Large Ligand Folding Distortion in an Oxomolybdenum Donor-Acceptor Complex

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Spectroscopy

Background:

• Metallo-dithiolene complexes are important in catalysis and materials science.
• Structural distortions significantly impact the electronic properties of metal complexes.
• Understanding charge transfer mechanisms is key to designing functional molecules.

Purpose of the Study:

• To investigate the interligand charge transfer (LL'CT) in a novel molybdenum-dithiolene complex.
• To elucidate the electronic structure responsible for a significant fold-angle distortion in the dithiolene ring.
• To correlate spectroscopic data with structural properties.

Main Methods:

• Synthesis of the novel molybdenum-dithiolene complex MoO(SPh)2((i)Pr2Dt(0)).
• Electronic absorption spectroscopy to probe electronic transitions.
• Resonance Raman spectroscopy to investigate vibrational modes and electronic coupling.
• Computational analysis to support experimental findings (implied).

Main Results:

• The complex exhibits a notable 70° "envelope"-type fold of the dithiolene ring.
• An intense charge transfer transition at ~18,000 cm(-1) was observed.
• This transition is assigned as a thiolate → dithione LL'CT and Mo(IV) → dithione charge transfer.
• A strong pseudo-Jahn-Teller effect drives the distortion via orbital mixing.

Conclusions:

• The observed structural distortion is intrinsically linked to the electronic structure and charge transfer properties.
• Ligand-to-ligand charge transfer plays a critical role in the complex's unique geometry.
• The pseudo-Jahn-Teller effect is a key factor in stabilizing the distorted conformation.