Syntheses, Structures, And Property Studies Of Coordination Polymers Assembled From 2, 4-Dibenzoylisophthalic Acid

Metal–organic coordination polymers have been attracted considerable attention because of their potential applications as function materials as well as their structure diversity and intriguing variety of topologies.The diversity in the framework structures of such materials greatly depends on the metal centers and the structure of the spacer ligands, as well as on the reaction pathway. Although a large number of polycarboxylate- based coordination polymers have been synthesized, systematic investigation of external physical or chemical stimuli effects on the structures of polycarboxylatebased coordination polymers remains rare. In this paper, we have successfully prepared five complexes by employing 2, 4-dibenzoylisophthalic acid (H₂L¹) and different auxiliary co-ligands with Cu^â…¡, Ni^â…¡transition metal ions under hydrothermal conditions. We characterized by IR, elemental analyses and X-ray single crystal diffractions. The thermal stabilities and magnetic properties of these complexes have also been studied.1. We have prepared four new Cu^â…¡and Ni^â…¡complexes by changing the N-donor auxiliary co-ligands which include rigid ligands (4, 4'-bpy) and flexible ligands (bbi and bth) under the same hydrothermal condition. {Cu₂(L¹)₂(4,4'-bpy)}_n (1) {Ni₂(L¹)₂(4,4'-bpy)}_n (2) {[Cu₁₀(L¹)₈(bbi)(μ₃-OH)₄(H₂O)₆]·4H₂O}_n (3) {[CuL¹(bth)(H₂O)]·H₂O}_n (4)Complexes 1 and 2 are isostructural and crystallized in the chiral space group P3₂21. They both possess three-dimensional coordination frameworks with 6-connected (4⁴·5¹⁰·7) topology that are incorporated left-handed helices and right-handed double helices substructures based on Cu/Ni paddle-wheel clusters. Complex 3 exhibits a 3D (4,5)-connected network with (4⁴·6²) (4⁴·6⁶) topology, in which dinuclear Cu₂(CO₂)₄ clusters act as 4-connected nodes and tetranuclear [Cu₄(μ₃-OH)₂]6+ clusters serve as 5-connected nodes. Complex 4 shows a two-dimensional parallelogrammic network with (4,4) topology. The magnetic properties for 1–3 have been investigated and the thermal stabilities for 1–4 exhibited have been studied.2. We have synthesized one new complex by the reaction of copper nitrate and two different dicarboxylate acid ligands under hydrothermal conditions. [Cu₂L¹L²(H₂O)₂]·3H₂O (5)Complex 5 has a 2D layer structure with (4⁴·6²) topology. The adjacent 2D layers are further extended via O–H···O hydrogen bonds into a three-dimensional supramolecular structure. The magnetic properties and the thermal stabilities for 5 have been studied.