Complexes of d and f metals with 2-methyl-3-hydroxy(amino)pyrido[1,2-a]pyrimidine-4-one. Crystal structure of 2-methyl-3-hydroxypyrido[1,2-a]pyrimidine-4-one

Six complexes of scandium(M), lanthanum(III), praseodymium(III), and copper(II) chlorides with 2-methyl-3-hydroxypyrido[1,2-a]pyrimidine-4-one (HL1) and 2-methyl-3-aminopyrido[1,2-a]pyrimidine-4-one (L-2), as well as hydrochloride and hydronitrate L-2, were isolated. The crystal and molecular structures of HL1 were determined. HL1 in CCl4 solution was shown (IR data) to occur as two forms, namely, neutral and zwitterionic forms. The structures for the complexes isolated were proposed.