4. Photoelectron spectra of amines, nitroso and nitro compounds |
199 |
FIGURE 19. PE spectrum of nitrobenzene
TABLE 18. Ionization potentials IP (eV) of substituted nitrobenzenesa
NO2
R1
R2
R3
|
R1 |
R2 |
R3 |
nOC /nO / 2 |
Ar |
References |
|
|
|
|
|
11.1, 11.23 |
9.93, 10.35 |
144 |
|
|
Me |
|
|
11.05 |
9.66 |
141 |
|
|
|
Me |
|
10.73, 11.06 |
9.69, 10.04 |
141 |
|
|
|
|
Me |
10.88, 11.12 |
9.5, 10.03 |
141 |
|
|
F |
|
|
11.29 |
9.86, 10.37 |
141 |
|
|
|
F |
|
11.35 |
10.08, 10.47 |
141 |
|
|
|
|
F |
11.12, 11.34 |
10.06, 10.45 |
141 |
|
|
|
|
|
|
|||
|
a R1. . . R3 is H if not indicated otherwise |
|
|
|
|||
Other compounds |
containing |
a nitrobenzene |
unit like substituted benzamides145, |
||||
azobenzenes146, N-benzylideneanilines147 and donor acceptor cyclophanes148 have been investigated by PES. The PE spectrum of 1-methyl-3-nitro-2-phenylindole (68) has been measured130.
200 |
Paul Rademacher |
NO2
N
Me
(68)
C. Miscellaneous Nitro Compounds
The PE spectra and electronic structures of some nitroalkenes like nitroethene149 and the isomeric nitropropenes150, including their thermolysis151, have been studied recently. A correlation diagram for the experimentally determined ionization potentials for the nitropropenes is reproduced in Figure 20.
As expected for the electron-withdrawing effect of the nitro group, the CDC orbital is stabilized appreciably in the nitropropenes relative to propene. When compared with nitromethane, the orbitals localized on the nitro group are in general destabilized owing to the larger electron-donating ability of the propenyl group compared to the methyl group. Among the nitropropenes there are only minor shifts in the relative energies of the nO orbitals, but there are appreciable variations in the position of 2. Thus in 3-nitropropene2 lies more than 0.3 eV below that of 1-nitropropene.
N,N-Dimethylnitramine has been studied by Rabalais and coworkers136 by UV and X-ray PES and by Rao137. Besides the characteristic orbitals of the nitro group there is another high-lying -type orbital which is largely localized on the amine nitrogen atom and can be termed nN. The corresponding ionizations are generally found between 9 and 12.5 eV. IPs of some nitramines are given in Table 19.
|
|
|
|
|
|
|
|
|
10.03 |
πC |
C |
|
10 |
|
|
|
|
|
|
|
|
|
|
|
|
|
10.73 |
|
10.71 |
|
10.65 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
(eV) |
|
|
11.12 |
|
11.21 |
|
11.20 |
|
|
|
|
11 |
11.31 |
11.31 |
|
|
n+, n− |
|
|
||||
|
|
|
|
|
|
||||||
i |
|
|
11.40 |
|
|
0 |
0 |
|
|
||
E |
|
|
|
|
|
|
|
|
|
|
|
|
|
11.72 |
|
|
|
|
11.65 |
π2 |
|
|
|
|
|
CH3 |
H |
|
H |
|
H |
|
|
|
|
|
|
C |
C |
|
|
C |
C |
|
|
|
|
|
12 |
H |
NO2 |
|
H |
|
CH2NO2 |
|
|
||
|
|
|
|
|
|
||||||
|
|
CH3NO2 |
H |
|
CH3 |
|
|
|
H |
|
H |
|
|
|
C |
C |
|
|
|
C |
C |
|
|
|
|
|
H |
|
NO2 |
|
|
|
H |
|
CH3 |
FIGURE 20. Ionization potentials of nitropropenes, nitromethane and propene. Reproduced with permission from Reference 150
|
4. Photoelectron spectra of amines, nitroso and nitro compounds |
201 |
|||||
TABLE 19. Ionization potentials (eV) of nitramines R2N NO2 |
|
|
|
||||
R2N |
|
nO |
nOC |
2 |
nN |
References |
|
R D Me |
9.91 |
10.45 |
10.93 |
11.63 |
136 |
|
|
R D Et |
|
9.62 |
10.36 |
10.64 |
11.39 |
26 |
|
N |
|
9.73 |
10.40 |
10.69 |
11.37 |
26 |
|
|
N |
9.66 |
10.46 |
10.85 |
11.52 |
26 |
|
O |
N |
9.95 |
10.56, 10.84a |
11.10 |
11.63 |
26 |
|
|
N |
9.42 |
10.31 |
10.51, 10.67 |
11.26 |
26 |
|
|
|
|
|
|
|
|
|
a nO of morpholine oxygen atom.
