Synthesis of secondary arylamine copolymers with Iron(II) clathrochelate units and their functionalization into tertiary Polyarylamines via Buchwald-Hartwig cross-coupling reaction

We report the synthesis of three secondary arylamine copolymers bearing iron(II) clathrochelate units (CLP1-3). Three of the latter copolymers were post-modified into their tertiary arylamine moieties (PCLP1-3) using a mild palladium-catalyzed Buchwald-Hartwig cross-coupling reaction. Interestingly, the functionalization of the secondary arylamine groups has resulted in the formation of highly soluble target compounds PCLP1-3, which allowed for their simple isolation and full analysis via various techniques. It is noteworthy that a prototypical secondary arylamine iron(II) clathrochelate monomer CLM1 was synthesized and post-modified into its tertiary arylamine target compound CLM2. The current study discloses the first examples on making secondary arylamine copolymers with clathrochelate constituents, and proves the possible post-modification of the latter compounds into tertiary arylamine, which proves the modularity of iron(II) clathrochelate unit to make functional polymers. Formation of the monomers and copolymers was confirmed by ¹H- and ¹³C- nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM), and UV–Vis absorption spectroscopy.