Three-Step Spin Crossover in a Pseudo-3D Hofmann-Type Complex Originating from Anisotropic Supramolecular...

Area of Science:

• Materials Science
• Inorganic Chemistry
• Supramolecular Chemistry

Background:

• Multistep spin crossover materials are crucial for molecular information processing and sensing.
• Synthesizing and understanding these materials presents significant challenges.

Purpose of the Study:

• To introduce the first iron(II) two-dimensional Hofmann structure incorporating 1,2,4-triazole derivatives and [Au(CN)2]- units.
• To investigate the spin crossover behavior and underlying mechanisms of the novel material.

Main Methods:

• Synthesis of the iron(II) complex Fe(MeOPhtrz)2[Au(CN)2]2.
• Characterization using magnetic susceptibility, differential scanning calorimetry, Raman spectroscopy, single-crystal X-ray diffraction (SXRD), and optical microscopy.
• Analysis of supramolecular interactions and crystallographic data.

Main Results:

• The synthesized complex exhibits a temperature-induced three-step spin crossover behavior.
• SXRD revealed a pseudothree-dimensional structure stabilized by hydrogen bonding, π-π stacking, and π-Au interactions.
• Anisotropic supramolecular framework and differential rigidity along crystallographic axes contribute to the multistep spin transition.

Conclusions:

• Supramolecular interactions play a critical role in controlling spin crossover properties in 2D Hofmann-like materials.
• This work opens new pathways for designing functional 2D materials with tunable spin crossover characteristics.