Fluctuating Behavior and Ligand-Dependent Reactivity of Isocyanates with Bis(pentafulvene)titanium Complexes

Area of Science:

• Organometallic Chemistry
• Titanium Complexes
• Isocyanate Chemistry

Background:

• Frustrated Lewis pairs and related systems are key in catalysis.
• Titanium complexes with unique ligand architectures offer novel reactivity.
• Isocyanates are versatile building blocks in organic synthesis.

Purpose of the Study:

• To investigate the reactions of bis(pentafulvene)titanium complexes with isocyanates.
• To characterize the resulting titanium amidato complexes.
• To explore the reactivity of these complexes in further transformations.

Main Methods:

• Synthesis of bis(pentafulvene)titanium complexes.
• Reaction with isocyanates under mild conditions.
• Characterization using single crystal X-ray diffraction, NMR, and IR spectroscopy.
• Investigation of reactivity via E-H cleavage and insertion reactions.
• Computational studies using DFT and variable temperature NMR.

Main Results:

• Selective insertion of one or two isocyanate equivalents into Ti-C bonds.
• Formation of K1O- and K1N-amidato titanium complexes.
• Demonstration of reactivity of single insertion products with alcohols, amines, ketones, and nitriles.
• Observation of K1N- to K1O-amidato complex transformations.

Conclusions:

• Bis(pentafulvene)titanium complexes provide a platform for controlled isocyanate insertion.
• The resulting titanium amidato complexes exhibit diverse reactivity.
• Ligand effects and reaction conditions influence the product distribution and transformations.