Features of the decomposition of the neutral nitrosyl iron complexes with aryl-containing thiolate ligands in various solvents. Reaction with glutathione

Abstract

The decomposition of two neutral binuclear nitrosyl iron complexes (NICs) of the µ-S structural type and general composition [Fe2(SR)2(NO)4]0 was studied in comparison. The exchange reaction of the thiophenol or 2-aminothiophenol thiolate ligand by glutathione (GSH) in neutral NICs was studied. The reaction system was analyzed by spectrophotometry to prove the presence of a new NICs with the GS– ligand in it. It was found that, unlike the earlier studied binuclear cationic NICs of the µ-S type and general composition [Fe2(µ-SR)2(NO)4]2+SO4•nH2O with cysteamine and penicillamine ligands in which both thiolate ligands exchange by GS–, in these neutral complexes both thiolate ligands are de-tached by only one GSH ligand is attached. A water molecule is inserted into the second free site. It is assumed that the antitumor activity of the neutral NICs can be determined not only by their NO-donor activity but also by their ability to exchange the thiolate ligand by GS–, i.e., "to remove" GSH from the medium as in the case of cationic NICs. The discovered reaction can prevent, most likely, the S-glutathionylation of important metabolites in the presence of GSH and is very significant for metabolism of NICs.