3
4
5
6
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S. C. Colley, D. C. Grills, N. A. Besley, S. Jockusch, P. Matousek,
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15 parts diluent QM 672 (dicyclopentenyloxyethyl acrylate,
Rohm and Haas).
10 parts HDODA (hexanedioldiacrylate).
10 parts N-vinylpyrrolidone.
2% by weight of the photoinitiators 1, 2, exo-2, endo-2 or 5
were dissolved in the formulation. For the measurement of the
reactivity, the formulation was applied as a film of 60 mm
thickness onto white cardboard. These samples were passed
under a PPG UV processor unit using two mercury medium-
pressure lamps of 80 W cmꢀ1 output with a belt speed of 20
m minꢀ1. The irradiation was repeated until a fully cured sur-
face, measured by drilling a soft tissue on the surface, was
obtained. If no fully cured surface was obtained after 20
passes, the experiment was stopped. The results are collected
in Table 1.
7
8
9
R. Husler, W. Rutsch and K. Dietliker, in Eur. Pat. Appl. 97124,
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CIDNP
CIDNP-experiments were performed on two different NMR-
1
spectrometers: An earlier set of H- and 13C-experiments were
carried out on a Varian XL-100 Fourier spectrometer. The
UV-source was a 1 kW SP-1000 Philips mercury high pressure
lamp (continuous light irradiation). The light was filtered by
an aqueous solution of NiSO4 and CuSO4 to eliminate most
of the infrared and visible light. Two quartz lenses focused
the light onto the polished end of a Suprasil quartz rod that
served as a light guide.
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27 N. J. Turro, Modern Molecular Photochemistry, University
Science Books, New York, 1991.
NMR and a second set of CIDNP experiments were carried
out on a Bruker AVANCE DPX 200 spectrometer with a wide
bore magnet. In these experiments, the light source was a
Questek excimer laser in combination with a Lambda Physik
dye laser (342.5 nm). The duration of the laser pulse was ca.
10 ns and the radiofrequency 30ꢄ pulse 1.5 ms. The CIDNP
experiments were carried out in benzene-d6 , cyclohexane-d12
and acetonitrile-d3 .
Selective decoupling, DEPT, HETCOR,32 INAPT33,34 and
gs-HMBC35 experiments were performed using multinuclear
broad band probe head with z-gradient.
28 I. J. Panmer, I. N. Ragazos, F. Bernardi, M. Olivucci and M. A.
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33 A. Bax, J. Magn. Reson., 1984, 57, 314.
Quantum mechanical calculations
The Gaussian 98 A.736 software package was used for all QM
calculations. Both structure optimizations and single point
energy calculations were performed by the B3LYP/6-31G*
method.37,38 For the GIAO39 calculations of 13C chemical
shifts the 6-311+G(2d,p) basis set was employed.
GC-MS
34 A. Bax, J. A. Ferretti, N. Nashed and D. M. Jerina, J. Org.
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35 W. Willker, D. Leibfritz, R. Kerssebaum and W. Bermel, Magn.
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A HP Series II 5980 instrument equipped with a 25 m 5%
phenyl-methyl-silicone (OV-3, SE-52) column was used for
the GC-MS measurements.
36 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A.
Robb, J. R. Cheeseman, V. G. Zakrzewski, J. J. A. Montgomery,
R. E. Stratmann, J. C. Burant, S. Dapprich, J. M. Millam, A. D.
Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi, V.
Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C.
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Baboul, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I.
Komaromi, R. Gomperts, R. L. Martin, D. J. Fox, T. Keith,
M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, C. Gonzalez,
M. Challacombe, P. M. W. Gill, B. G. Johnson, W. Chen,
M. W. Wong, J. L. Andres, M. Head-Gordon, E. S. Replogle
and J. A. Pople, GAUSSIAN 98 (Revision A.7), Gaussian, Inc.,
Pittsburgh, PA, 1998.
Acknowledgements
G.R. acknowledges a very helpful discussion with Dr T.
Winkler, Syngenta, Basel.
We thank the Swiss National Science Foundation and Ciba
Specialty Chemicals Inc. for financial support.
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