Strapped calix[4]pyrroles: from syntheses to applications

Abstract

Supramolecular chemistry is a central topic in modern chemistry.

A photoswitchable strapped calix[4]pyrrole receptor: highly effective chloride binding and release

“…These bridged systems have been termed "strapped calix [4] pyrroles" and they are receiving rapidly increasing attention. 9,10 As their binding properties were found to largely depend on the nature and the length of the strap, we became interested in incorporating a molecular photoswitch to allow structure postmodification, As far as we know, strap modulation by light has not yet been explored in these receptors. Our photoswitch of choice was stiff-stilbene because of its high thermal stability and large geometrical change upon isomerization.…”

Molecular recognition of pyrazine N,N′-dioxide using aryl extended calix[4]pyrroles

“…Calix [4]pyrroles (C4Ps) are a class of easy-to-prepare nonaromatic macrocycles that have been extensively studied for their ability to stabilise complexes with anions and ion pairs, particularly in non-competitive solvents. [6][7][8][9][10] Although an ability to form complexes with simple uncharged solvents was noted early on, 11 much less effort has been devoted to the recognition of neutral guests using unfunctionalised C4Ps. § In 2009, however, Ballester et al made a seminal contribution to the eld by showing that water-soluble C4P derivatives could be used to bind effectively pyridine N-oxides (PNOs) in aqueous media.…”

Bicarbonate Recognition Features of a Naphthobipyrrole‐strapped Calix[4]pyrrole

“…[26][27][28][29][30] To design and construct an anion receptor possessing high selectivity and affinity for HCO 3 − , a calix [4]pyrrole could be utilized as an attractive scaffold not only because of its inherent preorganized threedimensional structure but also because of its meso and β-pyrrolic carbon atoms which can be functionalized with relative ease by appropriate groups. [31][32][33][34][35][36][37] Especially, the so-called strapped calix [4]pyrroles are appealing as anion receptors with efficiency. 33,34,37 Their anion selectivities and affinities can be tuned by modulating the size and rigidity of the strap unit linking two diagonal meso carbons and by introducing auxiliary anion binding motifs such as hydrogen bonding donors and acceptors into the strap unit.…”

“…[31][32][33][34][35][36][37] Especially, the so-called strapped calix [4]pyrroles are appealing as anion receptors with efficiency. 33,34,37 Their anion selectivities and affinities can be tuned by modulating the size and rigidity of the strap unit linking two diagonal meso carbons and by introducing auxiliary anion binding motifs such as hydrogen bonding donors and acceptors into the strap unit. In addition, the introduction of a strap into the calix [4]pyrrole framework gives rise to a cryptand-like three-dimensional cavity which encapsulates anions and prevents them from being solvated.…”