BEGIN:VCALENDAR VERSION:2.0 PRODID:https://murmitoyen.com/events/vanille/udem/ X-WR-TIMEZONE:America/Montreal BEGIN:VEVENT UID:69da3071abc5f DTSTAMP:20260411T072849 DTSTART:20181112T113000 SEQUENCE:0 TRANSP:OPAQUE DTEND:20181112T123000 URL:https://murmitoyen.com/events/vanille/udem/detail/843317-surface-suppor ted-covalent-organic-networks-sylvain-clair-cnrs-aix-marseille LOCATION:Université de Montréal - Pavillon J.-Armand-Bombardier\, 5155\, chemin de la rampe \, Montréal\, QC\, Canada\, H3T 2B2 SUMMARY:Surface-supported covalent organic networks - Sylvain Clair (CNRS\, Aix-Marseille) DESCRIPTION:Surface-supported covalent organic networksSylvain ClairCNRS\, Aix-Marseille UniversitéIM2NP\, 13397 Marseille\, France Abstract: The co ncepts of supramolecular chemistry have been successfully applied in the l ast decades to create well-organized structures on surfaces. Precise contr ol of the spatial arrangement of nanometer-sized elementary building-block s during the “bottom-up” construction of two-dimensional monolayers is the key step to get well-defined functional surfaces. Recently\, a fundam ental progress has been made with the demonstration that covalent linkages between organic molecules can be created directly on a metal surface\, le ading to the emergence of the field of on-surface synthesis. In this way\, original reaction pathways can be explored thanks to the strong catalytic activity of the underlying metal substrate.[1] However\, difficulties are usually encountered during the delicate growth mode\, and side reactions and undesirable by-product formation are difficult to control. The develop ment of 2D covalent systems based on new and more efficient chemistries or with controllable growth conditions is highly necessary and will conditio n the future of this emerging technology.[2] Boronic acids can undergo a s elf-condensation (dehydration) reaction to create rigid boroxine rings and a planar polymer sheet. By using 1\,4-benzenediboronic acid (BDBA) evapor ated onto a well-defined metal surface extended nanoporous 2D networks cou ld grow. I will present scanning tunneling microscopy (STM) results of our group\, [3-9] reflecting various efforts to control the growth process of these two-dimensional covalent organic networks (influence of the deposit ion parameters\, local activation of the reaction\, coupling with an Ullma nn reaction\, etc.). In another work we investigated the catalytic behavio r of well-defined low-index surfaces of single crystal silver substrates r epresenting a model catalyst for the bimodal homo-coupling reaction of an indacene-tetrone precursor. Dehydrogenation of the precursor occurred upon adsorption\, representing a first intermediate state. Covalent coupling w as obtained after thermal activation and its chemical signature was measur ed by vibrational spectroscopy using HREELS (high resolution electron ener gy loss spectroscopy).[10] We found that on Ag(100) the temperature can ac hieve selectivity in the reaction pathway leading to distinct products. Mo st interestingly\, the crystallographic symmetry of the supporting surface is very effective in controlling its catalytic strength and/or the reacti on product type.[11] In particular\, the (111)-oriented surface appeared t o be the most reactive as compared to (100) or (110) surfaces. References 1. Clair\, S.\; Abel\, M.\; Porte\, L.\, Growth of boronic acid based two -dimensional covalent networks on a metal surface under ultrahigh vacuum. Chem. Comm. 2014\, 50\, 9627-9635. 2. Clair\, S.\; De Oteyza\, D. G.\, Con trolling a chemical coupling reaction on a surface: tools and strategies f or on-surface synthesis. In preparation 3. Faury\, T.\; Dumur\, F.\; Clair \, S.\; Abel\, M.\; Porte\, L.\; Gigmes\, D.\, Side Functionalization of D iboronic Acid Precursors for Covalent Organic Frameworks. CrystEngComm 201 3\, 15\, 2067–2075. 4. Faury\, T.\; Clair\, S.\; Abel\, M.\; Dumur\, F. \; Gigmes\, D.\; Porte\, L.\, Sequential linking to control the growth of a surface covalent organic framework. Journal of Physical Chemistry C 2012 \, 116\, 4819. 5. Clair\, S.\; Ourdjini\, O.\; Abel\, M.\; Porte\, L.\, Tw o-dimensional polymer as a mask for surface nanopatterning. Advanced Mater ials 2012\, 24\, 1252. 6. Clair\, S.\; Ourdjini\, O.\; Abel\, M.\; Porte\, L.\, Tip- or electron beam-induced surface polymerization. Chemical Commu nications 2011\, 47\, 8028. 7. Ourdjini\, O.\; Pawlak\, R.\; Abel\, M.\; C lair\, S.\; Chen\, L.\; Bergeon\, N.\; Sassi\, M.\; Oison\, V.\; Debierre\ , J.-M.\; Coratger\, R.\; Porte\, L.\, Substrate-mediated ordering and def ect analysis of a surface covalent organic framework. Phys. Rev. B 2011\, 84\, 125421. 8. Pawlak\, R.\; Nony\, L.\; Bocquet\, F.\; Olson\, V.\; Sass i\, M.\; Debierre\, J. M.\; Loppacher\, C.\; Porte\, L.\, Supramolecular A ssemblies of 1\,4-Benzene Diboronic Acid on KCl(001). Journal of Physical Chemistry C 2010\, 114\, 9290-9295. 9. Zwaneveld\, N. A. A.\; Pawlak\, R.\ ; Abel\, M.\; Catalin\, D.\; Gigmes\, D.\; Bertin\, D.\; Porte\, L.\, Orga nized Formation of 2D Extended Covalent Organic Frameworks at Surfaces. J. Am. Chem. Soc. 2008\, 130\, 6678-6679. 10. Kalashnyk\, N.\; Mouhat\, K.\; Oh\, J.\; Jung\, J.\; Xie\, Y.\; Salomon\, E.\; Angot\, T.\; Dumur\, F.\; Gigmes\, D.\; Clair\, S.\, On-surface synthesis of aligned functional nan oribbons monitored by scanning tunneling microscopy and vibrational spectr oscopy. Nat. Commun. 2017\, 8\, 14735. 11. Kalashnyk\, N.\; Salomon\, E.\; Mun\, S. H.\; Jung\, J.\; Giovanelli\, L.\; Angot\, T.\; Dumur\, F.\; Gig mes\, D.\; Clair\, S.\, The Orientation of Silver Surfaces Drives the Reac tivity and the Selectivity in Homo‐Coupling Reactions. ChemPhysChem 2018 \, 19\, 1802-1808. Lien vers l'Institut Matériaux Microélectronique et N anosciences de Provence Cette conférence est présentée par le RQMP Ve rsant Nord du Département de physique de l'Université de Montréal et de Génie physique de la Polytechnique. END:VEVENT BEGIN:VTIMEZONE TZID:America/Montreal X-LIC-LOCATION:America/Montreal END:VTIMEZONE END:VCALENDAR