Search form

Prof. Dr. Nikolai Kuhnert
Prof. Dr.
Professor of Chemistry
Life Sciences & Chemistry

Campus Ring 1 28759 Bremen Germany

Tel: 
+49 421 200-3120
Fax: 
+49 421 200-3102
Email: 
n.kuhnert [at] jacobs-university.de
Homepage: 
http://nkuhnert.user.jacobs-university.de/
Office: 
Research III, Room 117
Research Interests: 

Analytical Chemistry, Supramolecular chemistry, Natural Product Chemistry, Food Chemistry, Organic Synthesis, Nanomolecular Chemistry, Stereochemistry, Mass Spectrometry.

We have two main research interests. Firstly the chemistry of biologically active compounds from food sources in particular polyphenolics and secondly the supramolecular chemistry of polyphenolics in complex matrices such as food and the supramolecular chemistry of chiral macrocyclic compounds (see overleaf interests in nanomolecular science). Both interests are linked by the necessity for the development of novel powerful analytical techniques for the characterisation of complex natural products and supramolecular systems.

Chemistry of biologically active compounds from food sources
The tenet "Let food be thy medicine and medicine be thy food," espoused by Hippocrates nearly 2,500 years ago, is receiving renewed interest. In particular, there has been an explosion of consumer interest in the health-enhancing role of specific foods or physiologically-active food components, so-called functional foods. Clearly, all foods are functional, as they provide taste, aroma, or nutritive value. Within the last decade, however, the term functional as it applies to food has adopted a different connotation - that of providing an additional physiological benefit beyond that of meeting basic nutritional needs. Overwhelming evidence from epidemiological, in vivo, in vitro, and clinical trial data indicates that a plant-based diet can reduce the risk of chronic disease such as diabetes, cardiovascular disease and cancer. In order to put these findings on a sound scientific basis and to reach a position, in which consumer advice can be given with confidence organic and analytical chemistry is urgently required. We need to identify biologically active compounds in the diet in question, provide structure elucidation of the compounds in question and test their biological activity (both beneficial and adverse) once the compounds are available.
Within our research we focus on a class of compounds named polyphenolics. Polyphenolics are ubiquitous in the plant kingdom and the majority of plant based food contains large amount of these compounds. Most plants produce extremely complex mixtures of polyphenolics whose chemical structures are largely unknown.  In the last years we have concentrated our research efforts into the structural elucidation of polyphenolics from coffee and tea. We have developed novel mass spectrometrical methods for the discrimination of isomeric compounds (chlorogenic acids from coffee and other plant sources) and continue to use powerful fragmentation techniques to distinguish between stereo- and regioisomeric natural products. Black tea poses a completely different challenge since it contains a complex mixture of oligomeric and polymeric polyphenolics termed thearubigins, which comprise 70 % of its dry weight. We combine mass spectrometry with organic synthesis to elucidate the structure of the thearubigins.

Resesearch Interest in Nanomolecular Science
Supramolecular chemistry of chiral synthetic macrocycles
Over the last years we have developed synthetic methodology that allows us to efficiently synthesise chiral non racemic macrocycles that we named trianglimines and trianglamines. We are currently able to obtain these compounds in high yield and are able to tune the size of the macrocyclic "cavity" with accuracy. Furthermore we are able to synthesise highly functionalised macrocycles with an aim to binding complex organic guest molecules. Our macrocycles will find application in nanotechnology as parts of molecular machines and devices and due to their unique set of functionalities are highly suitable for dynamic combinatorial chemistry. Examples of molecular devices synthesised include molecular bearings and gears. In particular we are interested in chiral recognition processes and we have developed techniques for chiral analysis using ESI mass spectrometry. For the characterisation of supramolecular systems on the nanoscale using our trianglimine macrocycles we develop novel analytical techniques based on ESI mass spectrometry aiming at understanding the basis of supramolecular interactions in the mass spectrometer, Circular Dichroism spectroscopy  aiming at understanding stereoselective supramolecular interactions between chiral host and guest molecules and NMR spectroscopy (in particular diffusion NMR).Understanding supramolecular interactions is equally important in the study of dietary compounds. Further research deals with the understanding of the supramolecular chemistry of polyphenolic compounds from dietary sources and their potential as building blocks in nanomolecular science (see section above).

