208
R. Fausto and N. Kuş
the obtained population ratio at the photostationary state was explained based
on results of time-dependent dFt calculations. the potential energy profiles of
the excited states calculated as a function of the aldehyde group rotation showed
that all of S 1 , S 2 , and S 3 states have a minimum at the cis conformation, which is,
in those states, more stable than the trans conformation. In addition, the bright S 2
state shows a third minimum (global minimum) at a nearly perpendicular conformation of the aldehyde relatively to the molecule ring (~ 97°). Excitation of both
conformers with λ > 234 nm provides the excess energy of around 5.3 ev, which is
well above all the barriers on the S 2 surface and can be followed by fast internal
rotation in the S 2 excited state to the ∼ 97° minimum. Relaxation of S 2 from the
∼ 97° minimum can then produce either cis or trans ground state conformers by
internal rotation in S 0 . however, since the torsional coordinate at the minimum in
S 2 equals ∼ 97º, it is shifted in the direction of the trans conformer, thus leading to
the observed more favourable relaxation to this form [117].
Acknowledgements the authors thank all their colleagues involved in the studies described
in more detail in this Chapter. Finantial support from Fundação para a Ciência e a Tecnologia
(FCt – Portugal) is acknowledged.
References
1. Rosemeyer h (2004) Chem Biodiversity 1:361
2. Fischer E (1899) Ber deutsch Chem gesellschaft 32:2550
3. Yamada h, okamoto t (1972) Chem Pharm Bull 20:623
4. movassaghi m, hill md (2006) J Am Chem Soc 128:14254
5. Nelson dL, Cox mm (2008) Principles of biochemistry, 5th edn. W. h. Freeman and Company, pp. 272–274
6. Schertler gFX (2008) Nature 453:292
7. Saunders J (2003) Nature Rev microbiol 1:6
8. Sabbert d, Engelbrecht S, Junge W (1996) Nature 381:623
9. Whittle E, dows dA, Pimentel gC (1954) J Chem Phys 22:1943
10. Norman I, Porter g (1954) Nature 174:508
11. Lin CY, Krantz A (1972) J Chem Soc Chem Commun 1111/1112:1316
12. Chapman oL, mcIntosh CL, Pacansky J (1973) J Am Chem Soc 95:244
13. Pong RgS, Shirk JS (1973) J Am Chem Soc (95) 248
14. Breda S, Reva I, Lapinski L, Fausto R (2004) Phys Chem Chem Phys 6:929
15. Rochkind mm (1967) Anal Chem 39:567
16. Perutz RN, turner JJ (1973) J Chem Soc Faraday trans 2(69):452
17. Barnes AJ, Bignall JC, Purnell CJ (1975) J Raman Spectrosc 4:159
18. Fausto R, gómez-Zavaglia A (2009) Light-induced reactions in cryomatrices. In: Abini A
(ed) Specialist periodical reports—photochemistry, vol 37. the Royal Society of Chemistry
Publishing, pp 72–109
19. Fausto R, gómez-Zavaglia A (2010) Light-induced reactions in cryomatrices. In: Abini A
(ed) Specialist periodical reports—photochemistry, vol 38. the Royal Society of Chemistry
Publishing, pp 37–66
20. Fausto R, gómez-Zavaglia A (2011) Light-induced reactions in cryomatrices. In: Abini A
(ed) Specialist periodical reports—photochemistry, vol 39. the Royal Society of Chemistry
Publishing, pp 1–29
R. Fausto and N. Kuş
the obtained population ratio at the photostationary state was explained based
on results of time-dependent dFt calculations. the potential energy profiles of
the excited states calculated as a function of the aldehyde group rotation showed
that all of S 1 , S 2 , and S 3 states have a minimum at the cis conformation, which is,
in those states, more stable than the trans conformation. In addition, the bright S 2
state shows a third minimum (global minimum) at a nearly perpendicular conformation of the aldehyde relatively to the molecule ring (~ 97°). Excitation of both
conformers with λ > 234 nm provides the excess energy of around 5.3 ev, which is
well above all the barriers on the S 2 surface and can be followed by fast internal
rotation in the S 2 excited state to the ∼ 97° minimum. Relaxation of S 2 from the
∼ 97° minimum can then produce either cis or trans ground state conformers by
internal rotation in S 0 . however, since the torsional coordinate at the minimum in
S 2 equals ∼ 97º, it is shifted in the direction of the trans conformer, thus leading to
the observed more favourable relaxation to this form [117].
Acknowledgements the authors thank all their colleagues involved in the studies described
in more detail in this Chapter. Finantial support from Fundação para a Ciência e a Tecnologia
(FCt – Portugal) is acknowledged.
References
1. Rosemeyer h (2004) Chem Biodiversity 1:361
2. Fischer E (1899) Ber deutsch Chem gesellschaft 32:2550
3. Yamada h, okamoto t (1972) Chem Pharm Bull 20:623
4. movassaghi m, hill md (2006) J Am Chem Soc 128:14254
5. Nelson dL, Cox mm (2008) Principles of biochemistry, 5th edn. W. h. Freeman and Company, pp. 272–274
6. Schertler gFX (2008) Nature 453:292
7. Saunders J (2003) Nature Rev microbiol 1:6
8. Sabbert d, Engelbrecht S, Junge W (1996) Nature 381:623
9. Whittle E, dows dA, Pimentel gC (1954) J Chem Phys 22:1943
10. Norman I, Porter g (1954) Nature 174:508
11. Lin CY, Krantz A (1972) J Chem Soc Chem Commun 1111/1112:1316
12. Chapman oL, mcIntosh CL, Pacansky J (1973) J Am Chem Soc 95:244
13. Pong RgS, Shirk JS (1973) J Am Chem Soc (95) 248
14. Breda S, Reva I, Lapinski L, Fausto R (2004) Phys Chem Chem Phys 6:929
15. Rochkind mm (1967) Anal Chem 39:567
16. Perutz RN, turner JJ (1973) J Chem Soc Faraday trans 2(69):452
17. Barnes AJ, Bignall JC, Purnell CJ (1975) J Raman Spectrosc 4:159
18. Fausto R, gómez-Zavaglia A (2009) Light-induced reactions in cryomatrices. In: Abini A
(ed) Specialist periodical reports—photochemistry, vol 37. the Royal Society of Chemistry
Publishing, pp 72–109
19. Fausto R, gómez-Zavaglia A (2010) Light-induced reactions in cryomatrices. In: Abini A
(ed) Specialist periodical reports—photochemistry, vol 38. the Royal Society of Chemistry
Publishing, pp 37–66
20. Fausto R, gómez-Zavaglia A (2011) Light-induced reactions in cryomatrices. In: Abini A
(ed) Specialist periodical reports—photochemistry, vol 39. the Royal Society of Chemistry
Publishing, pp 1–29