π-π Stacking and ferromagnetic coupling mechanism on a binuclear Cu(II) complex

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Magnetochemistry

Background:

• Binuclear copper(II) complexes exhibit diverse magnetic properties.
• Understanding magnetic coupling pathways is crucial for designing molecular magnets.

Purpose of the Study:

• To investigate ferromagnetic couplings in a novel binuclear copper(II) complex.
• To elucidate the role of π-π stacking and bridging ligands in magnetic interactions.
• To explore the relationship between electronic structure and magnetic coupling.

Main Methods:

• Crystal structure analysis of [Cu(2)(μ(1,3)-SCN)(2)(PhenOH)(OCH(3))(2)(HOCH(3))(2)] complex.
• Variable-temperature magnetic susceptibility measurements.
• Theoretical calculations including DFT and Wiberg bond index analysis.

Main Results:

• Ferromagnetic coupling observed between adjacent Cu(II) ions (J = 50.02 cm⁻¹).
• Two π-π stacking pathways exhibit ferromagnetic couplings (J = 4.16 cm⁻¹, J = 2.75 cm⁻¹).
• Thiocyanate bridging pathway shows weaker ferromagnetic interaction (J = 0.88 cm⁻¹).
• Wiberg bond indexes correlate with magnetic coupling magnitude, indicating their significance.

Conclusions:

• Ferromagnetic coupling in the studied complex is influenced by both π-π stacking and μ(1,3)-SCN(-) bridging.
• Wiberg bond indexes are key factors determining magnetic coupling strength in π-π stacked systems.
• The observed coupling mechanisms deviate from the McConnell I spin-polarization model for π-π stacking.