Preparation and Property of Series of d-f Hetero-binuclear Luminescent Complexes

Preparation and Property of Series of d-f Hetero-binuclear Luminescent Complexes
　　】 Fifteen coordination complexes, including 12 d-f hetero-binuclear M-Ln complexes (M = Zn, Cd; Ln = Eu, Tb, Gd, Pr, Nd, Ho, Er, and Yb) and 3 homo-binuclear Ln-Ln complexes (Ln=Pr, Ho and Er), have been thermally synthesized and structurally characterized by X-ray diffraction. Their formulas are presented as following: EuCd(C8H7O3)5(phen)(H2O) (1) TbCd(C8H7O3)5(phen)(H2O) (2) GdCd(C8H7O3)5(phen)(H2O) (3) PrCd(C8H7O3)5(phen)(H2O) (4) NdCd(C8H7O3)5(phen)(H2O) (5) HoCd(C8H7O3)5(phen)(H2O) (6) ErCd(C8H7O3)5(phen)(H2O) (7) EuZn(C8H7O3)5(phen)(H2O) (8) TbZn(C8H7O3)5(phen)(H2O) (9) ErZn(C8H7O3)5(phen)(H2O) (10) YbZn(C8H7O3)5(phen)(H2O) (11) HoZn(C8H7O2)5(phen)(H2O) (12) Pr2(C7H4O2Cl)6(phen)2(H2O)2 (13) Ho2(C7H4O2Cl)6(phen)2 (14) Er2(C7H4O2Cl)6(phen)2 (15)The study on strong magnets luminescent property in the visible and NIR regions reveals that complexes (1) and (8) emit strong red light, complexes (2) and (9) emit strong green light, and the left complexes besides (13) emit weak fluorescence in the visible region; all the 15 complexes except (13)
　　show the characteristic emission of lanthanide ion in the NIR region.Compare and contrast the luminescence of d-f complexes and corresponding transition metal complexes (d complexes), the following rules are confirmed:(1) When the energy level of excited states between ligand and lanthanide ion is matching, the energy transferring between d block and f block in hetero-binuclear complexes is very efficient. This results in the strengthening of emission of f block and weakening of emission of d block, so much as quenching. That is to say, d block sensitize the emission of f block.(2) Although the lanthanide ion possesses abundant energy levels and which can matches the energy level of excited states of ligand, luminescence of the lanthanide ion in the NIR region leads to the weakening of its characteristic emission in the visible region and the strengthening of emission of d http://www.chinamagnets.biz/ block in the visible region. As a result, the emission of lanthanide ion in the visible region takes on zonal spectra, the sensitized action of d block is not obvious to the emission of f block(3) When the energy level of excited states between ligand and lanthanide ion is not matching (the energy level of excited states of lanthanide ion is much higher or lower), the energy transferring between d block and f block in hetero-binuclear complexes does not take place. So the characteristic emission of lanthanide ion is not observed in the visible region, however the emission of d block is strong, i.e., d block does not sensitize the emission of f block.In addition, the IR and UV-Vis-NIR of all complexes for the analysis and contrast of luminescent property are measured and analsized.