Modulating the reactivity of phosphanylidenephosphoranes towards water with Lewis acids. Issue 30 (29th June 2022)

• Record Type: Journal Article
• Authors: Dankert, Fabian; Fischer, Malte; Hering-Junghans, Christian
• Is Part Of: Dalton transactions. Volume 51:Issue 30(2022)
• Page Start: 11267
• Page End: 11276
• Publication Date: 2022-06-29
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt01575g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Prone to manipulations: Phospha-Wittig reagents react with water to give primary phosphine oxides, which form O-coordinated Lewis acid-base adducts. Adding the Lewis acid first and water in a second step afforded protio-phosphino-phosphonium cations. Abstract : Phosphanylidenephosphoranes of the type R–P(PR′3 ), also known as phospha-Wittig reagents, can be utilized in a variety of bond activation reactions exploiting their phosphinidenoid reactivity. Herein, we thoroughly show that a facile PMe3 for H2 O exchange gives access to various primary phosphine oxides of the general formula RP(H)2 O (R = Mes*, Mes Ter, Dip Ter) and the molecular structure of Dip TerP(O)H2 was determined. However, phosphanylidenephosphoranes are described to be highly nucleophilic as well. We show that the attachment of main group Lewis acids such as GaCl3 and GaI3 to R–P(PMe3 ) yielded the highly sensitive, yet stable coordination compounds [(RPGaX3 )PMe3 ] (R = Mes*, Dip Ter) or [(RPPMe3 )2 GaCl2 ]GaCl4 (R = Mes Ter). In contrast to the free phosphanylidenephosphoranes, these species reacted differently with H2 O, which was demonstrated for [(Mes*PPMe3 )GaI3 ]. Here the formation of the phosphino-phosphonium cation [Mes*P(H)PMe3 ] + and different anions was observed with combined NMR spectroscopic and SC-XRD (SC-XRD = single crystal X-ray diffraction analysis) studies. This work demonstrates that the ambiphilic character of phosphanylidenephosphoranes can be utilized to manipulate the reactivity of R–P(PMe3 ) towards water, giving primary phosphine oxides, whereas the Lewis acid adducts [(RPGaX3 )PMe3 ] gave phosphino-phosphonium species.