Research Papers

39. V. Ladanyi, P. Dvorak, J. Al Anshori, L. Vetrakova, J. Wirz and D. Heger, Azobenzene photoisomerization quantum yields in methanol redetermined, Photochemical & Photobiological Sciences, 2017, 16, 1757-1761.

38. L. Vetrakova, V. Ladanyi, J. Al Anshori, P. Dvorak, J. Wirz and D. Heger, The absorption spectrum of cis-azobenzene, Photochemical & Photobiological Sciences, 2017, 16, 1749-1756.

  • Azobenzene is very elemental molecule - in was first described in 1834, it's cis isomer discovered in 1937, we had synthetized it in the basic organic practicum. Azobenzene found a plenty of applications, most notably as a molecular switch and as an actinometer (to measure the amount of light incident on the sample). We were therefore surprized to found significant inconsistency by using two actinometers: azobenzene and ferrioxalate. It turned out, that the absorption spectra of the individual forms were mutually contaminated previously. Here, we separated the spectra by careful chemical treatment and "smart" mathematical minimization. The quantum yields had to be redetermined accordingly. 

37. Ľ. Vetráková, V. Vykoukal and D. Heger, Comparing the acidities of aqueous, frozen, and freeze-dried phosphate buffers: Is there a “pH memory” effect?, International Journal of Pharmaceutics, 2017, 530, 316-325.

  • In this paper we show, that the pH jump occurs predominantly in the freezing step and can be masked by the following sublimation in the process of lyophilization. Therefore, the pH change should be assesed in both stages of sample stabilization (after freezing and after freeze-drying). 

36. Ju, J.; Kim, J.; Vetráková, Ľ.; Seo, J.; Heger, D.; Lee, C.; Yoon, H.-I.; Kim, K.; Kim, J. Journal of Hazardous Materials 2017, 329, 330.

35. Fiala, T.; Ludvíková, L.; Heger, D.; Švec, J.; Slanina, T.; Vetráková, L. u.; Babiak, M.; Nečas, M.; Kulhánek, P.; Klán, P.; Sindelar, V. J. Am. Chem. Soc. 2017, 139, 2597.

34. Yang, X.; Neděla, V.; Runštuk, J.; Ondrušková, G.; Krausko, J.; Vetráková, Ľ.; Heger, D. Atmos. Chem. Phys. 2017, 17, 6291.

33. Ludvikova, L.; Fris, P.; Heger, D.; Sebej, P.; Wirz, J.; Klan, P. Photochemistry of Rose Bengal in Water and Acetonitrile: A Comprehensive Kinetic Analysis. Physical Chemistry Chemical Physics 2016, , 18, 16266..

32. Krausková, Ľ.; Procházková, J.; Klašková, M.; Filipová, L.; Chaloupková, R.; Malý, S.; Damborský, J.; Heger, D. Suppression of Protein Inactivation During Freezing by Minimizing Ph Changes Using Ionic Cryoprotectants. International Journal of Pharmaceutics 2016, 509, 41-49. 

31. Krausko, J.; Ondrušková, G.; Heger, D., Comment on “Photolysis of Polycyclic Aromatic Hydrocarbons on Water and Ice Surfaces” and on “Nonchromophoric Organic Matter Suppresses Polycyclic Aromatic Hydrocarbon Photolysis in Ice and at Ice Surfaces”. The Journal of Physical Chemistry A 2015, 119 (43), 10761-10763.

30. Bownik, I.; Šebej, P.; Literák, J.; Heger, D.; Šimek, Z.; Givens, R. S.; Klán, P., 4-Hydroxyphenacyl Ammonium Salts: A Photoremovable Protecting Group for Amines in Aqueous Solutions. The Journal of Organic Chemistry 2015, 80 (19), 9713-9721.

29. Krausko, J.; Malongwe, J. K. E.; Bičanová, G.; Klán, P.; Nachtigallová, D.; Heger, D. Spectroscopic Properties of Naphthalene on the Surface of Ice Grains Revisited: A Combined Experimental–Computational Approach. The Journal of Physical Chemistry A 2015, 119, 8565-8578.

28. Krausko, J.; Runštuk, J.; Neděla, V.; Klán, P.; Heger, D., Observation of a Brine Layer on an Ice Surface with an Environmental Scanning Electron Microscope at Higher Pressures and Temperatures. Langmuir 2014, 30, 5441-5447.

27. Kania, R.; Malongwe, J. K. E.; Nachtigallová, D.; Krausko, J.; Gladich, I.; Roeselová, M.; Heger, D.; Klán, P., Spectroscopic Properties of Benzene at the Air–Ice Interface: A Combined Experimental–Computational Approach. The Journal of Physical Chemistry A 2014, 118, 7535-7547.

26. Solomek, T.; Heger, D.; Ngoy, B. P.; Givens, R. S.; Klan, P. The Pivotal Role of Oxyallyl Diradicals in Photo-Favorskii Rearrangements: Transient Spectroscopic and Computational Studies. J. Am. Chem. Soc. 2013, 135, 15209-15215.

25. Kammath, V. B.; Solomek, T.; Ngoy, B. P.; Heger, D.; Klan, P.; Rubina, M.; Givens, R. S. A Photo-Favorskii Ring Contraction Reaction: The Effect of Ring Size. Journal of Organic Chemistry 2013, 78, 1718-1729.

24. Kammath, V.B., et al., A Photo-Favorskii Ring Contraction Reaction: The Effect of Ring Size. The Journal of Organic Chemistry, 2012.