V. ACKNOWLEDGEMENTS
The author wishes to express his gratitude to Mr Klaus Kowski for recording PE spectra and his technical assistance in the preparation of the manuscript. He is grateful to Dr Hubert Kuhn for assistance with OVGF calculations and to Mr W. Sicking for his help with MO plots. Financial support by the Fonds der Chemischen Industrie is gratefully acknowledged.
VI. REFERENCES
1.D. W. Turner, C. Baker, A. D. Baker and C. R. Brundle, Molecular Photoelectron Spectroscopy, Wiley-Interscience, London, 1970.
2.A. D. Baker and D. Betteridge, Photoelectron Spectroscopy. Chemical and Analytical Aspects, Pergamon Press, Oxford, 1972.
3.T. A. Carlson, Photoelectron and Auger Spectroscopy, Plenum Press, New York and London, 1975.
4.J. W. Rabalais, Principles of Ultraviolet Photoelectron Spectroscopy, Wiley, New York, 1977.
5.A. D. Baker and C. R. Brundle (Eds.), Electron Spectroscopy: Theory, Techniques and Applications, Vols. 1 5, Academic Press, London, 1977 1984.
6.R. E. Ballard, Photoelectron Spectroscopy and Molecular Orbital Theory, A. Hilger, Bristol, 1978.
7.J. Berkowitz, Photoabsorption, Photoionization and Photoelectron Spectroscopy, Academic Press, New York, 1979.
8.P. K. Ghosh, Introduction to Photoelectron Spectroscopy, Wiley, New York, 1983.
9.J. H. D. Eland, Photoelectron Spectroscopy, 2nd ed., Butterworths, London, 1984.
10.V. I. Nefedov and V. I. Vovna, Electron Structure of Chemical Compounds, Nauka, Moscow, 1987 (in Russian).
11.H. Bock, Angew. Chem., 89, 631 (1977); Angew. Chem., Int. Ed. Engl., 16, 613 (1977).
12.E. Heilbronner, in Molecular Spectroscopy (Ed. A. R. West), Heyden and Son Ltd., London, 1977, pp. 422 451.
13. |
N. Knopfel,¨ T. Olbricht and A. Schweig, in Physikalische Methoden in der |
Chemie (Eds. |
|
|
B. Schroder¨ and J. Rudolph), VCH Verlagsgesellschaft, Weinheim, 1985, pp. 205 |
|
227. |
|
|
||
14. |
J. W. Robinson, Handbook of Spectroscopy, CRC Press, Boca Raton, 1974; S. G. Lias, |
||
|
J. E. Bartmess, J. F. Liebman, J. L. Holmes, R. D. Levin and W. G. Mallard, J. Phys. Chem. Ref. |
||
|
Data, 17, Suppl. 1, 1 (1988); NIST Standard Reference Database 25, Structures and Properties, |
||
|
National Institute of Standards and Technology, Gaithersburg, MD, USA. |
|
|
15.A. D. Baker, J. Electron Spectrosc. Relat. Phenom., 66, 11 (1993).
