On the mechanism of imine elimination from Fischer tungsten carbene complexes

(Aminoferrocenyl)(ferrocenyl)carbene(pentacarbonyl)tungsten(0) (CO)5W=C(NHFc)Fc (W(CO)5(E-2)) is synthesized by nucleophilic substitution of the ethoxy group of (CO)5W=C(OEt)Fc (M(CO)5(1Et)) by ferrocenyl amide Fc-NH– (Fc = ferrocenyl). W(CO)5(E-2) thermally and photochemically eliminates bulky E-1,2-diferrocenylimine (E-3) via a formal 1,2-H shift from the N to the carbene C atom. Kinetic and mechanistic studies to the formation of imine E-3 are performed by NMR, IR and UV–vis spectroscopy and liquid injection field desorption ionization (LIFDI) mass spectrometry as well as by trapping experiments for low-coordinate tungsten complexes with triphenylphosphane. W(CO)5(E-2) decays thermally i…

Competitive NH···Ru/Fe Hydrogen Bonding in Ferrocenyl Ruthenocenyl Tosyl Hydrazone

A strong nonclassical NH···Fe intramolecular hydrogen bond (IHB) is present in the literature-known diferrocenyl tosyl hydrazone (1). Here, we confirm by NMR and IR spectroscopy as well as by XRD methods that an analogous NH···Ru IHB is present in the heavier homologue diruthenocenyl tosyl hydrazone (2). The NH···Ru IHB in 2 is stronger than the NH···Fe IHB in 1 by 6 kJ mol–1, as determined by IR spectroscopy. Further, we probed the E/Z isomer directing abilities of NH···M IHBs in the synthesis of the mixed metallocenyl compound ferrocenyl ruthenocenyl tosyl hydrazone (3). 3 is obtained as a mixture of the Z and E isomers (3a,b) with NH···Ru and NH···Fe IHBs, respectively. At 111 °C, 3a is …

Gold(ii) in redox-switchable gold(i) catalysis

Chemical communications 55(32), 4615 - 4618 (2019). doi:10.1039/C9CC00283A

Preparation, Properties, and Reactivity of (Aminoferrocenyl)(ferrocenyl)carbene(pentacarbonyl)chromium(0) as Bulky Isolobal Trimetallo-amide

Nucleophilic substitution of the ethoxy substituent in the Fischer carbene complex (ethoxy)(ferrocenyl)carbene(pentacarbonyl)chromium(0) (1) by ferrocenyl amide [Fc-NH]– [2-H]– gives the hetero trimetallic complex (aminoferrocenyl)(ferrocenyl)carbene (pentacarbonyl)chromium(0) (3). As the Cr(CO)5 fragment is isolobal to oxygen or sulfur 3 can be viewed as an isolobal metallo analogue to diferrocenylamide (Fc)(FcNH)C=O (4) and diferrocenylthioamide (Fc)(FcNH)C=S (5). The impact of the formal replacement of O/S by Cr(CO)5 in 3 is studied with respect to steric and electronic consequences as well as reactivity by spectroscopic, diffraction, electrochemical and theoretical methods.

Unexpected C–C bond formation with a ferrocenyl Fischer carbene complex

Diferrocenyl tosyl hydrazone with an ultrastrong NHFe hydrogen bond as double click switch.

The intramolecular NH⋯Fe hydrogen bond in diferrocenyl hydrazone 2 raises the barrier for intramolecular electron transfer in its mixed-valent cation 2+ and is only disrupted by double oxidation to 22+.

CCDC 1426094: Experimental Crystal Structure Determination

Related Article: Philipp Veit, Ephraim Prantl, Christoph Förster, Katja Heinze|2016|Organometallics|35|249|doi:10.1021/acs.organomet.5b00963

CCDC 1962440: Experimental Crystal Structure Determination

Related Article: Philipp Veit, Sebastian Seibert, Christoph Förster, Katja Heinze|2020|Z.Anorg.Allg.Chem.|646|940|doi:10.1002/zaac.201900350

CCDC 1426095: Experimental Crystal Structure Determination

Related Article: Philipp Veit, Ephraim Prantl, Christoph Förster, Katja Heinze|2016|Organometallics|35|249|doi:10.1021/acs.organomet.5b00963

CCDC 1962439: Experimental Crystal Structure Determination

Related Article: Philipp Veit, Sebastian Seibert, Christoph Förster, Katja Heinze|2020|Z.Anorg.Allg.Chem.|646|940|doi:10.1002/zaac.201900350

CCDC 1031559: Experimental Crystal Structure Determination

Related Article: Christoph Förster, Philipp Veit, Vadim Ksenofontov, Katja Heinze|2015|Chem.Commun.|51|1514|doi:10.1039/C4CC08868A

CCDC 1409670: Experimental Crystal Structure Determination

Related Article: Philipp Veit, Christoph Förster, Sebastian Seibert and Katja Heinze|2015|Z.Anorg.Allg.Chem.|641|2083|doi:10.1002/zaac.201500562