Cobaltocenylidene: A Mesoionic Metalloceno Carbene, Stabilized in a Gold(III) Complex. Issue 13 (5th February 2018)

• Record Type: Journal Article
• Authors: Vanicek, Stefan; Podewitz, Maren; Hassenrück, Christopher; Pittracher, Michael; Kopacka, Holger; Wurst, Klaus; Müller, Thomas; Liedl, Klaus R.; Winter, Rainer F.; Bildstein, Benno
• Is Part Of: Chemistry. Volume 24:Issue 13(2018)
• Page Start: 3165
• Page End: 3169
• Publication Date: 2018-02-05
• Subjects: cobalt -- density functional calculations -- gold -- mesoionic carbenes -- sandwich complexes; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201800147
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Oxidative addition of cobaltoceniumdiazonium bis(hexafluoridophosphate) with (pseudo)halide aurates gave gold(III) complexes containing zwitterionic cobaltoceniumide as a ligand. Its selenium derivative, cobaltoceniumselenolate, was obtained by an electrophilic aromatic substitution reaction of iodocobaltocenium iodide with Na2 Se. Spectroscopic and structural data in combination with DFT calculations showed that this cobaltocenylidene species is a mesoionic carbene quite different from common N‐heterocyclic carbenes. Its ligand properties (TEP, singlet‐triplet gap, nucleophilicity, π‐acidity, Brønsted basicity) are in part comparable to those of cyclic (amino)(alkyl/aryl)carbenes. Electrochemistry data showed that the mesoionic cobaltoceniumides are more electron‐rich than their parent ferrocenes. The reversible reduction of the tricyanido gold complex appears 50 mV negative of the cobaltocenium/cobaltocene couple, whereas that of the selenide derivative is shifted cathodically by 550 mV. Abstract : Sandwich time ! A neoteric organometallic carbene based on cobaltocenium is reported. Spectroscopic, structural, and DFT results were used to evaluate the general ligand properties of this first metalloceno carbene (see figure).