Halogenation effects on the conformational properties of alkanes

The rotational barriers of the CC bonds of halocarbons are believed to be rather different than those of hydrocarbons. We wish to systematically study the effect of halogen substituents on the conformational flexibility of hydrocarbons. As our initial approach to this problem, we have synthesized the following molecules: Pyrene–(CF2)n–Pyrene (n=3, 4, and 6) and Pyrene–(CF2)n–F (n=4 and 6). We describe here the concentration and temperature dependence of the emissive behavior of these materials.