G. Kaupp / Journal of Molecular Structure 786 (2006) 140–156
155
report based on an ab initio calculation proposes to try the
ozone isomerization via vibrational transitions along the
ground electronic surface [51].
[10] G. Kaupp, E. Teufel, H. Hopf, First spectroscopic detection of diradicals
in photocycloreversions, Angew. Chem. Int. Ed. Engl. 18 (1979)
2
15–217.
[
[
[
11] S. Ishikawa, J. Nakamura, S. Nagakura, Observation of intramolecular
excimer emission of benzyl radical pair produced by photolysis of [2.2]
paracyclophane, Bull. Chem. Soc. Jpn 53 (1980) 2476–2480.
12] P. Seiler, J. Wirz, Structure and photochemical reactivity. Photohydro-
lysis of trifluoromethyl-substituted phenols and naphthols, Helv. Chim.
Acta 55 (1972) 2693–2712.
4
. Conclusions
Irradiations in hard solvent glass matrices have important
advantages and complement (rare) gas matrix techniques. This
has been shown by very diverse applications. It was possible to
challenge some undue claims of fast transient spectroscopy and
so-called ‘adiabatic photochemistry’, which did not consider or
discuss the results of matrix isolation photochemistry and
spectroscopy. In particular, the highly structured stable
diradical [10] and quinodimethane spectra [9] of 2, 3, and 4
should not have been disregarded. The stable charge separation
at 15–77 K provided a new basis for single photo electron
transfer (PET) by the recording of apparently not otherwise
obtainable radical anion spectra. Furthermore, the occurrence
of chemiluminescence from photochemically produced short-
lived diradicals has been introduced. It is important to note that
minor temperature changes from 77 to 83 K in common
organic solvent glasses can make profound differences in the
photochemical outcome. New highly labile products such as
the zwitter ions 22 and 24 by hydrogen transfer within
technically used photostabilizers require biphotonic pulsed
laser irradiation at 10 K or slightly above. This secures the
mechanistic proposals for their most valuable action. The same
is true for the blue photostabilizer 38, which requires the
absorption of two photons for stable triaziridine formation at
13] T. Otsubo, H. Horita, S. Misumi, Layered compounds. Part XL. Studies
on the syntheses of multilayered [2.2]paracyclophanes, Synth. Commun.
6 (1976) 591–595.
[14] Union Carbide Corp., USA, Manufacture of [2C2] paracyclophane, EP
94651 A1 19881214, priority US 87-53730 19870526, Chem. Abstr. 110
1989) 135905.
2
(
[
15] T. Otsubo, S. Mizogami, I. Otsubo, Z. Tozuka, I. Otsubo, Y. Sakata,
S. Misumo, Layered compounds. XV. Synthesis and properties of
multilayered cyclophanes, Bull. Chem. Soc. Jpn 46 (1973) 3519–3530.
[16] J.M. Pearson, H.A. Six, D.J. Williams, M. Levy, Spectroscopic studies of
quinodimethanes, J. Am. Chem. Soc. 93 (1971) 5034–5036.
[
[
[
17] W. Gilb, K. Menke, H. Hopf, Cyclophanes. 5. [2.2.2.2] (1,2,3,5)
cyclophane, Angew. Chem. Int. Ed. Engl. 16 (1977) 191–192.
18] J. Kleinschroth, H. Hopf, Cyclophanes. 10. [2.2.2.2] (1,2,3,4) cyclophane,
Angew. Chem. Int. Ed. Engl. 18 (1979) 329–330.
6
19] Y. Sekine, V. Boekelheide, A study of the synthesis and properties of [2 ]
(1,2,3,4,5,6)cyclophane (superphane), J. Am. Chem. Soc. 103 (1981)
1777–1785.
[
[
[
20] G. Kaupp, D. Schmitt, Chemiluminescence of diradicals from lepidopter-
ene, dibenzylidenetriasterane, and diphenylbicyclooctadiene, Chem. Ber.
1
13 (1980) 3932–3936.
21] C.M. Brennan, R.A. Caldwell, J.E. Elbert, D.J. Unett, Nonvertical triplet
excitation transfer to arylalkene acceptors: further evidence that double
bond torsion is unimportant, J. Am. Chem. Soc. 116 (1994) 3460–3464.
22] H.D. Becker, K. Sandros, On the relationship between fluorescence and
molecular geometry. Formation of
a luminescent intramolecular
1
0–85 K. Also, the successful formations of cyclo-sulfur
anthracene-ethylene exciplex by electronic excitation of lepidopterene,
Chem. Phys. Lett. 55 (1978) 498–502.
dioxide and cyclo-nitro groups pave the way for the generation
and detection of cyclo-ozone with world-wide impact for the
atmosphere, a highly important project [46].
