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Institute of Chemical Process Fundamentals ASCR, v.v.i. Prague |
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(For current information click here) |
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People |
Head: J. Schraml
Deputy: J. Horacek
Research staff: M. Bartlova, V. Blechta, J. Karban, M. Kurfurst, E. Machackova, L. Soukupova, J. Sykora
Technical staff: J. Lnenickova, P. Nedvedova
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Fields of research |
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Applied research |
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Research projects |
Advanced techniques for 29Si NMR spectrometry
(J. Schraml, supported by GACR, grant No. GA203/06/0738)
Two topics - 29Si-13C spin-spin coupling constants and LC-29Si-NMR - are integrated under this project. The newly developed methods for measurements of the coupling constant and their relative signs [Ref. 1] enable otherwise difficult line assignments and comparison with theory [Ref. 7]. In the field of LC-NMR the aims of the project were already met in the previous year.
Reactivity of asymmetrically substituted epimino pyranoses
(J. Karban, joint project with CU, supported by ASCR, grant No. IAA400720703)
Methods of fluorine introduction in the vicinity of the aziridine ring of 1,6-anhydro-2,3,4-trideoxy-2,3-epimino-?-D-ribo/lyxo-pyranoses were studied. Cleavage of suitable dianhydro derivatives (carbohydrate epoxides) with KHF2 appears to be the most promising synthetic approach. An alternative approach utilizes clevage of 3,4-aziridines with F- on reaction with DAST followed by aziridine ring closure at positions 2,3. The study of the aziridine ring cleavage of 1,6-anhydro-2,3,4-trideoxy-2,3-tosylepimino-?-D-lyxo-pyranose continued and revealed that the nucleophilic cleavage reactions provided products of both trans-diaxial and trans-diequatorial cleavage depending on the reaction condition and the nucleophile. Conformation and conformational flexibility of 1,6-anhydro-epiminohexopyranoses was assessed by an X-ray analysis of a complete series of all configurational isomers of 2,3- and 3,4-aziridine derivatives [Ref. 9].
Structure of silyl moieties through J(29Si-13C) couplings as determined by triple {1H, 13C}29Si NMR experiment
(J. Schraml, supported by ASCR, grant No. IAA400720706)
New methods for measurement of spin-spin couplings between 29Si and 13C nuclei in solutions utilize instrumental possibilities of triple resonance of 1H-13C-29Si nuclei which enhance the sensitivity to the extent that expensive isotopic enrichment, common for bio-NMR, is not needed [Ref. 11]. The developed methods were extended to 15N couplings [Ref. 4]. Using these experiments model series of compounds are measured and calculated [Ref. 8] to produce the dependence of the vicinal 29Si-13C couplings on dihedral angles and, subsequently, also the dependence on the nature of substituents.
29Si-NMR structural analysis of branched organosilicon polymers and its application in LC-NMR
(J. Kurfurst, supported by GACR, grant No. GP203/08/P412)
Project objective is to evolve generally applicable NMR method for structural analysis of branched siloxanes based on Si-Si connectivity. Besides the well-known methods, new pulse sequences employing gradient and shaped pulses will be developed. Experiments will be initially conducted on commercially available model compounds; in later phase of project series of models will be synthesized. The research will advance from simple linear and branched oligosiloxanes towards to more complex macromolecules. Simultaneously, developed methods will be adapted for HPLC analysis of organosilicon polymers and copolymers with 29Si NMR detection in stop-flow mode.
Click here for explanation of abbreviations used on this page.
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International cooperations |
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Teaching |
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Publications |
Original papers
1. Blechta V., Schraml J.: Relative Signs of 29Si-13C Couplings. Magn. Reson. Chem. 46(8), 734-738 (2008).
2. Kurfurst M., Kozmik V., Svoboda J., Novotna V., Glogarova M.: Liquid Crystalline Benzothiophene Derivatives. Liq. Cryst. 35(1), 21-31 (2008).
