| In this paper, Four solid binary complexes of rare earth perchlorate RE(MABA-Si)3·(C1O4)3·5H2O (RE=Sm, Eu, Tb, Dy) with 3-(N,N’-Bis-3-(triethoxys ilyl)propylamide)-Benzoic Acid (MABA-Si) and eight solid ternary complexes of rare earth perchlorate RE(MABA-Si)·(phen)2·(C104)3·2H2O and RE(MABA-Si)· (dipy)2·(ClO4)3·2H2O with MABA-Si as the first ligand and phenanthroline, bipyridine as the second ligand have been synthesized and characterized. Besides that, Mono-dispersed SiO2 of 400nm and 600 nm were synthesized and the MABA-Si, binary, ternary complexes were coated onto mono-dispersed nano-SiO2. When the size of the SiO2 microsphere was 600nm, binary complexes as the shell, the binary core-shell rare earth submicrospheres SiO2(600)@RE(MABA-Si)3·(ClO4)3·5H2O were synthesized; Correspondingly, the ternary complexes as the shell, the ternary core-shell submicrospheres SiO2(600)@RE(MABA-Si)·(phen)2·(ClO4)3·2H2O and SiO2(600)@RE(MABA-Si)·(dipy)2·(ClO4)3·2H2O were synthesized, respectively. When the size of the SiO2 microsphere was 400nm, the binary core-shell rare earth submicrospheres SiO2(400)@RE(MABA-Si)3·(ClO4)3·5H2O were synthesized; Correspondingly, the ternary complexes as the shell, the ternary core-shell submicrospheres SiO2(400)@RE(MABA-Si)·(phen)2·(ClO4)3·2H2O and SiO2(400) @RE(MABA-Si)·(dipy)2·(ClO4)3·2H2O were synthesized, respectively.IR spectra,1HNMR and UV spectra studies indicated that MABA-Si bonded with RE3+ ions by the two oxygen atoms of the -COOH. The second ligand phen and dipy bonded with RE3+ ions by the nitrogen atoms. The molar conductivities of the all complexes in DMF solution indicated that two of the three ClO4- were no coordinated with RE3+. According to the SEM, TEM photographs and IR, these SiO2 microspheres were granules with smooth surface and good mono-dispersity. The TEM photographs showed that complexes continuously coated on the nanosized silica. The fluorescent spectra illustrated that the binary and ternary Sm3+, Eu3+, Tb3+, Dy3+complexes displayed characteristic rare earth ions fluorescence in solid state. Compared with the binary complexes, the ternary complexes of Sm3+, Eu3+ exhibited stronger fluorescence. Low temperature phosphorescent spectra showed that, the second ligand phen or dipy and the first ligand MABA-Si were able to transfer energy to Sm3+ and Eu3+ ions together by an efficient way, which made the fluorescence emission of the Sm3+ and Eu3+ ions in the ternary complexes increasing exponentially. The fluorescent decay curves illustrated that Eu3+, Tb3+rare earth complexes had long fluorescent lifetime. The fluorescent spectra illustrated that almost all the core-shell submicrospheres displayed stronger characteristic emission intensity than that of the homologous complexes. When the core of SiO2 microsphere was 400nm, the times of the fluorescence intensity changes of Sm3+, Eu3+, Tb3+ binary core-shell submicrospheres were 1.31,2.14,1.55 respectively. When the core of SiO2 microsphere was 600nm, the times of the fluorescence intensity changes of Eu3+ binary core-shell submicrospheres was 2.02. When the core of SiO2 microsphere were 400nm and 600nm, respectively, the phenanthroline was the second ligand, the the fluorescence intensity of Sm3+, Eu3+, Tb3+, Dy3+ ternary core-shell submicrospheres increase to 2.92,1.87,3.52,3.41,2.82,1.23,3.35,2.88 times. When the core of SiO2 were 400nm and 600nm, respectively, and the bipyridine was the second ligand, the characteristics of the fluorescence intensity of Sm3+, Eu3+, Tb3+, Dy3+ternary core-shell submicrospheres increase to 1.08,1.85,3.64,2.71,1.08,1.82,2.49,2.53 times. The results showed when the core of SiO2 was 400nm, the fluorescence intensity the core-shell rare earth submicrospheres were stronger. The fluorescent decay curves illustrated that all the core-shell submicrospheres had longer fluorescence lifetime. The fluorescent quantum yield of the Eu3+ core-shell submicrospheres were longer. |
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