[
[
23] J. Ferguson, R.J. Robbins, G.J. Wilson, Photophysics and photochemistry
of lepidopterene: ground-state processes, J. Phys. Chem. 90 (1986)
4
222–4224.
24] W. Adam, K. Schneider, M. Stapper, S. Steenken, Multiple-photon
chemistry of 9-(phenoxymethyl)- and 9,10-bis(phenoxymethyl)anthra-
cenes in the laser jet: generation, photochemistry, and time-resolved laser-
flash spectroscopy of anthracenylmethyl radicals and pulse radiolysis of
References
[
[
[
[
1] H. Hayashi, S. Nagakura, Y. Ito, Y. Umehara, T. Matsuura, Laser-
photolysis study of biradical formation from the triplet state of 2,4,6-
triisopropylbenzophenone, Chem. Lett. (1980) 939–942.
9
-(bromomethyl)anthracene, J. Am. Chem. Soc. 119 (1997) 3280–3287.
[
25] K. Tokumura, N. Mizukami, M. Udagawa, M. Itoh, Doublet-doublet
fluorescence and coupling reactions of 9-anthrylmethyl radical in fluid
hexane solution studied by two-step laser excitation fluorescence
spectroscopy, J. Phys. Chem. 90 (1986) 3873–3876.
2] P.J. Wagner, M.A. Meador, B. Zhou, B.S. Park, Photocyclization of a-(o-
Tolyl)acetophenones: triplet and 1,5-biradical reactivity, J. Am. Chem.
Soc. 113 (1991) 9630–9639.
0
3] M.A. Miranda, E. Font-Sanchis, J. Perez-Prieto, J.C. Scaiano, The 4,4 -(1,
[
[
[
26] H.D. Becker, K. Sandros, K. Andersson, Adiabatic photoreactions
involving anthracenes. Intramolecular exciplex formation by photolytic
cycloreversion, Chem. Phys. Lett. 77 (1981) 246–252.
2-ethanediyl)bisbenzyl biradical: its generation, detection, and (photo)
chemical behavior in solution, J. Org. Chem. 66 (2001) 2717–2721.
4] C.R. Flynn, J. Michl, p,p-Biradicaloid hydrocarbons. o-Xylylene.
Photochemical preparation from 1,4-dihydrophthalazine in rigid glass,
electronic spectroscopy, and calculations, J. Am. Chem. Soc. 96 (1974)
27] J. Ferguson, R.J. Robbins, G.J. Wilson, Photophysics and photochemistry
of coupled chromophores: lepidopterenes and its dimethyl derivative,
J. Phys. Chem. 88 (1984) 5193–5197.
3280–3288.
28] G. Kaupp, Laser research and technology, pre-investigation to light-
induced processes with lasers in Federal Ministry for Research and
Technology (BMFT), Final Report 13N5517/5, Bonn, Germany, pp. 1-63;
publication date: April 1992, distributed via Technical Information
Library TIB Hannover, Germany.
[
5] E. Migirdicyan, J. Baudet, On the electronic spectra of o- and m-xylylenes
and their methylated derivatives. An experimental and theoretical study,
J. Am. Chem. Soc. 97 (1975) 7400–7404.
[
6] K.L. Tseng, J. Michl, An approach to biradical-like species. Spectroscopy
of o-xylylene in argon matrix, J. Am. Chem. Soc. 99 (1977) 4840–4842.
7] P.M. Johnson, A.C. Albrecht, Assignment of excited electronic states of
benzyl radical by the method of three-step photoselection, J. Chem. Phys.
[
[29] G. Kaupp, E. Jostkleigrewe, Laser photolysis, a new means of charge
separation, Angew. Chem. Int. Ed. Engl. 21 (1982) 436–437 (Angew.
Chem. Suppl. (1982) 1089–1099).
48 (1968) 851–865.
[
[
8] G. Porter, E. Strachan, The electronic spectra of benzyl, Spectrochim.
Acta 12 (1958) 299–304.
[30] J. Ivanic, G.J. Atchity, K. Ruedenberg, Violation of the weak noncrossing
rule between totally symmetric closed-shell states in the valence-
9] G. Kaupp, [6C6] Photocleavages of [2.2]cyclophanes, Angew. Chem.
Int. Ed. Engl. 15 (1976) 442–443.
isoelectronic series O
4307–4317.
3 3 2 2
, S , SO , and S O, J. Chem. Phys. 107 (1997)