Two 3d-4f Heterometallic Coordination Polymers of Macrocyclic Oxamide with Benzotriazole-5-carboxylate Co-ligand: Syntheses, Crystal Structures and Magnetic Properties

Abstract

Two heterometallic 3d-4f coordination polymers, [Gd(CuL) 2 (Hbtca)(btca)(H 2 O)]·2H 2 O (1) and [Er(CuL) 2 (Hbtca)(btca) (H 2 O)]·H 2 O·CH 3 OH (2) (CuL, H 2 L = 2 ,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien; H 2 btca = benzotriazole-5carboxylic acid) were synthesized by solvothermal methods and characterized by single-crystal X-ray diffraction. Complexes 1 and 2 exhibit a double-strand meso-helical chain structures formed by [Ln III Cu II 2 ] * Dr. Y.-Q. Sun 1460(Ln III = Gd, Er) units by oxamide and benzotriazole-5-carboxylate bridges. They are isomorphic except that one free water molecule of 1 is replaced by a methanol molecule. All 1D chains are further interlinked by hydrogen bonds resulting in a 3D supramolecular architecture. The magnetic properties of the compound 1 and 2 are also discussed.cyclic oxamide and aromatic multicarboxylate have been obtained, [33][34][35][36][37][38] those containing 3d-4f have been prepared rarely. Scheme 1. The coordinated modes of macrocyclic oxamide complex ligands and benzotriazole-5-carboxylate (M = Cu, Ln = Gd, Er).

Recent advances in the coordination chemistry of benzotriazole-based ligands

“…Furthermore, these results added an extensive amount of scientific input in the currently underutilized [148] field of 1D CPs in catalysis. The first of these reports demonstrated [149] the synthesis of [Cu(bbom)2(MeCN)2]•(ClO4)2 (175), which presents a polymeric ribbon-like framework that extends to one dimension; each Cu II centre presents a {N6} octahedral coordination environment in which the axial positions are occupied by acetonitrile nitrogens (Figure 29). 175 was then found to exhibit promising homogeneous catalytic activity in a new synthetic pathway towards the synthesis of substituted 1,4-dihydropyridines.…”