Regular copolymers which incorporate 2-aceto-1,3-phenanthrenylene units in the copolymer backbone have been prepared by Ru catalyzed step-growth copolymerization of 2-acetylphenanthrene and α,Ï-dienes. Fluorescene spectra of copolymers are reported. Introduction: Polymers which incorporate phenanthrene as a pendant substituent or terminal group as well as polymers in which phenanthrene nuclei are part of the main polymer chain are known. For example, use of the anionic initiator formed by addition of n-butyllithium to 1-(9-phenanthryl)-1-phenylethylene to polymerize MMA yields PMMA which incorporates a phenanthrene chromophore at the end of each polymer chain [1]. Likewise, reaction of polystyryl lithium with 1-(9-phenanthryl)-1-phenylethylene yields PS which has a phenanthrene attached to the end of each polymer chain [2]. On the other hand, PS in which chains are randomly labeled with a number of phenanthrene units has been produced by photolysis of a solution of PS and 9-bromophenanthrene [3]. Polymers which incorporate phenanthrene in a regular way into backbone of the polymer chain have been prepared by chemical modiffication of polymers which have aromatic groups in their backbones For example, poly(1,3-arylene vinylenes) in which the vinyl carbons are substituted with electron rich aryl groups undergo oxidative cyclization with FeCl3 to yield poly(10-aryl-2,9-pnenanthrenytanes) [4]. Copoly(4,4â²-Z-stilbene/ethylene), formed by Mo catalyzed ROMP of [2,2]paracyclophan-1-ana, undergoes quantitative oxidative photocyclization in benzene solution in the presence of iodine to yield copoly(3,6-phenanthrenylene/ethylene) [5]. 2,2â²-Dibenzoylbiphenyl units present in poly(arylene ether)s can be converted into 9,10-diarylphenanthrene units by use of Lawesson's reagent [6,7]. The incorporation of phenanthrene nuclei in these polymers results in increased crystallinity, Tg and resistance to solvents. Properties of such phenanthrene labeled polymer chains can be studied either by absorption or fluorescence spectroscopy. We should like to report a novel method to directly incorporate phenanthrene nuclei in a regular manner into polymer backbones. Specifically 2-acetylphenanthrene undergoes Ru catalyzed copolymerization with α,Ï-dienes such as 1,3-divinyltetramethyldisiloxane or 3,3,6,6-tetramethyl-3,6-disila-1,7-octadiene to yield copolymers in which 2-aceto-1,3-phenanthrenylene units are regularly joined in the polymer backbone. We have previously carried out Ru catalyzed copolymerizations between acetophenone and α,Ï-dienes [10-14]. equation presented.
