Dinuclear Iron(II) Spin-Crossover Compounds: A Theoretical Study

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Quantum Chemistry

Background:

• Di-iron(II) complexes are crucial in understanding spin-crossover phenomena.
• Investigating the influence of ligand environment and crystal packing on metal complex properties is essential.

Purpose of the Study:

• To computationally investigate the structures and spin-state energetics of two di-iron(II) complexes.
• To assess the impact of crystal stabilization on the spin-state energy of these complexes.
• To validate a theoretical approach for studying multinuclear transition-metal complexes.

Main Methods:

• Density Functional Theory (DFT) was employed.
• Second-order perturbation theory based on the density matrix renormalization group approach (DMRG-CASPT2) was utilized.
• Calculations were performed for complexes in both gas phase and various crystalline environments.

Main Results:

• The theoretical approach accurately reproduced experimental data for the studied di-iron(II) complexes.
• Ground states and spin-crossover behaviors were correctly described.
• Significant structural changes and a large impact of crystal stabilization on relative spin-state energy were observed.

Conclusions:

• The DMRG-CASPT2 method provides quantitative insights into spin-state energetics of multinuclear complexes.
• Crystal environments play a critical role in modulating the electronic and structural properties of di-iron(II) complexes.
• This study highlights the predictive power of advanced computational methods in inorganic chemistry.