Novel zwitterionic complexes arising from the coordination of an ambiphilic phosphorus–aluminum ligand to gold

Abstract

Coordination of Mes2PC(=CHPh)AltBu2 to metal chlorides has been studied. Bridging P→M-Cl→Al coordinations were observed with Rh and Pd fragments, while chloride abstraction systematically occurred with gold. The resulting zwitterionic complexes have been fully characterized and analyzed by DFT calculations.

Activation of an Au−Cl Bond by a Pendent SbIII Lewis Acid: Impact on Structure and Catalytic Activity

“…Instead, when the structure is sufficiently flexible, the metal–boron interaction can cleave and participate in the activation of small molecules while also exposing a catalytically active metal center. The same general principle has been applied for the Lewis acid activation of different systems including gold catalysts such as complex C . This complex is obtained by reaction of the phosphine‐alane ligand L Al/P with (tht)AuCl resulting in chloride transfer to the aluminum center and formation of a zwitterionic structure .…”

“…The structure of this new complex revealed that the dichloroarylstibine moiety of L Cl had, as expected, activated the Au−Cl bond, forming a zwitterionic gold antimonate complex. This reactivity constitutes an unusual example of an intramolecular abstraction of an anionic ligand from a metal center by a proximal Lewis acid . Such species featuring trivalent antimony species as the Lewis acid are precedented by the work of Reid and co‐workers, who prepared Mn and Fe complexes in which an anion binds at the antimony center of a coordinated halostibine to form zwitterionic species .…”

“…Collectively,t hese resultss how that the Lewis acidity of the boron center is not necessarilyn eutralized by donation from the metal center.I nstead, when the structure is sufficiently flexible, the metal-boroni nteraction can cleave and participate in the activation of smallm oleculesw hilea lso exposingacatalyticallya ctive metal center. The same general principle has been applied for the Lewis acid activation of differents ystems [4] including gold catalysts such as complex C. [5] This complex is obtained by reactiono ft he phosphine-alane ligand L Al/P with (tht)AuCl resulting in chloride transfer to the aluminumc enter and formation of az witterionic structure. [5] This complex is an active carbophilicc atalyst and readily promotest he cyclization of propargylamides.…”

“…The same general principle has been applied for the Lewis acid activation of differents ystems [4] including gold catalysts such as complex C. [5] This complex is obtained by reactiono ft he phosphine-alane ligand L Al/P with (tht)AuCl resulting in chloride transfer to the aluminumc enter and formation of az witterionic structure. [5] This complex is an active carbophilicc atalyst and readily promotest he cyclization of propargylamides. The phenomenono f zwitterion formation has been observed for other ambiphilic ligandg old complexes containings trongly Lewis acidic group13compounds.…”

Dehydrochlorination of Carboxylic Acid Chlorides by an Aluminum/Phosphorus‐Based Frustrated Lewis Pair and the Formation of Ketene Adducts

“…The outstanding properties of these FLPs allowed the activation or complexation of various substrates such as carbon dioxide, [3][4][5] terminal alkynes, [3,6] alkenes, [7] hydrogen, [8] carbonyl compounds, [9] isocyanates, [5] hydrogen halides, [10] or transition metal complexes. [11] Their specific acceptor and donor capability was used for the unprecedented solubilization of alkali metal hydrides in hydride transfer reactions [12] and phase-transfer catal-of the C=O groups to the Lewis acidic aluminum and the Lewis basic phosphorus atoms (4 to 6). Five-membered AlC 2 PO heterocycles were formed, which had an exocyclic C=C double bond.…”