Paracyclophane and ferrocenophane derivatives

A solution of the high-cis polymer fluoresces when excited by irradiation at 330 nm. The initial spectrum displays a weak emission at about 370 nm attributed to 2% of tra s-stilbene segments originally present in the chains. With continued irradiation (2 min) there is an increase in the emission from this band as more trans double bonds are generated, and a new emission appears at 445-500 nm. After further irradiation, this intense red-shifted luminescence becomes the predominant feature before the polymer precipitates. In a statistical copolymer of 9% of 71 and 91% of norbomene, the units of 72 are isolated between norbomene units, and the fluorescence spectrum is confined to the shorter wavelength region with a maximum around 360 nm (Miao 1994a). 

The ROMP of [2.2]paracyclophane-1,9-diene (73) yields poly(p-phenylene-vinylene) (74) as an insoluble yellow fluorescent powder. Soluble copolymers can be made with an excess of cyclopentene (Thom-Csanyi 1992b), cycloocta-1,5-diene (Thom-Csanyi 1993a), or cyclooctene (Thom-Csanyi 1994c). The UV-visible absorption spectra of the copolymers with cyclooctene show separate peaks for sequences of one, two, and three /7-phenylene-vinylene units at 290, 345, and about 390 nm, respectively, with a Bemoullian distribution. The formation of the odd members of this series evidently involves dissection of the two halves of the original monomer units by secondary metathesis reactions. 

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