Sterically bulky tris(triazolyl)borate ligands as water-soluble analogues of tris(pyrazolyl)borate.

The recently synthesized 3-tert-butyl-5-methyl-1,2,4-triazole reacted with KBH4 to give the new potassium tris(3-tert-butyl-5-methyl-1,2,4-triazolyl)borate K(TtztBu,Me) ligand. TtztBu,Me formed a four-coordinate (TtztBu,Me)CoCl complex and five-coordinate (TtztBu,Me)CoNO3 and (TtztBu,Me)ZnOAc complexes. When these complexes were compared to their TptBu,Me analogues, it was found that TtztBu,Me resulted in negligible steric differences. K(TtztBu,Me) is more water-soluble than K(TptBu,Me), so bulky tris(triazolyl)borate ligands should lead to functional models for enzyme active sites in an aqueous environment and the creation of water-soluble analogues of Tp catalysts.