Structure of the binuclear tetranitrosyl iron complexes with a pyrimidin-2-yl ligand of the μ2-S type and the pH effect on its NO-donor ability in aqueous solutions

• Published in: Russian chemical bulletin Vol. 58; no. 3; pp. 572 - 584
• Main Authors: Sanina, N. A., Shilov, G. V., Aldoshin, S. M., Shestakov, A. F., Syrtsova, L. A., Ovanesyan, N. S., Chudinova, E. S., Shkondina, N. L., Emel’yanova, N. S., Kotel’nikov, A. I.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.03.2009
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Full Articles; Inorganic Chemistry; Organic Chemistry; sulfur-nitrosyl iron complexes; nitrosyl hemoglobin; pyrimidine-2-thiol; NO donors; X-ray diffraction analysis; Mössbauer spectroscopy
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-009-0058-7

New binuclear tetranitrosyl iron complex with pyrimidin-2-yl of the μ 2 -S type [Fe 2 (SC 4 H 3 N 2 ) 2 (NO) 4 ] ( 1 ) was synthesized by the exchange reaction of thiosulfate ligands in the [Fe(S 2 O 3 ) 2 (NO) 2 ] 3s- anion for pyrimidin-2-yl ligands. The crystal structure of complex 1 was studied by single-crystal X-ray diffraction analysis. According to the X-ray diffraction data, pyrimidin-2-yl is coordinated to the iron atom in the thiol form. According to the quantum chemical calculations, the low stability of complex 1 is related to a possibility of formation of the coordination bond of the iron atom with the atom of the pyrimidine cycle of the ligand after NO group detachment. The ability of complex 1 to donate NO and the kinetics of its hydrolysis in aqueous solutions were studied by electrochemical analysis using sensor electrodes ami NO-700, by spectrophotometry in the pH interval from 6.0 to 7.76, and in the reaction with hemoglobin. Complex 1 is most stable in a neutral medium and more vigorously evolves NO in acidic and alkaline media.