Biomimetic Chemistry with Tris(triazolyl)borate Ligands: Unique Structures and Reactivity via Interactions with the Remote Nitrogens

A review of the structures and reactivity of tris(triazolyl)borate (Ttz) ligands and closely related triazole-based ligands is presented, with an emphasis on complexes of the transition metals. Ttz ligands can form mononuclear complexes or coordination polymers of various dimensionalities. The extra nitrogens in Ttz ligands (relative to trispyrazolylborate, Tp, ligands) can bind to additional metals or acidic hydrogens, and through the latter interactions water solubility is improved. Ttz ligands are also weaker donors than Tp ligands, and this often leads to an increased coordination number in metal complexes. An in-depth discussion of recently developed bulky Ttz ligands and their use in forming biomimetic structures and catalyzing reactions is included.