154 Dr. A. E. Everest and Mr, A. J. Hall. 



Comparison of the Properties of various Salts and simple Phenolates of 

 Anthocyans and related Pyrylium Derivatives. 



From the authors' own observations and from previous work of other 

 investigators, it is now apparent that two distinct classes of metallic salts of 

 anthocyan pigments (or related hydroxylated pyrylium compounds) exist. 



The work of others has shown that in numerous pyrylium compounds 

 (oxonium salts) the addition of ferric chloride gives rise to iron compounds 



FeCli 

 I 



which can be represented by simple formulae of the type : | • They 



\/\/^-^ 

 c 



I 



H 



appear to be additive compounds of the iron salt and the oxonium salt of the 

 pyrylium derivative. In connection with other work, the present authors 

 have isolated compounds in which the iron chloride-content agrees with the 



FeCl4 FeCl4 

 I I 



structures : ^ ^ and \ / . 



c c 



k i 



When dilute solutions of the oxonium salts of many anthocyans have small 

 amounts of iron salts added to them, characteristic intensely coloured 

 solutions result (blue in the case of ferric chloride to cyanin or violanin 

 chloride) which are stable, and show no tendency to decolorise on standing. 

 The present authors agree that these are complex salts, but consider they 



FeCl4 



are probably of the type : 



H0-,/\Ac-/~V0H 



C 



HO I 



H 



On the other hand, sodium, potassium, calcium, or magnesium salts of the 

 anthocyans, when in solutions of similar dilution, gradually decolorise on 

 standing. The present authors are of the opinion that these are simple 

 phenolates, and related to the alkali salts of the flavonols described by 

 A, G. Perkin and others. 



This indicates clearly a very marked line of differentiation between the 



