Synthesis and Characterization of s-Triazine Derivatives Containing Theophylline Group, and Some Transition Metal Complexes

In this paper, two novel theophylline-substituted s-triazine ligands and their trinuclear complexes were synthesized. Theophylline-7-acetic acid (I) was reacted with thionyl chloride, resulting in chlorination of the acidic moiety to afford 2-(1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)acetyl chloride (II). This compound was reacted separately with o-phenylenediamine and p-phenylenediamine in the presence of AlCl₃ as a catalyst in dichloromethane at -10°C for 24 h. As a result of these reactions, compounds III and IV were obtained. Compounds III and IV were then separately reacted with 2,4,6-tri(p-formylphenoxy)-1,3,5-triazine (TRIPOD) in ethanol, yielding the s-triazine-cored tripodal ligands ACL1 and ACL2. Tripodal transition metal complexes (ACC1-ACC8) were obtained by reacting ACL1 and ACL2 with various transition metal salts (MCl2.nH2O, M=Mn2+, Co2+, Ni2+, and Cu2+). The structures of all obtained ligands were elucidated by 1H and 13C NMR, FTIR, and elemental analysis methods. The structures of the complexes were characterized using FTIR, magnetic susceptibility, ICP-OES, and TGA methods.