised by one bipyridine molecule in a chelating fashion. These complexes are unstable in solution, and in air and hydrolyse to monodeboronated ionic compounds having [nido-7-SB₁₀H₁₁]⁻ or [5-I-nido-7-SB₁₀H₁₀]⁻ anions which are also products of the reactions of 1a and 1b with other N-bases such as pyridine, ammonia and DABCO. The extrusion of one boron and one sulphur atom takes place when 1a reacts with 2,6-di-tert-butylpyridine to yield decaborane.