Tungsten Biscorroles: New Chiral Sandwich Compounds

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Corroles are macrocyclic ligands with unique electronic properties.
• Homoleptic sandwich compounds offer intriguing structural and electronic possibilities.
• Tungsten complexes are known for diverse catalytic and material applications.

Purpose of the Study:

• To synthesize and characterize novel tungsten(VI) biscorrole complexes.
• To investigate the structural, optical, and electrochemical properties of these new compounds.
• To explore the potential of metallobiscorroles as chiral chromophores.

Main Methods:

• Oxidative metalation of free-base meso-triarylcorroles with tungsten hexacarbonyl (W(CO)6).
• Single-crystal X-ray diffraction for structural determination.
• Density Functional Theory (DFT) calculations for stability analysis.
• UV-Vis spectroscopy and electrochemistry for property evaluation.

Main Results:

• Successful synthesis of three tungsten(VI) biscorroles, the first homoleptic corrole sandwich compounds.
• X-ray structures revealed square-antiprismatic coordination, domed ligands, and significant metal displacement.
• Complexes exhibit approximate C2 symmetry, indicating chirality, with configurationally stable enantiomers.
• Observed a blueshifted Soret band (357 nm), a near-IR feature (781 nm), and a low HOMO-LUMO gap (1.3 V).

Conclusions:

• Tungsten(VI) biscorroles represent a new class of homoleptic sandwich compounds.
• These complexes are inherently chiral and amenable to chiral resolution.
• The novel optical and electrochemical properties position metallobiscorroles as promising chiral chromophores.