Facile routes to abnormal-NHC-cobalt(II) complexes

Deprotonation of [IPrPh]I (1) with Co{N(SiMe3)(2)}(2) readily affords the abnormal N-heterocyclic carbene (aNHC) complex (aIPr(Ph))(2)CoI2 (2) (aIPr(Ph) = 1,3-bis(2,6-iPr(2)C(6)H(3))-2-phenyl-imidazol4-ylidene). Treatment of 1 with NaHBEt3 yields (aIPr(Ph)) BEt3 (3) that serves as an aNHC-transfer agent and yields (aIPr(Ph)) Co{N(SiMe3)(2)}(2) (4) on reaction with Co{N(SiMe3)(2)}(2).