Mesotomisation of Diammine-dinitro-oxalo-cobalt Complex. 11 



[Co(NH3)2(N02)2C204]NH4 were prepared from /-brucine-Z-diam- 

 mine-dinitro-oxalo-cobalt complex and c?-cinchonine-cZ-diammine- 

 dinitro-oxalo-cobalt complex, in quite the same manner as in the 

 case of the potassium salts, only using ammonium iodide instead 

 of potassium iodide. 



The /-and tZ-ammonium salts of the complex thus obtained 

 had the following specific rotations: 



[aj^»=-l07° (0-1%, 10 cm) 

 „ = + 116- („ , „ ) 



These values are practically the same as those of the potassium 

 salts. This is probably due to the fact that the difïerence between 

 the molecular weights of the potassium- (=302) and ammonium- 

 (=291) salts is not large enough to exert any distinct influence 

 upon their rotatory powers, which were always measured in so 

 diluted a solution as 0-1%, because of a fairly intense colour of the 

 solution. 



Sammary. 



1. Diammine-dinitro-oxalo-cobalt complex [Co(NH3)2(N02)2 

 C2O4] ' Me* has been resolved into the optically active isomers by 

 fractionation of the salts of brucine, strychinine and cinchonine. 



2. In the fractionation of the alkaloid salts of the complex, 

 either the /-alkaloid-/-cobalt complex or cZ-alkaloid-tZ-cobalt com- 

 plex was always found to separate out as the least soluble fraction, 

 while either the Z-alkaloid-cZ-cobalt complex or c?-alkaloid-/-cobalt 

 complex always constituted the most easily soluble fraction. 



3. The specific rotations of potassium and ammonium 

 diammine-dinitro-oxalo-cobaltiates, which have been obtainq^l 

 by replacing the alkaloid molecules with potassium-and am- 

 monium ions respectively, were measured, and found to have the 

 values of ca ±115", using sodium light. 



4. As a results of the mesotomisation of diammine-dinitro- 

 oxalo-cobalt complex, the configurations of this complex and also 

 of its mother substance, diammine-tetranitro-cobalt complex, have 

 been made clear, the possibility of mesotomisation indicating that 



