No abstract

[9] 3 : Pale yellow crystals, [all,, MeOH); CI) (MeOH). Acl,= -1.33, ACW= -0.91; UV (MeOH): L,,,,x(lgc)= 241 ( 3 67). 277 nm (3.87); 'H-NMR ([Dolacetone): 6 = 1.89 and 2.09 (each m: 2 6-H), 2.38 ( s ; 3 10-H), 2.46 (m; 2 7-H), 3.61 ( s ; OCH2), 3.95 (m: 5-H). 7.80 (br. s ; NH), 7.95 (br. s ; OH).

Die ersten Natrium-organomagnesate werden dargestellt und strukturell charakterisiert. Bei der Umsetzung von Phenylnatrium mit Diphenylmagnesium in Gegenwart des dreizanigen ChelatLiganden Pentamethyldiethylentriamin (PMDTA) entsteht m a@mdta)'J2[MgPh4] (5). Jedes der solvatisierten Na-Ionen ist in The preparation and structural characterisation of the first sodium organomagnesates is described. Reaction of phenylsodium with diphenylmagnesium in the presence of the tridentate chelate ligand pentamethyldiethylenetriamine (PMDTA) gives ma-Each of the solvated Na ions is in contact with two'phenyl groups which form asymmetric bridges to Mg.The coordination of Mg is tetrahedral, the Na ions achieve a Chem.

Chem. 90 (1978) 144: Angew. Chem. Inr. Ed. Engl. 17 (1978) 124. Dort ist Herstellung und Struktur eines tetrameren Komplexeb von 6 mit Tricyclohexylphosphan als Ligand beschrieben.

The great importance of the counterion in determining the structure of a carbanion is revealed by ab initio and MNDO calculations performed for allenyl anions and by the result of the X‐ray structure analysis of (I) (prepared by reaction of 2,2,5,8,8‐pentamethyl‐3,6‐nonadiyne with BuNa and excess of the diamine in H2O‐free hexane at ‐18 °C with a yield of 82%), which crystallizes in the space group P21/n with Z=4.