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COST 06
Electron driven
reactions in biosystems
Eugen Illenberger
and coworkers
Institut fuer Chemie und Biochemie
Physikalische und Theoretische Chemie
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Radiation Damage
Cancer Therapy
Electron driven rections
Interaction of Radiation with Biological Matter (Water)
0 5 10 15 20 25 300,0
0,1
Sec
onda
ry E
lect
ron
Dis
tribu
tion
Electron Energy (eV)
V. Cobut et al. Rad. Phys.Chem. 51, 229 (1998)
H2O → H2O* → H + OH
H2O → H2O+ + e-
Ionization
Excitation
Attachment
e-aqu
H+ + OH
104 electronsper 1 Mevprimary quanta
Sanche a.c. Science, 287 (2000) 1659
Plasmid DNA
Léon Sanche et al., PRL 93 (2004) 068101
Single strand breaksPlasmid DNA
Hydrogen loss from gas phase T
Léon Sanche et al.PRL 93 (2004) 068101
Molecular mechanisms for direct damage of DNA by low energy electrons
Operation of a radiosensitiser
Subexcitation energies (< 3eV) SSBs
Higher Energies (< 5eV): DSBs and SSBs
Guanine C5N5H5O: 78 electrons
ElectronMonochromator
Molecular Beam
Quadrupole
Faraday Cup
StagnationChamber
Skimmer
Detector
Nozzle
Computer
Laser (IR, UV)
e- + M → M-# → R + X-
EA(T-H) ≈ 3 - 4 eV
Sascha Gohlke et al.PRL 92 (2004) 168103
Thymine:
e-+T→T-# → (T-H)-+ H
�� � ��
DissociationAutodetachment
��
��
ResonantCapture
Thymine
Deuterated Thymine
(M-H)- but no (M-D)-
⇒ H loss from N sites
PRL 92 (2004) 168103
Capture of electrons at subexcitation energies
Bond selective decompositions: σ*(C-I) MOs
Site selective decompositions
Gas Phase
µ
Dipole moment: µ(T) ≈ 4.5 D
+
1
3
6
+ -
e-
Dipole-bound state
µ ≥ 2 D
Paul Burrow et al. Phys. Rev. Letters 92 (2004) 068102
Dipole supported vibrational Feshbach resonance
0 1 2 3 40
2
4
6
8
10
12C
ross
sect
ion
(Å2 )
Electron energy (eV)
π*
1
3
DB state
T-A Pairing
1 eV
1.8 eV
R. Barrios, P Skurski and J. Simons, JPC B 106 (2002) 7991
Simons et al. JACS 126 (2004) 6441.
No transfer of excess chargeinitially localised on T
• H. A.Carime et al., Chem. Phys. Letters 387 (2004) 267.• S. Ptasinska et al., Angew. Chem. Int. Ed. (in print).
1.8 eV
Ribose: equilibrium in liquid phase
Thermal evaporation: pyranosyl form in gas phase (Guler, Yu, Kentämaa, JPC 106 (2002) 6754)
Electron Interaction with Deoxyribose: S. Ptasinska, S. Denifl, P. Scheier, T. D. Märk, J. Chem. Phys. 120 (2004) 8505
M: Ribose 150 amu (C5H10O5) ⇒ 132amu/114 amu13C ribose 151 amu ⇒ 133amu/115 amu(C1-D) ribose 151 amu ⇒ 133amu/115 amu ⇒ no H2O loss from C1
(M-H2O)-
(M-2H2O)-
C4H5O3- + CO2 + H2 + H
C4H6O3- + CO2 + H2
⇒ selective excision of C5 ⇒ C1 and D remain on negative ion
Ilko Bald, Janina Kopyra, EI, submitted
C4H4O2- + CO2 + CH3OH + H2
Excision of 2 C containing units ⇒ C5 and D remain on negative ion fragment
Ilko Bald, Janina Kopyra, EI, submitted
Ilko Bald, Janina Kopyra, EI, submitted
HCOO- appears as DCOO- or H13C1OO-
Excision of DNA Base
Strand break
• No transfer of excess electrons from NBs to the backbone
• Sugar unit is very sensitive
• Phosphate group is sensitive
Respond of the Hydrogen Bridge?
1 eV
1.8 eV
HCOOH formic acid
Cluster Experiments(Supersonic beam)
CF3COOH / CF3COOD
• strong enhancement of electron capture cross section
• chemical reactions induced at very low energy
• No transfer of excess electrons from NBs to the backbone
• Sugar unit is very sensitive
• Phosphate group is sensitive
• Hydrogen bridge is sensitive
⇒Molecular mechanism(s) for strand breaks not yet clear
Subexcitation energies:
Bond-selective abstraction
of H- from thymine
S. Ptasinska, S. Denifl et al.
Angew. Chem. Int. Ed. 44 (2005) 2
(Innsbruck-Berlin)
D/eV
N1-H 4.4N3-H 5.8CH2-H 4,5C6-H 4.9
EA(H)=0.75 eV
S. Ptasinska, S. Denifl et al., Angew. Chem. Int. Ed. (in print).
(A-CN)-
CN- / C=CH2-
e- + T → T-# → (M-H)- + H
Quantum Chemistry Quantum Chemistry
Scattering Calculation
(F. Gianturco)
Hybridization
Tihomir Solomun et al. Eur. J. Physics D 35 (2005) 437.
Tilmann Märk, Paul Scheier, Universität InnsbruckRoger Azria, Université Paris Sud, OrsayNigel Mason, UCL London/ Open U. Milton KeynesStefan Matejcik, Michal Stano, Jan D. Skalny, Comenius University, BratislavaMichael Huels, Léon Sanche, Université de Sherbrooke, QuébecE. Krishnakumar, S.V. K. Kumar, Tata Institute, BombayAlexei Khrapak, Boris Smirnov, Dmitry Zhukhovitskii, Russian Academy of ScienceFranco Gianturco, Rome
Sascha Gohlke Janina KopyraRichard Balog Andrzej RosaJudith Langer Tibor SedlackoEsther Fischbach Constanze KönigIlko Bald Tomas SkalickyIsabel Martin Michal StanoHassan Abdoul-Carime Tihomir SolomunWerner F. Schmidt Jessica ScheikeMario Orzol
FU Berlin
Deutsche Forschungsgemeinschaft (DFG)European Union (EPIC, COST, EIPAM)Volkswagen StiftungBundesministerium für Wirtschaft und Arbeit (BMWA)INNOVENT Jena
Alexander-von-Humboldt-StiftungDeutscher Akademischer Austausch Dienst (DAAD)
Freie Universität Berlin
NATO Research Council
