Synthetic approaches to trialkyl(ferrocenylmethyl)ammonium salts as cationic templates for the preparation of ferromagnets on the basis of bimetal oxalates

Trialkyl(ferrocenylmethyl)ammonium salts and their 2-substituted analogs designed for the preparation of molecular ferromagnetics based on bimetallic oxalates were synthesized using classical alkylation of dialkylaminomethylferrocenes by alkyl halides and nucleophilic substitution reaction of 2-substituted dimethylaminomethylferrocene methiodides with trialkylamines. In the case of salts with electron-donating substituents in position 2, only the latter of the two proposed routes is applicable because N-alkylation with alkyl halides is accompanied by competing ferrocenylmethylation of the starting amine. On the contrary, the salts with electron-withdrawing 2-substituents should be prepared preferably by the reaction of amines with alkyl halides, while nucleophilic trialkylamination of methiodides is complicated by deprotonation induced by bases.