Electronically Strongly Coupled Divinylheterocyclic-Bridged Diruthenium Complexes.

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Ruthenium complexes are versatile in catalysis and materials science.
• Understanding charge delocalization in metal-organic frameworks is crucial for electronic applications.

Purpose of the Study:

• To synthesize and characterize novel ruthenium complexes with diverse heteroatoms and substituents.
• To investigate the electronic and structural properties of these complexes using spectroelectrochemical methods.

Main Methods:

• Synthesis of ruthenium complexes with varying heteroatoms (N, O, S) and R groups.
• Solid-state structure determination via X-ray crystallography.
• Spectroelectrochemical studies including cyclic voltammetry (CV), IR, UV/Vis/NIR, and EPR spectroscopy.
• Density Functional Theory (DFT) calculations for structural optimization.

Main Results:

• Four alkyne and two complex solid-state structures were determined.
• Spectroelectrochemical studies demonstrated moderate influence of heteroatom and R-group on properties.
• Two consecutive one-electron redox events were observed in CVs, with a linear correlation between redox potential and Hammett constants for a subset of complexes.
• IR, UV/Vis/NIR, and EPR studies confirmed full charge delocalization across the {Ru}CH-CH-heterocycle-CH-CH{Ru} backbone.
• These complexes are classified as Class III systems according to Robin and Day.
• DFT-optimized structures of neutral complexes correlated well with experimental data.

Conclusions:

• The synthesized ruthenium complexes exhibit significant charge delocalization, characteristic of Class III systems.
• The electronic and structural properties are tunable via heteroatom and substituent modifications.
• DFT calculations provide valuable insights into the structural changes during oxidation.