Recent Advancements in Calix[4]pyrrole‐Based Anion‐Receptor Chemistry

Abstract

Calix[4]pyrroles and their congeners are conformationally flexible, nonplanar tetrapyrrolic macrocycles that can recognize anionic substrates. Although the mother calix[4]pyrrole was reported more than 100 years ago, anion recognition accompanied with conformational changes was first discovered in 1996. These compounds have shown preferential binding of halide anions such as fluoride and chloride as well as that of phosphate and carboxylate anions. Extensive efforts have been made to improve the affinity and selectivity. Continuous expansion of related research makes this easy‐to‐make macrocycle more promising. In this review, recent synthetic developments and the anion binding properties of newly developed calix[4]pyrroles are discussed and accomplishments to date are summarized. We hope that this review provides a seed for future developments in this area of chemistry.

Shaping a Porphyrinoid Frame by Heteroatoms Extrusion: Formation of an Expanded [22]Triphyrin(6.6.0)

“…With an array of four CÀHb onds, 2-H 2 2 + belongs to ar elatively narrow class of anion-binding receptors with CH groups,e specially rare among porphyrinoids. [57][58][59][60] The extremelyf lexible macrocycle 2 is also ag ood candidate to serve as ac arbaporphyrinoid ligand for transition-metal cations. Ar elated [18]triphyrin(6.1.1) (21-vacataporphyrin) proved to be an excellent ligand,f orming organometallic complexes with avarietyo ft ransition metals.…”

Synthetic Evolution of the Multifarene Cavity from Planar Predecessors

“…The synthetic procedures and characterizations ( 1 Ha nd 13 CNMR, 2D-COSY and 2D-NOESY,a nd HRMS) of the compounds studied herein are available in the Supporting Information. VT-NMR data and compound structures used for DFT calculations are all part of the Supporting Information.…”

“…As a field that is heavily dependent on architectural design, the science of cavitands could benefit from our ability to construct such molecules from flat precursors. The most common cavitands, including calixarenes, resorcinarenes, calixpyrroles, pillararenes, cucurbiturils, and cyclodextrins, are all homo‐cyclo‐oligomers of a single building block. Consequently, their binding properties, substitution patterns, functionalization, and solubility, reflect the characteristics of the monomeric unit .…”

Steroid-photosensitizer conjugates: Syntheses and applications

“…In contrast to porphyrins, they are not planar and display remarkable anion-binding properties [87]. They have attracted interest as novel receptors for anions and neutral substrates [88]. Steroidal calix [4]pyrroles can be prepared in excellent yield by the Lindsey method starting from commercially available cholic acid derivatives.…”