Ruthenium Complexes Containing Pyridinyl-Derived Ligands as FLP Catalysts

Area of Science:

• Organometallic Chemistry
• Catalysis
• Supramolecular Chemistry

Background:

• Frustrated Lewis pairs (FLPs) are Lewis acid-base pairs that remain reactive due to steric hindrance.
• Transition-metal FLPs (TMFLPs) combine FLP reactivity with metal-centered catalysis.
• Developing novel TMFLP systems for challenging chemical transformations is an active area of research.

Purpose of the Study:

• To synthesize novel ruthenium-based frustrated Lewis pair (FLP) complexes.
• To investigate the hydrogen activation capabilities of these complexes.
• To evaluate their efficacy as catalysts for hydrogenation reactions.

Main Methods:

• Synthesis of ruthenium complexes with guanidinate (L1) and amidate (L2) ligands.
• Chloride abstraction and deprotonation to form FLP complexes.
• Spectroscopic characterization and reactivity studies, including H2 activation and catalytic hydrogenation.

Main Results:

• Successfully synthesized ruthenium-based FLP complexes 1 (L1) and 4 (L2).
• Demonstrated reversible heterolytic activation of H2 by complexes 1 and 4.
• Observed catalytic hydrogenation of C=C, C=O, and C=N bonds with high efficiency, including reactions in water.

Conclusions:

• Ruthenium FLP complexes exhibit reversible H2 activation.
• These TMFLP complexes are effective catalysts for diverse hydrogenation reactions.
• The developed catalytic system shows potential for green chemistry applications, such as reactions in aqueous media.