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

Three metal-organic frameworks (MOFs), namely, [Mn(CPP)(2)(H2O)](n) (I), [Cd(CPP)(2)(H2O)](n) (II) and {[Zn-2(CPP)(2)(CO3)]center dot(ClO4)center dot(H2O)(2)}(n) (III) (HCPP 4'-(4-(4-carboxylphenoxy)-2,2':6',2'-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 I and II display isomorphous and iso-structural, in which the central metal ions present distorted octahedral configurations. I and II feature fascinating 3D frameworks based on pi center dot center dot center dot pi and C-H center dot center dot center dot pi interactions between the pyridine rings appertaining CPP- ligands, while compound III possesses a 3D net interlinked via C-H center dot center dot center dot pi interactions between the phenyl rings belonging to the CPP- ligands. In their 3D frameworks, the {MnN3O3}, {CdN3O3} and {ZnO2N3}-{ZnO2N3} building units are observed, respectively. Luminescent properties of coordination polymer II and III demonstrate that they may be acted as fluorescent sensors toward Cu2+ cation and Tryptophan, respectively. Furthermore, investigations on magnetic property reveal that coordination polymer I presents antiferromagnetic coupling. (C) 2018 Elsevier B.V. All rights reserved.