Multi-Ferrocenyl Aryl Ethers - Applying Nucleophilic Aromatic Substitution Reactions to Aryl Fluorides

The reaction of ferrocenol [FcOH; Fc = Fe(eta(5)-C5H5)(eta(5)-C5H4)] with aryl fluorides ArH6-nFn (n = 3-6) within a nucleophilic aromatic substitution reaction (SNAr) gave ferrocenyloxy-substituted fluorobenzenes of general type C6H0-3F1-5(OFc)(1-5). For 1,3,5-C6H3F3, 1,2,4,5-C6H2F4, and C6H6-nFn (n = 5,6), one, two, and three F atoms, respectively, could be replaced by FcO units. The reaction of 1,4-(OFc)(2)-C6F4 with additional amounts of FcOH afforded the tetra- and penta-substituted arenes 3,6-F-2-C-6(OFc)(4) and C6F(OFc)(5). Electrochemical investigations of both compounds showed four or five Fc/Fc(+) related reversible redox processes that were attributed to electrostatic interactions. The addition of C6F6 as the electrophile after the anionic phospho-Fries rearrangement of a ferrocenyl phosphate (1,3-OC migration) to the 1,2-substituted ortho-phosphonato ferrocenol, resulted in the formation of the respective ortho-functionalized ether. The constitution of all compounds was verified by using F-19 NMR spectroscopy. Steric hindrance of the ortho-substituent resulted in a doubling of the signal sets for the C6F5 moiety in the C-13{H-1} and F-19 NMR spectra. The identity and substitution pattern of five compounds could also be determined by using single-crystal X-ray diffraction analysis, revealing the 1,4-constitution of double functionalized derivatives, intermolecular non-classical C-H center dot center dot center dot F interactions and pi interactions.