Synthesis of Monocyanopolyynes and Dicyanopolyynes with the Submerged Electric Arc - Polyynes: Synthesis, Properties, and Applications - page 323

FIGURE 15.4 Electronic absorption spectra of unknown products derived from the
decomposition or rearrangement of monocyanopolyynes.
solvent, which acts as a trap. In fact, in Figure 15.5 it is possible to see the
typical polyynes spectrum from the octane solution used as a trap of these
molecules.
Figure 15.5(B) shows the initial spectrum of the polyynes mixtures
produced from the graphite arc in liquid nitrogen at the beginning of the
experiment. In these conditions, the initial polyyne concentration was esti-
mated from their optical density in the spectrum to be around 10 7 M in the
n-octane trap. Furthermore, the spectrum in Figure 15.5(B) of the polyynes
produced from the arc in liquid nitrogen shows a different band pattern
than the mixture of polyynes produced by arcing graphite electrodes directly
into n-octane (compare Figure 15.5(B) with Figure 15.5(A)). In particular,
in Figure 15.5(B) we can observe two main bands at 261 and 283 nm while
the most intense bands in Figure 15.5(A) are located at 226, 239, and 251 nm.