Alternating Vinylarene–Carbon Monoxide Copolymers: Simple and Efficient Nonconjugated Luminescent Macromolecules

Development
of low-cost nontraditional intrinsic luminescence (NTIL)
polymers containing auxochromophores and understanding their luminescence
characteristics are highly desirable. In this paper, alternating vinylarene–carbon
monoxide copolymers (PK-X, X = H, Ph, tBu, OtBu, F, and Cl) were, for the first
time, reported as simple and efficient NTIL polymers, which were facilely
and precisely prepared by palladium-catalyzed coordination copolymerization
of vinylarene and CO. These nonconjugated polymers emitted intrinsic
blue light in both concentrated solutions and solid powders by the
clusterization-triggered emission mechanism. Theoretical calculations
and single-crystal analysis of the small molecular model clearly confirmed
that through-space intra- and interchain interactions by n−π
and π–π modes between the carbonyl and the phenyl
groups collectively formed clusteroluminogens. The copolymer quantum
yields greatly improved regardless of the introduction of an electron
acceptor or donor. The chloride-substituted copolymer had a high quantum
yield of up to 44.8% and showed great potential as a photoluminescent
material for improving the utilization of sunlight.