Homochiral coordination polymers based on proline-derivative: structures, magnetic properties, and selective detection of Cr2O72− anion

Abstract

By incorporating semi-rigid terephthaloyl mono proline-derived ligand [H2TMPro ​= ​terephthaloyl-mono(l-proline)] with the ancillary dipyridyl ligands [bpea ​= ​1,2-bis(4-pyridyl)ethane and bipy ​= ​4,4′-bipyridine], five new homochiral coordination polymers were synthesized. Compounds [Cu3(TMPro)2(μ3-OH)2]·4H2O (1) and [Zn3(TMPro)2(μ3-OH)2]·4H2O (2) are isostructural complicated 3D frameworks, which contain the intertwined right- and left-handed helical chains built from the butterfly-shaped [Cu4(μ3-OH)2(RCOO)6] units. Compound [Cu2(TMPro)2(bpea)2(H2O)2]·7H2O (3) displays a 3D framework composed of Cu1-TMPro left-handed helical chains and Cu2-TMPro right-handed helical chains connected by the bpea ligands. Compound [Cd4(TMPro)4(bpea)6]·10H2O·4C2H5OH (4) features a 3-fold interpenetrating 3D framework with 5-connected hexagonal bnn topological net constructed from the {Cd-TMPro} chains and bpea ligands. Compound [Ni(TMPro)(bipy)(H2O)3] (5) exhibits a {Ni-bipy}2+ 1D chain decorated by the TMPro2− anions. Magnetic susceptibility measurements indicate ferromagnetic exchange interactions between Cu(II) ions in 1. Photoluminescence spectra of 2 show corresponding emission bands of TMPro2− anions. Additionally, for 2, the Ksv value of 553 ​M−1 and detection limit of 70 ​μM imply it can detect the Cr2O72− anion.