Synthesis and characterization of luminescent metal–organic frameworks for the selective recognition of Cu2+ cation and Tryptophan

摘要： Three metal-organic frameworks (MOFs), namely, [Mn(CPP)2(H2O)]n (I), [Cd(CPP)2(H2O)]n (II) and {[Zn2(CPP)2(CO3)]·(ClO4)·(H2O)2}n (III) (HCPP = 4'-(4-(4-carboxylphenoxy)-2,2':60,20-terpyridine), were successfully achieved under hydrothermal conditions. The as-synthesized coordination polymers have been characterized by IR spectroscopy, elemental analyses and single crystal X-ray diffraction. Single-crystal X-ray diffraction analyses indicate that compounds ⅠⅠ and ⅡⅡ display isomorphous and isostructural, in which the central metal ions present distorted octahedral configurations. ⅠⅠ and ⅡⅡ feature fascinating 3D frameworks based on p/p and CeH/p interactions between the pyridine rings ligands, while compound ⅢⅢ possesses a 3D net interlinked via C-H/p interactions appertaining CPP ligands. In their 3D frameworks, the {MnN3O3}, {CdN3O3} and {ZnO2N3}e{ZnO2N3} building units are observed, respectively. Luminescent properties of coordination polymer ⅡⅡ and ⅢⅢ demonstrate that they may be acted as fluorescent sensors toward Cu2+ cation and Tryptophan, respectively. Furthermore, investigations on magnetic property reveal that coordination polymer ⅠⅠ presents antiferromagnetic coupling.