Synthesis, crystal structure and characterization of ternary complexes of lanthanide(III) 3,5-di-tert-butyl-γ-resorcylate with substituted pyridine-N-oxide

Twenty one ternary complexes of lanthanide with 3,5-di-tert-butyl-γ-resorcylic acid (L) and seven different substituted pyridine-N-oxides (L^1–7), with compositions of REL₃L^1–7₂·nH₂O (RE=Nd, Gd, Er; L¹=4-picoline-N-oxide; L²=4-phenyl-pyridine-N-oxide; L³=pyridine-N-oxide; L⁴=3-picoline-N-oxide; L⁵=quinoline-N-oxide; L⁶=iso-quinoline-N-oxide; L⁷=4-methoxyl-pyridine-N-oxide; n=0, 1, 2, 5), were synthesized and characterized by means of elemental analysis, electrical conductivity, thermal analysis and IR spectra. The novel crystal structure of ErL₃L³₂·(EtOH) has been determined by a single-crystal X-ray diffraction method. It shows that each erbium ion is linked to three 3,5-di-tert-butyl-γ-resorcylic acid ions through two different types of dentation modes in which only the carboxylate oxygen atoms participate. The coordination geometries of erbium ion can be described as a distorted octa-coordinated bicapped trigonal prism.