16.D. W. Turner, J. Electron Spectrosc. Relat. Phenom., 73, R11 (1995).
17.T. Koopmans, Physica, 1, 104 (1934).
202 |
Paul Rademacher |
18.M. J. S. Dewar, E. G. Zoebisch, H. F. Healy and J. J. P. Stewart, J. Am. Chem. Soc., 107, 3902 (1985).
19.D. Danovich, Y. Apeloig and S. Shaik, J. Chem. Soc., Perkin Trans. 2, 321 (1993).
20.R. Sustmann and W. Sicking, Chem. Ber., 120, 1323 (1987).
21.K. Kimura, S. Katsumata, Y. Achiba, T. Yamazaki and S. Iwata, Handbook of HeI Photoeletron Spectra of Fundamental Organic Molecules, Japan Scientific Societies Press, Tokyo, 1981.
22.M. Takahashi, I. Watanabe and S. Ikeda, J. Electron Spectrosc. Relat. Phenom., 37, 275 (1985).
23.I. Morishima, K. Yoshikawa, M. Hashimoto and K. Bekki, J. Am. Chem. Soc., 97, 4283 (1975).
24.C. Cauletti, M. L. D. Vona, P. Gargano, F. Grandinetti, C. Galli and C. Lillocci, J. Chem. Soc., Perkin Trans. 2, 667 (1986).
25.J. B. Peel and G. D. Willett, Aust. J. Chem., 30, 2571 (1977).
26.P. Rademacher, K. Kowski and R. Poppek, unpublished results.
27.H. Bock, W. Kaim, M. Kira, H. Osawa and H. Sakurai, J. Organomet. Chem., 164, 295 (1979).
28.L. N. Domelsmith, L. L. Munchausen and K. N. Houk, J. Am. Chem. Soc., 99, 4311 (1977).
29.H. J. Haink, J. E. Adams and J. R. Huber, Ber. Bunsenges. Phys. Chem., 78, 436 (1974).
30.K. Yoshikawa, A. Matsui and I. Morishima, J. Chem. Soc., Perkin Trans. 2, 1057 (1977).
31.A. Nagy, J. C. Green, L. Szepes and L. Zanathy, J. Organomet. Chem., 419, 27 (1991).
32.H. Baumgaertel, H. W. Jochims, E. Ruehl, H. Bock, R. Dammel, J. Minkwitz and R. Nass, Inorg. Chem., 28, 943 (1989).
33.D. H. Aue, H. M. Webb and M. T. Bowers, J. Am. Chem. Soc., 97, 4136 (1975).
34.D. H. Aue, H. M. Webb and M. T. Bowers, J. Am. Chem. Soc., 98, 311 (1976).
35.H. Bock, I. Gobel,¨ Z. Havlas, S. Liedle and H. Oberhammer, Angew. Chem., 103, 193 (1991);
Angew. Chem., Int. Ed. Engl., 30, 187 (1991).
36.V. Chaplinski, K. Kowski, P. Rademacher and A. de Meijere, to be published.
37.G. Distefano, S. Pignataro, L. Szepes and J. Borossay, J. Organomet. Chem., 102, 313 (1975).
38.H. Burger,¨ G. Pawelke, R. Dammel and H. Bock, J. Fluorine Chem., 19, 565 (1982).
39.S. Cradock, E. A. V. Ebsworth, W. J. Savage and R. A. Whiteford, J. Chem. Soc., Faraday Trans. 2, 68, 934 (1972).
40.P. Livant, M. L. McKee and S. D. Worley, Inorg. Chem., 22, 895 (1983).
41.S. F. Nelsen, J. Org. Chem., 49, 1891 (1984).
42.J. P. Maier and D. W. Turner, J. Chem. Soc., Faraday Trans. 2, 69, 521 (1973).
43.H. Bock and W. Fuß, Chem. Ber., 104, 1687 (1971).
