Sulfonamido tripods: tuning redox potentials via ligand modifications

Area of Science:

• Inorganic Chemistry
• Coordination Chemistry
• Organometallic Chemistry

Background:

• Tetradentate sulfonamido tripods are versatile ligands in coordination chemistry.
• Iron complexes exhibit diverse redox properties relevant to catalysis and bioinorganic chemistry.

Purpose of the Study:

• To synthesize and characterize novel iron(II) complexes with tunable electronic properties.
• To investigate the relationship between ligand electronic effects and the redox behavior of iron centers.

Main Methods:

• Synthesis of iron(II) complexes featuring tetradentate sulfonamido ligands.
• Full characterization including X-ray diffraction for structural determination.
• Cyclic voltammetry to determine Fe(II)/Fe(III) redox potentials.

Main Results:

• Successfully synthesized and structurally characterized a series of five-coordinate, trigonal bipyramidal Fe(II) complexes.
• Established a linear correlation between Hammett constants of para-substituents on aryl rings and redox potentials.
• Observed a 160 mV range in redox potentials across the synthesized complex series.

Conclusions:

• Ligand electronic properties significantly influence the redox potential of iron(II) centers in these complexes.
• The synthesized complexes provide a tunable platform for studying structure-redox relationships in iron coordination chemistry.