Oligothiophene-Bridged Conjugated Covalent Organic Frameworks

Abstract

Two-dimensional covalent organic frameworks (2D-COFs) are crystalline, porous materials comprising aligned columns of π-stacked building blocks. With a view toward the application of these materials in organic electronics and optoelectronics, the construction of oligothiophene-based COFs would be highly desirable. The realization of such materials, however, has remained a challenge, in particular with respect to laterally conjugated imine-linked COFs. We have developed a new building block design employing an asymmetric modification on an otherwise symmetric backbone that allows us to construct a series of highly crystalline quaterthiophene-derived COFs with tunable electronic properties. Studying the optical response of these materials, we have observed for the first time the formation of a charge transfer state between the COF subunits across the imine bond. We believe that our new building block design provides a general strategy for the construction of well-ordered COFs from various extended building blocks, thus greatly expanding the range of applicable molecules.

Fully Conjugated Two‐Dimensional sp2‐Carbon Covalent Organic Frameworks as Artificial Photosystem I with High Efficiency

“…[11][12][13][14] Covalent organic frameworks (COFs) take advantage of the structural selfhealing properties stemming from dynamic covalent bond formation. [15][16][17][18][19][20][21] This advancement has made it possible to synthesize well-defined 2D structures with diverse functionalities.A mong all synthetic strategies of COFs,t he most frequently used dynamic covalent-bond-formations trategies are the Schiff base condensation reaction and the boronate ester bond formation. Despite the fact that the extended pconjugation can propagate through the -N = C-double bonds in the Schiff base structure,t he imine-linkage displays relatively poor stability and weak electron delocalization.…”

Crystal structure of (E)-3-(pyren-1-yl)-1-(pyridin-4-yl)prop-2-en-1-one, C24H15NO

“…Pyrenes are considered to be excellent organic fluorophores and they are applied as environmental probes with distinct morphology and tunable emission in various micro environments due to their polarity dependent vibronic emission, high charge carrier mobility, fluorescence lifetime and chemical stability [3][4][5][6]. Up to now, numerous pyrene derivatives with good fluorescence properties have been reported.…”

Fully Conjugated Two‐Dimensional sp2‐Carbon Covalent Organic Frameworks as Artificial Photosystem I with High Efficiency

“…However, the delicate control over specific arrangements of functional units to obtain highly ordered 2D materials is still a great challenge . Covalent organic frameworks (COFs) take advantage of the structural self‐healing properties stemming from dynamic covalent bond formation . This advancement has made it possible to synthesize well‐defined 2D structures with diverse functionalities.…”