Synthesis of several novel coordination complexes: ion exchange, magnetic and photocatalytic studies

Abstract

Eight new coordination polymers (CPs) based on a V-shaped carboxylate ligand H₂L (H₂L = 5-(1-oxo-1,3-dihydro-isoindol-2-yl)-isophthalic acid), namely {[Zn(L)(H₂O)]·H₂O}_n (1), {[Zn₂(L)₂(phen)₂(H₂O)₂]·CH₃OH·2H₂O}_n (2), {[Zn(L)(2,2′-bpy)(H₂O)]·H₂O}_n (3), [Zn₂(L)₂(4,4′-bpy)]_n (4), {[Cu(L)(H₂O)]·H₂O·0.5(CH₃OH)·0.5(DMF)}_n (5), [Cu₃(L)₂(phen)₃(ClO₄)₂]_n (6), {[Co(L)(dbpy)(H₂O)]·3CH₃CN}_n (7), and {[Co(L)(phen)(H₂O)₂]·DMA·3H₂O}_n (8), have been synthesized and characterized by IR, XRD, TG analysis, elemental analysis and single crystal X-ray diffraction measurement. Reactions of H₂L and ZnSO₄ with different auxiliary ligands in similar solvents occurred at the temperature of 80 °C, yielding similar 1D chains 1–3 and a three-dimensional (3D) framework 4. Besides, reactions of H₂L and Cu²⁺ in the absence or presence of phen formed CPs of 5 and 6 associated with the reduction of dimensionality of the self-assembled products from 3D to 2D. Complex 5 presents a 3D framework with nanosize channels which are comprised of interlocked six-fold one-dimensional helical chains, while compound 6 shows a 2D structure. Additional reactions of H₂L, Co²⁺ and auxiliary ligands give rise to two structurally related 2D CPs 7 and 8. Single-crystal-to-single-crystal studies show that Zn²⁺ ions in complexes 1–3 could be partially exchanged with Cu²⁺ ions. And we elaborated the reasons for different exchange degrees by comparing the coordination energies of Zn²⁺. Furthermore, by comparing the photoluminescence and photocatalytic mutation results induced by the interconversion of metal ions, we confirm that the property mutation induced by metal ions is greatly controllable and obvious. Magnetic studies show that there are strong antiferromagnetic interactions in 5 and 6. Moreover, complexes 5–8 are also applied to catalyze the reaction of MB under high-pressure mercury lamp irradiation.