Naslov
Study of the stable L-alanine radicals by advanced EPR spectroscopes

Autori
Rakvin, Boris

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
EPRBioDose 2010 International conference / - Mandelieu-La-Napoule, 2010, 82-82

Skup
EPRBioDose 2010 International conference

Mjesto i datum
Mandelieu-la-Napoule, Francuska, 10.10.2010. - 14.10.2010

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
L-alanin ; paramagnetski defekti
(L-alanine ; paramagnetic centers)

Sažetak
Study of the stable L-alanine radicals by advanced EPR spectroscopes B. Rakvin Ruđer Bošković Institute, P.O. Box 180, 10002, Zagreb, Croatia rakvin@irb.hr The first stable L-alanine radical, •CHCH3COOH, henceforth, SAR1, has been studied over many years and remains the most highly studied paramagnetic center of a simple amino acid in the solid form. It has been examined by various electron paramagnetic resonance, EPR, techniques including continuous wave (CW-EPR), electron nuclear double resonance (ENDOR), and other nonlinear EPR methods. Despite of these investigations, the molecular environment of the SAR1 regarding the unusual large shift of the central carbon atom, Cα, (containing 0.75 unpaired spin density) as well as the dynamic processes associated with motion of CH3 and NH3 groups, is still not fully understood. In the recent theoretical modeling of such centers SAR1 center was found restricted only on the center itself without any interaction with surrounding atoms. The environment of the SAR1 was studied by ENDOR spectroscopy1, 2, 3. The obtained results based only on distant proton splitting indicated that as the C-N bond ruptured and the SAR1 was formed the Cα atom shifted by distance of 1.5 Å. This finding was unexpected since atomic position usually remains in the closer vicinity of the original position in the irradiated crystal. Possible detection of NH3 may provide additional information that could help to explain complex environment of the SAR1 center in the L-alanine lattice. Recently, several advanced EPR methods such as Two-dimensional hyperfine sublevel correlation (2D-HYSCORE)4, Pulsed high field EPR5 and ENDOR6 have been applied to reach more accurate experimental parameters of stable radicals in L-alanine. The obtained results have been discussed as potential new elements for description of the environment, dynamics properties and stability of L-alanine radicals in the crystal lattice. 1S. –i. Kuroda, I. Miyagawa, J. Chem. Phys. 76 (1982) 3933. 2K. Matsuki, I. Miyagawa, J. Chem. Phys. 76 (1982) 3945. 3E. Sagstuen, E. O. Hole, S. R. Haugedal and W. H. Nelson, J. Phys. Chem. A101 (1997) 9763. 4B.Rakvin, N. Maltar-Strmečki, Chem. Phys. Lett. 415 (2005) 161. 6B. Rakvin, N. Maltar-Strmečki, R. Kappl and J. Hüttermann, Appl. Magn. Reson. 36 (2009), 275 5B. Rakvin, N. Maltar-Strmečki, D. Kattnig and G. Grampp ; Mol. Phys. 105 (2007), 2087.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

POVEZANOST RADA