No abstract

Quantification of the effect of partial dehalogenation on SAMN of a bromo-substituted heterotriangulene molecule by a comprehensive DFT/MC model.

We report the systematic investigation of the effects of oxygen on the synthesis of 3p sub-family armchair graphene nanoribbons (3p-AGNRs), which revealed a strong catalytic effect with a reduction in the reaction temperature by approximately 180 K without degradation of the AGNRs. Poly(para-phenylene) (3-AGNR) was generated through Ullmann-type coupling of 4,4''-dibromo-p-terphenyl on Cu(111), which was then converted into wider 3p-AGNRs via lateral fusion. Scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy demonstrated the formation of different ribbons up to 12-AGNR, which contained regions exhibiting increased STM contrast that we attribute to the intercalation of Br atoms during lateral fusion.

Surface-confined reactions represent a powerful approach for the precise synthesis of low-dimensional organic materials. A complete understanding of the pathways of surface reactions would enable the rational synthesis of a wide range of molecules and polymers. Here, we report different reaction pathways of tetrathienylbenzene (T1TB) and its extended congener tetrakis­(dithienyl)­benzene (T2TB) on Cu(111), investigated using scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. Both T1TB and T2TB undergo desulfurization when deposited on Cu(111) at room temperature. Deposition of T1TB at 453 K yields pentacene through desulfurization, hydrogen transfer, and a cascade of intramolecular cyclization. In contrast, for T2TB the intramolecular cyclization stops at anthracene and the following intermolecular C–C coupling produces a conjugated ladder polymer. We show that tandem desulfurization/C–C coupling provides a versatile approach for growing carbon-based nanostructures on metal surfaces.