Intramolecular dynamics of lanthanide(III) tetraoxadiaza macrocycle complexes in solution as studied by NMR

Аннотация

¹H and ¹³C NMR and ¹H NMR relaxation spectroscopy (RS) measurements are reported for the CDCl₃ and CD ₂Cl₂ solutions of [La(NO₃)₃ (diaza-18-crown-6)] (I), [Pr(NO₃)₃ (diaza-18-crown-6)] (II) and [Nd(NO₃)₃ (diaza-18-crown-6)] (III) complexes. Temperature dependencies of the ¹H NMR spectra of II have been analyzed using the dynamic NMR methods for multi-site exchange. Enantiomeric isomer interconversion in II is characterized by ΔH‡ = 21.5 ± 4 kJ mol^-1. Studies of the values of the lanthanide-induced shifts and the longitudinal relaxation rate enhancement revealed that the structure of complexes in solution is similar to that reported for the [La(NO₃)₃(18-crown-6)] complex in the crystal state. Nevertheless, it appears that the principal values of the molar paramagnetic susceptibility tensor (χ_i) significantly differ in complexes II and III. The possible reasons for the different characteristics of these complexes are discussed.

Язык оригинала	Английский
Страницы (с-по)	25-29
Число страниц	5
Журнал	Journal of Inclusion Phenomena and Macrocyclic Chemistry
Том	43
Номер выпуска	1-2
DOI	https://doi.org/10.1023/A:1020492027829
Состояние	Опубликовано - 2002
Опубликовано для внешнего пользования	Да

ASJC Scopus subject areas

Chemistry(all)
Condensed Matter Physics

Доступ к документу

10.1023/A:1020492027829

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Intramolecular dynamics of lanthanide(III) tetraoxadiaza macrocycle complexes in solution as studied by NMR. / Babailov, S. P.; Nikulina, L. D.; Krieger, J. H.

В: Journal of Inclusion Phenomena and Macrocyclic Chemistry, Том 43, № 1-2, 2002, стр. 25-29.

Результат исследований: Материалы для журнала › Статья › рецензирование

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abstract = "1H and 13C NMR and 1H NMR relaxation spectroscopy (RS) measurements are reported for the CDCl3 and CD 2Cl2 solutions of [La(NO3)3 (diaza-18-crown-6)] (I), [Pr(NO3)3 (diaza-18-crown-6)] (II) and [Nd(NO3)3 (diaza-18-crown-6)] (III) complexes. Temperature dependencies of the 1H NMR spectra of II have been analyzed using the dynamic NMR methods for multi-site exchange. Enantiomeric isomer interconversion in II is characterized by ΔH‡ = 21.5 ± 4 kJ mol-1. Studies of the values of the lanthanide-induced shifts and the longitudinal relaxation rate enhancement revealed that the structure of complexes in solution is similar to that reported for the [La(NO3)3(18-crown-6)] complex in the crystal state. Nevertheless, it appears that the principal values of the molar paramagnetic susceptibility tensor (χi) significantly differ in complexes II and III. The possible reasons for the different characteristics of these complexes are discussed.",

keywords = "Complexes of lanthanides, Crown ethers, Dynamic NMR, Enthalpy of activation, Molecular dynamics",

author = "Babailov, {S. P.} and Nikulina, {L. D.} and Krieger, {J. H.}",

year = "2002",

doi = "10.1023/A:1020492027829",

language = "English",

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T1 - Intramolecular dynamics of lanthanide(III) tetraoxadiaza macrocycle complexes in solution as studied by NMR

AU - Babailov, S. P.

AU - Nikulina, L. D.

AU - Krieger, J. H.

PY - 2002

Y1 - 2002

N2 - 1H and 13C NMR and 1H NMR relaxation spectroscopy (RS) measurements are reported for the CDCl3 and CD 2Cl2 solutions of [La(NO3)3 (diaza-18-crown-6)] (I), [Pr(NO3)3 (diaza-18-crown-6)] (II) and [Nd(NO3)3 (diaza-18-crown-6)] (III) complexes. Temperature dependencies of the 1H NMR spectra of II have been analyzed using the dynamic NMR methods for multi-site exchange. Enantiomeric isomer interconversion in II is characterized by ΔH‡ = 21.5 ± 4 kJ mol-1. Studies of the values of the lanthanide-induced shifts and the longitudinal relaxation rate enhancement revealed that the structure of complexes in solution is similar to that reported for the [La(NO3)3(18-crown-6)] complex in the crystal state. Nevertheless, it appears that the principal values of the molar paramagnetic susceptibility tensor (χi) significantly differ in complexes II and III. The possible reasons for the different characteristics of these complexes are discussed.

AB - 1H and 13C NMR and 1H NMR relaxation spectroscopy (RS) measurements are reported for the CDCl3 and CD 2Cl2 solutions of [La(NO3)3 (diaza-18-crown-6)] (I), [Pr(NO3)3 (diaza-18-crown-6)] (II) and [Nd(NO3)3 (diaza-18-crown-6)] (III) complexes. Temperature dependencies of the 1H NMR spectra of II have been analyzed using the dynamic NMR methods for multi-site exchange. Enantiomeric isomer interconversion in II is characterized by ΔH‡ = 21.5 ± 4 kJ mol-1. Studies of the values of the lanthanide-induced shifts and the longitudinal relaxation rate enhancement revealed that the structure of complexes in solution is similar to that reported for the [La(NO3)3(18-crown-6)] complex in the crystal state. Nevertheless, it appears that the principal values of the molar paramagnetic susceptibility tensor (χi) significantly differ in complexes II and III. The possible reasons for the different characteristics of these complexes are discussed.

KW - Complexes of lanthanides

KW - Crown ethers

KW - Dynamic NMR

KW - Enthalpy of activation

KW - Molecular dynamics

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