Macromolecules, Vol.38, No.25, 10413-10420, 2005
Synthesis of strained macrocyclic biaryls for enthalpy-driven ring-opening polymerization
Polymerizable macrocyclic biarylene-ether-ketones and biarylene-ether-sulfones are accessible from linear, bis(chloro)-terminated oligomers via nickel-catalyzed, intramolecular coupling under pseudo-high-dilution conditions. Single-crystal X-ray analyses of the resulting cyclo-oligomers reveal extremely distorted and highly strained geometries, with 4,4 '-biphenylene units showing deviations of up to 70 degrees from linearity.