Diruthenium analogues of Hexaborane(12) and Pentaborane(9): synthesis and structural characterization of [(1,2-Cp*Ru)₂B₂H₆S₂] and [(2,3-Cp*Ru)₂B₃H₆ (μ-η¹-EPh)], (E = S, Se and Te) (Cp* = η⁵-C₅Me₅)

Abstract

In an objective to synthesize metallaheteroboranes containing heavier chalcogen atoms, we performed the reaction of dimetallaborane analogues of pentaborane(9) with various chalcogen sources. As a result, the thermolysis of nido-[1,2-(Cp*RuH)₂B₃H₇], 1 (Cp* = η⁵-C₅Me₅) with mixture of S and Se powder was carried out, that led to the isolation of half sandwich dimetallaheteroborane arachno-[(1,2-Cp*Ru)₂B₂H₆S₂], 2. On the other hand, the reaction of nido-1 with diorganyldichalcogenide ligands, [Ph₂E₂] afforded chalcogen bridged half sandwich complexes [(2,3-Cp*Ru)₂B₃H₆ (μ-η¹-EPh)], 4a-c (4a: E = S; 4b: E = Se and 4c: E = Te). Compound 2 can be derived from a closo-snub disphenoid by removing a 5-connect vertex followed by the removal of a 3-connect vertex. Compound 4a–c can be described as nido-square pyramidal structures, isoelectronic and isostructural with nido-1. All the compounds have been characterized by mass spectrometry, ¹H, ¹¹B, ¹³C spectroscopy. Further, the geometry of compounds 2, 3, 4b and 4c were unequivocally established by crystallographic analysis.