Formation of new nickel-containing nineteen-vertex metallaborane clusters prepared from the anti-B18H22borane cluster: molecular structures of [Ni(THF)4(H2O)2][B18H20Ni(η5-C5H5)]2 and [B18H19(2-THF)Ni(η5-C5H5)]

Abstract

The reaction of the anti-B₁₈H₂₂ borane cluster with nickelocene produced several new metallaborane species, [Ni(THF)₄(H₂O)₂][B₁₈H₂₀Ni(η⁵-C₅H₅)]₂ (1a), [B₁₈H₂₀Ni(η⁵-C₅H₅)] (1b) and [N(CH₃)₄][B₁₈H₁₉(2-THF)Ni(η⁵-C₅H₅)] (2), in relatively high yields. These new complexes were fully characterized by multinuclear NMR (¹H, ¹³C, ¹¹B), IR and UV-Vis spectroscopy. Single-crystal X-ray diffraction analyses of complexes 1a and 2 confirmed their structures as 19-vertex conjuncto-metallaborane clusters. The structures consist of ten-vertex nido-borane subunits edge-shared with eleven-vertex nido-cluster subunits. In compound 2, formed through the THF reflux of compound 1, a THF molecule was found to coordinate at the 2-position of the borane framework.