Fluorous modification of 2,2′-bipyridine

A series of 2,2′-bipyridines featuring fluorinated alkyl groups (CH₂)₃(CF₂)_xCF₃: x = 0, (1); 5, (2); 7, (3); 9 (4)] appended in the 4 and 4′ positions have been prepared. 1-4 were characterized by spectroscopy and physical methods including partition coefficient (biphase: perfluoromethylcyclohexane/toluene) and cyclic voltammetry (THF). Ab-initio calculations of vertical ionization potentials (VIPs) for 1-4 confirm the insulating role of the methylene spacers as the electrochemical reduction potentials of 1-4 are almost identical to that of 2,2′-bipyridine. Calculations for (CH₂)_nCF₃ derivatives (n = 0-10) describe a limit for impact of the CF₃ group through 9-10 methylenes. From both physical and theoretical data fluorinated alkyl groups of the formula (CH₂)₃(CF₂)_xCF₃ x = 0-9] are inductively equivalent to a hydrogen substituent when appended to the bipyridine moiety.