Paramagnetic properties and molecular structure of coordination saturated inclusive lanthanide complexes with 18-crown-6 using NMR
Earlier NMR spectra of lanthanide complexes [Ln(18-crown-6)(NO3)3] have been analyzed by us (Babailov in Inorg Chem 51(3):1427–1433, 2012), where Ln3+ = La3+ (I), Ce3+ (II), Pr3+ (III) and Nd3+ (IV). The NMR signal assignment and conformational molecular dynamic have been found by 1D NOE and relaxation spectroscopy as well as on 2D NOESY and EXSY experiments at 170 K. In the present paper the 1H NMR method is used to study the features of paramagnetic properties of complexes I–IV and [Eu(18-crown-6)(NO3)3] (V) at ambient temperature. The investigation was carried out by special method based on analysis of Δδ/<Sz> on k(Ln)/<Sz> (where k(Ln) is Bleaney’s constant, Δδ is paramagnetic contribution to the lanthanide-induced shifts). The obtained results indicate that the structure of the complexes (in CDCl3 and CD2Cl2) are very similar.
KeywordsComplexes of lanthanides Crown ethers 18-Crown-6 Structure similarity Paramagnetic lanthanide-induced shifts NMR
The study was carried out with partial financial support of the Russian Foundation for Basic Research (Grants Nos. 11-03-00197-a and N 14-03-00386-a).
- 7.Piguet, C., Geraldes, C.F.G.C.: In: Gschneidner, K.A., Bünzli, J.-C.G., Pecharsky, V.K. (eds.) Handbook on the Physics and Chemistry of Rare Earths, vol. 33, pp. 353–463. Elsevier Science, Amsterdam (2003)Google Scholar
- 9.Babailov, S.P., Krieger, J.H., Gabuda, S.P.: 1H NMR study of the dynamic structure of nitrate complexes of lanthanides with 18-crown-6. Bull. Acad. Sci. SSSR Div. Chem. Sci. 11, 2661 (1990)Google Scholar
- 11.Babailov, S.P., Krieger, J.H., Martynova, T.N., Nikulina, L.D., Polyanskaya, T.M.J.: NMR study of mixed-ligand complexes of lanthanides. Lanthanide-induced enhancement in the spin-lattice relaxation. Struct. Chem. (USSR) 29, 80 (1988)Google Scholar
- 12.Babailov, S.P., Krieger, J.H., Martynova, T.N., Nikulina, L.D.J.: Study the geometric structure of mixed-ligand complexes of the heaviest lanthanides by NMR and NMR relaxation. Struct. Chem. (USSR) 31, 44 (1990)Google Scholar
- 22.Babailov, S.P.: Nanosized thermometric NMR sensors based on double-decker paramagnetic lanthanide(III) complexes with porphyrins for temperature determination in solutions. Macroheterocycles 3, 209 (2010)Google Scholar
- 23.Bleaney, B.: Nuclear magnetic resonance shifts due to lanthanide ions. J. Magn. Reson. 25, 91 (1972)Google Scholar
- 24.De Boer, J.W.M., Sakkers, P.J.D., Hilbers, C.W., De Boer, M.: Lanthanide shift reagents. J. Mag. Reson. 25, 455 (1977)Google Scholar