Four cadmium(II) coordination polymers with an N- and O-donor ligand: Structural characterization, in situ reaction and fluorescent property

Abstract

Cadmium nitrate tetrahydrate reacts with 5-(1H-benzotriazol-1-ylmethyl)isophthalic acid (H2L) under hydrothermal conditions to yield four complexes, [Cd(L1)(py)2(H2O)] (1), [Cd(L)(DMF)(H2O)] (2), [Cd(L)] (3) and [Cd(L)] (4) [L1=in situ generated 5-(2H-benzotriazol-2-ylmethyl)isophthalate, py=pyridine, DMF=N,N-dimethylformamide], which have been characterized by single crystal and powder X-ray diffraction, IR, elemental and thermogravimetric analyses. Complexes 1–4 exhibit structural diversity, which is dependent upon different experimental conditions. As a result, complex 1 has a chain structure, which can be further linked by hydrogen bonding and C–H⋯π interactions to form a 2D network structure; 2 displays a double-stranded chain structure and a 3D supramolecular framework can be built via hydrogen bonding and π–π stacking interactions; 3 and 4 are a pair of isomers: 3 is a binodal (3,6)-connected 2D kgd network with (43)2(46·66·83) topology, while 4 displays a binodal (3,6)-connected 3D rtl (4·62)2(42·610·83) framework architecture. Significantly, an in situ rearrangement reaction of H2L to H2L1 occurs during the synthesis of 1. The influential factors of the synthetic strategies on the coordination modes of the ligand and the structures of resultant complexes are discussed. Furthermore, the fluorescent properties of 1–4 were preliminarily investigated.