1345984-67-9Relevant academic research and scientific papers
Carbon radical generation by d0 tantalum complexes with α-diimine ligands through ligand-centered redox processes
Tsurugi, Hayato,Saito, Teruhiko,Tanahashi, Hiromasa,Arnold, John,Mashima, Kazushi
, p. 18673 - 18683 (2011)
High-valent tantalum complexes having redox-active α-diimine ligands, (α-diimine)TaCln (n = 3, 4), are prepared by the reaction of TaCl5, α-diimine ligands, and an organosilicon-based reductant, 1-methyl-3,6-bis-(trimethylsilyl)-1,4-cyclohexadiene. Reductive cleavage of the C-Cl bond of polyhaloalkanes is accomplished by trichlorotantalum complexes having dianionic α-diimine ligands via electron transfer from the dianionic ligands, whereas oxidative decomposition of tetraphenylborate is observed using tetrachlorotantalum complexes with monoanionic α-diimine ligands through electron transfer to the monoanionic ligands. Chemically oxidized or reduced complexes of (α-diimine)TaCl4 are isolated as ligand-centered redox products, [Cp2Co][(α-diimine)TaCl 4] and [(α-diimine)TaCl4][WCl6], where the α-diimine ligand coordinates to the metal center as a dianionic or neutral ligand, respectively. On the basis of EPR measurements of (α-diimine)TaCl4 complexes (which are key intermediates for reductive cleavage of C-Cl bond and oxidative decomposition of tetraphenylborate), two redox isomers-a tantalum-centered radical and ligand-localized radical-are present in solution.
