Hexagonal hexaminophenyl benzene, tetragonal tetrakis(4-aminophenyl) ethane, and trigonal 1,3,5-tris(-formylphenyl)benzene were all joined together by imine linkages to yield a 2D porous covalent organic framework with unprecedented topology, termed COF-346. Unlike the 5 simple existing 2D topologies reported in COFs, COF-346 has 3 kinds of vertices and 2 kinds of edges and is constructed with linkers of 3 kinds of connectivity, and thus represents a higher degree of complexity in COF structures. The success in crystallizing COF-346 was based on precisely chosen geometry and metrics of the linkers and error correction offered by dynamic imine formation. We also report two additional related COFs: a crystalline, porous COF, termed COF-360 with a rare topology, as well as the first crystalline, porous COF with defected topology, termed COF-340.
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http://dx.doi.org/10.1021/jacs.9b05626 | DOI Listing |
Nanoscale
January 2025
Dept. of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA.
Identifying facile strategies for hierarchically structuring crystalline porous materials is critical for realizing diffusion length scales suitable for broad applications. Here, we elucidate synthesis-structure-function relations governing how room temperature catalytic conditions can be exploited to tune covalent organic framework (COF) growth and thereby access unique hierarchical morphologies without the need to introduce secondary templates or structure directing molecules. Specifically, we demonstrate how scandium triflate, an efficient catalyst involved in the synthesis of imine-based COFs, can be exploited as an effective growth modifier capable of selectively titrating terminal amines on 2D COF layers to facilitate anisotropic crystal growth.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemistry, Central Tribal University of Andhra Pradesh (CTUAP), Andhra Pradesh, 535003, India.
Hydrogen is a zero-emissive fuel and has immense potential to replace carbon-emitting fuels in the future. The development of efficient H sensors is essential for preventing hazardous situations and facilitating the widespread usage of hydrogen. Chemiresistors are popular gas sensors owing to their attractive properties such as fast response, miniaturization, simple integration with electronics and low cost.
View Article and Find Full Text PDFJ Sep Sci
January 2025
Electroanalytical Chemistry Research Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran.
Herein, an amino-functionalized covalent organic framework was synthesized and accommodated in the pores of porous hollow fiber. In this context, tetra (4-aminophenyl) porphyrin was synthesized for preparing the desired covalent organic framework as the extracting sorbent and employed for hollow fiber solid-phase microextraction of tebuconazole and propiconazole. With respect to the amino groups of the as-synthesized porphyrin-based covalent organic framework, the extracting device has the ability of establishing a hydrogen bond with the selected model analytes.
View Article and Find Full Text PDFSe Pu
February 2025
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
Solid-phase microextraction (SPME) is a fast and simple sample preparation technique that enables the enrichment of analytes, and it is used in combination with other detection techniques to provide accurate and sensitive analytical methods. SPME is widely used in environmental monitoring, food safety, life analysis, biomedicine, and other applications. The extractive coating is the core of the SPME technique, and the properties of the extractive coating greatly influence extraction selectivity and efficiency, as well as the enrichment effect.
View Article and Find Full Text PDFSe Pu
February 2025
College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing 102249, China.
Trace contaminants are toxic and their widespread presence in the environment potentially threatens human health. The levels of these pollutants are often difficult to determine directly using instruments owing to the complexities of environment matrices. Hence, pretreatment steps, such as sample purification and concentration, are key along with various processes that enhance the accuracy and sensitivity of the detection method.
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