Complexes of some pyrido[1,2-a]pyrimidinium perchlorates with scandium, yttrium, and lanthanum. Crystal and molecular structure of 3-chloro-9-hydroxy-2,4-dimethylpyrido[1,2-a]pyrimidinium perchlorate

Complexes of scandium, yttrium, and lanthanum nitrates with 3-chloro-9-hydroxy-2,4-dimethylpyrido[1,2-a]pyrimidinium perchlorate ((HLClO4)-Cl-1) and 9-hydroxy-2,4-dimethylpyrido[1,2-a]pyrimidinium perchlorate ((HLClO4)-Cl-2) were obtained. Their composition was formulated as Sc(LClO4)(2)(NO3) and M(LClO4)(2)(NO3)(2) (L = L-1 or L-2; M =Y or La); structures for the complexes obtained were proposed. The crystal and molecular structure of (HLClO4)-Cl-1 was determined. Dissociation and complexation of (HLClO4)-Cl-1 and (HLClO4)-Cl-2 in aqueous ethanol were studied using the spectroscopic method. Ligand dissociation and complexation constants were calculated. It was shown that a chlorine-containing organic ligand only slightly changes the composition and stability of the metal complexes.