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Investigation of Photo-Responsive Chiral Polyisocyanates

Abstract A new class of polyisocyanates incorporating the 8-phenylmethylenebicyclo [3.2.1]octan-3-one chromophore through three different linkage patterns to the polymer backbone was synthesized. Photoresolution and photoracemization experiments were conducted to test its response to circularly polarized light (CPL). Irradiation of the polymers with CPL leads to the partial photoresolution of the bicyclicketone chromophore. This enantiomeric excess causes the polyisocyanate chain to favor one helical sense over the other. The handedness of the polymer chain can be switched with the sense of the circularly polarized light, leading to novel photoresponsive polyisocyanates.