In einem bisher unbekannten Reaktionstyp ergibt [η5‐CpFe(CO)2]2 mit Phosphor‐Yliden Ph3PCHR (R = H, Me, iPr) die cis‐ und trans‐Alkyliden‐Komplexe (1) bzw. (2) sowie wenig Organometall‐substituiertes Ylid (3). Analoge Mangan‐Komplexe reagieren mit Methylenphosphoran überraschenderweise unter ortho‐Acylierung einer der P‐Phenylgruppen.

containing by-product, for which we have proposed the structure 18,19-didehydrocobyrinic acid c-amide (3)I2I.Such a compound is of interest in its metal-free, non-amidated form as the connecting link between metal-free and cobalt-containing corrinoids in the biosynthesis of vitamin Bl2I2]. We have now unambiguously proved the structure of the hexamethyl ester of (3) as dicyano-18,19-didehydrocobyrinic acid hexamethyl ester c-amide (4).The absorption spectrum of (4) shows the typical a,o,ystructure of cobalt-containing corrinoids. The substantial bathochromic shift of the main absorption bands (369-396 nm, 545-590 nm, and 584-626 nm) compared to those of the heptamethyl ester of dicyanocobyrinic acid ("cobester") indicates a lengthening of the corrin chromophore.The presence of the same peripheral groups as in the hexamethyl ester of (2) follows from the 'H-NMR spectrum, which contains the signals of the protons of one amide group and of six methoxy-and eight angular methyl groups. An AB system (J=16.7 Hz) appears at 6=3.47/ 3.38 which is assigned to the methylene group of a [q5-CpFe(CO)z]s + Ph3P=CH

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1906. DOI:10.1002/anie.198219060

No abstract

Abstract In this paper we report two improved preparation methods for [(CH3)2N]6W2 (W≡W) (1), one starting from WCl4 (yield 51%), and a second one starting from W2C16(THF)4 (ca. 60% yield). We have studied the reactions of 1 with different nucleophiles, among them triphenylalkylidenphosphoranes (like Ph3P=CH2 and Ph3P=CHPh·LiCl; Ph = phenyl), sulfur and CS2 .1 reacts with S8 and CS2 in hexane to yield the two new compounds (Me2NCS2)2WS(S2) (4) and W(CS2H)(Me2NCS2)2 (5), both containing dithiocarbamato ligands formed by insertion of CS2 into the W-N bond. The two mononuclear compounds were characterized spectroscopically, in the case of 4 an X-ray diffraction structure analysis was performed. The reaction of 1 with Se and CS2 , leads to the compounds 4, (Me2NCS2)2W2S4 (6) and [(Me2N)2C]CS2 (7), which were also characterized spectroscopically. No Se-containing compounds could be isolated.4 crystallizes monoclinically, C52h-P21/n, with a = 648.6(3), b = 1346.7(6) and c = 1745.9(7) pm, β = 91.85(3)°, V = 1524x106 pm3 , Z = 4. The structure of the seven-coordinate tungsten compound is discussed and compared to complexes with similar ligands and geometry.