C 4 Dissymmetric resorcinarene derivatives: synthesis, crystal structure and micelle formation

Abstract

The synthesis of a C 4 dissymmetric resorcinarene tetracarboxylic acid derivative and determination of its critical micelle concentration is reported. The tetrahydroxy derivative was prepared by reduction of the tetra-acid. The low-temperature single crystal X-ray structure of the methyl ester derivative of the tetra-acid is also reported. This crystallised with two independent molecules of similar boat (flattened cone) conformation within the asymmetric unit.

Correlating Solution‐ and Solid‐State Structures of Conformationally Flexible Resorcinarenes: Significance of a Sulfonyl Group in Intramolecular Self‐Inclusion

“…The boat conformation is defined by two resorcinol rings being almost vertically oriented and the two remaining ones horizontally aligned. Previously, self‐inclusion dimers of resorcinarene tetrapodands have been observed by us and others . Nevertheless, resorcinarene podands tend to display collapsed cavities in the solid state …”

“…Previously,s elf-inclusion dimers of resorcinarene tetrapodands have been observed by us [31,32] and others. [33][34][35][36] Nevertheless,r esorcinarene podands tend to display collapsed cavities in the solid state. [37][38][39][40][41][42][43][44][45] The crystal structures of conformationally flexible macrocycles lead to the question of how to correlate the solid-state structurew ith the conformation of the molecule in solution.…”

Methodologies for the Derivatization of Resorcin[4]arenes at the Upper Rim ortho‐Positions

“…Finally, the cavity of the molecule is non-polar in nature and surrounded by the polar wide rim, a feature that equips resorcin [4]arenes for micellar behavior. [20,21] Looking at these properties it is not surprising that these compounds have found their way into a number of applications such as molecular receptor systems, [22,23] photo resists, [24,25] selective membranes, molecular sensing, [26,27] drug delivery, [28,29] ion channel mimics, [30] metal ion extraction agents, [31,32] molecular switches, [33,34] stationary phases in GC and HPLC, [35][36][37][38] ligands for organometallic catalysts, [39][40][41] host-guest chemistry, [14,42] and starting materials in synthesis of supramolecular compounds. [43] Several relatives of these molecules have been developed and studied such as the closely related cavitands, [44] carcerands and hemicarcerands; [45] also pyrogallol [4]arenes, [46] catechol [4]arenes, [47] pillar [4]arenes, [48] pyridin [4]arenes; [49] calix [4]arenes, [50] and other structurally similar compounds.…”

“…They have 3‐dimensional bowl‐like structures capable of encapsulating guest molecules. Finally, the cavity of the molecule is non‐polar in nature and surrounded by the polar wide rim, a feature that equips resorcin[4]arenes for micellar behavior [20,21] . Looking at these properties it is not surprising that these compounds have found their way into a number of applications such as molecular receptor systems, [22,23] photo resists, [24,25] selective membranes, molecular sensing, [26,27] drug delivery, [28,29] ion channel mimics, [30] metal ion extraction agents, [31,32] molecular switches, [33,34] stationary phases in GC and HPLC, [35–38] ligands for organometallic catalysts, [39–41] host‐guest chemistry, [14,42] and starting materials in synthesis of supramolecular compounds [43] .…”