Reduced Arene Complexes of Scandium

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Scandium anilide complexes serve as precursors for novel organometallic compounds.
• Reduced aromatic ligands offer unique electronic and coordination properties.
• Understanding metal-ligand interactions is crucial for designing new materials.

Purpose of the Study:

• To synthesize and characterize novel scandium complexes with reduced arene ligands.
• To investigate the coordination modes of naphthalene and anthracene dianions with scandium(III).
• To explore the electronic properties and reactivity of these new organoscandium compounds.

Main Methods:

• Reaction of alkali metal naphthalenide/anthracenide with scandium(III) anilides.
• Single-crystal X-ray diffraction for structural determination.
• Multinuclear NMR spectroscopy (including 45Sc NMR) and UV/Vis spectroscopy for characterization.
• Quantum chemical calculations to confirm oxidation states and electronic properties.

Main Results:

• Synthesis of scandium complexes [M(thf)n][Sc{N(tBu)Xy}2(RA)] containing reduced naphthalene (3-Naph-K) or anthracene (3-Anth-M) ligands.
• Naphthalene dianion coordinated in a σ2:π-fashion, while anthracene dianion showed σ2-coordination to Sc(III).
• Spectroscopic and computational studies confirmed Sc(III) oxidation state and revealed ligand-to-metal charge transfers as the origin of intense color.

Conclusions:

• Novel scandium complexes with reduced arene ligands were successfully synthesized and characterized.
• The coordination modes of the arene ligands are dependent on the specific aromatic system.
• These complexes exhibit interesting electronic properties and reactivity, with potential for further functionalization.