Bonding modes of stanna-closo-dodecaborate: η1(Sn) to η3(BH) rearrangement reactions in zwitterionic stanna-closo-dodecaborate ruthenium complexes

Abstract

Reaction of the stanna-closo-dodecaborate salt [Bu₃MeN]₂[SnB₁₁H₁₁] with the dimeric ruthenium complex [Ru₂(µ-Cl)₃(triphos)₂]Cl (triphos = {MeC(CH₂PPh₂)₃}) in refluxing acetonitrile yields the zwitterionic compound [Ru(SnB₁₁H₁₁)(MeCN)₂(triphos)] (4) which has been characterized by single-crystal X-ray diffraction analysis and solid-state NMR spectroscopy. Refluxing the zwitterion 4 in acetone leads to an η¹(Sn) to η³(BH) rearrangement with formation of [Ru(SnB₁₁H₁₁)(triphos)] (5) whose structure has been confirmed by X-ray diffraction and multinuclear NMR spectroscopy in solution and in the solid state. Furthermore, two isomeric zwitterions fac- and mer-[Ru(SnB₁₁H₁₁)(dppb)(MeCN)₃] (6a, 6b) and their rearrangement reactions as well as their NMR properties are described.