Activation of an Au-Cl Bond by a Pendent Sb-III Lewis Acid: Impact on Structure and Catalytic Activity

作者：Jones J Stuart; Gabbai Francois P

来源：Chemistry - A European Journal, 2017, 23(5): 1136-1144.

DOI：10.1002/chem.201604521

• antimony
• catalysis
• gold
• Lewis acid
• ligand

With the objective of identifying new coordination modes of ambiphilic ligands, we have investigated the bidentate Sb/P ligands (o-(Ph2P) C6H4)SbCl2 (L-Cl) and (o( Ph2P)C6H4) SbPh2 (L-Ph). Reaction of these ligands with (tht)AuCl affords the monoligated species (LAuCl)-Au-cl (1) and (LAuCl)-Au-Ph (2), respectively, in which the antimony centers are only weakly engaged with the coordinated gold atom. Treatment of 1 with PPh3 induces an intramolecular transfer of a chloride ligand from gold to antimony to form the zwitter-ionic species o-(Cl3Sb)C6H4(Ph2P)Au(PPh3) (3). Natural bond orbital (NBO) calculations show that the antimony and gold centers are involved in weak Sb -> Au and Au -> Sb interactions, the latter reflecting the Lewis acidity of the pendent antimony group. Finally, we demonstrate that the ability of the antimony center in 1 to abstract a gold-bound chloride in the presence of a Lewis basic substrate may be utilized to activate the gold center for the electrophilic cycloisomerization of propargylic amides.

• 出版日期2017-1