Synthesis, Structure And Photophysical Properties Of Series Ag-Ln Coordination Polymers

Five Ag-Ln heterometallic coordination polymers, five Ln coordination polymers andthree Ag coordination polymers are synthesized by hydrothermal methods. The single-crystalof these coordination polymers is obtained and their structure are determined by X-singlecrystal diffraction, their molecular formulas are presented as followed:（1）[SmAg（INA-）₄]n （8）{[Eu(2,5-pydc^2-)（Ac-）·H₂O]·2H₂O}n（2）[TbAg（INA-）₄]n （9）[Eu2(1,3-bdc^2-)2（2-pydc-）（Ac-）]n（3）[EuAg（INA-）₄]n （10） Na[Pr（C10H12N2O8）·3H₂O]·5H₂O（4）{[ErAg（2-pzc-）22（C2O-4）]·H₂O}n （11）[Ag（2-pzc-）]n（5）{H[SmAg4(2,5-pydc^2-)4·（H₂O）12]}n （12） Ag[（HNA）（NA-）（H₂O）4]（6）{[Sm(2,5-pydc^2-)（Ac-）·H₂O]·2H₂O}n （13）[Ag1Ag2(2,3-pydc^2-)]n（7）{[Nd(2,5-pydc^2-)（Ac-）·H₂O]·2H₂O}nThe structural analyses reveal that Polymers （1）-（5） are Ag-Ln Coordination polymerswith3D infinite structure, Ag+ions and Ln3+ions are bridged by INA-,2-pzc-and OX2-anf2,5-pydc^2-ligands, respectively. Polymers （6）-（10） are five Ln （Ln=Sm, Nd, Eu, Pr） polymerswith different structures, which are bridged by2,5-pydc^2-, Ac-,1,3-bdc^2-,2-pydc-, andC10H12N2O84-, respectively. Polymers （11）-（13） are three Ag polymers owning3D infinitestructures bridging by2-pzc-, NA-,2,3-pydc^2-, respectively.The photophysical properties of the polymers are characterized by IR spectra,UV-Vis-NIR absorption spectra, Vis and NIR emission spectra. We comparatively analyze anddiscuss the luminescence properties of the polymers. We can find that the luminescenceproperties are restricted by ligands and Ln3+ions by comparison of the emission spectra ofdifferent polymers in Vis region. The same ligand has different effects on the emissions ofdifferent Ln（III） ions, however, the influence of different ligands on luminescence from thesame Ln（III） ions is also obviously different. Moreover, the introduction of Ag+ions whichowning d10configuration can enhance the light-emitting of the polymers. By comparisonsome of the polymers which obtaining the only rigid carboxylic acid ligands in the NIRregion, it is found that the luminescent properties of the polymers can be enhanced byintroducting of the flexible carboxylic acid ligands. Other found is that the energy of ligandabsorbed exist certain competition for luminenece in the UV-Vis and NIR regions.