Elettra-Sincrotrone Trieste S.C.p.A. website uses session cookies which are required for users to navigate appropriately and safely. Session cookies created by the Elettra-Sincrotrone Trieste S.C.p.A. website navigation do not affect users' privacy during their browsing experience on our website, as they do not entail processing their personal identification data. Session cookies are not permanently stored and indeed are cancelled when the connection to the Elettra-Sincrotrone Trieste S.C.p.A. website is terminated.
More info
OK

2H-TPP on Ag: carbon de-hydrogenation

Formation of a monolayer of 2H-tetraphenylporphyrins (2H-TPP) on Ag(111), either by sublimation of a multilayer in the range 525–600 K or by annealing (at the same temperature) a monolayer deposited at room temperature, induces a chemical modification of the molecules. We observe a selective carbon de-hydrogenation with the formation of new aryl-aryl bonds between phenyl groups as well as their rotation in a flat conformation. G. Di Santo et al., Chem. - A Europ J. 17(51), 14354-9 (2011)

In our recent investigations we have demonstrated that one monolayer of 2H-TPP, prepared by thermal desorption of the corresponding multilayer at 550 K on Ag(111), adsorbs with the macrocycle and the phenyl flat. This information has been directly addressed by means of X-ray absorption and photoemission experiments.


Theoretical calculations suggest a possible molecular reaction and modification of porphyrins, in order to explain this adsorption conformation: the de-hydrogenation of eight carbon atoms in the remaining monolayer after the multilayer desorption, with the formation of four new aryl-aryl carbon bonds. While the reaction takes place also in the deposited monolayer annealed at 550 K, the initial presence of the multilayer favors a decrease of the aryl-aryl coupling barrier and the selection of a spiral conformation in the de-hydrogenated molecule. The chemical reaction produces a stable molecule that forms a patterned square lattice on Ag(111) and that can be further modified by the introduction of central metal atoms.



Retrieve article

Supramolecular Engineering through Temperature-Induced Chemical Modification of 2H-Tetraphenylporphyrin on Ag(111): Flat Phenyl Conformation and Possible Dehydrogenation Reactions

G. Di Santo1, S. Blankenburg2, C. Castellarin-Cudia1, M. Fanetti1, P. Borghetti3, L. Sangaletti3, L. Floreano4, A. Verdini4, E. Magnano4, F. Bondino4, C. A. Pignedoli2, M.-T. Nguyen2, R. Gaspari2, D. Passerone2, A. Goldoni1,*

Chemistry - A European Journal vol 17, Issue 51, pages 14354–14359, December 16, 2011
DOI: 10.1002/chem.201102268
Publication Date (Web): November 23, 2011
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim



































               
     

Ultima modifica il Lunedì, 07 Gennaio 2013 18:07