Tris(triazolyl)borate ligands of intermediate steric bulk for the synthesis of biomimetic structures with hydrogen bonding and solubility in hydrophilic solvents

Tris(triazolyl)borate ligands (Ttz) of intermediate steric bulk were synthesized to investigate their potential for hydrogen bonding and improved solubility in hydrophilic solvents as applied to biomimetic chemistry. The crystal structure of 3-phenyl-5-methyl-1,2,4-triazole (HtzPh,Me) revealed hydrogen bonding and π stacking interactions. The new ligand salt, potassium tris(3-phenyl-5-methyl-1,2,4-triazolyl)borate (KTtzPh,Me) was synthesized as the first example of a Ttz ligand of intermediate steric bulk. Metathesis between KTtzPh,Me and NaCl followed by recrystallization produced [NaTtzPh,Me] · 6CH3OH in which the geometry around the sodium is octahedral with an unusual N3O3 donor set; this structure also shows that a hydrogen bonding network is formed by methanol molecules and triazole nitrogens. (TtzPh,Me)ZnCl was synthesized and characterized crystallographically as [(TtzPh,Me)ZnCl] · 0.5CH3OH in which the zinc is tetrahedral and the triazole rings are within hydrogen bonding distance of CH3OH. All of these new compounds are methanol soluble to varying degrees and HtzPh,Me and KTtzPh,Me are soluble in methanol/water mixtures.