title: Isolation of a non-heteroatom-stabilized gold-carbene complex.
abstract: Gold-carbene complexes are essential intermediates in many gold-catalyzed organic-synthetic transformations. While gold-carbene complexes with direct, vinylogous, or phenylogous heteroatom substitution have been synthesized and characterized, the observation in the condensed phase of electronically non-stabilized gold-carbenes has so far remained elusive. The sterically extremely shielded, emerald-green complex [IPr**Au=CMes2](+)[NTf2](-) has now been synthesized, isolated, and fully characterized. Its absorption maximum at 642 nm, in contrast to 528 nm of the red-purple carbocation [Mes2CH](+), clearly demonstrates that gold is more than just a "soft proton".
authors: Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany) http://www.uni-heidelberg.de/fakultaeten/chemgeo/oci/akstraub.
authors: Matthias W
authors: MW
authors: Hussong
authors: Frank
authors: F
authors: Rominger
authors: Petra
authors: P
authors: Krämer
authors: Bernd F
authors: BF
authors: Straub
keywords: bond order; carbenes; gold; homogeneous catalysis; intermediates