Calix[4]pyrroles bearing proximally meso–meso linking straps: synthesis and anion binding properties

Abstract

Calix[4]pyrroles bearing two proximally crossing straps on the same or the opposite sides have been synthesized for the first time. The doubly cis-strapped compound exhibited highly cooperative six-point hydrogen bonding interactions with the anion involving both pyrrolic N-Hs and Ar-Hs.

Recognition, Sensing, and Trapping of Bicarbonate Anions with a Dicationic meso-Bis(benzimidazolium) Calix[4]pyrrole

“…Structural modifications to the basic tetrapyrrolic core have been used extensively as a means of modulating the inherent substrate selectivities of calix [4]pyrroles. [32][33][34][35] In the context of this latter effort, we sought to prepare a dicationic system that might display relatively enhanced anion affinities. This led to the design of calix [4]pyrrole 3.…”

Octatosylaminophthalocyanine: A reusable chromogenic anion chemosensor

“…Ideally, chemosensors for anions should allow for an ability to selectively recognize and sense anionic analytes via color changes that can be followed readily by eye, through changes in absorption or fluorescence spectral features, or modulations in an electrochemical responses [10]. Recent publications in the area of anion sensing have exploited the anion binding properties of macrocycles, such as calix [4]pyrroles [11][12][13][14], porphyrins [15][16][17][18], N-confused porphyrins [19,20], saphyrins [21][22][23], porphyrazines [24], subphthalocyanines [25,26], as well as other anion-binding compounds [27]. Interestingly, however, in spite of being reported as gas sensors [28], to the best of our knowledge, phthalocyanines have never been successfully used as anion sensors.…”

Anion Responsive Molecular Switch Based on a Doubly Strapped Calix[4]pyrrole

“…These short contacts allow the molecules to pack regularly into pillars with a short interplanar distance (6.2 Å) between the mean planes defined by the four pyrrolic nitrogens. The previously investigated cis ‐ 2 [23] (NEHHUF) formed less regular twisted pillars and retained slightly longer distance between the adjacent calix[4]pyrroles (6.8 Å interplanar distance of pyrrolic nitrogens) while incorporating solvent molecules hydrogen bonded to the down‐pointing pyrrole NH groups.…”