Triazine–polycarboxylic acid complexes: synthesis, structure and photocatalytic activity

Abstract

Four novel transition metal complexes, [Zn₂(Bpz*eaT)₂(HBTC)₂]·(CH₃OH)₃ (1), [Co(Bpz*eaT)(HBTC)]·(CH₃CH₂OH)_0.5·(H₂O)_0.5 (2), [Zn(Bpz*eaT)(H₂BTA)(pz*H)] (3) and [Cu₄(Mpz*T-O₂)₄(BTA)(H₂O)₈]·4H₂O (4) (Bpz*eaT, 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-diethylamino-1,3,5-triazine; Mpz*T-O₂, 6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4(1H,3H)-dione; pz*H, 3,5-dimethyl-1H-pyrazole; H₃BTC, benzene-1,3,5-tricarboxylic acid; and H₄BTA, 1,2,4,5-benzenetetracarboxylic acid), were synthesized by the reaction of metal salts (ZnSO₄·7H₂O, CoCl₂·6H₂O or CuCl₂·2H₂O), pincer N-heterocyclic triazine derivatives and aromatic polycarboxylate ligands. All the complexes were characterized by elemental analysis, IR spectroscopy, UV-vis spectroscopy, thermal gravimetric analysis and single-crystal X-ray diffraction. Structural analysis reveals that complexes 1 and 2 are 2-D layers and complex 4 is a 3-D network structure with hydrogen bonding. In addition, the photocatalytic performances of complexes 1–4 were studied under UV irradiation at room temperature and their photocatalytic activity was also discussed. The result showed that complex 1 possessed higher photocatalytic activity.