Coordination polymers based on 3,3′,4,4′-benzophenone-tetracarboxylate and N-containing pillars: syntheses, structure, characterization and properties

Abstract

Three novel coordination polymers including {[Mn₂(bptc)₂(phen)₄]·2H₂O}_∞ (I), [Zn₂(bptc)₄·(bpy)₂·H₂O]_∞ (II), and {[Zn₂(bptc)₄·(bpy)₂·H₂O] ⊃ bpy}_∞ (III) (bptc = 3,3′,4,4′-benzophenone-tetracarboxylate, bpy = 4,4′-bipyridine, phen = 1,10-phenanthroline) were prepared under hydrothermal conditions and characterized by elemental analysis, infrared spectrometry, and single crystal X-ray diffraction. Moreover, the thermal stability of as-synthesized coordination polymers was evaluated by thermogravimetric analysis; and their magnetic and luminescent properties were also investigated. Findings indicate that coordination polymer I displays a three-dimensional (3D) network constructed via π–π interactions of the building block {[Mn₂(bptc)₂(phen)₄]·2H₂O}. Besides, Zn(1) and Zn(2) centers in coordination polymer II are four-coordinated and six-coordinated, respectively, thereby affording two-dimensional (2D) planar sheet and 3D porous frameworks that are interlinked through identical linkers of four-coordinated motif (COO–Zn–COO). As-synthesized coordination polymer III contains a 3D framework similar to that of II, but the cavities in III are occupied by uncoordinated bpy guest molecules. Moreover, as-synthesized coordination polymer I presents antiferromagnetic coupling through the (O₂C–C–C–CO₂)₂ bridges, and II displays selectivity towards Hg⁺ ion in terms of the luminescent emission.