Ewald Lücke

Cycloaddition Reactions with Metallated Diphosphenes

Abstract Several types of cycloaddition reactions performed with metal-functionalized diphosphenes are discussed.

Übergangsmetallkomplexe instabiler Ylide, X [1] Chemische und elektrochemische Untersuchungen zu den Redox-Eigenschaften cyclischer Tetracarbonylchrom-Ylidchelatkomplexe / Transition Metal Complexes of Unstable Ylides, X [1] Chemical and Electrochemical Investigations of the Redox Properties of Cyclic Tetracarbonylchromium-Ylide-Chelate-Complexes

Abstract Treatment of the ylide chelate complexes (CO)4 (1) with (C5H5)2Fe+PF6- leads to the organometallic radical cations 2. The oxidation process of 1 is also checked electrochemically by means of cyclovoltammetry, which exhibits a reversibel one electron oxidation between -0.1 and +0.3 V vs. SCE. These potentials are more negative than in any other complex of the general type Cr(CO)4L2 (L e.g. = PR3, CNR).

Übergangsmetallkomplexe instabiler Ylide, IX [1] Zur Reaktivität von Pentacarbonyl(dimethyloxosulfoniomethanid)chrom(0) gegenüber Organoelementmethyldiphenylphosphanen RnECH2PPh2 (ERn = Ph2Sb, MeS, PhS, PhSe) und (RnE)2CH2 (RnE = Ph2Sb, MeS)

Abstract Treatment of the sulfur ylide complex (CO)5Cr[CH2S(O)Me2] (1) with the bifunctional phosphines Ph2PCH2ERn (ERn = SMe, SPh, SePh) lead to pentacarbonylchromium phosphorus ylide complexes (CO)5CrCH2PPh2CH2ERn. Only the S-methyl derivate could be converted to the metallocycle (CO)4[xxx] (ERn = SMe) by UV-irridiation. The ylide chelate complex (CO)4[xxx]Ph2 is formed directly by the thermal reaction of Ph2PCH2SbPh2 with 1. N o ylide complexes result from the reaction of 1 with (Ph2Sb)2CH2 and (MeS)2CH2. The only products identified were (CO)5Cr[Ph2SbCH2SbPh2] and [(CO)5CrS(Me) - ]2CH2, respectively.