Calix(4)pyrroles as ligands

• Verfasst von: Ruppert, Heiko [VerfasserIn]
• Verfasst von: Sigmund, Lukas M. [VerfasserIn]
• Verfasst von: Greb, Lutz [VerfasserIn]
• Titel: Calix(4)pyrroles as ligands
• Titelzusatz: recent progress with a focus on the emerging p-block element chemistry
• Verf.angabe: Heiko Ruppert, Lukas M. Sigmund and Lutz Greb
• E-Jahr: 2021
• Jahr: 13 October 2021
• Umfang: 13 S.
• Fussnoten: Im Titel steht 4 in eckiger Klammer ; Gesehen am 05.10.2022
• Titel Quelle: Enthalten in: Chemical communications
• Ort Quelle: Cambridge : Soc., 1965
• Jahr Quelle: 2021
• Band/Heft Quelle: 57(2021), 89, Seite 11751-11763
• ISSN Quelle: 1364-548X
• DOI: doi:10.1039/D1CC05120B
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1818064243

Abstract

Calix[4]pyrroles are readily synthesized in one step from pyrroles and ketones. For several decades, these macrocycles have been exploited as powerful anion receptors or ligands for transition and rare-earth metals. In contrast, calix[4]pyrrolates as ligands for p-block elements were established only in 2018. The present feature article reviews these developments, together with the recent progress on s-, d-, and f-block element complexes of the calix[4]pyrroles. Particular focus is given on the calix[4]pyrrolato aluminate and the corresponding silane, both featuring square planar-coordinated p-block elements in their highest oxidation states. These unique “anti-van’t-Hoff-Le-Bel” structures introduce valuable characteristics into main-group element chemistry, such as agostic interactions or ligand-to-metal charge transfer absorptions. The most vital reactivities are highlighted, which rely on properties ranging from amphoterism, redox-activity, and a small HOMO-LUMO gap up to the ability to provide a platform for additional external stimuli. Overall, these developments underscore the beneficial impact of structural constraint of p-block elements and element-ligand cooperativity to enhance the functionality of the most abundant elements in their native oxidation states.