Alkyne substituted mononuclear photocatalysts based on [RuCl(bpy)(tpy)]⁺

Area of Science:

• Coordination Chemistry
• Photocatalysis
• Organic Synthesis

Background:

• 2,2':6',2''-terpyridine (tpy) ligands are crucial in coordination chemistry.
• Functionalization of ligands can tune the properties of metal complexes.
• Ruthenium complexes are known for their catalytic applications.

Purpose of the Study:

• To synthesize and characterize new ruthenium complexes with ethynyl-phenylene substituted terpyridine ligands.
• To investigate the influence of alkynyl substituents on the electronic, photochemical, and redox properties.
• To evaluate the photocatalytic activity of these complexes in alcohol oxidation.

Main Methods:

• Synthesis of four new [RuCl(2,2'-bipyridine)(L(n))]PF6 complexes.
• Spectroscopic techniques: Electronic absorption, resonance Raman, cyclic voltammetry, spectroelectrochemistry.
• Computational methods: Density Functional Theory (DFT) calculations.
• Photocatalysis experiments for 4-methoxybenzyl alcohol oxidation.

Main Results:

• Successfully synthesized four novel ruthenium(II) complexes with varying ethynyl-phenylene tpy ligands.
• Alkynyl substituents significantly influence the electronic structures and redox potentials.
• Complexes exhibit favorable photochemical properties for catalysis.
• No detrimental effect on photocatalytic oxidation of 4-methoxybenzyl alcohol observed.

Conclusions:

• Ethynyl-phenylene substitution on tpy ligands is a viable strategy to tune ruthenium complex properties.
• These functionalized complexes maintain or enhance photocatalytic efficiency.
• The developed complexes show promise for sustainable chemical transformations.