University Education: 
  • Diplom Chemiker, University of Würzburg, Germany (1993)
  • Ph.D. in Inorganic Chemistry and Pharmaceutical Biology, University of Würzburg, Germany (1995)
  • Postdoctoral Fellow, University of Cambridge, UK (1996-1997)
  • Postdoctoral research assistant, The Dyson-Perrins Laboratory, University of Oxford, UK (1997-1998)
  • Lecturer in organic chemistry, Department of chemistry, The University of Surrey, UK (1998-2006)
  • Senior Lecturer in organic chemistry, School of Biomedical and Molecular Sciences, The University of Surrey, UK (2006)
Fellowships and Awards: 
  • DFG postdoctoral fellowship (1996-1997)
  • CASE award from Eli Lilly (2002) and Unilever (2005)
Research and Teaching Positions: 

ul>

  • Tutor in organic chemistry, Hertford College, University of Oxford, UK (1997-1998)
  • Tutor in organic chemistry, Stanford centre, Keble college, University of Oxford, UK (1997-1998)
  • Lecturer in organic chemistry, Department of chemistry, The University of Surrey, UK (1998-2006)
  • Visiting Professor, Universität des Saarlandes, Germany (June 2000)
  • Innovartec guest chair for combinatorial chemistry, Universität Regensburg (December 2001)
  • Visiting Professor, International University of Bremen (April 2006)
  • Senior Lecturer in organic chemistry, School of Biomedical and Molecular Sciences, The University of Surrey, UK (2006)
Funded Projects: 

Our work was funded by the EPSRC, The European Union, Eli Lilly, Nestlé and Unilever.

Publications: 
  • "The characterisation by LC-MSn of coffee bean caffeoylferuloylquinic acids", M. N. Clifford, K. L. Johnston, S. Knight and N. Kuhnert, J. Agr. Food. Chem., 2003, 51, 2900-2911.
  • "Discriminating between the six isomers of dicaffeoylquinic acid by LC-MSn" M. Clifford, S. Knight and N. Kuhnert, J. Agr. Food Chem 2005 , 53, 3821-3832.
  • "On the Scope and Limitations of the [3+3] Cyclocondensation Reaction of of Aromatic Dicarbonyl Compounds and 1R, 2R-cyclohexanediamine", N. Kuhnert, A. Lopez-Periago and G. M. Rossignolo, Org. Biomol. Chem. 2003, 1, 1157 - 1170. 
  • "The synthesis and conformational properties of oxygenated trianglimine macrocycles" N. Kuhnert, A. Lopez-Periago and G. M. Rossignolo, Org. Biomol. Chem. 2005, 3, 524-537.
  • "On the Synthesis of Upper Rim Tetraacrylamidocalix[4]arenes and their Dimerisation to Form Molecular Capsules Using Eight Hydrogen Bonds", N. Kuhnert and A. Le-Gresley, Chem. Commun. 2003, 2426-2427.
  • "Varying the size of the trianglimine cavity", N. Kuhnert, C. Patel, N. Burzlaff und A. Lopez-Periago, Org. Biomol. Chem. 2005, 3, 1911-1921.

Full list of Academic Publications:


