Methyl cyclopentadienyl

Iron, cyclopentadienyl[(dimethyl-aminomethyl)cyclopenta-dienyl]-, methiodide j, 40,31 (Iron, cyclopentadienyl[(hydroxy-methyl)cyclopentadienyl]- [,... 

Of course, the stereoselectivity (and hence the isospecificity) of the catalytic models strongly depends on the encumbrance of the jt-ligand, increasing along the following series 3-methyl-cyclopentadienyl (e.g., 3.7 kcal/mol for 10), indenyl (e.g., 4.9 kcal/mol for 13), 4,7-dimethyl-indenyl (e.g., 5.3 kcal/mol for 17), and tetrahydroindenyl (e.g., 5.9 kcal/mol for 18). This is in good qualitative agreement, for instance, with the percent of mmmm pentads evaluated for polypropylene samples obtained for different catalytic systems in strictly similar conditions by Resconi and co-workers.58... 

TMU 11, HMPA. Filled circles, Cp=,Co+/0 (Cp = pentamethylcyclopentadienyl) filled squares, Cp2 Co+/0 (Cpe= (carboxy-methyl)cyclopentadienyl) filled triangles, Cp2Co+/0 (Cp = cyclopentadienyl) open triangles, Cp2Fe+/0 open squares, (hydroxyl-methyl)ferrocenium/ferrocene [6a]. 

The absolute detection limit for manganese was 8-22pg for various organomanganese compounds including methyl cyclopentadienyl manganese tricarbonyl. 

In the case of propylene polymerisation with class III catalysts based on rac.-dimethylsilylenebis[l-(3-methylcyclopentadienyl)]zirconium dichloride [rac.-Me2Si(MeCp)2ZrCl2] (Table 3.1) or rac.-dimethylsilylenebis[l-(3-methyl-cyclopentadienyl)]hafnium dichloride [rac.-Me2Si(MeCp)2HfCl2] as a procatalyst, isoblock polypropylene is obtained [132]. 

The method is suitable for the determination of Mn, present as methyl-cyclopentadienyl manganese tricarbonyl, in gasoline in the range 0.5— 40/igml 1. The sample is reacted with bromine then diluted with MIBK and the standards prepared in a similar manner. This ensures an equal response from the Mn species in both sample and standard solutions. 

The first phenolic derivative of ferrocene to be reported, di(l-hy-droxy-3-methyl-cyclopentadienyl) iron, was prepared by the reaction between 3-methyl-2-cyclopentanone, sodamide, and ferrous chloride in liquid ammonia. This compound is remarkably unstable, being extremely sensitive to air. It is a yellow substance which sublimes at 130-140° at 0.1 mm pressure, and is readily soluble in methylene dichloride but insoluble in carbon tetrachloride and in n-heptane. In water saturated with nitrogen a yellow solution is produced which rapidly bec( nes blue-green on exposure to air. The compound forms a benzoate (mp 121-123.5°) which is stable in air. An analogous derivative of the dicyclo-pentadienyl cobalt (III) cation has also been obtained (6). 

The produced dibenzylsilyl(3-methyl-cyclopentadienyl)zirconium dichloride 1 exists in racemic and meso forms. Figure 1 shows the H-NMR spectra of zirconocene 1 with different molar ratios of the racemic and meso-diastereomers. 

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