From Discrete Complexes to Metal-Organic Layered Materials: Remarkable Hydrogen Bonding Frameworks

Area of Science:

• Coordination Chemistry
• Materials Science
• Inorganic Chemistry

Background:

• Metal-organic coordination complexes offer tunable properties based on metal centers and organic ligands.
• Alkaline-earth metals (Mg, Ca, Ba) are less explored in coordination chemistry compared to transition metals.
• 5-aminoisophthalate (aip^2-) is a versatile ligand capable of forming diverse network structures.

Purpose of the Study:

• To synthesize and characterize novel metal-organic coordination complexes using alkaline-earth metals and 5-aminoisophthalate.
• To investigate the structural diversity and dimensionality of the resulting coordination materials.
• To evaluate the thermal stability of the synthesized complexes.

Main Methods:

• Solvothermal synthesis of metal-organic coordination complexes.
• Single-crystal X-ray diffraction for structural determination.
• Thermogravimetric analysis (TGA) for thermal stability assessment.

Main Results:

• A series of complexes with Mg(II), Ca(II), and Ba(II) centers and the 5-aminoisophthalate ligand were successfully synthesized.
• Structural diversity was observed, ranging from discrete 0D complexes to 1D chains and 2D layers.
• The hydrogen bonding networks within the structures were analyzed.
• Most complexes exhibited significant thermal stability, remaining intact up to 450 °C.

Conclusions:

• The combination of alkaline-earth metals and 5-aminoisophthalate yields a rich variety of coordination architectures.
• The dimensionality of the metal-organic frameworks can be controlled by the choice of metal ion and reaction conditions.
• The synthesized materials possess excellent thermal stability, suggesting potential applications in high-temperature environments.