Crystal and molecular structures of 2,4-dimethyl-9-hydroxypyrido[1,2-a]pyrimidinium perchlorate: Its complexes with praseodymium, neodymium, samarium, and europium

Reaction of Ln(NO3)3 · 6H2O with 2,4-dimethyl-9-hydroxypyrido[ 1,2-a]pyrimidinium perchlorate (HLClO4) in acetone gave complex compounds LnL2(ClO4)2NO3 · nH2O (Ln = Pr, Nd, Sm, and Eu; n 3-7) and Eu(HL)2(ClO4)2(NO3)3 · 5H2O. The compounds were characterized by IR and electronic absorption spectroscopy. The crystal and molecular structures of HLClO4 were established. The coordination mode of L and HL+ in their complexes with rare-earth elements is suggested on the basis of the spectroscopic data.