Cyclic and open-chain tautomerism and complex formation behaviour of the condensation product of 2-amino-3-aminomethyl-4- methoxymethyl-6-methylpyridine with salicylaldehyde

Abstract

The crystalline product obtained by the condensation of 2-amino-3-aminomethyl-4-methoxymethyl-6-methylpyridine and salicylaldehyde was characterized by spectrometric methods (UV, IR, 1H NMR and MS). It was shown that the dissolution of the crystalline cyclic diamine afforded its tautomeric conversion to the enolimine form of the Schiff base [2-amino-4-methoxymethyl-6-methyl-3(salicylideneaminomethyl) pyridine] with a rate of the process and a ratio of both forms attained at equilibrium dependent upon the solvent. The presence of the ketoamine form was not evidenced. The behaviour of the condensation product as the ligand in formation of complexes with Cu(II), Ni(II), Co(II) and Cd(II) was investigated in methanolic solution. Coordination with Cu(II) and Ni(II) caused partial hydrolysis of the ligand and the formation of complexes of the bis Schiff base [4-methoxymethyl-6-methyl-2-(salicylideneamino)-3-(salicylideneaminomethyl)pyridine] characterized after their isolation by elemental analyses and spectrometric data.