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001-es BibID:	BIBFORM086049
Első szerző:	Bodor Andrea
Cím:	Thallium(III) coordination compounds: chemical information from Tl-205 NMR longitudinal relaxation times / Andrea Bodor, István Bányai, Jozef Kowalewski, Julius Glaser
Dátum:	2002
ISSN:	0749-1581
Megjegyzések:	Tl-205 longitudinal relaxation rate measurements were performed on several thallium(III) complexes with the composition Tl(OH)(n)(H2O)(6-n)((3-n)+) (n = 1,2), Tl(Cl)(n)(H2O)(m-n)((3-n)+), Tl(Br)(n)(H2O)(m-n)((3-n)+) (m = 6 for n = 1-2, m = 5 for n = 3, m = 4 for n = 4), Tl(CN)n(H2O)(m-n)((3-n)+) (m = 6 for n = 1-2, m = 4 for n = 3-4) in aqueous solution, at different magnetic fields and temperatures. C-13 and D-2 isotopic labelling and 114 decoupling experiments showed that the contribution of the dipolar relaxation path is negligible. The less symmetric lower complexes (n < 4) had faster relaxation rate dominantly via chemical shift anisotropy contribution which depended on the applied magnetic field: T, values are between 20 and 100 ms at 9.4 T and the shift anisotropy is &UDelta;σ = 1000-2000 ppm. The tetrahedral complexes, n = 4, relax slower; their T-1 is longer than 1 s and the spin-rotation mechanism is probably the dominant relaxation path as showed by a temperature dependence study. In the case of the TICl4- complex, presumably a trace amount of TICl52- causes a large CSA contribution, 300 ppm. Since the geometry and the bond length for the complexes in solution are known from EXAFS data, it was possible to establish a correlation between the CSA parameter and the symmetry of the complexes. The relaxation behaviour of the Tl-bromo complexes is not in accordance with any known relaxation mechanism.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk NMR Tl-205 longitudinal relaxation aqueous solution thallium halide complexes thallium cyanide complexes
Megjelenés:	Magnetic Resonance In Chemistry. - 40 : 11 (2002), p. 716-722. -
További szerzők:	Bányai István (1953-) (vegyész) Kowalewski, Jozef Glaser, Julius
Pályázati támogatás:	T035127 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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