Syntheses, Structure And Photo-Physical Properties Of Series Of D-f Coordination Polymers

[1] A series of d-f coordination complexes have been synthesized by hydrothermal method. Crystal structures of the ten coordination complexes are determined by X-ray diffraction and their formulas are presented as following: (1) [Sm₂Zn₂(C₆H₅COO)₁₀(Imh)₂(H₂O)₂] (2) [Er2Zn(2,5-pdc)₄(H₂O)₈]_n (3) [ErZn₂(C₆H₅COO)₇(Imh)₂] (4) {[NdZn(2,5-pdc)₂(tpha)0.5(H₂O)]·2H₂O}_n (5) [Nd₂Zn₂(C₆H₅COO)₁₀(Imh)₂(H₂O)₂] (6) [Pr₂Zn₂(C₆H₅COO)₁₀(Imh)₂(H₂O)₂] (7) [TbZn₂(C₆H₅COO)₇(Imh)₂] (8) [EuZn₂(C₆H₅COO)₇(Imh)₂] (9) [HoZn₂(C₆H₅COO)₇(Imh)₂] (10){[SmZn(2,5-pdc)₂(tpha)0.5(H₂O)]·2H₂O}_n[2] At room temperature,the IR,UV-Vis-NIR,FP excitation and exemission spectra of the four complexes were characterized and analyzed. The emission bands of complexes (2),(3),(4),(5),(6),(9) should be very obvious in near-infrared region. However,due to the instrument excuses,NIR spectrums of these complexes have not been determined.[3] The analyses and assignments of the UV-Vis fluorescence emission spectra emphasis in this paper. We could speculate that organic conjugated ligands in Zn-Ln coordination complexes could sansitize Ln(III);and then the fluorescent strength may be increased with adding Zn(II). For example,①the emission spectrum of polymers (1) and (10) exhibit characteristic emission bands corresponding the transitions of Sm(III) ion,but the emission bands of the ligands are quenched completely. One reason is the level of Sm(III) ion matches with the excited level of the ligands,and ultraviolet light will ligand energy through the form of channeling jump to rare earth ions effectively excited level. Another reason is adding Zn(II)(d¹⁰),it could sansitize Sm(III). Simultaneously,the rare earth ions can be excited and ground just fall in the visible differential area. Thus,the emission spectrums exhibit obvious f-f emission bands.Another example,②the emission spectrum of complex (8) exhibit characteristic emission bands corresponding the transitions of Eu(III) ion,but the emission bands of the ligands are quenched completely. One reason is the level of Eu(III) ion matches with the excited level of the ligands;another reason is adding Zn(II)(d¹⁰),it could sansitize Eu(III) preferably. And ultraviolet light will ligand energy through the form of channeling jump to rare earth ions effectively excited level. Simultaneously,the rare earth ions can be excited and ground just fall in the visible differential area. Thus,the emission spectrums of complex (8) exhibit obvious emission bands.