om9b00609_si_002.xyz (22.45 kB)
B–H Functionalization of Hydrogen-Rich [(Cp*V)2(B2H6)2]: Synthesis and Structures of [(Cp*V)2(B2X2)2H8] (X = Cl, SePh; Cp* = η5‑C5Me5)
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posted on 2019-12-16, 05:30 authored by Anagha Haridas, Sourav Kar, Beesam Raghavendra, Thierry Roisnel, Vincent Dorcet, Sundargopal GhoshWe have recently reported the perchlorinated diniobaborane
species
[(Cp*Nb)2(B2H4Cl2)2] from [(Cp*Nb)2(B2H6)2] using CCl4 as a chlorinating agent. In an attempt
to isolate the vanadium analogue, we have isolated [(Cp*V)2(B2H6)2] (1) from the
reaction of (Cp*VCl2)3 with [LiBH4·THF] followed by thermolysis with excess [BH3·THF].
Subsequently, the thermolysis of 1 with CCl4 for a prolonged period of time afforded the perchlorinated divanadaborane
[(Cp*V)2(B2H4Cl2)2] (2) along with the formation of the bichlorinated
divanadaborane [(Cp*V)2(B2H5Cl)2] (3) and trichlorinated divanadaborane [(Cp*V)2(B2H4Cl2)(B2H5Cl)] (4). Similarly, in order to functionalize
the terminal B–H by a {SePh} group, thermolysis of 1 was carried out with Ph2Se2, which yielded
the persubstituted divanadaborane [(Cp*V)2{B2H4(SePh)2}2] (5) in
parallel to the formation of [(Cp*V)2{B4H11(SePh)}] (6). Compound 5 is very
fascinating in that all of the terminal B–H hydrogens of 1 have been substituted by {SePh} ligands. All of the compounds
have been characterized by 1H, 11B, and 13C NMR spectroscopy, mass spectrometry, IR spectroscopy, and
single-crystal X-ray analysis. Density functional theory (DFT) and
TD-DFT calculations provided a further understanding regarding the
electronic structures, bonding, and electronic transitions of these
persubstituted vanadaborane species.
