Two novel 3D borates: porous-layer and layer-pillar frameworks.

Area of Science:

• Inorganic Chemistry
• Materials Science
• Crystal Engineering

Background:

• Borates and aluminoborates are classes of compounds with diverse structural motifs and potential applications.
• The synthesis of novel crystalline materials with unique architectures is crucial for advancing materials science.
• Understanding the structure-property relationships in these materials can lead to new technological developments.

Purpose of the Study:

• To synthesize and characterize two new borate and aluminoborate compounds.
• To elucidate the crystal structures of the newly synthesized materials.
• To investigate the optical properties of the new compounds.

Main Methods:

• Solvothermal synthesis method was employed for the preparation of the new compounds.
• Single-crystal X-ray diffraction was used to determine the detailed crystal structures.
• UV-vis diffuse reflectance spectroscopy was utilized to study the optical properties.

Main Results:

• Two new compounds, NaK1.5[B{B5O9(OH)}{B5O8(OH)2}1/2] and Na3.5[Al{B3O6(OH)}{B5O10}1/2{BO(OH)}], were successfully synthesized.
• Structure 1 features a 3D porous layer constructed from oxoboron clusters and BO4 tetrahedra with 11-membered ring windows.
• Structure 2 presents a 3D pillar-layered aluminoborate with interconnected B-O layers and 1D tubular aluminoborate units.
• Both compounds exhibit wide band gaps (>5.7 eV) with cut-off edges below 190 nm.

Conclusions:

• The solvothermal method is effective for synthesizing complex borate and aluminoborate structures.
• The detailed structural analysis reveals novel 3D porous architectures in both compounds.
• The wide band gaps suggest potential applications in areas requiring UV absorption or high-energy photon interactions.