Titanium(III) trisamidotriazacyclononane: reactions with C60 and radicals

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Titanium complexes with amidotriazacyclononane ligands are of interest for their unique reactivity.
• Fullerenes like C60 are versatile building blocks in materials science and organic synthesis.
• Understanding ligand rearrangement and redox processes in organometallic complexes is crucial for catalyst design.

Purpose of the Study:

• To investigate the reaction of titanium trisamidotriazacyclononane with C60.
• To explore the reactivity of the resulting titanium-fullerene complex with alkyl halides.
• To characterize novel titanium complexes formed through ligand rearrangement and redox reactions.

Main Methods:

• Synthesis of titanium trisamidotriazacyclononane, [Ti{N(Ph)SiMe2}3tacn] (1).
• Reaction of complex 1 with C60 to form [Ti{N(Ph)SiMe2}3tacn]C60 (2).
• Treatment of complex 2 with benzyl bromide and methyl iodide to yield new titanium species.
• Spectroscopic analysis (NMR, Mass Spectrometry) and X-ray crystallography to characterize products.

Main Results:

• High yield synthesis of the titanium-fullerene adduct [Ti{N(Ph)SiMe2}3tacn]C60 (2).
• Formation of a titanium bromide complex and a benzylfullerene radical upon reaction with benzyl bromide.
• Synthesis of a titanium iodide complex and a novel imido-amido ligand complex (5) via reaction with methyl iodide, involving ligand rearrangement and redox processes.
• Observation of fluxional processes including reversible 1,3-silyl shifts and racemization in complex 5 in solution.

Conclusions:

• The titanium trisamidotriazacyclononane complex readily reacts with C60 and undergoes further transformations.
• Ligand rearrangement, redox chemistry, and radical formation are key features of these reactions.
• The study reveals dynamic behavior in solution, including isomerism and fluxionality, for the novel titanium complexes.