Formation of C H Ablation of Graphite, Coal or C Particles Suspended in Selected Solvents - Polyynes: Synthesis, Properties, and Applications - page 138

FIGURE 7.9 HPLC chromatograms of products resulting from unfocused 355 nm
laser irradiation on C 60 particles suspended in hexane or methanol solution for
60min.

completely dissolved in toluene solution. When 355 nm Nd:YAG laser beam
was directed into C 60 solution in toluene, no appreciable color change in
purple solution was observed. HPLC chromatograph of products consisted
of only a strong peak due to reagent C 60 . In the second experiment, C 60
particles were suspended in hexane or methanol solution because of low
solubility of C 60 in these solvents. For example, Figure 7.9(a and b) shows
typical HPLC chromatographs at 355 nm laser irradiation in hexane and
methanol solutions, respectively. Three product peaks, which can be
assigned to C 8 H 2 ,C 10 H 2 , and C 12 H 2 polyynes by absorption spectra, are

observed at retention times of 2.2, 2.4, and 2.9min, respectively. In Figure

7.10 ( a and b) and Table 7.2 are summarized the absorbances and the relative

abundance of C 4-6) in hexane or methanol solution after 266, 355,

532, and 1064 nm laser irradiation for 60min. The following general aspects

2n H 2 (n

¼

were found from these data.

1. Although short-chain C 2n H 2 (n ¼ 4-6) polyynes are observed from

C 60 , 7 and 8) polyynes could not be

detected. In general, the n-distribution of C 2n H 2 has a sharp peak
at n

long-chain C 2n H 2 (n ¼

¼ 4 and rapidly decreases with increasing n.