Insertion and Substitution Chemistry at the Boron Fourth Position in Charge-Neutral Zwitterionic Tripodal Tris(methimazolyl)borate Ligands

A number of new charge-neutral zwitterionic tris­(methimazolyl)­borate ligands have been synthesized, either by substitution of the dimethylamine group in the adduct (dimethylamine)­tris­(methimazolyl)­borane (1) or by insertion into its B–N­(dimethylamine) bond by an unsaturated Lewis base. Two new anionic ligands, (thiocyanato)­tris­(methimazolyl)­borate and (cyano)­tris­(methimazolyl)­borate, have also been accessed by this method.