Synthesis, Characterization, and X-ray Molecular Structure of Tantalum CCC-N-Heterocyclic Carbene (CCC-NHC) Pincer Complexes with Imidazole- and Triazole-Based Ligands
文摘
Unprecedented Ta bis(NHC) pincer complexes have been synthesized and characterized by extension of the early-transition-metal amido methodology. The reaction of 1,3-bis(3-butylimidazol-1-yl)benzene diiodide (1) with stoichiometric and substoichiometric amounts of (tert-butylimido)tris(dimethylamido)tantalum(V) yielded (1,3-bis(3-butylimidazol-1-yl-2-idene)-2-phenylene)(tert-butylimido)diiodotantalum(V) (2) and (1,3-bis(3-butylimidazol-1-yl-2-idene)-2-phenylene)(tert-butylimido)(dimethylamido)iodotantalum(V) (3). Use of excess (tert-butylimido)tris(dimethylamido)tantalum(V) to metalate 1,3-bis(3-butylimidazol-1-yl)benzene diiodide (1) yielded (1,3-bis(3-butylimidazol-1-yl-2-idene)-2-phenylene)(tert-butylimido)(dimethylamido)iodotantalum(V) (3) exclusively. Furthermore, the first early-transition-metal (group 3鈥?) triazole-based NHC complex, (1,3-bis(3-butyltriazol-1-yl-2-idene)-2-phenylene)(tert-butylimido)(dimethylamido)iodotantalum(V) (5), has been synthesized via amine elimination of 1,3-bis(3-butyltriazol-1-yl)benzene diiodide (4) with (tert-butylimido)tris(dimethylamido)tantalum(V).