Modular assembly of porous organic cage crystals: isoreticular quasiracemates and ternary co-crystal

Abstract

a Small changes in molecular structure and crystallisation conditions can have a profound effect on the crystal packing of molecules. Increasing the system complexity-for example, by introducing multiple components-greatly increases the number of potential outcomes. Hence, the rational design of porous cocrystals with multiple components is challenging. Here, we report a family of isoreticular quasiracemate crystalline phases for porous organic cages, FT-RCC3-R·CCX-S (where X = 1, 2, or 4), that were prepared in a modular and predictable fashion. By using directional intermolecular interactions between cages, we were able to prepare a rare ternary co-crystal, (CC3-S 0.5 CC4-S 0.5 )·(CC13-S 0.5 CC3-S 0.25 CC4-S 0.25 ).

A Chiral Bis‐Naphthylated Tetrandrine Dibromide: Synthesis, Self‐Assembly into an Organic Framework Based On Nanosized Spherical Cages, and Inclusion Studies

“…Molecular crystals are usually maintained by stronger intermolecular interactions such as hydrogen bonds or electrostatic forces. [8][9][10][14][15][16][17][18][19][20][21][22][23][34][35][36][37][38] The methanol content in DNT-MeOH ( Figure S6, Supporting Information) was estimated from the number of diffuse electrons determined by the SQUEEZE routine [39] within the solvent accessible voids, after eliminating the contribution of the bromide anions (96 × 36 e). The determined electrons correspond to approx.…”

“…These compounds are characterized by applications for molecular sieving, hydrogen storage, iodine capture, optoelectronics, superconductors, organic magnets and organic photocatalysis. [18][19][20][21][22][23] Recently, Liu and co-workers have reported a macrocycle with a hydrophobic core and hydrophilic groups on the surface that folds through non-covalent interactions such as π···π contacts into a complex secondary and tertiary structure, resembling a protein. [24] There are two categories for crystalline frameworks having interconnected cavities or infinite channels.…”

Systematic synthesis of a 6-component organic-salt alloy of naftopidil, and pentanary, quaternary and ternary multicomponent crystals

“…Furthermore, this is the first report of six different molecular components for an organic-salt alloy of an active pharmaceutical ingredient solved and refined by singlecrystal X-ray diffraction. Binary, ternary and even quaternary cocrystals have been reported by several research groups during the past three decades (Reddy et al, 1994;Thakur et al, 2010;Sada et al, 2005;Hasell et al, 2012;Tothadi et al, 2017;Dabros et al, 2007;Allu et al, 2017). The bar was raised by Desiraju with the synthesis of 4-and 5-component molecular assemblies in 2016 (Mir et al, 2016;Dubey et al, 2016), and now a 6-component molecular solid (Paul et al, 2018) has been achieved by combining the design strategies of cocrystals and solid solution.…”

“…They upgraded the initial 4-component synthetic dead-end cocrystal to a 6-component solid solution by incorporating molecules of a similar shape/size. In addition to the challenge of synthetic design, geometric and chemical matching, and supramolecular assembly of multicomponent organic crystals with six components, there are crystal structure refinement difficulties caused by overlap of electrondensity maps of molecules having similar size/placement of functional groups, and sometimes disorder in the cocrystal (Tothadi & Desiraju, 2013;Thakur et al, 2010;Hasell et al, 2012;Tothadi et al, 2017). Chemical factors start to taper off for 4-component crystals because weaker interactions provide only limited enthalpic advantage to molecular assembly in the cocrystal (Mir et al, 2016;Dubey et al, 2016).…”

Porosity Switching in Polymorphic Porous Organic Cages with Exceptional Chemical Stability

“…Porous organic cages (POCs) are au nique class of porous material composed of discrete organic molecules with guestaccessible voids. [1] Theu nique feature of POCs,w hich sets them apart from other organic/inorganic framework materials,i st heir solution processability,w hich allows these molecules to combine in am odular way and generate porous co-crystals, [2] alloys, [3] and more recently,p orous liquids. [4] These POCs are held together by weak intermolecular interactions,w hich make them prone to structural transformation in response to an external stimulus.A s ar esult, porous molecular crystals could be more polymorphic than other crystalline porous frameworks,s uch as zeolites,c ovalent organic frameworks (COFs), and metalorganic frameworks (MOFs).…”