  • "Stereo- and Enantioselective Reactions of Organosulfur Compounds Mediated by Transition Metal Complexes", W. A. Schenk, J. Bezler, N. Burzlaff, E. Dombrowski, J. Frisch, N. Kuhnert, I. Reuther, Phosphor Sulfur Silicon Rel. Elem. 1995, 95, 1995.
  • "Stereochemically Controlled Synthesis of Substituted 1,2 Oxathianes", J. Eames, N. Kuhnert, R. V. H. Jones and Stuart Warren, Tetrahedron Lett. 1998, 39, 1251-1254.
  • "Scope and Limitation of [1,4]-S-Benzyl Participation and Debenzylation in the Stereochemically Controlled Synthesis of Substituted Thiolanes", J. Eames, N. Kuhnert, R. V. H. Jones and S, Warren, Tetrahedron Lett. 1998, 39, 1247-1250.
  • "Bis-Trifluoromethansulfonimide in the Catalytic Conjugate Allylation of a,b-Unsaturated Carbonyl Compounds", N. Kuhnert, J. Peverley and J. Robertson, Tetrahedron Lett. 1998, 39, 3215-3216.
  • "Kinetic Versus Thermodynamic Control in the Stereospecific Synthesis of Tetrahydro-Pyrans and Furans: Exo Versus Endo Transition States and [1,2] Versus [1,4] Phenylsulfanyl Participation", J. Eames, N. Kuhnert and S. Warren, Synlett 1999, 8, 1211-1214.
  • "[1,2]- and [1,4] Phenylsulfanyl Migrations as Alternative Cascade Sequences for the Stereocontrolled Synthesis of Tetrahydrofurans", J. Eames, N. Kuhnert and S. Warren, Synlett 1999, 8, 1215-1218.
  • "Acetylsalicylsäure feiert Ihren 100. Geburtstag ", Chemie in unserer Zeit 1999, 33, 213-220.
  • "Aspirin, das erfolgreichste Arzneimittel des letzten Jahrtausends", Pharmazie in unserer Zeit 2000, 14, 1-8.
  • "Halfsandwich Ruthenium Complexes of Sulfinic Esters", N. Kuhnert and W. A. Schenk, Z. Naturforsch B 2000, 55, 527 - 535.
  • "1282 Chemische Bachelor und Master-Studiengänge in Grossbritannien", N. Kuhnert, Nachrichten aus Chem. und Technik 2000, No 11, 1352-1356.
  • "Synthesis of 14-C-Labelled Sulforaphane", N. Kuhnert, G. Williamson and B. Holst, J. Labelled Comp. Radiopharm., 2001, 44, 347-355.
  • "Synthesis of 3-Chloro-3-Formylpyrrole Derivatives", J. Robertson, N. Kuhnert and Y. Zhao, Heterocycles 2000, 53, 2415-2420.
  • "Scope and Limitation of the [1,2]-Alkylsulfanyl (SMe, SEt and SCH2Ph) and Sulfanyl (SH) Migration in the Stereospecific Synthesis of Substituted Tetrahydrofurans", J. Eames, N. Kuhnert and S. Warren, J. Chem. Soc. Perkin Trans. 1, 2001, 138-143.
  • "Highly Diastereoselective Synthesis of Homochiral 1,3-Oxazolidines under Thermodynamic Control Using Focused Microwave Irradiation under Solvent Free Conditions", N. Kuhnert and T. N. Danks, Green Chem. 2001, 3, 68-70.
  • "Unkonventionell Techniken in der Organischen Synthese" N. Kuhnert, Nachr. Chemie und Technik 2001 (Trendberichte), 306-310.
  • "Microwave Accelerated Synthesis of Cyclopentadienyl Bis-Phosphine Ruthenium Thiolato Complexes Using Focused Microwave Irradiation", N. Kuhnert and T. N. Danks, J. Chem. Res. (S)  2002, 66-68.
  • "Scope and Limitation of [1,4]-S-Benzyl Participation and Debenzylation in the Stereochemically Controlled Synthesis of Substituted Thiolanes", J. Eames, N. Kuhnert and S. Warren,  J. Chem. Soc. Perkin Trans. 1, 2001, 1504-1511.
  • "Boron-Trifluoride Mediated Synthesis of 2-Deoxy-anthocyanidines including a Total Synthesis of Tricetanidin from Black Tea (Camilla Sinensis)" N. Kuhnert, M. Clifford and A.-G. Radenac, Tetrahedron Lett. 2001, 42, 9261-9264.
  • "Scope and Limitation of the Heck Reaction of Upper Rim Substituted Tetraiodo Calix[4]-arenes" N. Kuhnert and A. Le-Gresley, J. Chem. Soc. Perkin Trans. 1, 2001, 3393- 3398.
  • "Synthesis, Reactivity, Structure and Dynamic Behaviour of Ruthenium Sulfine Complexes", N. Kuhnert, N. Burzlaff, E. Dombrowski uns W. A. Schenk Z. Naturforsch B, 2002, 57, 259-274.
  • "Synthesis of Enantiomerically Pure 42 and 30 Membered Ring Trianglimine and Tranglamine Macrocycles" N. Kuhnert, C. Straßnig and A. M. Lopez-Periago, Tetrahedron Asymm. 2002, 13, 123-128.
  • "Synthesis of Chiral Non-Racemic Macrocycles of the Trianglimine and Trianglamine Type", N. Kuhnert und A. Lopez-Periago, Tetrahedron Lett. 2002, 43, 3329-3332.
