The Syntheses,Structures And Properties Of Ln/Cd And Lanthanide-cadmium Heterometal-Organic Complexes

Due to fascinating structural topologies and a variety of advanced applications in molecular magnets,molecular recognition,luminescent materials,molecular adsorption and semiconductors,the design and syntheses of Cd/Ln coordination polymers are drawing a mass of interest.As one of their branches,transition metal cadmium?Cd2+?is introduced into Ln organic coordination polymers to construct Ln-Cd heterometallic organic polymers?HOPs?with novel structures and excellent properties.The introduction of Cd can not only enrich structure of Ln-Cd HOFs,but also can tune energy levels of the compounds so as to affect the compound luminescence.In our work,four types of different Ln-Cd HOPs,two Cadmium complexes and one type of lanthanide-oxo-cluster polymers were synthesized under hydrothermal conditions using flexible and rigid ligands.X-ray single-crystal diffraction,elementary analysis,FTIR,XRD,UV-Vis,TGA were utilized to determine structures and investigate the properties of these compound.Also,we conduct the exploration of fluorescence probe of some compounds.The primary contents of our work are described as follows:?1?Ln-Cd HOPs 1 and 2a-2f with two different structures were hydrothennally synthesized by the same flexible ligand of H4EDTA?ethylene diamine tetraacetic acid?with different lanthanide cations.The two compounds possess 2D layer structures which were constructed based on the same Ln-O-Cd-O cluster chains,with the difference in connection modes of lanthanide cations and cadmium cations.Solid Luminescent spectra reveal that compound 2a,2c,2e exhibit characteristicemission bands of Ln3+.Compound 2a exhibits interesting luminescent sensor to La3+,Ba2+,Pr3+,Nd3+ and Cu2+.Cu2+,which quenched the luminescence of the compound.?2?Ln-Cd HOPs 3a-3c and 4 with 3D layer-pillared structures were hydrothennally synthesized by rigid ligand of H3tda?1H-1,2,3-triazole-4.5-imidazole dicaboxylic acid?and "pillar ligand" from Hina to 4,4'-Hpbc ligand with different lengths.The structures of compounds 3 and 4 consist of the same layer.The pillar ligands of different sizes link the layers into the 3D metal-organic framework s with channels of different sizes.Solid Luminescent spectra reveal that compounds 3a,3c,4 exhibit characteristic emission bands of Ln3+.Compound 3a exhibits interesting luminescent sensor to 1,2-propane.?3?Cadmium organic polymers 5 and 6 were hydrothennally synthesized by ri-gid ligand of H3tda?1H-1,2,3-triazole-4.5-imidazole dicaboxylic acid?and 4-?yl-1,3-imidazole?benzoic acid.Interestingly,1,2,3-Triazole were in situ generated by decomposition of H3tda ligand in compound 5.Compound 5 is a 3D inorganic-organic hybrid compound based on inorganic CdCl framework with 3D cross channels.The chelated taz3-ligands point away from the CdCl frameworkand into the 12-ring channels.Compound 6 is mononuclear Cd complex,which is extended to 2D layer structure by O-H...O hydrogen bonds.Compound 5 displays green luminescence and compound 6 shows green emission band,too.?4?Two lanthanide-oxo-cluster polymers 7a and 7b were synthesized by hydrothermal reaction using Ln2O3 as initial lanthanide materials.Compound 7a is a 3D lanthanide cluster polymer based on tetranuclear cubane-like[Er4??3-OH?4]8+ cations and SO42-anions.The overall structure of 7a can be assigned to 6-connected pcu-type topology with the point symbol of(4¹².6³).