Combinatorics

Nanotechnology

Organic chemistry

Covalent bond

Topology (electrical circuits)

Powder diffraction

Mathematics

Porosity

Crystallography

Crystal structure

Rietveld refinement

Natural bond orbital

Transmission electron microscopy

Chemistry

Materials science

Molecule

Crystallinity

Journal of the American Chemical Society

The synthesis of three-dimensional (3D) covalent organic frameworks (COFs) requires high-connectivity polyhedral building blocks or the controlled alignment of building blocks. Here, we use the latter strategy to assemble square-planar cobalt(II) phthalocyanine (PcCo) units into the nbo topology by using tetrahedral spiroborate (SPB) linkages that were chosen to provide the necessary 90° dihedral angles between neighboring PcCo units. This yields a porous 3D COF, SPB-COF-DBA, with a noninterpenetrated nbo topology. SPB-COF-DBA shows high crystallinity and long-range order, with 11 resolved diffraction peaks in the experimental powder X-ray diffraction (PXRD) pattern. This well-ordered crystal lattice can also be imaged by using high-resolution transmission electron microscopy (HR-TEM). SPB-COF-DBA has cubic pores and exhibits permanent porosity with a Brunauer–Emmett–Teller (BET) surface area of 1726 m2 g–1.

A Cubic 3D Covalent Organic Framework with nbo Topology