Synthesis and Spectroscopic Studies of Macrocyclic Polystyrene Containing Two Fluorene Units and Single 9,10-Anthracenylidene Group
journal contributionposted on 25.08.2009, 00:00 by Rong Chen, Jun Ling, Thieo E. Hogen-Esch
The synthesis of narrow distribution model macrocyclic polystyrenes initiated with 1,4-dipotassio-bis-1,4-(9′,9′-dimethyl-2′-fluorenyl)butane (DMFB) containing 12 to 55 styrene units and coupled to a single 9,10-anthracenylidene (AN) unit (PS-DMFB-AN) is reported. The initiator is formed via electron transfer/coupling from potassium naphthalenide to give nearly pure DMFB, followed by the addition of styrene and protonation or intramolecular end-to-end coupling with 9,10-bis(chloromethyl)anthracene to give the linear and cyclic polymers, respectively. Förster transfer from the 9,9-dimethyl-2-fluorenyl (DMF) group donors to the AN groups, surprisingly, only slightly increased with lower degrees of polymerization of the PS segments. Extensive simulations indicate the presence of highly asymmetrical polymers in which the two arms of the polymer dianion significantly differ in the degree of polymerization. This appears to be partially due to chain statistics but also to slow initiation relative to polymerization.