Self-Assembly of Mercaptane−Metallacarborane Complexes by an Unconventional Cooperative Effect: A C−H···S−H···H−B Hydrogen/Dihydrogen Bond Interaction

The existence of a dihydrogen bond (S−H···H−B) and its combination with a C−H···S hydrogen
bond in an unusual cooperative effect are demonstrated from a combination of experimental and theoretical
methods. This cooperative effect seems to be responsible for self-assembly of mercaptane−metallacarborane complexes such as closo-[3-Ru(η6-C6H6)-8-HS-1,2-C2B9H10] (1) and closo-[3-Co(η5-C5H5)-8-HS-1,2-C2B9H10] (3), which present identical supramolecular two-dimensional polymeric networks. The findings,
besides documenting structurally the first S−H···(H−B)2 dihydrogen bond and the unconventional
cooperative ability of a boron-attached SH group, prove that substituted carboranes have the potential to
serve as building blocks for assembling complex structures.