Coordination Compounds of Hexamethylenetetramine with Metal Salts: A Review Properties and applications of a versatile model ligand

Hexamethylenetetramine (hmta) was chosen as a model ligand. Each of the four nitrogen atoms has a pair of unshared electrons and behaves like an amine base, undergoing protonation and N-alkylation and being able to form coordination compounds with many inorganic elements. The ligand can be used as an outer coordination sphere modulator of the inner coordination sphere and as a crosslinking agent in dinuclear and multinuclear coordination compounds. It can also be used as a model for bioactive molecules to form a great number of complexes with different inorganic salts containing other molecules. Studies of hmta coordination compounds with different metal salts have therefore attracted much attention. The present review summarises the synthesis, preparation, structure analysis and applications of coordination compounds of hmta with different metal salts.