Carbonyl(pentaphosphacyclopentadienyl)-Transition Metal Complexes (M Cr, Mo, W, Mn) through Directed Syntheses with cyclo-P

✍ Scribed by Prof. Dr. Marianne Baudler; Dipl.-Chem. Thomas Etzbach

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 369 KB
• Volume: 30
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.199105801

✦ Synopsis

phosphorus (3Jc-p = 6.2 and 5.7 Hz, respectively) indicating an antiperiplanar conformation of the C-S-C-P fragment and hence the prevailing equatorial position of the triphenylphosphonium group in solution. The y-effect values (+ 0.135 and -0.26 for 3 and 4, respectively) are also in accord with this interpretation.

Chemical equilibration (CD,CI,, Et,N, 293 K, ,,'P-NMR assay) of the conformationally fixed diastereomeric dithianes 5 and 6, initiated from both sides, allowed us to estimate the following equilibrium constants and AGO values : K = 1.74, AG",,, = -0.32 kcal mol-' for 5 and K = 6.10, AG",,, = -1.05 kcal mol-' for 6. The K and AGO values for