Synthesis and structure of d-metal complexes with derivatives of 9-oxypyrido[1,2a]pyrimidine-2-one. Crystal structure of 4-methyl-9-oxypyrido[1,2a]pyrimidine-2-one

By reacting Cu(I), Cu(II), Ni(II), Co(II), and Mn(II) chlorides and Ag(I) n itrate with 4-methyl-(8-nitro)-9-oxypyrido[1,2-a]pyrimidine-2-ones (HL1, HL 2), the complex compounds ML and MHLCl2 . nH(2)O (n = 1-3) were produced (8 compounds in all). The spectral characteristics of the neutral, anionic, a nd cationic forms of ligands were determined and the crystal structure of 4 -methyl-9-oxypyrido[1,2-a]pyrimidine-2-one was resolved. It was found that the monovalent metal complexes contain ligands in the anionic form, while t he ligands in the bivalent metal complexes are in bipolar form. Coordinatio n is realized with the involvement of the hydroxyl oxygen atoms and the cyc lic nitrogen atom.