| Full text | |
| Author(s): |
Moreno-Lopez, Juan Carlos
[1, 2]
;
John Mowbray, Duncan
[2, 3, 4]
;
Perez Paz, Alejandro
[2, 3, 4]
;
de Campos Ferreira, Rodrigo Cezar
[5]
;
dos Santos, Alisson Ceccatto
[5]
;
Ayala, Paola
[1, 2]
;
de Siervo, Abner
[5]
Total Authors: 7
|
| Affiliation: | [1] Univ Vienna, Fac Phys, A-1090 Vienna - Austria
[2] Yachay Tech Univ, Sch Phys Sci & Nanotechnol, Urcuqui 100119 - Ecuador
[3] Univ Basque Country, UPV EHU, Nanobio Spect Grp, E-20018 San Sebastian - Spain
[4] Univ Basque Country, UPV EHU, Dept Fis Mat, ETSF Sci Dev Ctr, E-20018 San Sebastian - Spain
[5] Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | CHEMISTRY OF MATERIALS; v. 31, n. 8, p. 3009-3017, APR 23 2019. |
| Web of Science Citations: | 0 |
| Abstract | |
Surface diffusion, molecular conformation, and on-surface coupling reactions are key processes for building tailored molecular nanostructures such as graphene nanoribbons, polycyclic aromatic hydrocarbons, and one-dimensional/two-dimensional (2D) polymers. Here, we study the surface diffusion and coupling in situ of a chlorinated porphyrin, namely 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin (Cl4TPP), using a combined scanning tunneling microscopy (STM), density functional theory (DFT), and X-ray photoelectron spectroscopy approach. Using STM, we obtain surface migration and rotation barriers Delta E of 0.77 +/- 0.09 and 0.93 +/- 0.28 eV, respectively, indicative of covalent binding to the surface. In fact, we find that the precursors as well as all the reaction species exclusively (approximate to 100%) adopt a peculiar ``inverted{''} conformation covalently bonded to Cu(111). Using DFT, we have mapped two coupling reaction pathways: direct dechlorination and Cu adatom-mediated Ullmann coupling. We find that the latter is essentially barrierless, whereas the former faces a barrier of about 0.9 eV for inverted Cl4TPP on Cu(111). Our STM measurements show that C-Cu-C organometallic species are the main final products in the presence of Cu adatoms, which is explained by our DFT reaction profile when heat dissipation to the substrate is taken into account. This work not only highlights the relevance of surface adatoms in selecting the reaction pathway but also opens the possibility of precisely tailoring 2D molecular assemblies by controlling the supply of Cu adatoms. (AU) | |
| FAPESP's process: | 17/08846-7 - Determination of thermodynamic parameters in the diffusion and formation of tetra-4-chlorophenylporphyrin nanomembranes on Cu(111) |
| Grantee: | Alisson Ceccatto dos Santos |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| FAPESP's process: | 07/54829-5 - Electronic and geometric structure of nano-materials: synchrotron radiation studies |
| Grantee: | Richard Landers |
| Support Opportunities: | Research Projects - Thematic Grants |