Related Experiment Video
Updated: Jul 12, 2026

Microfluidic-based Synthesis of Covalent Organic Frameworks (COFs): A Tool for Continuous Production of COF Fibers and Direct Printing on a Surface
Published on: July 10, 2017
Crystalline 3D covalent organic frameworks with nbo topology
Soshi Hirota1,2, Haruki Sugiyama1,2,3, Nao Hirata1
1Institute for Molecular Science, Myodaiji, Okazaki, 444-8787, Japan.
None:
Three-dimensional covalent organic frameworks (3D COFs) are promising crystalline porous materials, but the elucidation of their structure remains challenging, particularly for those featuring spiroborate linkages. Herein, we report the synthesis of a 3D crystalline COF with nbo topology, constructed from a rigid square-planar monomer, tetracyclopentatetraphenylene (TCTP), and spiroborate linkages. Theoretical calculations revealed that the TCTP core has higher rigidity than phthalocyanine, effectively suppressing structural fluctuations during framework formation. The structure of the resulting TCTP-COF was successfully determined using microcrystal electron diffraction (MicroED), revealing a noninterpenetrated cubic framework. TCTP-COF exhibits high crystallinity, thermal stability up to 320°C, and permanent porosity with a Brunauer-Emmett-Teller surface area of 1360 square meters per gram. This work represents the structural determination of a spiroborate-linked 3D crystalline COF using MicroED methods, providing a design strategy for expanding the chemical space of highly ordered 3D COF architectures.
Related Concept Videos
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Network Covalent Solids
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
Crystallographic Point Groups
Determination of Crystal Structures
Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous overlap of p...

