Chemistry. — "Investigations on Pasteur's Principle concerning the 

 Relation between Molecular and Crystallonoinical Dissymmetry: 

 VII. On optically active Salts of the Tri-ethylenediamiiie- 

 Chromi-series." By Prof. F. M. Jaeger and William Thomas. 



(Communicated in the meeting of June 29, 1918). 



^ 1. Some lime ago it was already found ') by one of us, that 

 racemic tri-ethylenediamine-chromichloride: \Cr{Eme)j\Cls -{-SH^O, was 

 completely isomorphous with the corresponding cohalti- and rhodiuDi- 

 com pounds. We prepared this salt according to a method indicated 

 by Pfeiffer "), from the tripyridyl-chroini-chloride : \Or[Pyr.)^\Cli by 

 heating this product with ethylenediamine, and subsequent purification. 

 Then it was separated into its optical antipodes by means of 50(//?«/^- 

 a-camphor-nitronate '), and these were obtained in this way as the 

 pure iodides. 



In this fission 6 grams of the racemic salt were dissolved in 

 20 ccm water, and a solution of 6 gr?iV(\s oï pnve sodium-tt-camphor- 

 nitronate in 15 ccm water subsequently added. A pale yellowish 

 precipitate of d-triethylenediamine-chromi-d-camphornitronate is form- 

 ed ; it is sucked off and to the mother liquid 2 more grams of 

 sodium-a-camphornitronate are then added, and the solution allowed to 

 stand for a few hours, when some more of the precipitate is separated. 



After filtration the mother liquid was used for preparing the 

 corresponding laevogyratory component. The precipitate, thoroughly 

 washed with alcohol and ether, was ground in a mortar with an 

 excess of finely pulverised sodium-iodide, some water added, and 

 the dark yellow liquid sucked off from the precipitate, which was 

 well washed with alcohol and ether, dissolved in a small quantity 

 of water, and again precipitated by an excess of sodium-iodide. 



The mother liquid formerly mentioned, containing the camphor- 

 nitronate of the laevogyrsiie salt, was precipitated by addition of 

 5 grams sodium-iodide. The precipitate formed appeared, after 

 being thoroughly washed, to be the racemic iodide. The remaining 



1) F. M. Jaegee, Proceed. R. Acad., Amsterdam. 20. 247. (1917). 

 3) P. Pfeiffer, Zeits. f. anorg. Chemie, 24. 282, 286. (1900). 

 ») A. Werner, Ber. d. deutsch Chem. Ges. 45. 865. (1912;. 



15 

 Proceedings Royal Acad. Amsterdam Vol. XXI. 



