The effect of concentration of Eu(III) on its lumnescence decay constant and complexation of trivalent lanthanides with aromatic (mellitic, pyromellitic, hemimellitic, trimellitic, trimesic, phthalic, isophthalic, terephthalic and benzoic) and aliphatic (malonic, succinic, glutaric and adipic) carboxylic acids and ethylenediamine were studied by luminescence, absorption and NMR spectroscopic methods and luminescence lifetime measurements. / At constant ionic strength (0.1 M NaClO$\sb4$), Eu(III) luminescence decay constant increases as its concentration decreases from 0.2 M to 10$\sp{-5}$ M while the Eu(III) $\rm\sp7F\sb0\to$ $\sp5D\sb0$ excitation spectra were unchanged. / Both luminescence spectra and decay constants indicate that mellitate, pyromellitate, hemimellitate, trimellitate, trimesate and terephthalate form ML complex while phthalate, isophthalate, benzoate and the aliphatic dicarboxylates form ML and ML$\sb2$ complexes at 25$\sp\circ$C and 0.1 M ionic strength (0.1 M NaClO$\sb4$). Using the SQUAD program, stability constants of Eu(III) with above carboxylate ligands were calculated from the $\rm\sp7F\sb0\to$ $\sp5D\sb0$ excitation spectra of Eu(III). The luminescence decay constants indicate that aromatic carboxylates with adjacent carboxylates groups are bidentate and replace two water molecules upon complexation. Benzoate and terephthalate are unidentate. Isophthalate and trimesate replace ca. 1.5 water molecules. For the aliphatic dicarboxylates, as the carbon chain increases, the number of water molecules released from the inner sphere upon complexation decreases from 2.7 (malonate) to 1.8 (adipate). / The oscillator strengths of Nd(III) and Ho(III) complexes with carboxylates in the hypersensitive trantion ranges were calculated and the relationships between stability constant, oscillator strength and ligand basicity were examined. / Luminescence and NMR studies show that Eu(III) forms ML, ML$\sb2$, and ML$\sb3$ complexes with ethylenediamine in DMSO. The quenching effect of N-H on Eu(III) and Tb(III) luminescence is linearly proportional to the number of N-H groups in the inner sphere of the metal ion. / It was found that formation of Eu(III) complexes causes shift of the maxima of Eu(III) $\rm\sp7F\sb0\to$ $\sp5D\sb0$ excitation spectra towards lower frequency. The magnitude of the shift linearly correlates with the total ligand coordination number. / Source: Dissertation Abstracts International, Volume: 55-08, Section: B, page: 3305. / Major Professor: G. R. Choppin. / Thesis (Ph.D.)--The Florida State University, 1994.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77226 |
| Contributors | Wang, Zheming., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 216 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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