Halogen-Substituted Spin-Crossover Fe(III) Compounds with Photoresponsive Properties

Area of Science:

• Inorganic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Spin crossover (SCO) materials are promising for molecular switches.
• Tuning SCO properties through ligand design is crucial for material development.
• Iron(III) complexes offer tunable electronic and magnetic properties.

Purpose of the Study:

• To synthesize and characterize novel halogen-substituted Fe(III) compounds.
• To investigate the spin crossover properties and photoresponsive behavior of these compounds.
• To explore their potential for applications in switchable materials.

Main Methods:

• Synthesis of halogen-substituted Fe(III) complexes.
• Variable-temperature magnetic susceptibility measurements.
• Photo-switching studies using different light wavelengths.

Main Results:

• Compounds 1, 4·MeOH, and 4 maintained a high-spin state.
• Compounds 2 and 3 displayed gradual, incomplete spin crossover.
• Compounds 2 and 3 exhibited light-induced excited spin-state trapping (LIESST) and reversible switching; compound 4·MeOH showed a reverse-LIESST effect.

Conclusions:

• Halogen substitution influences spin crossover behavior in Fe(III) complexes.
• Photoresponsive switching and LIESST effects were observed in specific SCO-active compounds.
• These findings contribute to the design of novel photoresponsive switchable materials.