Interligand communication in a metal mediated LL'CT system - a case study.

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Dithiolene ligands are versatile ligands in coordination chemistry.
• Oxo-molybdenum complexes exhibit diverse reactivity and electronic properties.

Purpose of the Study:

• Synthesize and characterize novel oxo-molybdenum(IV) complexes with distinct dithiolene ligand oxidation states.
• Investigate the electronic structure and charge transfer properties of these complexes.

Main Methods:

• Synthesis and characterization of oxo-molybdenum(IV) complexes.
• Single-crystal X-ray diffraction analysis.
• Density Functional Theory (DFT) calculations, including Time-Dependent DFT (TD-DFT).

Main Results:

• Successful synthesis of [MoO(Dt^2-)(Dt⁰)] complexes with various dithiolene ligands.
• Structural analysis revealed a significant ligand fold angle in [MoO(tdt)(Pr₂Dt⁰)].
• DFT calculations indicated HOMO localization on the Dt^2- ligand and virtual orbitals on Mo and Dt⁰.
• TD-DFT attributed the low-energy electronic transition to ligand-to-ligand charge transfer (LL'CT).
• Electron density difference maps confirmed charge donation from the electron-rich Dt^2- to the electron-deficient Dt⁰ ligand.

Conclusions:

• The Mo-monooxo center and coordination sphere distortion facilitate electronic communication between dithiolene ligands.
• The observed LL'CT transition is a key feature of these oxo-molybdenum dithiolene systems.