Preparation of novel bimetallic and trimetallic species containing the cyclopentadienyliron moiety
In light of the recently reported synthesis of oligomeric ethers containing the cyclopentadienyliron moiety, this work details three strategies towards the functionalization of these materials. These strategies focus on the incorporation of specific moieties due to their chemical behavior, as well as the incorporation of novel linkages, which would alter the tensile characteristics of the resulting oligomeric species. Phenolphthalein was examined as an etheric bridge for bimetallic species due to the possibility of chemical modification of the lactone ring with a nucleophile. However, reaction with primary amines was found to cause an etheric cleavage reaction to occur, most likely through the formation of a tertiary carbocation intermediate. Interestingly, this reaction was found to be useful synthetically in the preparation of cyclopentadienyliron complexed anilines which may not be prepared via nucleophilic aromatic substitution of complexed chloroarenes or nitroarenes. Etheric cleavage was also shown tooccur in the presence of potassium permanganate, which caused the formation of a cyclopentadienyliron complexed phenol. This class of compounds has been synthesized previously only by nucleophilic displacement of a chlorine atom by the hydroxide ion. The resulting material is quite unstable, and decomposes over the course of a few days, even when stored at low temperature. A third attempt to functionalize bim tallic analogues resulted in the successful formation of trimetallic and macrocyclic esters containing both ferrocene and cyclopentadienyliron moieties. Although it was hoped that these compounds would exhibit unique electrochemical behavior, the presence of strong electron withdrawing groups impeded the oxidation of the ferrocene moiety.