Oxidative dehydrogenation of N-(2-hydroxy-3,5-R1,R2-benzyl)-4-aminoantipyrines in the complexation reaction

• Published in: Russian journal of coordination chemistry 2012, Vol.38 (2), p.126-133
• Main Authors: Medzhidov, A. A., Fatullaeva, P. A., Peng, S. M., Ismaiylov, R. G., Lee, G. H., Garaeva, S. R.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Physical Chemistry
• ISSN: 1070-3284; 1608-3318
• DOI: 10.1134/S1070328412010071

Reactions of N-(2-hydroxy-3,5-R 1 ,R 2 -benzyl)-4-aminoantipyrines with copper acetate in ethanol gave complexes with Schiff bases (SBs) rather than the expected complexes with reduced SBs; i.e., the starting ligands undergo oxidative dehydrogenation during the complexation reaction. The corresponding complexes with reduced SBs were obtained from sodium salts of the ligands and cupric sulfate in aqueous solutions. Kinetic measurements showed that oxidative dehydrogenation occurs in the heteroleptic complexes Cu(L i )(CH 3 COO)(X) (L i H are derivatives of N-(2-hydroxy-3,5-R 1 ,R 2 -benzyl)-4-aminoantipyrines; i = 6–10; X = H 2 O, CH 3 OH, CH 3 CH 2 OH) but does not occur in the complexes CH 3 OH, CH 3 CH 2 OH. The absence of oxidative dehydrogenation of the ligands in Cu(L i ) 2 · H 2 O can be explained by the octahedral environment of the Cu 2+ ion and, accordingly, the absence of the coordination site for molecular oxygen. The molecular structures of two Cu(II) complexes with SBs were determined by X-ray diffraction.