B. Nardone

C. De Cola

C. Tedesco

F. De Riccardis

G. Cerasuolo

G. Vaughan

I. Izzo

L. Erra

ERRA, LOREDANA

TEDESCO, Consiglia

IZZO, Irene

DE RICCARDIS, Francesco

Archivio della Ricerca - Università di Salerno

MS43-O4 Self-assembly of highly charged fullerenefragment: Structural mystery resolved. Marina A.Petrukhina,a Alexander V. Zabula,a Alexander S. Filatov,a SarahN. Spisak.a aDepartment of Chemistry, University at Albany,State University of New York, Albany, NY 12222, USAE-mail: mpetrukhina@albany.eduThe long-standing mystery behind the structure formedby the highly reduced smallest fullerene fragment, thecorannulene tetraanion C20H104-, is now resolved [1].Notably, the above corannulene anion having one electron perfive carbon atoms is more electron rich than the hexaanion ofC606- (one electron per ten carbon atoms). The firstsingle-crystal X-ray diffraction analysis of its lithium saltreveals the formation of a sandwich-type supramolecularaggregate with a high degree of alkali metal intercalation. Incontrast to the previously proposed model based on in situNMR spectroscopy study, it is now revealed that five Li+ ionsare sandwiched between the two tetrareduced corannulenedecks to form the supramolecular dimer in the solid state. Thelatter also exists in solutions, as revealed by 7Li NMRspectroscopy. These results establish a new paradigm forlithium intercalation between the curved carbon surfaces ofbuckybowls, fullerenes, and nanotubes. Structuraldeformations caused by adding multiple electrons to abowl-shaped polyarene [2, 3] as well as self-assembly of theresulting non-planar carboanions in different solvent mediawill also be discussed and compared.[1] Zabula, A. V., Filatov, A. S., Spisak, S. N., Rogachev, A. Yu.,Petrukhina, M. A. (2011). Science 333, 1008-1011.[2] Spisak, S. N., Zabula, A. V., Filatov, A. S., Rogachev, A. Yu.,Petrukhina, M. A. (2011). Angew. Chem. Int. Ed. 50,8090-8094.[3] Zabula, A. V., Spisak, S. N., Filatov, A. S., Grigoryants, V.M., Petrukhina, M. A. (2012). Chem. Eur. J. VIP, in press.Keywords: curved polyarene; multi-electron reduction;metal bindingMS43-O5 Exploring the solid state conformation andassembly of cyclic peptoids derivatives. Loredana Erra,aConsiglia Tedesco,b Giovanna Cerasuolob, Chiara De Cola,bBrunello Nardone,b Irene Izzo,b Gavin Vaughan,a FrancescoDe Riccardisb aESRF, 6 rue Jules Horowitz, BP220, 38043Grenoble, France, bDipartimento di Chimica e Biologia,Università di Salerno, via Ponte don Melillo, I-84084Fisciano, ItalyE-mail: loredana.erra@esrf.frThe molecular conformation control is a key need in drugdesign: in fact, being inspired from the biological world, it isevident that the structure determines each single function abiological system expresses. The structure-function relation isthe concept to keep in mind to achieve results in drug relatedresearch fields.[1] Over the years it has been proved that thepolypeptides beeing chemically similar to the proteins, are thebest candidates to interact with them: in particular, cyclicpeptides form a class of compounds of crucial impact for thetratement of several diseases [2]. The preference on the cycliccompounds over the linear ones has some rationals: usually theconformational rigidity ensured by the cyclization correspondsto a better chemical stability together with an increased receptorselectivity. Indeed extensive efforts have been also devoted tosynthetise peptidomimentic compounds having an increasedproteolytic stability because of their abiotic character [3].Among them an interesting class of molecules are the cyclopeptoids. In general peptoids are oligomers of N-substitutedglycine. They differ from peptides because the side chain isattached to the backbone amide nitrogen instead of the á-carbon,the peptoid backbone is achiral and the lack of the amide protonprevents the formation of H-bonds involving this site. Moreovertertiary amide bonds can isomerise between cis and transconformation [4]. Here we report and analyze the solid statemolecular conformation and the crystal structure of two newderivatives: the cyclo hexa N-(benzyl) glycine 1 and cyclo[N-(benzyl)glycine-N-(t-butyldiphenylsilyloxyethyl)glycine]3 2[5]. Moreover we compare our results with the few ones alreadyreported [3] with the aim to rationalize how the chemicalinteractions inside the structures define both the molecularconformation and the general solid state assembly.Fig. 1 Molecular structure as obtained by X-ray single crystaldiffraction for the compounds 1 (left) and 2 (right).[1] Yoo, B., Shin, S. B. Y., Huang, M. L. & Kirshenbaum, K.(2010). Chem. Eur. J., 16, 5528-5537.[2] Katsara, M., Tselios, T., Deraos, S., Deraos, G., Matsoukas,M., Lazoura, E., Matsoukas, J. & Apostolopoulos, V. (2006).Cur. Med. Chem., 13, 2221-2232.[3] Shin, S. B. Y., Yoo, B., Todaro, L. J. & Kirshenbaum, K.(2007) J. Am. Chem. Soc., 129, 3218-3225.[4] Culf, A. S. & Ouellette, R. J. (2010) Molecules, 15,5282-5335.[5] Tedesco, C., Erra, L., Cerasuolo, G., De Cola, C., Nardone, B.,Izzo, I., Vaughan, G. & De Riccardis, F. in preparation.Keywords: peptoids; conformation; crystal structure124Oral Lectures – MS 43: Hot topics and structures in molecular chemistry

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Exploring the solid state conformation and assembly of cyclic peptoids derivatives

Exploring the solid state conformation and assembly of cyclic peptoids derivatives

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