From n-alkane to polyacetylene on Cu (110): Linkage modulation in chain growth

Direct coupling or transformation of inert alkanes based on the selective C-H activation is of great importance for both chemistry and chemical engineering. Here, we report the coupling of polyenes that are transformed from n-dotriacontane (n-C32H66) through on-surface cascade dehydrogenation on Cu (110) surface, leading to the formation of polyacetylene (PA). Three distinct linkages have been resolved by scanning tunneling microscope (STM) and noncontact atomic force microscope (nc-AFM). Apart from the alpha-type linkage which is the stemless coupling of the terminal C-C double bond in trans-configuration, beta- and gamma-type linkages appear as knots or defects which are, in fact, the C-C couplings in cis-configurations. Interestingly, the defects can be effectively suppressed by adjusting the surface coverage, thus making it of general interest for uniform structure modulation.

Automated summary

In this study, we report the coupling of polyenes by transforming n-dotriacontane on a copper surface through on-surface cascade dehydrogenation, resulting in the formation of polyacetylene. Three distinct linkages have been observed using scanning tunneling microscope (STM) and noncontact atomic force microscope (nc-AFM). It was found that the defects can be effectively suppressed by adjusting the surface coverage, making it of general interest for uniform structure modulation.