Synthesis, structure, NO donor activity of iron–sulfur nitrosyl complex with 2-aminophenol-2-yl and its antiproliferative activity against human cancer cells

Abstract

A new tetranitrosyl binuclear iron complex, [Fe₂(SC₆H₆N)₂(NO)₄] (1), has been synthesized by two methods. Molecular and crystalline structure of 1 were determined by X-ray analysis; the complex is binuclear of “μ-S” type with ~2.7052(4) Å between the irons. The compound crystallizes in monoclinic, space group P2₁/n, Z = 2; parameters of the unit cell: a = 6.6257(2) Å, b = 7.9337(2) Å, c = 16.7858(4) Å, β = 96.742(2)°, V = 876.26(4) ų. Parameters of Mössbauer spectrum for 1 are: isomer shift δ_Fe = 0.096(1) mm/s, quadrupole splitting ΔE_Q = 1.122(1) mm/s, line width 0.264(1) mm/s at 293 K. As follows from the electrochemical analysis of aqueous solutions of 1, it generates NO in protonic media without additional activation. NO amount and the rate of its activation are much higher in acidic solutions than in neutral and alkali ones. The constants of hydrolytic decomposition of 1 were calculated. The geometry and electronic structure of isolated 1 were studied using the density functional theory. Differential sensitivity of four lines of human tumor cells of various genesis to 1 has been determined (ovarian carcinoma (SCOV3), large intestine cancer (LS174T), mammary gland carcinoma (MCF7), and non-small cell carcinoma of lung (A549)); dependence of tumor cells amount on the complex concentration has been studied in order to use the complex as a promising antitumor agent for trials in vivo.

Keywords:

• Sulfur-nitrosyl iron complexes
• X-ray analysis
• MTT assay

Acknowledgments

The work has been supported by the Program of the Presidium of RAS “Fundamental sciences for medicine.”