The Interaction of Vacuum Ultraviolet Light with Crystalline Monoacetylenes: A Progress Report

Abstract

Abstract With an eye toward a study of crystalline monoacetylene solid state reactivity as an approach to crystallographically ordered polyacetylenes, the crystallographic and absorption and emission spectral characteristics of 10-undecynamide and the cyclohexylurethanes of 5-hexyn-1-o1 and 10-undecyn-1-o1 have been studied at ambient temperature. Spectral studies at short wavelengths were performed using vacuum ultraviolet radiation from the National Synchrotron Light Source. The compounds investigated are not thermally reactive at temperatures below their melting points and are effectively inert to 60Co gamma radiation at room temperature. The crystal structures of 10-undecynamide and the cyclohexylurethane of 5-hexyn-1-o1 have been solved, and both reveal contacts shorter than 3.70 A between acetylenic carbon atoms. For 10-undecynamide, excitation at all wavelengths between 120 and 300 nm leads to emission at wavelengths greater than 300 nm.