Designed synthesis of CO2-promoted copper(ii) coordination polymers: synthesis, structural and spectroscopic characterization, and studies of versatile functional properties

Abstract

A series of CO₂-promoted Cu(II) coordination polymers in different coordination environments has been synthesized. The molecular description and properties of the four complexes have been investigated by CHN, MS, UV-VIS, IR, PXRD, TEM, SQUID, SC-XRD, NLDFT, and electrical property characterizations. Single crystal X-ray structure determination of [Cu(bpy)(C₂O₄)]_n (1) and [Cu(2-AMP)₂(C₂O₄)]_n (2) depicts their polynuclearity [bpy = 2,2′-bipyridine, 2-AMP = 2-aminopyridine; 2-AMP is a cleaved ligand of starting ligand L¹ = N-(phenyl(pyridin-2-ylamino)methyl)pyridin-2-amine]. Both complexes have distorted octahedral geometry. Starting from another tripodal ligand L² [L² = 2-((((2-(pyridin-2-yl)ethyl)(pyridin-2-yl)methyl)amino)methyl)phenol, L^2′ (cleaved L² ligand) = 2-(pyridin-2-yl)-N-((pyridin-2-yl)methyl)ethanamine], a mononuclear complex [Cu(L²)(Cl)] (3) has been obtained with a distorted square pyramidal geometry. Polynuclear complexes 1, 2, and 4 are CO₂-mediated functional materials that have been produced in benzonitrile solvent medium. Interestingly, complex 4 of cleaved L² ligand is a wonderful copper-based functional material with appreciable surface area. Powder XRD and TEM analysis of complex 4 supports its mesoporosity. Moreover, all four complexes can function as semiconductors over a wide temperature range.