Nitric oxide (NO) plays major roles in facilitating muscle relaxation, lowering blood pressure, and preventing memory loss. The half-life of NO is only a few seconds, so a carrier mechanism is required for pharmaceutical applications. Non-heme dinitrosyl iron complexes (DNICs) have shown potential in the controlled release of nitric oxide. These DNICs are paired with ligands that can interact with proteins or DNA in the body.
Our research focuses on the isolation and structural studies of non-heme iron nitrosyls that mimic biologically active compounds. We have shown that reactions between Fe(NO)2(CO)2 and a series of imidazoles or N,N'-chelating ligands generate iron dinitrosyl complexes of the form Fe(NO)2(L)2 or tetrameric cluster of [Fe(NO)2(L)]4. Using thiols or thiolate ligands, sulfur-bridged iron dinitrosyl complexes with the general formula [Fe(µ-RS)(NO)2]2 can be prepared. Similarly, using bidentate phosphine ligands, a series of dinitrosyl iron complexes with the formula [(DPPX)Fe(NO)2] has been synthesized and characterized, where DPPX represents bidentate phosphines.
Compounds containing pyrazole moieties are found in several pharmaceutical drugs that target inflammation, viruses, bacteria, or fungi. Recently, novel DNICs were synthesized and characterized by reacting Fe(NO)2(CO)2 with pyrazole-derived ligands. Crystal structure data revealed that two pyrazole ligands coordinate with two iron centers. The chemical and electronic properties of these complexes were studied using spectroscopic techniques such as IR, NMR, UV-vis, and X-ray crystallography. Investigating these properties, as well as nitric oxide release, may prove valuable for pharmaceutical research.