Assignment of the He@C84 isomers in experimental NMR spectra using density functional calculations

0350727 - ÚOCHB 2011 RIV NL eng J - Journal Article
Štěpánek, P. - Bouř, Petr - Straka, Michal
Assignment of the He@C84 isomers in experimental NMR spectra using density functional calculations.
Chemical Physics Letters. Roč. 500, 1/3 (2010), s. 54-58. ISSN 0009-2614. E-ISSN 1873-4448
R&D Projects: GA ČR GA203/09/2037
Grant - others:7th European Community Framework Program(XE) 230955
Institutional research plan: CEZ:AV0Z40550506
Keywords : 3He NMR * density functional theory * endohedral fullerenes
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.282, year: 2010

The 3He chemical shifts were calculated for Hen@C84 (n = 1, 2) fullerenes to obtain characteristic NMR patterns for distinguishing their isomers in a mixture. The density functional methods were calibrated on experimental data. Accuracy within 1 ppm could be reached without further fitting of individual shifts. Such precision allows for a semi-quantitative assignment of 3He NMR spectra. Additional criteria in the identification are discussed, such as the relative energies of the isomers, positions of the satellite di-helium peaks, and the differential 3He shifts in the fullerenes reduced to anions. Endohedral 3He shifts are predicted for so far experimentally unknown He@C84 and He@C84(6-) isomers.
Permanent Link: http://hdl.handle.net/11104/0006146