Manipulating magnetism: Ru₂⁵⁺ paddlewheels devoid of axial interactions

Area of Science:

• Inorganic Chemistry
• Materials Science
• Computational Chemistry

Background:

• Diruthenium complexes are crucial in coordination chemistry.
• Understanding axial ligand effects is key to tuning electronic properties.
• Diarylformamidine (DArF) ligands offer tunable steric and electronic properties.

Purpose of the Study:

• To investigate the influence of axial ligands on diruthenium electronic structure.
• To elucidate the nature of metal-ligand interactions in Ru2(DArF)4Cl and [Ru2(DArF)4]BF4 systems.
• To characterize the electronic configuration and magnetic properties of these diruthenium complexes.

Main Methods:

• Variable-temperature magnetic susceptibility measurements.
• Variable-temperature single-crystal X-ray diffraction.
• Density Functional Theory (DFT) calculations.
• Electron Paramagnetic Resonance (EPR) spectroscopy.

Main Results:

• Axial chlorine ligand significantly alters the electronic structure of the diruthenium core.
• Evidence of π interactions between chlorine p orbitals and Ru2(5+) π* orbitals.
• Magnetic and structural data support combined ligand σ/metal σ and ligand pπ/metal-dπ interactions.
• EPR spectroscopy confirms unpaired electrons are localized in metal-based molecular orbitals.

Conclusions:

• Axial ligands play a critical role in modulating the electronic properties of diruthenium complexes.
• The observed interactions provide insights into bonding and electronic structure.
• These findings contribute to the design of novel diruthenium compounds with tailored magnetic and electronic characteristics.