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[n]cycloparaphenylenes with charges: cyclic conjugation at last
dc.contributor.author | Casado-Cordón, Juan | |
dc.date.accessioned | 2016-07-27T12:24:30Z | |
dc.date.available | 2016-07-27T12:24:30Z | |
dc.date.created | 2016-06-12 | |
dc.date.issued | 2016-07-27 | |
dc.identifier.uri | http://hdl.handle.net/10630/11901 | |
dc.description.abstract | Oligophenylenes (polyphenylenes) are constituted by an array of conjugated benzenes where inter-ring electron delocalization tends to extend over the whole chain (linear conjugation) being intrinsically limited, among other factors, by terminal effects. Alternatively, cyclic conjugation is envisaged as the unlimited free-boundary versionofconjugation which will impact the structure of molecules in rather unknown ways. The cyclic version of oligophenylenes, cycloparaphenylenes ([n]CPPs with n the number of phenyl rings) were first synthesized in 2008 by Beztozzi and Jasti.1 Today the whole [n]CPP series from [5]CPP to [18]CPP has been prepared. [n]CPPs represent ideal models to investigate new insights of the electronic structure of molecules and cyclic conjugation when electrons or charges circulate in a closed circuit without boundaries. Radical cations and dications of [n]CPP from n=5 to n=12 have been prepared and studied by Raman spectroscopy.2 Small [n]CPP dications own their stability to the closed-shell electronic configuration imposed by cyclic conjugation. However, in large [n]CPP dications cyclic conjugation is minimal and these divalent species form open-shell biradicals. The Raman spectra reflect the effect of cyclic conjugation in competition with cyclic strain and biradicaloid aromatic stabilization. Cyclic conjugation provokes the existence of a turning point or V-shape behavior of the frequencies of the G bands as a function of n. In this communication we will show the vibrational spectroscopic fingerprint of this rare form of conjugation. [1] R. Jasti, J. Bhattacharjee, J. B. Neaton, C. R. Bertozzi, “Synthesis, Characterization, and Theory of [9]-, [12]-, and [18]Cycloparaphenylene: Carbon Nanohoop Structures”, J. Am. Chem. Soc. 130 (2008), 17646–17647. [2] M. P. Alvarez, P. M. Burrezo, M. Kertesz, T. Iwamoto, S. Yamago, J. Xia, R. Jasti, J. T. L. Navarrete, M. Taravillo, V. G. Baonza, J. Casado, “Properties of Sizeable [n]CycloParaPhenylenes As Molecular Models of Single-Wall Carbon Nanotubes By Raman Spectroscopy: Structural and Electron-Transfer Responses Under Mechanical Stress”, Angew. Chem. Int. Ed. 53, (2014), 7033−7037. | es_ES |
dc.description.sponsorship | Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. | es_ES |
dc.language.iso | eng | es_ES |
dc.rights | info:eu-repo/semantics/openAccess | es_ES |
dc.subject | Espectroscopía | es_ES |
dc.subject.other | Spectroscopy | es_ES |
dc.subject.other | Molecular materials | es_ES |
dc.title | [n]cycloparaphenylenes with charges: cyclic conjugation at last | es_ES |
dc.title.alternative | [n]cycloparaphenylenes with charges | es_ES |
dc.type | info:eu-repo/semantics/conferenceObject | es_ES |
dc.centro | Facultad de Ciencias | es_ES |
dc.relation.eventtitle | 24 INTERNATIONAL CONFERENCE ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS | es_ES |
dc.relation.eventplace | GUANGZHOU | es_ES |
dc.relation.eventdate | 25 junio 2016 a 1 de julio de 2016 | es_ES |
dc.cclicense | by-nc-nd | es_ES |