An Azine-Linked Covalent Organic Framework

Abstract

Condensation of hydrazine with 1,3,6,8-tetrakis(4-formylphenyl)pyrene under solvothermal conditions yields highly crystalline two-dimensional covalent organic frameworks. The pyrene units occupy the vertices and the diazabutadiene (-C═N-N═C-) linkers locate the edges of rohmbic-shaped polygon sheets, which further stack in an AA-stacking mode to constitute periodically ordered pyrene columns and one-dimensional microporous channels. The azine-linked frameworks feature permanent porosity with high surface area and exhibit outstanding chemical stability. By virtue of the pyrene columnar ordering, the azine-linked frameworks are highly luminescent, whereas the azine units serve as open docking sites for hydrogen-bonding interactions. These synergestic functions of the vertices and edge units endow the azine-linked pyrene frameworks with extremely high sensitivity and selectivity in chemosensing, for example, the selective detection of 2,4,6-trinitrophenol explosive. We anticipate that the extension of the present azine-linked strategy would not only increase the structural diversity but also expand the scope of functions based on this highly stable class of covalent organic frameworks.

Tunable Water and CO2 Sorption Properties in Isostructural Azine-Based Covalent Organic Frameworks through Polarity Engineering

“…19 A broad band above 3000 cm -1 indicates water within the pores, which has also been detected by means of 1 H ssNMR (ESI, Figures S14, S21-22). The lack of the aldehyde Fermi double resonance at 2872 and 2747 cm -1 suggests the absence of the starting material 1,3,5-triformylbenzene.…”

Self-templated chemically stable hollow spherical covalent organic framework

“…These materials showcase promising applications in the field of gas storage [2][3][4][5] , opto-electronics 6 , catalysis [7][8][9] and sensing 10 because of their crystalline and periodic structure with high surface area and thermal stability. COFs are usually synthesized as microcrystalline powders and their long-range growth is limited in the nano/micro domain due to the internal defects [11][12][13] .…”

Moving Beyond Boron: The Emergence of New Linkage Chemistries in Covalent Organic Frameworks

“…Azines join two aldehydes through the and open pores achieved by these frameworks were leveraged for methane storage 73 as well as the capture and detection of explosives. 74 Jiang and co-workers incorporated azine linkages into a pyrene-containing framework ( Figure 2). The azines serve as Lewis basic sites to bind guests, as demonstrated by the detection of trinitrophenol through its ability to quench the COF's fluorescence.…”