Structural assembly from phosphate to germanophosphate by applying germanate as a binder

Area of Science:

• Inorganic Chemistry
• Materials Science
• Crystal Engineering

Background:

• Phosphate-based materials are crucial in various applications.
• Germanate compounds offer unique structural possibilities.
• Controlling framework assembly is key for designing functional porous materials.

Purpose of the Study:

• To synthesize novel germanophosphate porous compounds.
• To investigate the structural assembly using germanate as a binder.
• To explore the tunability of the framework based on transition metal properties.

Main Methods:

• Hydrothermal synthesis of germanophosphate compounds.
• Single-crystal X-ray diffraction for structural determination.
• Characterization of porous framework and channel systems.

Main Results:

• Two isotypic porous compounds, K3[M(II)4(HPO4)2][Ge2O(OH)(PO4)4]·xH2O (M(II) = Fe, Cd), were successfully synthesized.
• A 3D open-framework structure was formed, incorporating transition-metal phosphate layers and germanate chains.
• The framework exhibits 1D 12-ring channels occupied by K+ ions and water molecules.
• The Jahn–Teller effect of transition metals influences the curvature of layers and channel window shape.

Conclusions:

• Germanate serves as an effective binder for constructing germanophosphate frameworks.
• The synthesized compounds exhibit tunable structural features based on transition metal choice.
• The discovered materials possess potential for applications in areas requiring porous structures with specific channel characteristics.