Catecholate-salicylate bonding

These results thus support the model proposed above in which one-proton reactions are due to a shift from a catecholate to a salicylate mode of bonding. 

Of course, phenols also react with FeCla (p. 188). However, in methanolic solution only those phenols react which carry in the ortho position of the phenolic hydroxyl a group capable of the formation of a chelate bond, as, for example, in catechol or salicylic acid. Trans-enols do not produce a color in methanolic solutions, but do in aqueous solution. For more detailed information of the relationship between the reactivity and the color and the structure of enols see (3). 

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