Synthesis of iron‐containing polymers with azo dyes in the backbones or side chains

Abstract

AbstractThe synthesis of cationic cyclopentadienyliron‐containing polymers with pendent azobenzene chromophores was accomplished via metal‐mediated nucleophilic aromatic substitution reactions. All of the desired polymers were isolated as vibrantly coloured materials and displayed excellent solubility in polar aprotic solvents. Cationic and neutral cyclopentadienyliron polymers incorporating azo dyes in the backbone were also prepared. Reactions of azo dyes with dichlorobenzene complexes allowed for the isolation of cationic cyclopentdienyliron (CpFe+) complexes with azo dye chromophores. These complexes were then reacted with 1,1′‐ferrocenedicarbonyl chloride to produce the trimetallic monomers with terminal chloro groups. These monomers contained two pendent CpFe+ cations and a neutral iron moiety in the backbone. Nucleophilic substitution reactions of these monomers with oxygen and sulfur containing dinucleophiles gave rise to a new class of polymeric materials. The pendent CpFe+ moieties could also be cleaved from the polymer backbones using photolysis to afford novel ferrocene based polymers. The UV‐vis spectra of the organoiron monomers and polymers display similar wavelength maxima however incorporating azobenzene chromophores with electron‐withdrawing substituent into the polymer chains resulted in bathochromic shifts of the λmax values.