Porous organic cages

Abstract

Porous materials are important in a wide range of applications including molecular separations and catalysis. We demonstrate that covalently bonded organic cages can assemble into crystalline microporous materials. The porosity is prefabricated and intrinsic to the molecular cage structure, as opposed to being formed by non-covalent self-assembly of non-porous sub-units. The three-dimensional connectivity between the cage windows is controlled by varying the chemical functionality such that either non-porous or permanently porous assemblies can be produced. Surface areas and gas uptakes for the latter exceed comparable molecular solids. One of the cages can be converted by recrystallization to produce either porous or non-porous polymorphs with apparent Brunauer-Emmett-Teller surface areas of 550 and 23 m2 g(-1), respectively. These results suggest design principles for responsive porous organic solids and for the modular construction of extended materials from prefabricated molecular pores.

Porous covalent electron-rich organonitridic frameworks as highly selective sorbents for methane and carbon dioxide

“…The methane uptake capacities of these samples are still high at 298 K with the maximum uptake of 0.67 mmol g − 1 at a pressure of 1 bar observed for PECONF-4. This methane uptake (15 cc g − 1 ) is higher compared with the methane sorption (0.8 wt % or 11.1 cc g − 1 ) of microporous tris-o-phenylenedioxycyclotriphosphazene van der Waals crystals 34 reported by Sozzani et al 35 but somewhat smaller than those of covalent organic cages reported by Tozawa et al 36 However, the latter can only be made by an expensive synthesis procedure. The methane sorption capacities of PECONF-1, PECONF-2, and PECONF-3 are 0.53, 0.63, and 0.58 mmol g − 1 , respectively at 298 K ( Supplementary Fig.…”

Computational Screening of Porous Organic Molecules for Xenon/Krypton Separation

“…Examples of some of the porous organic molecules can be seen in Figure 2. 42 1,2-dipropylamine, 42 1,2-diaminocyclohexane, 42 1,2-diaminocyclohexane (reduced and tied), 43 1,2-diaminocyclopentane, 44 1,2-diphenylethylenediamine. 45 Next to the structures our CDB names are given.…”

Core–Shell Crystals of Porous Organic Cages

“…CC3 ‐ R (Figure 1 a, left) was synthesized from 1, 3, 5‐triformylbenzene (TFB) and (1 R , 2 R )‐(−)‐1,2‐diaminocyclohexane ( R , R ‐CHDA) 15a. In the CC3a crystal form CC3 ‐ R packs in a window‐to‐window fashion to create 3D diamondoid pores connected through the internal cage voids (Brunauer–Emmett–Teller surface area, SA BET , 409 m 2  g −1 ; Figure 1 c, left) 18. The opposite CC3 cage enantiomer can be formed using (1 S , 2 S )‐(−)‐1,2‐diaminocyclohexane ( S , S ‐CHDA).…”