Photochemistry has continued to contribute to the development of various types of optoelectronics materials, such as optical fibers, microlenses, optical memories, switching devices, optical waveguides, liquid-crystal-display components and polymer light-emitting diodes.1, 2, 3 In particular, significant attention has been devoted to the photochemical control of refractive indices of polymer films, owing to their potential use in optical network technology.3 Extensive studies have been conducted on the photoinduced decrease in refractive indices of polymer films,4, 5, 6, 7, 8 whereas only a few attempts have been made to enhance the refractive index through photochemical transformations.9, 10, 11 The photo-Fries rearrangement in polymers bearing aromatic ester pendants causes a large increase in refractive indices of these polymer films.12, 13, 14, 15 The refractive-index changes described above appear to be of sufficient magnitude to utilize these polymers as optical materials. To develop more sophisticated optical materials, it is necessary to precisely control the molecular weights of the above polymers containing covalently bound chromophores, because many polymers exist as a mixture with different chain lengths, thus making it difficult to quantitatively discuss their photoreactivity and optical properties on the basis of those of the corresponding monomer units.

Substituted 4-tert-butylcalix[8]arenes 1c and 1d were prepared according to the standard procedures shown in Scheme 1. O-Alkylation of 4-tert-butylcalix[8]arene with ethyl bromoacetate in dry 1-methyl-2-pyrrolidone followed by alkaline hydrolysis of the resulting ester derivative in aqueous ethanol yielded the corresponding carboxylic acid. The reaction of the acid derivative with thionyl chloride resulted in a highly reactive acid chloride, which, in turn, was coupled with 4-benzyloxyaniline in dry N,N-dimethylformamide (DMF) to produce the amide conjugate. Catalytic debenzylation of this conjugate in tetrahydrofuran (THF) followed by the acylation of the deprotected phenolic hydroxyl group formed 4-tert-butylcalix[8]arenes 1c and 1d substituted with eight 4-acyloxyanilinocarbonyl chromophores. Procedures similar to those given in Scheme 1 were applied to the synthesis of the reference 4-tert-butylphenol derivatives 1a and 1b using 4-tert-butylphenol as a starting material.

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