B-H Functionalization of Hydrogen-Rich [(CpV)(2) (B2H6)(2)]: Synthesis and Structures of [(CpV)(2)(B2X2)(2)H-8] (X = CI, SePh; Cp = eta(5)-C5Me5)

• Published in: Organometallics Vol. 39; no. 1; pp. 58 - 65
• Main Authors: Haridas, Anagha, Kar, Sourav, Raghavendra, Beesam, Roisnel, Thierry, Dorcet, Vincent, Ghosh, Sundargopal
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13.01.2020
• Subjects: Chemical Sciences
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/acs.organomet.9b00609

We 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 [LiBH4THF] followed by thermolysis with excess [BH3 center dot 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 H-1, B-11, and C-13 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.