Effective Control of the Electron‐donating Ability of Phosphines by using Phosphazenyl and Phosphoniumylidyl Substituents. Issue 13 (23rd April 2020)

• Record Type: Journal Article
• Authors: Werra, Janina A.; Wünsche, Marius A.; Rathmann, Patrick; Mehlmann, Paul; Löwe, Pawel; Dielmann, Fabian
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 646:Issue 13(2020)
• Page Start: 794
• Page End: 799
• Publication Date: 2020-04-23
• Subjects: Ligand design -- Phosphines -- Gold -- Single substituent parameter -- Phosphazenyl -- Phosphoniumylidyl; Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.202000028
• Languages: English
• ISSNs: 0044-2313

Abstract

Abstract : Phosphoniumylidyl and phosphazenyl groups are effective substituents to increase the electron‐donating ability of tertiary phosphines. However, the influence of structural variations among those substituents on the electronic properties of the phosphines is little explored. Herein, we show that protonation of the ylidic carbon atom of phosphoniumylidyl phosphines increases the Tolman electronic parameter (TEP) by ΔTEP = 16.0–18.8 cm –1 . Furthermore, phosphazenyl phosphines were synthesized with isopropyl groups (NP{ i Pr}3 ) and tetramethylguanidino groups (NP{tmg}3 ) at the phosphonium center. Determination of their TEP values reveals a remarkable low substituent parameter of χ = –18.5 cm –1 for the NP(tmg)3 group. In addition, we prepared the corresponding gold(I) complexes and determined their solid‐state structures using single‐crystal X‐ray diffraction studies to analyze the steric profile of the new phosphine ligands. Abstract :