Substitution at B-H vertices of group 5 metallaborane clusters

• Published in: Journal of organometallic chemistry 2022-03, Vol.961, p.122250, Article 122250
• Main Authors: Haridas, Anagha, Bedajna, Shantabh, Ghosh, Sundargopal
• Format: Article
• Language: English
• Subjects: Boranes; Niobium; Oxametallaborane; Substitution; Vanadium
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/j.jorganchem.2021.122250

•A novel dioxadivanadaborane cluster consisting two μ3O units and two terminal persubstituted divanadaborane clusters have been synthesised.•The electronic properties of these complexes has been described.•The experimental results were complemented and rationalized by means of DFT studies. Thermolysis of an in situ generated intermediate which was formed by the reaction of [Cp*VCl2]3 (Cp* = η5-C5Me5) and LiBH4.THF with excess of BH3.THF (THF = tetrahydrofuran) led to the formation of a novel dioxadivandaborane, [(Cp*V)2(OBH3)2], 2 along with divanadaborane [(Cp*V)2(B2H6)2], 1. In an attempt to functionalize the terminal B-H vertices by different aryl chalcogenides, 1 was thermolyzed with dinaphthyl diselenide, [Nap2Se2] and dimesityl diselenide, [Mes2Se2], leading to the formation of persubstituted divanadaboranes, [(Cp*V)2{B2H4(SeNap2)}2], 3 and [(Cp*V)2{B2H4(SeMes2)}2], 7. All these compounds were fully characterized with the help of mass spectrometry and 1H, 11B{1H} and 13C{1H} NMR spectroscopy and the dioxadivandaborane species 2 was additionally characterized by X-ray diffraction analysis. Density Functional Theory (DFT) calculations show geometries in agreement with the structural determinations. The reduction in the HOMO-LUMO gap due to the introduction of chalcogenide ligands in 2, 3 and 7 is in respectable agreement with their UV–Vis absorption spectra. [Display omitted]