Topology Selectivity of a Conformationally Flexible Precursor by Selenium Doping

Conformational arrangements within nanostructures play a crucial role in shaping the overall configuration and determining the properties, for example in covalent/metal organic framework (COF/MOF) synthesis. In on-surface synthesis, conformational diversity often leads to uncontrollable or disordered structures. Therefore, exploration on controlling and directing the conformational arrangements is significant in achieving desired nanoarchitectures. In this study, a conformationally flexible precursor 2,4,6-tris(3-bromophenyl)-1,3,5-triazine ( m TBPT) was employed, and a random phase consisting of C 3h and C s conformers was first obtained after deposition of m TBPT on Cu(111) from room temperature (RT) to ~365 K as expected. By low coverage (0.01 ML) selenium (Se) doping, we achieved the selectivity of the C 3h conformer greatly and improved the nanopore structural homogeneity. The ordered 2D metal organic nanostructure from m TBPT could be fulfilled by Se doping from RT to ~365 K, and the deposition sequence of m TBPT and Se did not make any difference. Through the combination of high-resolution scanning tunneling microscopy and non-contact atomic force microscopy, we explored the regulation of the conformationally flexible m TBPT on Cu(111) and achieved the high topology selectivity by low coverage Se doping. Density functional theory calculations revealed the energy regulation of organometallics before and after Se doping at atomic level. These results could enrich the on-surface synthesis toolbox of conformationally flexible precursors, for the design of complex nanoarchitectures, and for future development of engineered nanomaterials and nanodevices. Figure 1