44.D. H. Aue, H. M. Webb, W. R. Davidson, M. Vidal, M. T. Bowers, H. Goldwhite, L. E. Vertal,
J.E. Douglas, P. A. Kollman and G. L. Kenyon, J. Am. Chem. Soc., 102, 5151 (1980).
45.P. Rademacher, G. Irsch, W. Sicking and E. -U. Wurthwein,¨ J. Mol. Struct., 197, 291 (1989).
46.F. P. Colonna, G. Distefano, S. Pignato, G. Pitacco and E. Valentin, J. Chem. Soc., Faraday Trans. 2, 71, 1572 (1975).
47.H. -J. Altenbach, D. Constant, H. -D. Martin, B. Mayer, M. Muller¨ and E. Vogel, Chem. Ber., 124, 791 (1991).
48.G. Spanka and P. Rademacher, J. Org. Chem., 51, 592 (1986).
49.G. Spanka, R. Boese and P. Rademacher, J. Org. Chem., 52, 3362 (1987).
50.D. H. Aue, H. M. Webb and M. T. Bowers, J. Am. Chem. Soc., 97, 4137 (1975).
51.G. Bieri and E. Heilbronner, Helv. Chim. Acta, 57, 546 (1974).
52.R. W. Alder, R. J. Arrowsmith, A. Casson, R. B. Sessions, E. Heilbronner, B. Kovac, H. Huber and M. Taagepera, J. Am. Chem. Soc., 103, 6137 (1981).
53.S. F. Nelsen, C. R. Kessel and D. J. Brien, J. Am. Chem. Soc., 101, 702 (1980).
54.C. Worrell, J. W. Verhoeven and W. N. Speckamp, Tetrahedron, 30, 3525 (1974).
55.M. K. Livett, E. Nagy-Felsobuki, J. B. Peel and G. D. Willett, Inorg. Chem., 17, 1608 (1978).
56.D. Colbourne, D. C. Frost, C. A. MeDowell and N. P. C. Westwood, Can. J. Chem., 57, 1279 (1979).
57.E. Nagy-Felsobuki, J. B. Peel and G. D. Willett, J. Electron Spectrosc. Relat. Phenom., 13, 17 (1978).
58.E. Nagy-Felsobuki and J. B. Peel, J. Electron Spectrosc. Relat. Phenom., 15, 61 (1979).
59.E. Nagy-Felsobuki and J. B. Peel, J. Chem. Soc., Faraday Trans. 2, 74, 1927 (1978).
60.F. Carnovale, T. -H. Gan and J. B. Peel, Aust. J. Chem., 32, 719 (1979).
61.V. Chaplinski, A. de Meijere, T. Haumann and R. Boese, to be published. An X-ray structure analysis of the hydrochloride salt has recently been published: M. L. Gillaspy, B. A. Lefker,
W.A. Hada and D. J. Hoover, Tetrahedron Lett., 41, 7399 (1995).
62.B. J. Cocksey, J. H. D. Eland and C. J. Danby, J. Chem. Soc. (B), 790 (1971).
63.M. D. Rozeboom and K. N. Houk, J. Am. Chem. Soc., 104, 1189 (1982).
4. Photoelectron spectra of amines, nitroso and nitro compounds |
203 |
64.K. Mutai, K. Kobayashi and T. Kobayashi, Chem. Lett., 1047 (1977).
65.N. Bodor, M. J. S. Dewar, W. B. Jennings and S. D. Worley, Tetrahedron, 26, 4109 (1970).
66.M. Klessinger and P. Rademacher, Angew. Chem., 91, 885 (1979); Angew. Chem., Int. Ed. Engl., 18, 826 (1979).
67.R. S. Brown and F. S. Jorgensen, Electron Spectroscopy: Theory, Techniques and Appli-
cations (Eds. C. R. Brundle and A. D. Baker), Vol. 5., Academic Press, London, 1984,
pp. 1 122.
