Magneto–structural maps and bridged-ligand effect for dichloro-bridged dinuclear copper(ii) complexes: a theoretical perspective

Abstract

Theoretical understanding of magneto–structural correlations in dichloro-bridged dicopper(II) complexes can guide the design of magnetic materials having broad-scale applications. However, previous reports suggest these correlations are complicated and unclear. To clarify possible correlations, magnetic coupling constants (J_calc) of variants of a representative {Cu–(μ-Cl)₂–Cu} complex A were calculated through BS-DFT. The variation of the Cu–(μ-Cl)–Cu angle (α), Cu⋯Cu distance (R₀), and Cu–Cl–Cu–Cl dihedral angle (τ) followed by structural optimization and calculation of the magnetic coupling constant (J_calc) revealed several trends. J_calc increased linearly with R₀ and τ, and initially increased and then decreased with α. Further, bridging ligand effects on J_calc for dicopper(II) complexes were evaluated through BS-DFT; the results revealed that J_calc increased with increasing ligand field strength (I⁻ < Br⁻ < Cl⁻ < N₃⁻ < F⁻). Furthermore, a linear relationship was found between the spin density of the bridging ligand and J_calc.