3D Framework and Supramolecular Structures Assembly from a Carboxyphosphonic Acid and Transition Metals: Sensing of Nitro Compounds and Surface Photovoltage Properties

Abstract

AbstractThree new metal carboxyphosphonates with 3D framework and supramolecular structures, namely, [Zn(H4L)2] (1), [Cu2(HL)(H2O)2] (2) and [NH(CH2)4NH]0.5[Cu(H3L)] (3) (H5L=4‐HOOC‐C6H4‐CH2N‐(CH2PO3H2)2), have been synthesized under hydrothermal conditions. For compound 1, {ZnO6} and {CPO3} polyhedra are interconnected into a 2D layer via corner‐sharing, which is further assembled into a 3D supramolecular structure through π‐π stacking interactions. Compound 2 exhibits a 3D framework structure. The interconnection of {CuO4N}, {CuO5} polyhedra and {CPO3} tetrahedra via corner‐sharing forms a 2D inorganic layer. These inorganic layers are further linked via the organic backbone {−C6H4CH2N(CH2)2−} of the carboxyphosphonate ligands, generating a 3D framework structure. In compound 3, two {CuO4N} polyhedra and four {CPO3} tetrahedra are interconnected into a unit, and then these units are further connected into a 1D infinite chain via corner‐sharing. Neighboring chains are assembled into a 2D layered structure through hydrogen bond interactions between the nitrogen atoms from piperazine and uncoordinated phosphonate oxygen atoms. Then, such layers are further assembled into a 3D supramolecular network via interlayer hydrogen bonds. Compound 1 has been realized for the sensitive sensing of 4‐nitrophenol (4‐NP) by luminescence quenching method in the liquid phase. Surface photovoltage properties of compounds 2 and 3 have been investigated.