68.D. G. Lister, J. K. Tyler, J. H. Hog and N. W. Larsen, J. Mol. Struct., 23, 253 (1974).
69.Y. Wang, S. Saebo and C. U. Pittman, J. Mol. Struct. (Theochem), 281, 91 (1993).
70.A. D. Baker, D. P. May and D. W. Turner, J. Chem. Soc. (B), 22 (1968).
71.T. Debies and J. W. Rabalais, J. Electron Spectrosc. Relat. Phenom., 1, 355 (1973).
72.S. A. Cowling and R. A. W. Johnstone, J. Electron Spectrosc. Relat. Phenom., 2, 161 (1973).
73.T. Kobayashi and S. Nagakura, Bull. Chem. Soc. Jpn., 47, 2563 (1974).
74.F. Marschner, Tetrahedron, 31, 2303 (1975).
75.M. H. Palmer, W. Moyes, M. Spiers and J. N. A. Ridyard, J. Mol. Struct., 53, 235 (1979).
76.J. Nordgren, L. Selander, L. Petterson, R. Brammer, M. Backstr¨om,¨ C. Nordling and H. Agren, Chem. Phys., 84, 333 (1984).
77.K. D. Jordan, J. A. Michejda and P. D. Burrow, J. Am. Chem. Soc., 98, 7189 (1976).
78.G. Distefano, A. G. Giumanini, A. Modelli and G. Poggi, J. Chem. Soc., Perkin Trans. 2, 1623 (1985).
79.X. Song, M. Yang, E. R. Davidson and J. P. Reilly, J. Chem. Phys., 99, 3224 (1993).
80.C. N. R. Rao, Tetrahedron, 32, 1561 (1976).
81.W. Rettig and R. Gleiter, J. Phys. Chem., 89, 4676 (1985).
82.P. Rademacher, V. -M. Bass, M. Wildemann and H. Weger, Chem. Ber., 110, 1939 (1977).
83.G. Distefano, G. Granozzi, R. Bertonello, P. R. Olivato and S. A. Guerro, J. Chem. Soc., Perkin Trans. 2, 1459 (1987).
84.D. G. Streets, W. E. Hall and G. P. Ceasar, Chem. Phys. Lett., 17, 90 (1972).
85.J. P. Maier and D. W. Turner, Discuss. Faraday Soc., 54, 149 (1972).
86.J. P. Maier, Helv. Chim. Acta, 57, 994 (1974).
87.L. Klasinc, B. Kovac and H. Gusten,¨ Pure Appl. Chem., 55, 289 (1983).
88.R. W. Alder, Chem. Rev., 89, 1215 (1989).
89.H. A. Staab and T. Saupe, Angew. Chem., 100, 895 (1988); Angew. Chem., Int. Ed. Engl., 27, 865 (1988).
90.H. -D. Martin and B. Mayer, Angew. Chem., 95, 281 (1983); Angew. Chem., Ed. Int. Engl., 22, 283 (1983).
91.D. K. Bohme in The Chemistry of Functional Groups. Supplement F: The Chemistry of Amino, Nitroso and Nitro Compounds and their Derivatives, Vol. 2 (Ed. S. Patai), Wiley, Chichester, 1982, pp. 731 762.
92.S. Campbell, E. M. Marzluff, M. T. Rodgers, J. L. Beauchamp, M. E. Rempe, K. F. Schwinck and D. L. Lichtenberger, J. Am. Chem. Soc., 116, 5257 (1994).
93.R. W. Alder and R. J. Arrowsmith, J. Chem. Res., (S), 163; (M), 2301 (1980).
94.E. Heilbronner, E. Honegger, J. Lecoultre, C. A. Grob. R. Houriet and E. Rolli, Helv. Chim. Acta, 69, 2114 (1986).
95.L. Klasinc, B. Rusic, A. Sabljic and N. Trinajstic, J. Am. Chem. Soc., 101, 7477 (1979).
