Morphological Evolution of Two-Dimensional Porous Hexagonal Trimesic Acid Framework

Abstract

For the first time a hexagonal single crystal structure (Form II) of trimesic acid (TMA) was isolated by dissolving the interpenetrated Form I of TMA in THF. To the best of our knowledge, this is the smallest building block which selfassembles to a 2D hydrogen bonded framework structure. A detailed time dependent FESEM study established a strong correlation between molecular level structure with morphology of TMA. The external morphology of the Form II (hexagonal) illustrates layered hexagonal structure while an inside-out Ostwald ripening is responsible for hexagonal hollow tube formation. These hollow tubes are used for Rhodamine B dye adsorption study, which shows uptake of 82%, much more significant than Form I (interpenetrated) (39%).

Benzothiazole-Linked Metal-Free Covalent Organic Framework Nanostructures for Visible-Light-Driven Photocatalytic Conversion of Phenylboronic Acids to Phenols

“…Field-emission scanning electron microscopy (FE-SEM) (Figure 3g,h) analysis of both the COFs demonstrates rod-like morphology interconnected with each other to develop a dense cluster island. 26 Furthermore, transmission electron microscopy (TEM) (Figure 3i,j) images also established a similar rod-like morphology, having an average rod diameter of 10 ± 5 nm, and confirmed the ordered porosity in the framework for both the as-synthesized COFs. Additionally, corresponding elemental mapping analysis of the selected specific area (Figure 3k,l) of the respective TEM images clearly revealed homogeneous distribution of C (green), N (yellow), and S (blue) at nearly the same locations, in accordance with the energy-dispersive X-ray spectroscopy (EDX) (Figure S6, Supporting Information) analysis.…”

“…Field-emission scanning electron microscopy (FE-SEM) (Figure g,h) analysis of both the COFs demonstrates rod-like morphology interconnected with each other to develop a dense cluster island . Furthermore, transmission electron microscopy (TEM) (Figure i,j) images also established a similar rod-like morphology, having an average rod diameter of 10 ± 5 nm, and confirmed the ordered porosity in the framework for both the as-synthesized COFs.…”

“…Notably, the absorption band edge of BTZ-TPA-COF at 458 nm red-shifted by an extensive range of 58 nm over BTZ-BCA-COF. The shift in the peak position can be associated with the presence of more electron-donating triphenylamine (TPA) moieties in the core framework of BTZ-TPA-COF compared with BTZ-BCA-COF. , Moreover, the shoulder peak at 570 and 538 nm for BTZ-TPA-COF and BTZ-BCA-COF, respectively, could be related to the intramolecular charge transfer (CT) due to extended π-conjugation characters throughout the conjugated polymeric network . According to the Kubelka–Munk equation, we also calculated the corresponding optical band gaps from Tauc plots for both BTZ-TPA-COF (2.14 eV) and BTZ-BCA-COF (2.36 eV) materials.…”

“…Photophysical Properties of Benzothiazole-Linked COFs. The electronic structure and photophysical properties of BTZ-TPA-COF and BTZ-BCA-COF were analyzed through UV−vis diffuse reflectance spectroscopy (UV−vis DRS) and 26,27 Moreover, the shoulder peak at 570 and 538 nm for BTZ-TPA-COF and BTZ-BCA-COF, respectively, could be related to the intramolecular charge transfer (CT) due to extended πconjugation characters throughout the conjugated polymeric network. 28 According to the Kubelka−Munk equation, we also calculated the corresponding optical band gaps from Tauc plots for both BTZ-TPA-COF (2.14 eV) and BTZ-BCA-COF (2.36 eV) materials.…”

Hidden Solvates and Transient Forms of Trimesic Acid

“…Trimesic acid is a common acid that is used in crystal engineering studies. The ability to form strong intermolecular interactions through the use of its three carboxylic acid groups gives scientists a great tool to work with for both organic and metal organic framework studies [1][2][3][4][5]. To date there are 148 entries for "organic" structures in the Cambridge Structural Database [6] for TMA in its neutral form.…”