Phosphine-ligated dinitrosyl iron complexes for redox-controlled NO release

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Dinitrosyl iron complexes (DNICs) are crucial in biological systems and catalysis.
• Developing novel DNICs with tailored properties is essential for advancing chemical applications.
• Phosphine ligands offer versatile coordination possibilities for metal complexes.

Purpose of the Study:

• To synthesize and characterize new dinitrosyl iron complexes (DNICs) utilizing silicon- and carbon-derived phosphine ligands.
• To investigate the structural, spectroscopic, and electrochemical properties of these novel DNICs.
• To explore the nitric oxide (NO) release capabilities of DNICs in different oxidation states.

Main Methods:

• Synthesis of four dinitrosyl iron complexes (DNICs) with di- and tripodal phosphine ligands.
• Characterization using IR spectroelectrochemistry, UV-vis spectroscopy, and Mössbauer spectroscopy.
• Density Functional Theory (DFT) analysis to understand electronic structures and NO release mechanisms.

Main Results:

• Successful synthesis and characterization of four novel DNICs.
• Observed η(2)-binding mode for most complexes, with one complex undergoing Si-C bond cleavage.
• Demonstrated NO ligand release from the oxidized {Fe(NO)2}(9) state, but not the reduced {Fe(NO)2}(10) state.

Conclusions:

• The synthesized DNICs exhibit distinct coordination behaviors and electronic properties.
• The oxidized {Fe(NO)2}(9) state is key for NO ligand release, offering potential for controlled NO delivery.
• DFT analysis provides insights into the electronic factors governing NO release in these organometallic complexes.