2D corrugated magnesium carboxyphosphonate materials: topotactic transformations and interlayer "decoration" with...

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• 2D layered coordination polymers offer unique structural properties.
• Bis-phosphonomethylglycine (BPMGLY) is a versatile ligand for metal coordination.
• Understanding topotactic transformations is crucial for designing functional materials.

Purpose of the Study:

• To synthesize and characterize the 2D layered coordination polymer Mg(BPMGLY)(H2O)2.
• To investigate the topotactic transformations of this material upon thermal treatment and ammonia exposure.
• To analyze the structural and coordination changes during these transformations.

Main Methods:

• Single-crystal X-ray diffraction for structural characterization.
• Thermogravimetric analysis to study thermal stability.
• Infrared spectroscopy to monitor chemical changes.

Main Results:

• The synthesis of Mg(BPMGLY)(H2O)2 with a distorted octahedral Mg coordination was achieved.
• Topotactic dehydration to Mg(BPMGLY)(H2O) resulted in a trigonal bipyramidal Mg environment.
• Ammonia insertion into Mg(BPMGLY)(H2O) yielded Mg(BPMGLY)(H2O)(NH3) with a pseudo-octahedral Mg environment, preserving the 2D structure.

Conclusions:

• Mg(BPMGLY)(H2O)2 serves as a versatile precursor for topotactic transformations.
• The layered structure is robust and adaptable to changes in coordination and guest molecules.
• These transformations highlight the potential for designing responsive materials based on coordination polymers.