Studies on Crown Ether Complexes. XXXI. Synthesis, Properties and Structure of the Complexes of Lighter Lanthanide Nitrates With (Z)-2,3-Diphenyl-1,4,7,10,13-pentaoxacyclopentadec-2-ene (Stilbeno-15-crown-5)

Abstract

Complexes of the lighter lanthanide nitrates with stilbeno-15-crown-5 (L) have been prepared in ethyl acetate. These new complexes with the general formula Ln (NO₃)₃.L.H₂O ( Ln = La, Ce , Pr, Nd ) have been characterized by means of elemental analyses, i.r . spectra, ¹H n.m.r. spectra and conductivity measurements. The crystal structure of La(NO₃)₃.L has been determined by X-ray methods, and refined to a residual R 0.0513 for 4937 independent reflections with I ≥ 1.5σ(I). It crystallizes in the monoclinic space group P2₁/a with a 16.090(5), b 15.654(8), c 22.687(2) Ǻ, β 93.96(4)°, V 5700(4)Ǻ³, and Z 8. There are two independent La(NO₃)₃.L monomers in one asymmetric unit; in each the coordination number is 11.