N1-Alkylated Pyrimidine Films as a New Potential Optical Data Storage Medium

We investigate several compounds of the type 1,1‘-(α,ω-alkanediyl)bis[pyrimidine] and 1-(ω-bromoalkyl)uracil, which can undergo photoinduced (2π + 2π) cycloaddition reactions on exposure to UV light at 254 and 257 nm, which have been synthesized for application in high capacity optical data storage. Their dimerization efficiency was compared, in solution, with uracil as a reference, and as films, to investigate the correlation between solution and film. Films of good quality displaying excellent thermal and optical stability can be fabricated. A significant optical contrast between the irradiated and nonirradiated medium was observed. 1,1‘-(1,3-Propanediyl)bis[uracil], 1,1‘-(1,8-octanediyl)bis[uracil], and 1-(6-bromohexyl)uracil showed remarkably good dimerization efficiency and are a significant improvement compared to previously reported similar systems. Gray scale and holographic grating storage are also demonstrated in the films. Writing and reading of the gray scale can be performed at the same wavelength.