Josef Weichmann

Metallcarbonyl-synthesen: XIII. Eine mangan—mangan-dreifachbindung☆

Abstract Photolysis of the manganese half-sandwich complex (η 5 -C 5 Me 5 )Mn(CO) 3 ( 1 ) in tetrahydrofuran (THF) yields cleanly the solvent complex (η 5 -C 5 Me 5 )(Mn(CO) 2 THF ( 2 ). Compound 2 undergoes spontaneous elimination of carbon monoxide to give at ambient temperature in approx. 20 h, or upon removal of solvent in vacuo, the novel dinuclear derivative (η 5 -C 5 Me 5 ) 2 Mn 2 (μ-CO) 3 ( 3 ). Elemental analyses and infrared and mass as wel as the 1 H and 13 C NMR spectra unequivocally demonstrate this compound to adopt a triply carbonyl-bridged structure containing the first example of a manganesemanganese multiple bond.

Komplexchemie reaktiver organischer verbindungen ☆: XXXVII. Metallinduzierter abbau eines σ,π-koordinierten ketens in ein π-allyl/σ-aryl/π-olefin-system

Abstract Photolysis of diphenylketene in the presence of pentacarbonyliron yields the π-allyl/σ-acyl type compound [η3:η1-(C6H5)2CCO)Fe(CO)3 (III) the molecular structure of which has been established by means of X-ray diffraction techniques. Metal-centered carboncarbon bond breaking and bond making in III is evident from 13CO labelling and crossover experiments. The dinuclear compound IV, structurally characterized by the π-allyl/σ-aryl/π-olefin hydrocarbon ligand CH(C6H4)C6H5, is formed upon irreversible decarbonylation of the ketene precursor III.

Komplexchemie reaktiver organischer verbindungen : XXXIX. Synthese eines 1,3-dien-komplexes durch metallzentrierte ethylen-isomerisierung unter CC-kupplung

Abstract Metal-centered ethylene isomerization occurs under relatively mild conditions when the η 1 -acyl/η 3 -allyl type diphenylketeneiron complex [(C 6 H 5 ) 2 CCO]Fe(CO) 3 is treated with ethylene. The resulting, structurally characterized 1,3-diene complex formally results from replacement of an ethylidene building block (ex ethylene) for the carbonyl moiety of the heterocumulene ligand.