Two-Dimensional Coordination Polymer Showing Spin-Crossover Behavior with a 64 K Wide Hysteresis Loop

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Spin crossover (SCO) materials are of interest for molecular switches and sensors.
• Designing SCO materials with large hysteresis and unique thermal properties remains a challenge.

Purpose of the Study:

• To synthesize and characterize a novel two-dimensional grid-like coordination polymer.
• To investigate the spin crossover properties and thermal behavior of the synthesized material.

Main Methods:

• Synthesis of the coordination polymer [Fe(NCBH3)2(Py2ttz)2]·4CHCl3.
• Characterization using X-ray diffraction and variable-temperature magnetic susceptibility measurements.

Main Results:

• The compound [Fe(NCBH3)2(Py2ttz)2]·4CHCl3 exhibits a one-step complete spin crossover.
• An unusually wide hysteresis loop of 64 K was observed.
• A temperature-induced excited spin-state trapping effect was identified below 91 K.

Conclusions:

• The novel coordination polymer demonstrates significant potential for applications requiring bistable magnetic states.
• The observed wide hysteresis and spin-state trapping highlight unique SCO characteristics.