Klaus Praefcke (3 January 1933 – 20 November 2013)TU Berlin
/ref> was a German chemist. He was born in Wustrow and studied in Berlin under the supervision of Alexander Schönberg. After completing his Ph.D. in 1963 and his habilitation in 1970, he became Professor of Organic Chemistry at

Technische Universität Berlin The Technical University of Berlin (official name both in English and german: link=no, Technische Universität Berlin, also known as TU Berlin and Berlin Institute of Technology) is a public research university located in Berlin, Germany. It was ...

in 1971. He stayed dedicated to the research until 1998 at the same institution. Praefcke has published more than 300 scientific papers dedicated to organic synthesis. He is known for his contributions to preparative organic

photochemistry Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible light (400–7 ...

(a) J. Martens and K. Praefcke: ''Organische Schwefelverbindungen VII : Photochemische α-Spaltung von Thiobenzoesäure-S-p-tolylestern in Lösung'',

Chemische Berichte ''Chemische Berichte'' (usually abbreviated as ''Ber.'' or ''Chem. Ber.'') was a German-language scientific journal of all disciplines of chemistry founded in 1868. It was one of the oldest scientific journals in chemistry, until it merged with ' ...

''107'' (1974) 2319; (b) G. Buchholz, J. Martens and K. Praefcke: ''2- und 4-Azathioxanthone durch Photoumlagerung von Thionicotinsäure-S-arylestern'',

Angewandte Chemie ''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length ...

''86'' (1974) 562;

Angewandte Chemie International Edition in English ''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length ...

''13'' (1974) 550; (c) G. Buchholz, J. Martens and K. Praefcke: ''Photochemische Thioxanthon-Synthese aus Halogenthiobenzoesäure-S-arylestern'', Synthesis ''1974'', 666; (d) J. Martens, K. Praefcke and H. Schwarz: ''Organische Schwefelverbindungen VI : Thioxanthonsynthese durch Photoumlagerung von Diaryl-α-ketosulfiden (Thiolestern), eine neue lichtinduzierte aromatische Substitutionsreaktion'',

Tetrahedron In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the o ...

''30'' (1974) 2565; (e) G. Buchholz, J. Martens and K. Praefcke: ''Organische Photochemie VII : Photosubstitution von 1-Halogenthioxanthonen'',

Tetrahedron Letters ''Tetrahedron Letters'' is a weekly international journal for rapid publication of full original research papers in the field of organic chemistry. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 2.415. Index ...

''1975'', 3213; (f) J. Martens, K. Praefcke and U. Schulze: ''Intramolekulare Photo-Friedel-Crafts-Reaktionen; ein neues Syntheseprinzip für Heterocyclen'',

Synthesis Synthesis or synthesize may refer to: Science Chemistry and biochemistry *Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors ** Organic synthesis, the chemical synthesis of organ ...

''1976'', 532; (g) J. Martens, K. Praefcke and H. Simon: ''Photochemistry of Selenol Esters'', Zeitschrift für Naturforschung ''31b'' (1976) 1717; (h) R. Lüdersdorf, J. Martens, B. Pakzad and K. Praefcke, Organische Photochemie XIV: ''Photoreaktionen sulfinylsubstituierter Carbonsäure-, Thiocarbonsäure- und Selenocarbonsäurederivate in Lösung; lichtinduzierte Säurespaltungen, Heterocyclenbildungen und Photosubstitutionen'',

Liebigs Annalen der Chemie ''Justus Liebigs Annalen der Chemie'' (often cited as just ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig ...

''1977'', 1992-2017; (i) W. Lohner, J. Martens, K. Praefcke and H. Simon: ''Organische Tellurverbindungen III. Photoreaktionen von Tellurolestern in Lösung'', Journal of Organometallic Chemistry ''154'' (1978) 263; (j) J. Martens and K. Praefcke : ''Photochemistry of Organic Selenium and Tellurium Compounds'',

Journal of Organometallic Chemistry The ''Journal of Organometallic Chemistry'' is a peer-reviewed scientific journal published by Elsevier, covering research on organometallic chemistry. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impa ...

''198'' (1980) 321. as well as physics and chemistry of

liquid crystals Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way. Th ...

.(a) G. Heppke, J. Martens, K. Praefcke and H. Simon:'' Selenolester – eine neue Klasse flüssigkristalliner Verbindungen'', Angewandte Chemie ''89'' (1977) 328; Angewandte Chemie International Edition in English ''16'' (1977) 318; (b) K. Praefcke, J. Martens ''et al.'': ''Tellurolester im Vergleich mit isoelektronischen, flüssig-kristallinen O-, S- und Se-Estern'', Chemiker-Zeitung ''101'' (1977) 450; (c) K. Praefcke: ''Can thermotropic biaxial nematics be made real?'' Molecular Crystals and Liquid Crystals 364 (2001) 15. Several novel types of liquid crystals have been synthesized by Praefcke for the first time.George W. Gray, CBE, FRS:'' People in the News: Professor K. Praefcke Symposium'', Liquid Crystals Today ''8'' (1998) 6-7.

References

{{DEFAULTSORT:Praefcke, Klaus 1933 births 2013 deaths 20th-century German chemists Academic staff of Technische Universität Berlin Scientists from Mecklenburg-Western Pomerania People from Bezirk Rostock