Isolated silver intermediate of gold precatalyst activation

• Verfasst von: Weber, Simone G. [VerfasserIn]
• Verfasst von: Rominger, Frank [VerfasserIn]
• Verfasst von: Straub, Bernd Franz [VerfasserIn]
• Titel: Isolated silver intermediate of gold precatalyst activation
• Verf.angabe: Simone G. Weber, Frank Rominger, Bernd F. Straub
• E-Jahr: 2012
• Jahr: 25 April 2012
• Umfang: 5 S.
• Fussnoten: Gesehen am 03.04.2019
• Titel Quelle: Enthalten in: European journal of inorganic chemistry
• Ort Quelle: Weinheim : Wiley-VCH, 1998
• Jahr Quelle: 2012
• Band/Heft Quelle: (2012), 17, Seite 2863-2867
• ISSN Quelle: 1099-0682
• DOI: doi:10.1002/ejic.201200327
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Aurophilic interactions
• Sach-SW: Carbene ligands
• Sach-SW: Gold
• Sach-SW: Silver
• K10plus-PPN: 1662763697

Abstract

The silver chloride and gold chloride complex of the extremely sterically shielding N-heterocyclic carbene ligand IPr** have been synthesized and characterized. Formally, eight methyl groups of IPr have been replaced by 4-tert-butylphenyl substituents, and two para-methyl groups have been added. The world record for the ligand's buried volume (55.4 % for IPr**AuCl, and 56.7 % for IPr**AgCl) has been determined by single-crystal X-ray analyses. Reaction of IPr**AuCl with AgSbF6 in toluene yields AgCl and a cationic gold complex with toluene coordination. The same reaction in 1,2-dichloroethane leads to precipitation of AgCl and an equilibrium of [IPr**Au]SbF6 and [IPr**AuClAg]SbF6. Single crystals of the latter were suitable for an X-ray structure analysis, which reveal an Au-Cl-Ag triangle with an almost undisturbed IPr**-Au-Cl fragment and the coordination of two IPr** arenes to a silver cation. The structural parameters emphasize the role of NHC-Au cations as highly electrophilic “soft protons”.