Metallaheteroboranes containing group 16 elements: An experimental and theoretical study

Abstract

Thermolysis of diphenyl dichalcogenides, Ph2E2 (E = S, Se and Te) with an insitu generated intermediate, obtained from the reaction of [Cp*WCl4] (Cp* = η5-C5Me5) with [LiBH4·THF], yielded new tungstaheteroboranes, [(Cp*W)2(μ-EPh)(μ3-E)(μ-H)(B3H2EPh)], 1 and 2 (1: E = S; 2: E = Se), and [(Cp*W)2(μ-TePh)B5H5(μ-H)3], 4. Formation of compounds 1 and 2 substantiate the evidence of [(Cp*W)2B4H10], which supports our previous studies. Compound 4 has a capped octahedral geometry that is unique due to the presence of three W-H-B bridging hydrogens in a closo cluster. Alternatively, the shape of cluster 4 can be defined as oblatoarachno that can be derived from a heptagonal bipyramid. All the compounds have been characterized by mass spectrometry, 1H, 11B{1H}, IR and 13C{1H} NMR spectroscopy in solution and the structural architectures of 1 and 4 were unequivocally established by X-ray crystallographic analysis. The density functional theory calculations also yielded geometries in close agreement with the observed structures.