23. Klicova, L., et al., Adiabatic Triplet State Tautomerization of p-Hydroxyacetophenone in Aqueous Solution. Journal of Physical Chemistry A, 2012. 116(11): p. 2935-2944.

22. Walsh, Z., et al., Polymerisation and surface modification of methacrylate monoliths in polyimide channels and polyimide coated capillaries using 660 nm light emitting diodes. Journal of Chromatography A, 2011. 1218(20): p. 2954-2962.

21. Veetil, A.T., et al., Photochemistry of S-Phenacyl Xanthates. Journal of Organic Chemistry, 2011. 76(20): p. 8232-8242.

20. Roubal, Z., et al. The design of high-impedance and high-voltage input amplifier for measurement of electropotentials on solid-liquid phase boundary. 2011. Marrakesh.

19. Heger, D., et al., Self-Organization of 1-Methylnaphthalene on the Surface of Artificial Snow Grains: A Combined Experimental-Computational Approach. Journal of Physical Chemistry A, 2011. 115(41): p. 11412-11422.

18. Givens, R.S., et al., p-Hydroxyphenacyl photoremovable protecting groups - Robust photochemistry despite substituent diversity. Canadian Journal of Chemistry-Revue Canadienne De Chimie, 2011. 89(3): p. 364-384.

17. Kammari, L., et al., Orthogonal Photocleavage of a Monochromophoric Linker. Journal of the American Chemical Society, 2010. 132(33): p. 11431-11433.

16. Stensrud, K., et al., Competing Pathways in the Photo-Favorskii Rearrangement and Release of Esters: Studies on Fluorinated p-Hydroxyphenacyl-Caged GABA and Glutamate Phototriggers. Journal of Organic Chemistry, 2009. 74(15): p. 5219-5227.

15. Khan, M.S.A., et al., Remarkable Salt Effect on Stability of Supramolecular Complex between Modified Cueurbit[6]uril and Methylviologen in Aqueous Media. Journal of Physical Chemistry B, 2009. 113(32): p. 11054-11057.

14. Walsh, Z., et al., Photoinitiated polymerisation of monolithic stationary phases in polyimide coated capillaries using visible region LEDs. Chemical Communications, 2008(48): p. 6504-6506.

13. Stensrud, K.F., et al., Fluorinated photoremovable protecting groups: the influence of fluoro substituents on the photo-Favorskii rearrangement. Photochemical & Photobiological Sciences, 2008. 7(5): p. 614-624.

12. Givens, R.S., et al., The photo-Favorskii reaction of p-hydroxyphenacyl compounds is initiated by water-assisted, adiabatic extrusion of a triplet biradical. Journal of the American Chemical Society, 2008. 130(11): p. 3307-3309.

11. Heger, D. and P. Klan, Interactions of organic molecules at grain boundaries in ice: A solvatochromic analysis. Journal of Photochemistry and Photobiology a-Chemistry, 2007. 187(2-3): p. 275-284.

10. Born, R., et al., Photochromism of phenoxynaphthacenequinones: diabatic or adiabatic phenyl group transfer? Photochemical & Photobiological Sciences, 2007. 6(5): p. 552-559.

9. Plistil, L., et al., Photochemistry of 2-alkoxymethyl-5-methylphenacyl chloride and benzoate. Journal of Organic Chemistry, 2006. 71(21): p. 8050-8058.

8. Heger, D., J. Klanova, and P. Klan, Enhanced protonation of cresol red in acidic aqueous solutions caused by freezing. Journal of Physical Chemistry B, 2006. 110(3): p. 1277-1287.

7. Heger, D., J. Jirkovsky, and P. Klan, Aggregation of methylene blue in frozen aqueous solutions studied by absorption spectroscopy. Journal of Physical Chemistry A, 2005. 109(30): p. 6702-6709.

6. Zabadal, M., et al., Intramolecular triplet-triplet energy transfer in short flexible bichromophoric amino acids, dipeptides and carboxylic acid diester. Collection of Czechoslovak Chemical Communications, 2004. 69(4): p. 776-796.

5. Zabadal, M., et al., N-(1-Naphthylacetyl)glycine phenacyl ester and phenacyl (1-naphthylacetoxy)acetate. Acta Crystallographica Section C-Crystal Structure Communications, 2003. 59: p. O77-O79.

4. Literak, J., et al., Photochemistry of alkyl aryl ketones on alumina, silica-gel and water ice surfaces. Journal of Photochemistry and Photobiology a-Chemistry, 2003. 154(2-3): p. 155-159.

3. Klanova, J., et al., Comparison of the effects of UV, H2O2/UV and gamma- irradiation processes on frozen and liquid water solutions of monochlorophenols. Photochemical & Photobiological Sciences, 2003. 2(10): p. 1023-1031.

2. Klan, P., et al., Temperature-sensitive photochemical aromatic substitution on 4-nitroanisole. Photochemical & Photobiological Sciences, 2002. 1(12): p. 1012-1016.

1.Klan, P., M. Zabadal, and D. Heger, 2,5-dimethylphenacyl as a new photoreleasable protecting group for carboxylic acids. Organic Letters, 2000. 2(11): p. 1569-1571.


  1. Bartels-Rausch, T.; ., et al., A review of air–ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow. Atmos. Chem. Phys. 2014, 14, 1587-1633.
  2. McNeill, V.F., et al., Organics in environmental ices: sources, chemistry, and impacts. Atmos. Chem. Phys., 2012. 12: p. 9653-9678.


Publications Overview

  • 41 research papers, h-index: 15, Sum of the Times Cited: 744 (December 2017)