3. Posta M., Cermak Jan, Sykora J., Vojtisek P., Cisarova I., Fajgar R.: Square-Planar Diphosphinoazine Rhodium(I) Amido Carbonyl Complexes with an Unsymmetrical PNP’ Pincer-type Coordination. J. Organomet. Chem. 693(11), 1997-2003 (2008).
4. Schraml J., Cigler P.: 15N–1H and 15N–13C Couplings in 15N-Enriched Dihydroxamic Acids. Magn. Reson. Chem. 46(8), 748-755 (2008).
5. Stibor I., Budka J., Michlova V., Tkadlecova M., Pojarova M., Curinova P., Lhotak P.: Systematic Approach to New Ligands for Anion Recognition Based on Ureido-4. New J. Chem. 1597-1607 (2008).
6. Storch J., Cermak Jan, Posta M., Sykora J., Cisarova I.: Palladium(II) Aryl-amido Complexes of Diphosphinoazines in Unsymmetrical PNP‘ Pincer-type Configuration. J. Organomet. Chem. 693(18), 3029-3034 (2008).
7. Sychrovsky V., Benda L., Prokop A., Blechta V., Schraml J., Spirko V.: Probing the Flexibility of Internal Rotation in Silylated Phenols with the NMR Scalar Spin-Spin Coupling Constants. J. Phys. Chem. A 112(23), 5167-5174 (2008).
8. Sykora J., Blechta V., Soukupova L., Schraml J.: 29Si - 13C Spin-Spin Couplings over a Si–O–Csp3 Link. Magn. Reson. Chem. 46(12), 1112-1118 (2008).
9. Sykora J., Karban J., Cisarova I., Hilgard S.: Molecular Structure of Eight Possible Configurational Isomers of 2,3- and 3,4-Epimino Derivatives of 1,6-Anhydro-beta-D-Hexopyranoses: Conformation Analysis, Intra and Intermolecular Hydrogen Bonds. Carbohydr. Res. 343(16), 2789-2796 (2008).
10. Sabata S., Lehnert R., Karban J., Hetflejs J., Kuncova G.: Dekontaminace podzemni vody obsahujici terc-butylmethyleter a aromaticke uhlovodiky fotolyzou peroxidu vodiku. (Czech) Decontamination of Ground Water Containing tert-Butyl Methyl Ether (MTBE) and Aromatic Compounds (BTEX) by Photolysis of H2O2. Chem. Listy 102(12), 1115-1120 (2008).
11. Blechta V., Schraml J.: Measurement of Small Long-Range Couplings between Heteronuclei (29Si-13C) at Natural Abundance. Magn. Reson. Chem., submitted.
12. Gulkova D., Kaluza L., Vit Z., Horacek J., Machackova E., Zdrazil M.: High Surface Area Hydrodesulfurization MoO3/TiO2 Catalysts. Reac. Kinet. Catal. Lett., in press.
13. Posta M., Cermak Jan, Vojtisek P., Sykora J., Cisarova I.: Diphosphinoazine Rhodium(III) and Iridium(III) Octahedral Complexes. Inorg. Chim. Acta, in press.
14. Sabata S., Blechta V., Karban J., Pleska A., Vcelak J., Hetflejs J.: Selective Synthesis of Z-1,4-Disilyl-2-Butenes. Phosphorus, Sulfur and Silicon, submitted.
15. Topka P., Zub Y.L., Karban J., Solcova O.: Designing (Al-)SBA-15 Catalyst Pellets with Unique Properties. Stud. Surf. Sci. Catal., in press.
Chapters in books
16. Blechta V.: Applications of 29Si-13C Coupling Constants. In: Annual Reports on NMR Spectroscopy. (Webb, G.A., Ed.), Elsevier, Amsterdam, in press.
International conferences
17. Blechta V., Schraml J.: Measurement of Relative Signs of 29Si-13C Couplings. 23rd NMR Valtice, Sbornik abstraktu, p. C-27, Valtice, Czech Republic, 20-23 April 2008.
18. Blechta V., Sykora J., Kurfurst M., Schraml J.: LC-29Si-NMR of Organosilicon Polymers. Magnetic Moments in Central Europe 2008, Program and Book of Abstracts, p. 16, Ljubljana, Slovenia, 29 February 2008.
