Bespoke photoreductants: tungsten arylisocyanides

Area of Science:

• Organometallic Chemistry
• Photochemistry
• Materials Science

Background:

• Tungsten complexes with isocyanide ligands are known for their photophysical properties.
• Tuning ligand structure can modify metal complex characteristics.

Purpose of the Study:

• To develop modular syntheses of oligoarylisocyanide ligands.
• To investigate the photophysical and electrochemical properties of novel tungsten complexes incorporating these ligands.

Main Methods:

• Modular synthesis of oligoarylisocyanide ligands.
• Spectroscopic characterization of tungsten complexes.
• Photophysical studies including excited-state lifetime and quantum yield measurements.
• Electrochemical analysis using cyclic voltammetry.

Main Results:

• Developed modular syntheses for oligoarylisocyanide ligands.
• Tungsten complexes (W(CNAr)6) exhibit intense, red-shifted metal-to-ligand charge-transfer absorptions compared to W(CNdipp)6.
• Achieved enhanced excited-state properties: longer lifetimes and very high quantum yields.
• Observed solvent-dependent decay kinetics and temperature-dependent lifetimes, indicating nonradiative decay mechanisms.
• Demonstrated that W(CNAr)6 complexes are exceptionally strong reductants (potentials < -2.7 V vs [Cp2Fe](+)/Cp2Fe).

Conclusions:

• Novel oligoarylisocyanide ligands enable significant tuning of tungsten complex properties.
• These complexes possess superior photophysical and electrochemical characteristics.
• The findings open avenues for applications in areas requiring strong reductants or efficient light-absorbing materials.