Methane, carbon dioxide and hydrogen storage in nanoporous dipeptide-based materials

Abstract

Dipeptide crystals containing nanochannels of various sizes show remarkable and selective absorption of methane, carbon dioxide and hydrogen.

Porous organic molecular solids by dynamic covalent scrambling

“…Unlike porous molecular crystals [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] , these amorphous solids comprise a distribution of molecular species, which can be controlled by the diamine feed ratio (Fig. 3a).…”

“…There has been less focus here in comparison with the preparation of ordered porous solids using crystal engineering [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] . Polymers of intrinsic microporosity (PIMs), for example, form amorphous microporous solids-that is, amorphous solids with pore dimensions smaller than 2 nm-as a result of their rigid and contorted chain structures 30,31 .…”

“…Metal organic polyhedra 25 and heme-like coordination crystals 26 also exhibit intrinsic porosity of this type. Other systems have 'extrinsic' porosity [15][16][17]19 and the pore structure arises purely from the molecular packing. In these cases, porosity may not be obvious from inspection of the isolated molecular structure 24 .…”

“…Calixarenes, in particular, can exhibit 'porosity without pores' 10,11 : that is, the solid materials can adsorb guests by cooperative diffusion, despite having isolated voids rather than interconnected pore structures. Permanent, interconnected porosity in discrete organic molecules with low molar mass is rarer 11 and is typically confined to certain ordered molecular crystals [12][13][14][15][16][17][18][19][20][21][22][23][24] . Examples include modified calixarenes [12][13][14] , 3,3′,4,4′-tetra(trimethylsily lethynyl)biphenyl 15 , tris-o-phenylenedioxycyclotriphosphazene 16 , 4-hydroxyphenyl-2,3-4-trimethylchroman 17 , cucurbit [6]uril 18 , some dipeptides 19 , diyne macrocycles 20 and imine-linked porous organic cages 21,22 .…”

Hydrophobic dipeptide crystals: a promising Ag-free class of ultramicroporous materials showing argon/oxygen adsorption selectivity

“…Samples of dipeptides VI, IA, IV and VV were purchased from Bachem. Samples are received as a crystalline white powder 9 , which were regenerated overnight, under vacuum (< 1 mbar), at 70 ºC, before being used in the adsorption experiments. The adsorption isotherms were determined using the volumetric method.…”