In the field of cluster chemistry, metallaborane compounds incorporating early transition metals are less explored[1]. Examples of structurally characterized group 5 metallaboranes, especially vanadaboranes are very less and hence, their synthesis and reactivity became of interest[2]. In that context, we have treated [Cp*VCl2]3 (Cp* = η5-C5Me5) with an excess of LiBH4.THF at low temperature followed by pyrolysis in presence of BH3.THF that resulted in formation of divanadaboranes [(Cp*V)2(B2H6)2], [(Cp*V)2B6H10] and divanadadioxaborane, [(Cp*V)2(OBH3)2]. Further, the reactivity of the divanadaborane, [(Cp*V)2(B2H6)2] with CCl4 and various diaryl diselenides were explored, which led to the isolation of a series of terminal persubstituted divanadaboranes. In an attempt to functionalize these group 5 metallaboranes, the reactions of in situ generated intermediates, generated from the reaction of [Cp*VCl2]3 or Cp*MCl4 (M=Ta or Nb) and LiBH4·THF, with 2-mercaptobenzothiazole and 2-mercaptopyridine ligands were performed. Although the reactions with V precursor led to the decomposition of starting material, both Nb and Ta led to the formation of κ2-N,S chelated complexes [Cp*M(ƞ2-S2){κ2-N,S-(NC5H4S)}2] (M = Nb, Ta)[3].

References
[1] C. Elschenbroich, Organometallics (3rd Edition), Wiley-VCH 2006.
[2] S. K. Bose, K. Geetharani, V. Ramkumar, S. M. Mobin, S. Ghosh, Chem. Eur. J, 2009, 15, 13483.
[3] (a) A. Haridas, S. Kar, B. Raghavendra, T. Roisnel, V. Dorcet, S. Ghosh, Organometallics 2020, 39, 58 (b) A. Haridas, S. Kar, D. Chatterjee, G. Joshi, E. D. Jemmis, S. Ghosh, (manuscript under preparation) (c) R. Prakash, A. Haridas, K. Bakthavachalam, T. Roisnel, J. -F. Halet, S. Ghosh, Dalton Trans. 2021, 50, 4036 (d) A. Haridas, S. Bedajna, S. Ghosh, J. Organomet. Chem. 2022, 961, 122250 (e) S. Saha, A. Haridas, F. Assanar, C. Bansal, P. K. S. Antharjanam, S. Ghosh, Dalton Trans. 2022 (Under minor revision).