Abstract
1H and 13C NMR measurements are reported for the CDCl3 and CD2Cl2 solutions of [La(NO 3)3(18-crown-6)] (I), [Pr(NO3) 3(18-crown-6)] (II) and [Ce(NO3)3(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. Two types of conformational dynamic processes in II were identified (the first one with activation enthalpy ΔH‡=26 ± 4 kJ/mol is conditioned by interconversion of complex enantiomeric form and pseudorotation of macrocycle molecule upon the C2 symmetry axis, the second one with ΔH‡=46 ± 5 kJ/mol is conditioned by macrocycle molecule inversion). Studies of the values of the lanthanide-induced shifts revealed that the structure of complexes in solution is similar to that reported for the complex I in the crystal state.
| Original language | English |
|---|---|
| Pages (from-to) | 103-109 |
| Number of pages | 7 |
| Journal | Journal of Inclusion Phenomena and Macrocyclic Chemistry |
| Volume | 51 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Feb 2005 |
| Externally published | Yes |
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Keywords
- 18-crown-6
- Complexes of lanthanides
- Crown ethers
- Dynamic NMR
- Enthalpy of activation
- Interconversion of enantiomers
- Inversion and pseudorotation of macrocycle molecule
- Molecular dynamics
- Multi-site exchange
- Twelve-site exchange
ASJC Scopus subject areas
- Chemistry(all)
- Condensed Matter Physics
Cite this
NMR studies of mixed-ligand lanthanide complexes in solution : Pseudorotation and ring inversion of 18-crown-6 molecule in cerium subgroup chelates. / Babailov, Sergey P.; Nikulina, Lubov D.
In: Journal of Inclusion Phenomena and Macrocyclic Chemistry, Vol. 51, No. 1, 02.2005, p. 103-109.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - NMR studies of mixed-ligand lanthanide complexes in solution
T2 - Pseudorotation and ring inversion of 18-crown-6 molecule in cerium subgroup chelates
AU - Babailov, Sergey P.
AU - Nikulina, Lubov D.
PY - 2005/2
Y1 - 2005/2
N2 - 1H and 13C NMR measurements are reported for the CDCl3 and CD2Cl2 solutions of [La(NO 3)3(18-crown-6)] (I), [Pr(NO3) 3(18-crown-6)] (II) and [Ce(NO3)3(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. Two types of conformational dynamic processes in II were identified (the first one with activation enthalpy ΔH‡=26 ± 4 kJ/mol is conditioned by interconversion of complex enantiomeric form and pseudorotation of macrocycle molecule upon the C2 symmetry axis, the second one with ΔH‡=46 ± 5 kJ/mol is conditioned by macrocycle molecule inversion). Studies of the values of the lanthanide-induced shifts revealed that the structure of complexes in solution is similar to that reported for the complex I in the crystal state.
AB - 1H and 13C NMR measurements are reported for the CDCl3 and CD2Cl2 solutions of [La(NO 3)3(18-crown-6)] (I), [Pr(NO3) 3(18-crown-6)] (II) and [Ce(NO3)3(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. Two types of conformational dynamic processes in II were identified (the first one with activation enthalpy ΔH‡=26 ± 4 kJ/mol is conditioned by interconversion of complex enantiomeric form and pseudorotation of macrocycle molecule upon the C2 symmetry axis, the second one with ΔH‡=46 ± 5 kJ/mol is conditioned by macrocycle molecule inversion). Studies of the values of the lanthanide-induced shifts revealed that the structure of complexes in solution is similar to that reported for the complex I in the crystal state.
KW - 18-crown-6
KW - Complexes of lanthanides
KW - Crown ethers
KW - Dynamic NMR
KW - Enthalpy of activation
KW - Interconversion of enantiomers
KW - Inversion and pseudorotation of macrocycle molecule
KW - Molecular dynamics
KW - Multi-site exchange
KW - Twelve-site exchange
UR - http://www.scopus.com/inward/record.url?scp=18844442908&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=18844442908&partnerID=8YFLogxK
U2 - 10.1007/s10847-004-4673-5
DO - 10.1007/s10847-004-4673-5
M3 - Article
VL - 51
SP - 103
EP - 109
JO - Journal of Inclusion Phenomena and Molecular Recognition in Chemistry
JF - Journal of Inclusion Phenomena and Molecular Recognition in Chemistry
SN - 1388-3127
IS - 1
ER -