Phosphazenyl Phosphines: The Most Electron‐Rich Uncharged Phosphorus Brønsted and Lewis Bases. Issue 30 (24th June 2019)

• Record Type: Journal Article
• Authors: Ullrich, Sebastian; Kovačević, Borislav; Xie, Xiulan; Sundermeyer, Jörg
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 30(2019)
• Page Start: 10335
• Page End: 10339
• Publication Date: 2019-06-24
• Subjects: basicity -- phosphane ligands -- phosphanes -- phosphazenes -- superbases; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201903342
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: It was discovered that phosphazenyl phosphines (PAPs) can be stronger P‐superbases than the corresponding Schwesinger type phosphazene N‐superbases. A simple synthetic access to this class of PR3 derivatives including their homologization is described. XRD structures, proton affinities (PA), and gas‐phase basicities (GB) as well as calculated and experimental p K BH + values in THF are presented. In contrast to their N‐basic counterparts, PAPs are also privileged ligands in transition metal chemistry. In fact, they are currently the strongest uncharged P‐donors known, exceeding classical and more recently discovered ligands such as PtBu3 and imidazolin‐2‐ylidenaminophosphines (IAPs) with respect to their low Tolman electronic parameters (TEPs) and large cone angles. Abstract : New markers at the upper end of the THF basicity scale and in terms of P‐donor strength are provided by phosphazenyl phosphines. Experimental and theoretical data indicate their suitability as the strongest known electron‐donating ligands for application in transition metal complexes.