Synthesis and Study of Coordination Compounds of Rare-Earth Nitrates with N,N′-Tetraethyl-N"-(Trichloroacetyl)phosphorictriamide

Coordination compounds of general formula Ln(NO(3))(3)(HL)(3) [Ln = La, Ce-Nd, Sm-Yb, and Y; HL = CCl(3)C(O)N(H)P(O)(NEt(2))(2)] were synthesized. The complexes are studied by the IR, (1)H NMR, (31)P NMR, and electronic spectroscopies. X-ray diffraction analysis indicates that all the synthesized complexes are isostructural. According to the electronic spectroscopy data, the coordination sphere of the complexes exhibits the same composition in both the acetone solutions and crystalline state. The method of separation of the isotropic chemical shift into the contact and pseudocontact components is used to reveal the occurrence of the two series of conformation isomers for the axially symmetric complexes in the acetone solutions. The hyperfine structure constants Ln-P are equal to 0.28 and 0.39 MHz for heavy lanthanides (Ho-Tm) and lanthanides of the Ce subgroup (Ce-Tb), respectively.