NHC adducts of tantalum amidohalides: the first example of NHC abnormally coordinated to an early transition metal

Abstract

The reaction of Ta(NMe₂)₅ with NHC·HBF₄ (NHC = IMes and SIMes) leads to new carbene adducts of the mixed Ta^V amidofluoride, [(NHC)TaF₃(NMe₂)₂]. On the contrary, the reaction of Ta(NMe₂)₅ with IMes·HCl gives a complex mixture, where [(aIMes)TaCl₂(NMe₂)₃] is identified as one of the products. This is the first example of abnormal NHC coordination to an early transition metal.