Agradecimentos: The author thanks the financial support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) under the project numbers 2007/08244-5, 2007/54829-5, 2017/18574-4, and 2021/08409-1 and from Conselho Nacional Científico e Tecnológico (CNPq) under the project numbers 304119/2019-9, and 302400/2022-2. D.J.M. has employed the Imbabura cluster of Yachay Tech University, purchased under contract 2017-024 (SIE-UITEY-007-2017). N.H.R. thanks CNPq for the studentship support. A.C.S. thanks FAPESP for the studentship support under project numbers 2021/04411-1 Ver menos

Abstract: The production of single-layer polymer ribbons and sheets composed of fused porphyrin rings, named porphene, an analog to graphene, has been aimed over the years as a promising material for applications. Several attempts to polymerize porphyrin rings have used the Ullmann-coupling reaction among the different synthesis routes. In this paper, we report the on-surface synthesis of organometallic molecular chains (1D) and porous networks (2D) from the free-base 5,10,15,20-tetrakis(4-bromophenyl)-porphyrin (H2TBrPP) on Ag(100). We investigated the adsorption of H2TBrPP using a comprehensive multitechnique approach combining scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), with density functional theory (DFT) based calculations. We find that distinct thermal stimuli applied to the substrate during the deposition lead to different final nanostructures (1D and 2D). This shows an evident thermal selectivity related to porphyrin conformation and substrate interaction, revealing different activation energies. Free-based porphyrins are shown to adopt the so-called "inverted" conformation on Ag(100), which was previously reported exclusively on the Cu(111) surface. Here, we explain the coexistence of these two porphyrins' molecular conformations ("inverted" versus "saddle"). Moreover, based on DFT calculations, we propose a mechanism to overcome the kinetically trapped intermediate organometallic state to allow complete C-C coupling during the Ullmann reaction of porphyrin ring derivatives Ver menos