96.R. W. Alder, R. J. Arrowsmith, C. St. J. Boothby, E. Heilbronner and Y. Zhong-zhi, J. Chem. Soc., Chem. Commun., 940 (1982).
97.P. Rademacher, Chem. Soc. Rev., 24, 143 (1995).
98.R. W. Alder and R. B. Sessions, in The Chemistry of Functional Groups. Supplement F: The Chemistry of Amino, Nitroso and Nitro Compounds and their Derivatives, Vol. 2 (Ed. S. Patai), Wiley, Chichester, 1982, pp. 763 803.
99.R. Hoffmann, Acc. Chem. Res., 4, 1 (1971).
100.M. Braga and S. Larsson, J. Phys. Chem., 96, 9218 (1992).
101.T. M. McKinney and D. H. Geseke, J. Am. Chem. Soc., 87, 3013 (1965).
102.P. Bischof, J. A. Hashmall, E. Heilbronner and V. Hornung, Tetrahedron Lett., 4025 (1969).
103.E. Heilbronner and K. A. Muszkat, J. Am. Chem. Soc., 92, 3818 (1970).
104.S. F. Nelsen and J. M. Buschek, J. Am. Chem. Soc., 96, 7930 (1974).
105. R. W. Alder, E. Heilbronner, E. Honegger, A. B. McEwen, R. E. Moss, E. Olefirowicz, P. A. Petillo, R. B. Sessions, G. R. Weisman, J. M. White and Z. -Z. Yang, J. Am. Chem. Soc., 115, 6580 (1993).
204 |
Paul Rademacher |
106.P. Rademacher, U. Schule,¨ H. -D. Beckhaus and C. Ruchardt,¨ J. Chem. Res., (S), 20; (M), 274 (1995).
107.H. -D. Martin and B. Mayer, Angew. Chem., 95, 281 (1983); Angew. Chem., Int. Ed. Engl., 22, 283 (1983).
108.R. Gleiter, M. Kobayashi and J. Kuthan, Tetrahedron, 32, 2775 (1976).
109.V. Galasso, J. Mol. Struct. (Theochem), 336, 47 (1995).
110.K. Beck, S. Hunig,¨ R. Poppek, F. Prokschy and P. Rademacher, Chem. Ber., 119, 554 (1986).
111.W. Schmidt, Tetrahedron, 29, 2129 (1973).
112.S. F. Nelsen and P. J. Hintz, J. Am. Chem. Soc., 94, 7114 (1972).
113.S. Peng, A. Padva and P. R. LeBreton, Proc. Natl. Acad. Sci. U.S.A., 73, 2966 (1976).
114.D. Dougherty, K. Wittel, J. Meeks and S. P. McGlynn, J. Am. Chem. Soc., 98, 3815 (1976).
115.C. Yu, S. Peng, I. Akiyama, J. Lin and P. R. LeBreton, J. Am. Chem. Soc., 100, 2303 (1978).
116.J. Lin, C. Yu, S. Peng, I. Akiyama, K. Li, L. K. Lee and P. R. LeBreton, J. Am. Chem. Soc., 102, 4627 (1980).
117.J. Lin, C. Yu, S. Peng, I. Akiyama, K. Li, L. K. Lee and P. R. LeBreton, J. Phys. Chem., 84, 1006 (1980).
118.S. Urano, X. Yang and P. R. LeBreton, J. Mol. Struct., 214, 315 (1989).
119.K. Tasaki, X. Yang, S. Fetzer and P. R. LeBreton, J. Am. Chem. Soc., 112, 538 (1990).
120.R. E. Ballard, J. Jones and D. Read, Chem. Phys. Lett., 121, 45 (1985).
121.T. P. Debies and J. W. Rabalais, J. Electron Spectrosc. Relat. Phenom., 3, 315 (1974).
