Synthesis and cluster structure distortions of biscarborane dithiol, thioether, and disulfide

Abstract

The synthesis and structural characterization of the first sulfur-containing derivatives of the C,C-biscarborane {ortho-C₂B₁₀}₂ cluster – thiol, thioether, and disulfide – are reported. The biscarboranyl dithiol (1-HS-C₂B₁₀H₁₀)₂ exhibits an exceedingly long intracluster carbon–carbon bond length of 1.858(3) Å, which is attributed to the extensive interaction between the lone pairs of the thiol groups and the unoccupied molecular orbital of the carborane cluster. The structures of the doubly deprotonated biscarboranyl dithiolate anion (1-S-C₂B₁₀H₁₀)₂²⁻ with various counter cations feature an even longer carbon–carbon bond length of 2.062(10) Å within the cluster along with a short carbon–sulfur bond of 1.660(7) Å, both indicative of significant delocalization of electron density from the sulfur atoms into the cluster.