SYNTHESIS AND NONLINEAR-OPTICAL ANALYSIS OF TRIBLOCK COPOLYMERS CONTAINING DISCRETE POLYENES

Ring-opening metathesis polymerization of methyltetracyclododecene with Mo(CHCMe3)(NAr)(OCMe3)2(Ar = 2,6-diisopropylphenyl) followed by termination with an excess of conjugated dialdehyde yielded end-functionalized homopolymers with low polydispersities. Subsequent linking of the homopolymers with either a conjugated, difunctional molybdenum alkylidene complex or a bisphosphonate ester resulted in triblock copolymers containing a discrete 9-, 10-, 11-, or 12-ene. The hyperpolarizabilities of the polyenes were measured with electronic field induced second harmonic generation and corresponded well with polyene hyperpolarizabilities found in a previous study of triblock copolymers containing a distribution of polyenes.