Series of open-framework aluminoborates containing [B5O10] clusters

Area of Science:

• Inorganic Chemistry
• Materials Science
• Solid-State Chemistry

Background:

• Open-framework aluminoborates (ABOs) are a class of materials with diverse structures and potential applications.
• Exploring new ABOs with unique structural motifs and functional properties is crucial for materials discovery.

Purpose of the Study:

• To synthesize and characterize novel open-framework aluminoborates.
• To investigate their structural features, including channel systems.
• To evaluate their optical and nonlinear optical (NLO) properties.

Main Methods:

• Solvothermal synthesis.
• Elemental analysis, IR, TGA, UV-vis spectroscopy.
• Powder and single-crystal X-ray diffraction (XRD).
• Fluorescence spectroscopy and NLO determination.

Main Results:

• Three new ABOs, Rb2AlB5O10·4H2O, [C5N2H16]AlB5O10, and [H2dap][(CH3)2NH]AlB5O10, were successfully synthesized.
• Two distinct structural types were identified, with two compounds being isostructural in acentric space groups (C2221 and P212121) featuring helical channels.
• The third compound crystallized in a centrosymmetric space group (Pbca) with a CrB4 topology and complex ring channels.
• All synthesized ABOs exhibited wide band gaps and promising nonlinear optical properties.

Conclusions:

• The successful synthesis of three new open-framework aluminoborates expands the library of known ABO structures.
• The diverse structural architectures, including intersecting helical and ring channels, highlight the versatility of ABO frameworks.
• The observed wide band gaps and good NLO properties suggest potential applications in semiconductor and nonlinear optical devices.