Tris(4-oxy-pyridinium)nitrato lanthanide complexes [M(4-O-C6H4NH)3(NO3)2(H2O)2][NO3] {M = La, Ce, Pr, Nd, Eu, Gd} – Synthesis, properties and structural characterization

Preferential formation and X-ray structures of tris(4-hydroxypyridinium) nitrato complexes [M(4-O-C6H4NH)3(NO3)2(H2O)2][NO3] {M = La, Ce, Pr, Nd, Eu, Gd} in the simple reaction of 4-hydroxypyridine with the respective nitrates is described. All these compounds are isostructural and crystallize in the space group P212121. There are, however, minor differences in the hydrogen bonding features. The central metal ion in all these complexes has a coordination number of nine and the geometry may be described as tricapped trigonal prism. The neodinium complex has a chirality opposite to that of the rest of the structures. TGA data are also consistent with the solid state structures of these compounds.