Rim-functionalized cryptophane-111 derivatives via heterocapping, and their xenon complexes

Abstract

Capping of cyclotriphenolene (3a) by the more available cyclotriguaiacylene (3c) or trisbromocyclotriphenolene (3b) gives the first rim-functionalized cryptophane-111 derivatives. Crystal structures of the xenon complexes reveal high cavity packing coefficients and unprecedentedly short Xe···C contacts.

Extreme Confinement of Xenon by Cryptophane‐111 in the Solid State

“…[1][2][3][4] Relatedly, there are as of yet no generally accepted waste forms for storage of 85 Kr, though sequestration in a stable solid form would be advantageous, as highlighted by recent efforts focusing on capture of gaseous iodine. [10][11][12][13][14][15] Pioneered by Collet and coworkers, cryptophanes are cage-like molecules comprised of two cyclotribenzylene cups that are connected so as to enforce lipophilic cavities of tunable volumes. [8] Concurrent with materials research aimed at rare gas inclusion are efforts toward optimizing xenon complexation in solution.…”

“…[6] To this end, the cryptophane-nmm family of molecular containers (Figure 1) are the most actively studied hosts, owing to their unprecedented xenon affinities. [11] Derivatives of 111 for possible sensing applications are forthcoming; [14,15] the first reported watersoluble derivative of 111 binds xenon with K a = 2.9(2) 10 4 L mol À1 (298 K) in D 2 O, as established by 129 Xe NMR spectroscopy. [10] The (AE)-cryptophane-222 (222) core structure has served as the platform for most cryptophane derivatives employed to date in sensing applications, with certain derivatives exhibiting room temperature xenon binding constants (K a ) approaching 10 5 in aqueous solutions.…”

“…[6] To this end, the cryptophane-nmm family of molecular containers (Figure 1) are the most actively studied hosts, owing to their unprecedented xenon affinities. [10][11][12][13][14][15] Pioneered by Collet and coworkers, cryptophanes are cage-like molecules comprised of two cyclotribenzylene cups that are connected so as to enforce lipophilic cavities of tunable volumes. [10] The (AE)-cryptophane-222 (222) core structure has served as the platform for most cryptophane derivatives employed to date in sensing applications, with certain derivatives exhibiting room temperature xenon binding constants (K a ) approaching 10 5 in aqueous solutions.…”

“…[13] The room temperature xenon binding constant of 111 in non-competitive (CDCl 2 ) 2 (K a % 10 4 L mol À1 ) is over twice that of 222 (K a % 3000 L mol À1 ). [11] Derivatives of 111 for possible sensing applications are forthcoming; [14,15] the first reported watersoluble derivative of 111 binds xenon with K a = 2.9(2) 10 4 L mol À1 (298 K) in D 2 O, as established by 129 Xe NMR spectroscopy. [14] Surprisingly, despite the high gas affinity of cryptophane hosts, and a figurative call-to-arms for the study of intrinsically porous cage-like molecular materials, [16] the materials properties of empty cryptophanes or gas-filled cryptophane clathrates have not been much studied, [17] particularly in the context of their potential for rare gas sorption/desorption or storage.…”

Microporosity of a Guanidinium Organodisulfonate Hydrogen‐Bonded Framework

“…Additionally,p orous molecular solids derived from shape-persistent building blocks can be among the most chemically and thermally stable porous materials;s ome are essentially incollapsible,a st heir most thermodynamically stable crystalline form is intrinsically porous. [15][16][17][18] Of the porous molecular solids family, p-HOFs are of particular interest as they are amenable to structural design. [19,20] Given the extraordinary propensity of GS compounds to form 2D and 3D frameworks that can be occupied by am yriad of guests,i ti sp erhaps surprising that conventional porosity in this class of materials has not yet been formally demonstrated, likely because the focus has been primarily on their inclusion behavior.T his is also remarkable given the recent demonstration of porosity in related alkyl ammonium sulfonates.…”