A study of some metal complexes occurring as intermediates in the metal catalysis of transamination reaction

Abstract

The aim of this research was to isolate metal complexes which occurred as intermediates in the metal catalysis of the transamination reaction of pyridoxal phosphite and [alpha]-glutamic acid (pyridoxamine phosphate and [alpha]-keto glutaric acid). Metal ions used were gallium, copper, nickel, cobalt(ll), iron(III) and aluminium. The infra-red ultra-violet and visible spectra of the complexes have been measured and assignments of bands made, with special reference to previous work in the field. Mass spectra were performed on several copper complexes, and fragmentation patterns have been evaluated. It was found that mixed metal Schiff base species occurred in the reaction of pyridoxal phosphate with glutamic acid to form pyridoxarnine phosphate and [alpha]-keto glutaric acid. In all the metal species, there was a 1:1 ratio of metal ion to Schiff base species, and the remaining coordination positions of the metal ion were occupied by either an amino acid molecule, or anion radicals (such as OH- or SO42-). Bridging metal dimers tended to be more the rule than the exception.