Preparation, Crystal Structure, Thermal Decomposition Kinetics Of Complexes Samarium Aromatic Carboxylic Acid | | Posted on:2009-07-11 | Degree:Master | Type:Thesis | | Country:China | Candidate:H Y Zhang | Full Text:PDF | | GTID:2121360245462265 | Subject:Inorganic Chemistry | | Abstract/Summary: |  PDF Full Text Request | | Fourteenth ternary complexes of Sm(Ⅲ) have been synthesized in this paper, in which benzoic acid and its derivatives were as the first ligand, and 2,2'-bipyridine as the second ligand. They are [Sm(BA)3bipy]2,[Sm(p-MBA)3bipy]2,[Sm(o-MOBA)3bipy]2·H2O,[Sm(m-MOBA)3bipy]2·H2O,[Sm(p-MOBA)3bipy]2·(C2H5OH)2,[Sm(o-ClBA)3bipy]2?2H2O,[Sm(m-ClBA)3bipy]2?4H2O,[Sm(p-ClBA)3bipy·H2O]2,[Sm (2,4-DClBA)3 bipy]2,[Sm(o-BrBA)3bipy]2·2H2O,[Sm(m-BrBA)3bipy]2·3H2O,[Sm(p-BrBA)3bipy?H2O]2?H2O,[Sm(o-NBA)3bipy]2·2H2O and [Sm(p-NBA)3bipy]2·2H2O;five quaternary Sm(III) complexes with benzoic acid derivative and 2,2'-bipyridine, 1, 10-phenanthroline as neuter-ligands, They are Sm2(m-MOBA)6(phen)(bipy)(H2O),Sm2(p-MOBA)6(phen)(bipy)(H2O),Sm2(o-MBA)6(bipy)(phen),Sm2(p-MBA)6(bipy)(phen),Sm2(m-MBA)6(bipy)(phen). They were characterized by elemental analysis, IR and UV spectroscopy, thermal analysis and X-ray diffractometer. The structures of four ternary complexes of [Sm(BA)3bipy]2,[Sm(p-ClBA)3bipy·H2O]2,[Sm(p-MOBA)3bipy]2·(C2H5OH)2 and [Sm(p-BrBA)3bipy·H2O]2·H2O have been determined using crystal X-ray diffraction. They all exist as binuclear molecules.The carboxylate groups are bonded to the samarium ion in four modes: (1) mondentate (2) bidentate chelating, (3) bidentate bridging, (4) tridentate chelating-bridging. The crystal structure of [Sm(BA)3bipy]2 is monoclinic with space group P2(1)/n, eight coordinate with a trigondodecahedron. The crystal structure of [Sm(p-MOBA)3bipy]2·(C2H5OH)2 is triclinic system with space group Pī, nine coordinate with a tri-capped triangular prism geometry. The crystal of [Sm(p-ClBA)3bipy·H2O]2 and [Sm(p-BrBA)3bipy·H2O]2·H2O are both triclinic with space group Pī, eight coordinate with a bi-capped triangular prism geometry. The thermal decomposition processes of the complexes were determined using TG-DTG and IR techniques. The non-isothermal kinetics of the complexes were investigated using a advanced double equal-double step method. The most probable mechanism functions, activation energy E and pre-exponential factor A of the first thermal decomposition stage for complexes [Sm(BA)3bipy]2,[Sm(p-MOBA)3bipy]2·(C2H5OH)2,Sm2(m-MBA)6(bipy)(phen),Sm2(p-MBA)6(bipy)(phen),[Sm(2,4-DClBA)3bipy]2 and [Sm(p-MBA)3bipy]2, and of the second stage for complexes[Sm(o-MOBA)3bipy]2·H2O,[Sm(p-ClBA)3bipy·H2O],[Sm(o-BrBA)3bipy]2·2H2O,[Sm(o-NBA)3bipy]2?2H2O and [Sm(m-MOBA)3bipy]2·H2O were obtained from analysis of the TG-DTG curves, and the Gibbs free energy of activation△G≠, the enthalpy of activationΔH≠, the entropy of activationΔS≠were also calculated, the thermodynamic parameters(ΔH≠,△G≠andΔS≠) were calculated. Meanwhile, the complexes without crystal waters of the lifetime equation at weight-loss of 10% of five complexes, namely:[Sm(BA)3bipy]2,[Sm(p-MBA)3bipy]2,Sm2(o-MBA)6(bipy)(phen),Sm2(m-MBA)6(bipy)(phen) and Sm2(p-MBA)6(bipy)(phen)were obtained. The thermal ability of a series of complexes was compared. The results will provide some valuable materials for the choice of the functional materials of rare-earth complexes.
| | Keywords/Search Tags: | Samarium complexes, benzoic acid and its derivatives, crystal structure, thermal decomposition, non-isothermal kinetics | | PDF Full Text Request | Related items |
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