Paramagnetic properties and molecular structure of coordination saturated inclusive lanthanide complexes with 18-crown-6 using NMR

Abstract

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/ on k(Ln)/ (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.