  • "Is There a Special Non-Thermal Microwave Effect", N. Kuhnert, Angew. Chem. Int. Ed. Engl. 2002, 41, 1863-1866.
  • "Stereochemically Controlled Synthesis of Substituted 1,2 Oxathianes", J. Eames, N. Kuhnert and S. Warren, J. Chem. Soc. Perkin Trans. 1, 2002, 2282-2287..
  • "Funktionelle Lebensmittel-Eine Kritische Betrachtung", N. Kuhnert, Nachr. Chemie und Technik 2002, 50, 142-147.
  • "On the Steric Acceleration of Ene Reactions", N. Chooney, N. Kuhnert, P. G. Sammes, G. Smith, R. W. Ward, J. Chem. Soc. Perkin Trans. 1, 2002, 1999-2006.
  • "The characterisation by LC-MSn of coffee bean caffeoylferuloylquinic acids", M. N. Clifford, K. L. Johnston, S. Knight and N. Kuhnert, J. Agr. Food. Chem., 2003, 51, 2900-2911.
  • "On the Scope and Limitations of the [3+3] Cyclocondensation Reaction of of Aromatic Dicarbonyl Compounds and 1R, 2R-cyclohexanediamine", N. Kuhnert, A. Lopez-Periago and G. M. Rossignolo, Org. Biomol. Chem. 2003, 1, 1157 - 1170. 
  • "On the Synthesis of Upper Rim Tetraacrylamidocalix[4]arenes and their Dimerisation to Form Molecular Capsules Using Eight Hydrogen Bonds", N. Kuhnert and A. Le-Gresley, Chem. Commun. 2003, 2426-2427.
  • "Detection and Imaging of Vibrationally Labelled Biologically Active Compounds in Living Cells Using Raman Microscopy", N. Kuhnert, A. Thumser, J. Labl. Comp. Radiopharm. 2004, 47, 493-500.
  • "The synthesis of 1,1’,2,2’,3,3’,4,4’-Octadetero-Sulforaphane and Erucine" N. Kuhnert and Y. Lu, J. Labl. Comp. Radiopharm. 2004, 47, 501-507.
  • "A powerful aqueous solvent effect in an intramolecular Diels-Alder cyclisation" N. Kuhnert, P.G. Sammes, G. Smith and R. W. Ward, J. Chem. Res. 2004, 608-610.
  • "Discriminating between the six isomers of dicaffeoylquinic acid by LC-MSn" M. Clifford, S. Knight and N. Kuhnert, J. Agr. Food Chem 2005 , 53, 3821-3832.
  • "The synthesis and conformational properties of oxygenated trianglimine macrocycles" N. Kuhnert, A. Lopez-Periago and G. M. Rossignolo, Org. Biomol. Chem. 2005, 3, 524-537.
  • "The synthesis of static and dynamic combinatorial libraries using deep cavity tetra-formyl calix[4]arenes" N. Kuhnert and A. Le-Gresley, Tetrahedron Lett. 2005, 46, 2059-2062.
  • "Modulation of hepatic cytochromes P450 and phase II enzymes by dietary doses of sulforaphane in rats: implications for its chemopreventive activity", V. Yoxall, P. Kentish, N. Coldham, N. Kuhnert, M. J Sauer1 and C. Ioannides, Int. J. Cancer, 2005,  117,  356-362.
  • "On the activation of valerolactam using triflic anhydride", N. Kuhnert, I. Clemens, R. Walsh, Org. Biomol. Chem. 2005, 3, 1694-1701.
  • "Varying the size of the trianglimine cavity", N. Kuhnert, C. Patel, N. Burzlaff und A. Lopez-Periago, Org. Biomol. Chem. 2005, 3, 1911-1921.
  • "Synthesis and capsule formation of tetra-acrylamido calix[4]arenes", N. Kuhnert und A. Le-Gresley, Org. Biomol. Chem.  2005, 3, 2175-2182.
  • "Synthesis of chiral non racemic polyimine macrocycles by cyclocondensation of biaryl and terphenyl dicarboxaldehydes and 1R, 2R diamino cyclohexane" N. Kuhnert, C. Patel and F. Jami., Tetrahedron Lett. 2005, 46, 7575-7579.
  • "Total synthesis of chrysophanol and sennoside C aglycon" N. Kuhnert and H.Y. Molod, Tetrahedron Lett. 2005, 46, 7571-7573.
  • "Synthesis of diastereomeric trianglamine cyclodextrin [2] catenanes", N. Kuhnert and B. Tang, Tetrahedron Lett. 2006, 47,.  2985-2988.
  • "The chlorogenic acids of Hemerocallis" M. N. Clifford, W. Wu and N. Kuhnert, Food Chem. 2006, 95, 574-578.
  • "Characterisation by LC-MSn of four new classes of chlorogenic acids in green coffee beans: dimethoxycinnamoylquinic acids, diferuloylquinic acids, caffeoyl dimethoxycinnamoylquinic acids and feruloyl dimethoxycinnamoylquinic acids" M. N. Clifford, S. Knight, B. Surucu and N. Kuhnert, J. Agr. Food. Chem. 2006, 54, 1957-1969.
Other Professional Activities: 
  • Royal Society of Chemistry (MRSC)
  • Gesellschaft Deutscher Chemiker (GDCh)
  • President of Surrey Chemical Society (2001-2006)
  • GDCh Auslandstutor (1997-2006)