122.L. Klasinc, J. Electron Spectrosc. Relat. Phenom., 8, 161 (1976).
123.L. Klasinc, Int. J. Quantum Chem., Quantum Biol. Symp., 5, 373 (1978).
124.W. Luttke,¨ P. N. Skancke and M. Traetteberg, Theor. Chim. Acta, 87, 321 (1994) and references cited therein.
125.H. Bergmann, S. Elbel and R. Demuth, J. Chem. Soc., Dalton Trans., 401 (1977).
126.N. P. Ernsting, J. Pfab, J. C. Green and J. Romelt,¨ J. Chem. Soc., Faraday Trans. 2, 76, 844 (1980).
127.H. Bergmann and H. Bock, Z. Naturforsch., 30B, 629 (1975).
128.R. Egdell, J. C. Green, C. N. R. Rao, B. G. Gowenlock and J. Pfab, J. Chem. Soc., Faraday Trans. 2, 72, 988 (1976).
129.J. W. Rabalais and R. J. Colton, J. Electron Spectrosc. Relat. Phenom., 1, 83 (1972/73).
130.M. Colonna, L. Greci, M. Poloni, G. Marrosu, A. Trazza, F. P. Colonna and G. Distefano, J. Chem. Soc., Perkin Trans. 2, 1229 (1986).
131.P. Dedeva, G. Fronzoni, G. de Alti and A. Lisini, J. Mol. Struct., 226, 265 (1991) and references cited therein.
132.F. A. Houle and J. L. Beauchamp, J. Am. Chem. Soc., 100, 3290 (1978).
133.D. R. Battiste, L. P. Davis and R. V. Nauman, J. Am. Chem. Soc., 97, 5071 (1975).
134.D. Betteridge, S. K. Hasanuddin and D. I. Rees, Anal. Chem., 48, 1078 (1976).
135.T. Kobayashi, Z. Physik. Chem., 97, 269 (1975).
136.M. G. White, R. J. Colton, T. H. Lee and J. W. Rabalais, Chem. Phys., 8, 391 (1975).
137.C. N. R. Rao, Ind. J. Chem., 14A, 147 (1976).
138.R. Ellerbrock and P. Rademacher, J. Mol. Struct., 265, 93 (1992).
139.J. W. Rabalais, J. Chem. Phys., 57, 960 (1972).
140.T. Kobayashi and S. Nagakura, Chem. Lett., 903 (1972).
141.M. H. Palmer, W. Moyes, M. Spiers and J. N. A. Ridyard, J. Mol. Struct., 55, 243 (1979).
142.S. Katsumata, H. Shiromaru, K. Mitani, S. Iwata and K. Kimura, Chem. Phys., 69, 423 (1982).
143.C. Y. Mok, W. S. Chin and H. H. Huang, J. Electron Spectrosc. Relat. Phenom., 57, 213 (1991).
144.W. S. Chin, C. Y. Mok, H. H. Huang, S. Masuda, S. Kato and Y. Harada, J. Electron Spectrosc. Relat. Phenom., 60, 101 (1992).
145.E. J. McAlduff, B. M. Lynch and K. N. Houk, Can. J. Chem., 56, 495 (1978).
146.S. Millefiori and A. Millefiori, Can. J. Chem., 59, 821 (1981).
147.L. Klasinc, B. Ruscic, G. Heinrich and H. Gusten,¨ Z. Naturforsch., Part B, 32, 1291 (1977).
148.R. Gleiter, W. Schafer¨ and H. A. Staab, Chem. Ber., 121, 1257 (1988).
149.L. Pasa-Tolic, L. Klasinc and S. P. McGlynn, Chem. Phys. Lett., 170, 113 (1990).
150.W. S. Chin, C. Y. Mok and H. H. Huang, J. Chem. Soc., Faraday Trans., 87, 1685 (1991).
151.W. S. Chin, C. Y. Mok and H. H. Huang, J. Am. Chem. Soc., 112, 2053 (1990).