Engineering solid-state porosity of synthetic supercontainers via modification of exo-cavities

Abstract

Two new coordination supercontainers have been successfully isolated from the self-assembly reactions of the container precursor p-phenylsulfonylcalix [4]arene, Ni(II) or Co(II) ion, and diphenylmethane-4,4'-dicarboxylic acid. Crystal structure analysis revealed that these two coordination supercontainers possess a similar endo cavity and two deeper exo cavities compared to the related supercontainers based on p-tert-butylsulfonylcalix [4]arene . Gas and vapor adsorption studies indicated that the new compounds are permanently porous and show much better CO2/O2 and CO2/N2 selectivity and higher vapor adsorption than the tert-butyl analogues. Molecular containers possessing hollow space have received considerable attention in view of their promising applications in a wide array of areas, including stabilization of highly reactive species, transportation of small molecules, gas storage and separation, sensing, supramolecular catalysis and molecular recognition.[1-6] Because of the relatively robust and reversible nature of coordination bonding between metal and ligand, coordination-driven self-assembly affords an excellent means to construct elegant supramolecular architectures containing hollow structures.[7-13] We have focused on the construction of coordination containers featuring unique multiple binding cavities within a single host structure by incorporating sulfonylcalix[4]arenes[14] as container precursors. A new family of coordination containers, namely, metal-organic supercontainers (MOSCs), have been obtained from the assembly of sulfonylcalix[4]arenes, divalent metal ions and carboxylate linkers of trigonal, linear, angular-planar, or angularnonplanar shape.[15-18] The lower rim of sulfonylcalix[4]arenes was bridged by the carboxylate linkers via both binding to the same metal ions to generate four prototypes of MOSCs that possess a characteristic multi-pore architecture, i.e., an endo cavity and multiple exo cavities. Related

Porous Zr6L3 Metallocage with Synergetic Binding Centers for CO2

“…For linear connection of trinuclear Zr clusters, banana-shaped linkers lead to the best assembly. This type of assembly featuring a linear connection between the metal cluster and organic component has been utilized in metal–organic supercontainers with interesting properties. − The molecular height and inner pore size of the self-assembled metallocage are approximately 1.8 and 0.63 nm, respectively. Hydrogen bonds between μ 2 -OH and Cl – (OH···Cl···HO) connect the cages and balance framework charge (Figure S1).…”

“…31−3233 The main applications for these compounds have been host−guest binding, 30,31 chemical sensing, 31,32 supramolecular catalysis, 32 and porosity. 33 We envision that these metallocages can be new candidate materials for CO 2 adsorption, capable of sharing the advantages of porous organic cages and MOFs. The remaining issues have been: (1) strengthening intercage interactions for permanent porosity and ( 2 1), which was crystallized in monoclinic space group P2 1 (Table S1), collected at the Pohang Accelerator Laboratory in Korea.…”

“…Another type of cage compounds, studied extensively but seldom used for CO 2 adsorption, are coordination-driven metallocages, which exhibit diverse ligand symmetries and metal connectivities . Some well-known examples are M 6 L 3 and M 8 L 4 metallocages − with trigonal and tetragonal bipyramidal geometries, respectively, as exemplified by the works from Severin , and Wang. − The main applications for these compounds have been host–guest binding, , chemical sensing, , supramolecular catalysis, and porosity . We envision that these metallocages can be new candidate materials for CO 2 adsorption, capable of sharing the advantages of porous organic cages and MOFs.…”

Permanently Microporous Metal–Organic Polyhedra

“…Since the first report of these thiacalixarene and sulfonylcalixarene cages, a large number of additional structures have been reported. − They have varied in size, shape, and overall metal:ligand ratios and have displayed surface areas that range from 26 to 1239 m 2 /g. Although most of these MOPs have surface areas well below 1000 m 2 /g, they have shown utility for gas separation applications.…”

Cooperative Binding and Stepwise Encapsulation of Drug Molecules by Sulfonylcalixarene-Based Metal-Organic Supercontainers

“…Over the years, considerable attention has been paid to coordination containers possessing a well-defined hollow space that is suitable for guest encapsulation and allows them to be widely applied in a number of applications, such as guest recognition [10][11][12], drug delivery [13,14], and supramolecular catalysis [15,16]. A new class of coordination containers, namely, metal-organic supercontainers (MOSCs), incorporating macrocyclic container thia-or sulfonyl-calix [4]arenes as precursors [17], have been well demonstrated by us and others [18][19][20][21][22][23][24][25][26][27][28]. The MOSCs are demonstrated to possess several unique features such as their modular synthesis, robust architecture, and multiple binding domains (containing both endo and exo cavities).…”