A Cubic 3D Covalent Organic Framework with nbo Topology

Abstract

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.

Electrochemical (Bio)Sensors Based on Covalent Organic Frameworks (COFs)

“…In this way, as depicted in Figure 1A, a linear monomer could generate hexagonal networks by cyclotrimerization (for example boroxine formation) or produce square COFs if it is combined with a C 4 linker. Following the pioneering work of Yaghi and the co-workers of Yaghi [9], several structural motifs have been described, including hexagonal [10,11], kagome [12][13][14] or square [15,16] two-dimensional networks (2D-COFs), and diamonoid [17,18], Cubic [19], or PtS [20] three-dimensional architectures (3D-COFs). It is worth pointing out that the dimensionality of the COF network is also determined by the linkers employed in the polymerization.…”

Three‐Dimensional Crystalline Covalent Triazine Frameworks via a Polycondensation Approach

“…Up to now, most efforts in this attractive area have been devoted to 2D COFs, 3D COFs have been studied much less, and there are still lots of problems, e.g ., crystallization problems, complicated structural determination, very few network topologies and limited building blocks, which block the exploration of 3D COFs [3] . Since the first 3D COF announced in 2007 by Yaghi and co‐workers, [4] only limited 3D COFs topologies have been successfully fabricated based on polyhedron‐shaped building blocks, including tetrahedral ( T d ) units based dia , [5] ctn , [6] bor , [7] pts , [8] ljh , [9] lon , [10] rra , [11] trigonal prism ( D 3 h ) units based stp , [12] ceq , [13] acs , [14] triangular ( D 3 ) unit based srs , [15] tbo , [16] ffc , [17] triangular antiprism ( D 3 d ) based pcu , [18] octahedral ( O h ) units based soc , [19] planar square ( D 4 ) units based nbo , [20] fjh [21] and cubic ( O h ) units based bcu [22] . In spite of these problems, their unique characteristics ( e.g ., large void space, large surface areas, hierarchical nanopores, low densities and abundant open active sites [23] ) make them ideal candidates for further applications, especially for excellent gas uptake, size‐selective catalysis and chromatographic separation [6, 23a, 24] …”

Morphology induced enhanced photoconductivity of a phthalocyanine-based benzimidazole linked two-dimensional conjugated covalent organic polymer

“…Most of the current strategies to obtain Pc-based polymers in the literature are mainly based on dynamic covalent chemistry reactions such as boronic acid condensation, and boronate ester formation with octa-hydroxy Pc. 14,17,22,26,[38][39][40][41][42][43] These polymers are not conjugated yet and possess moderate conductivity due to p-stacking induced conduction paths. Lately conjugated and columnar stacked 2D Pc-COFs based on imine formation were reported and proved to exhibit high intrinsic conductivity.…”