Dipeptide Crystals as Excellent Permselective Materials: Sequential Exclusion of Argon, Nitrogen, and Oxygen

Abstract

Gas storage and gas separation using porous solids are important technologies that have attracted great attention because of their environmental and energetic applications. Highly porous materials, such as zeolites, silicate, and carbonbased materials, [1] have long-established specific applications. The key for new applications is the development of new frameworks. Advances in gas sorption capacities were achieved through the synthesis of materials such as metalorganic frameworks (MOFs), organic polymers, and microporous organic crystals.[2] Recently, crystals formed by dipeptides were tested as adsorbents [3] with significant results in hydrogen absorption and methane purification from carbon dioxide.

Dielectric and Sorption Responses of Hydrogen-Bonding Network of Amorphous C60(OH)12 and C60(OH)36

“…Although LMW organic compounds usually form the closest packing structures in solids with the absence of pores, two kinds of approaches to obtain the intrinsic and extrinsic pores within the crystalline materials have been used to design a reversible adsorption-desorption crystalline environment. [15][16][17] The former intrinsic pores of LMW organic compounds have been reported in calix [4]arene, [18][19][20][21][22][23] [4+6]cycloimine cages, [24][25][26][27][28][29] cucurbit [6]uril, [30][31] etc., [32][33][34][35][36][37][38][39] whose intrinsic nanopores can be utilized as adsorption-desorption environments for gaseous CO2, N2, H2, and CH4. In contrast, the extrinsic pores of LMW organic compounds of tris(o-phenylenedioxy)cyclotriphosphazene, [40][41] 3,3',4,4'-4 tetra(trimethylsilylethynyl)biphenyl, 42 triptycenetrisbenzimidazolone, 43 and others, [44][45][46][47][48][49][50][51] can be reversibly formed by removing the crystallization solvents.…”

Non-zeolitic properties of the dipeptide l-leucyl–l-leucine as a result of the specific nanostructure formation

“…33 As a result, such crystals exhibit zeolite-like properties, 34,35 and can selectively bind some gases 36,37 or separate mixtures of gases. 38,39 The weak interactions between the monomer units in oligopeptide crystals leads to a complex dependence of the oligopeptides sorption properties on the molecular size of the sorbate (i.e. guest).…”

Permeation of Light Gases through Hexagonal Ice

“…Crystalline materials, displaying unidirectional and single-sized pores are promising candidates for membrane synthesis. Metal-organic frameworks (MOFs) [ 3 , 4 ] and peptide supramolecular systems [ 5 , 6 , 7 , 8 ] are among the most promising crystal structures, due to the variety of pore sizes and high pore density. Nevertheless, the key challenge in the context of using crystalline materials is to scale up the fabrication techniques of either dense polycrystalline layers [ 3 ] or mixed matrix membranes, which embed the selective particles inside the polymeric matrix [ 4 ].…”