19. Gulkova D., Kaluza L., Vit Z., Horacek J., Machackova E., Zdrazil M.: High Surface Area Hydrodesulfurization MoO3/TiO2 Catalysts. 18th International Congress of Chemical and Process Engineering CHISA 2008, Summaries 1, pp. 97-98 (2 pp. full text on CD-ROM), Praha, Czech Republic, 24-28 August 2008.
20. Chlebek J., Musilova L., Jun D., Opletal L., Kurfurst M., Schraml N., Dohnal V., Jahodar L.: Vliv isochinolinovych alkaloidu z frakce A (Cl- nerozp. v CHCl3/fenolicke) z Corydalis Cava(Fumariaceae) na cholinesterazy. (Czech) Influence of Isochinolinic A-Fraction (Phenolic CHCl3 Insoluble Cl- > Salts) Alkaloids from Corydalis Cava (Fumariaceae) on Cholinesterases. 37. Konference Synteza a analyza leciv, Book of Abstracts, Chemicke Listy 102 (Issue 14), s221-s222, Brno, Czech Republic, 08-10 September 2008.
21. Kurfurst M., Schraml J.: LC-29Si NMR Analysis of Silicon Copolymer Mixtures. International Conference on LC-NMR and Related Techniques: "Challenges in Biological Systems", Program - Abstract - Information, p. 35, Jena, Germany, 27-29 August 2008.
22. Opletal L., Cahlikova L., Dohnal V., Kurfurst M., Schraml J., Jun D., Musilova L., Dolezal J., Jahodar L.: Screeningova studie vlivu nekterych alkaloidu z Eschscholtzia Californica Cham. (Papaveraceae) na lidskou erytrocytarni acetylcholinesterasu. (Czech) Screening Study of Influence of Selected Alkaloids from Eschscholtzia Californica Cham. (Papaveraceae) on Human Erythrocytal Acetylcholinesterase. 37. Konference Synteza a analyza leciv, Book of Abstracts, Chemicke Listy 102 (Issue 14), s238, Brno, Czech Republic, 08-10 September 2008.
23. Sajfrtova M., Sovova H., Karban J., Pavela R.: Insecticide Activity of Herb Extracts Isolated by Different Methods. 18th International Congress of Chemical and Process Engineering CHISA 2008, Summaries 2, p. 541 (7 pp. full text on CD-ROM), Praha, Czech Republic, 24-28 August 2008.
24. Schraml J., Blechta V., Sykora J., Kurfurst M.: Current Topics in 29Si NMR of Solutions. SMASH 2008, Conference Program, p. 1, Santa Fe, New Mexico, Mexico, 07-10 September 2008.
25. Schraml J., Cigler P.: 15N Couplings in Dihydroxamic Acids. 23rd NMR Valtice, Sbornik abstraktu, p. C-28, Valtice, Czech Republic, 20-23 April 2008.
26. Sychrovsky V., Benda L., Prokop A., Blechta V., Schraml J., Spirko V.: Probing the Flexibility of Internal Rotation in Silylated Phenols with the NMR Scalar Coupling Constants. 23rd NMR Valtice, Sbornik abstraktu, p. C-29, Valtice, Czech Republic, 20-23 April 2008.
27. Sykora J., Storch J., Karban J., Cermak Jan: Atropisomerism of 1,8-bis-(2-Propynyl-phenyl)-naphthalene. International Conference on LC-NMR and Related Techniques: "Challenges in Biological Systems", Program - Abstract - Information, p. 20, Jena, Germany, 27-29 August 2008.
28. Syc M., Pekarek V., Fiserova E., Karban J., Puncochar M.: The Effect of MSWI Start-up and Shut-down on Congener Profiles of PCDD/F Precursors. 28th International Symposium on Halogenated Persistant Organic Pollutants-Dioxin 2008, Organohalogen Compounds, Vol. 70, pp. 001810-001813, Birmingham, Great Britain, 17-22 August 2008.
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