Humidity Sensitive Structural Dynamics and Solvatomagnetic Effects in a 3D Co(II)-Based Coordination Polymer.

Area of Science:

• Coordination Chemistry
• Materials Science
• Crystallography

Background:

• Chiral coordination polymers offer unique structural and functional properties.
• Understanding guest molecule interactions is crucial for designing responsive materials.

Purpose of the Study:

• To synthesize and characterize a chiral cobalt-based coordination polymer.
• To investigate its structural transformations, color changes, and magnetic properties in response to dehydration and humidity.

Main Methods:

• Single-crystal X-ray diffraction to monitor structural changes.
• Thermogravimetric analysis to study dehydration steps.
• Variable-temperature magnetic susceptibility measurements to probe magnetic behavior.

Main Results:

• A 3D hyperkagomé chiral cobalt coordination polymer, [Co3(pimda)2(H2O)5], was synthesized.
• Reversible single-crystal-to-single-crystal transformations occurred upon stepwise dehydration, forming [Co3(pimda)2(H2O)4] and [Co3(pimda)2(H2O)3].
• Observed color changes from pink to dark violet correlated with coordination geometry changes and a solvatomagnetic effect, transitioning from paramagnetic to weak ferromagnetism.

Conclusions:

• The cobalt coordination polymer demonstrates humidity-sensitive structural dynamics and tunable magnetic properties.
• The reversible dehydration and associated property changes highlight its potential for sensor applications.