Organic Chemistry

 

Ronny Neumann, Head
The Rebecca and Israel Sieff Professorial Chair of Organic Chemistry

The research in the Department of Organic Chemistry spans a wide range of topics, including synthetic-, mechanistic and structural aspects of organic, inorganic-, organometallic-, polymer-, bioorganic-, biological- and computational chemistry.

Soluble metal oxide clusters termed polyoxometalates are being investigated and developed as homogeneous oxidation catalysts by Ronny Neumann. Polyoxometalates have the ability to activate environmentally benign oxygen donors such as molecular oxygen, hydrogen peroxide, nitrous oxide and ozone. In the presence of hydrocarbons, selective oxidation reactions can be carried out. Catalytic oxidation reactions which are being investigated include the epoxidation of alkenes, the hydroxylation of alkanes, oxydehydrogenation of alcohols and other substrates and oxyhalogenation. Mechanistic and kinetic studies using a large variety of spectroscopic and chromatographic techniques allow the identification of active intermediates, the determination of different modes of activation of oxygen donors and the preparation of improved catalysts.

The team of Milko van der Boom is working to create novel films with desirable electronic and optical qualities. The formation of organic thin films is at the forefront of nanotechnology research. His team is hoping to replace today's conventional inorganic materials with organic compounds, which would be much easier to modify, thus offering far better, cheaper devices. The challenges of creating these films, however, are considerable - from effectively integrating custom-designed organic and metal-organic molecules into thin films, to creating materials that are highly ordered and smooth as well as thick enough to efficiently convey optical signals.

The group of Michael Bendikov who has joined the department recently, explores the structure–property relationship in conducting polymers and their oligomers, aiming at the design of novel electronic materials. The chemical reactivity of carbon-nanotubes is also explored. The research combines synthesis, physical measurements and theoretical quantum mechanical studies.

The computational chemistry group of Jan (Gershom) Martin is engaged both in the development of highly accurate ab initio computational thermochemistry methods (W1 and W2 theory) and in the methodology and applications of density functional theory, with a particular focus on organometallic reaction mechanisms relevant to homogenous catalysis. Theoretical vibrational spectroscopy beyond the harmonic approximation and basis set development (the SDB-cc-pVnZ basis sets) are subsidiary research interests.

Electron-rich complexes of transition metals, capable of insertion and activation of some of the strongest bonds are being developed by David Milstein. The selective insertion of a metal into a simple carbon-carbon bond presents new prospects for selective hydrocarbon functionalization. Activation of N-H and O-H bonds opens new directions for the selective use of ammonia and water. Facile activation of bonds to carbon by specifically-designed complexes has led to new catalytic reactions of significance to the chemical and pharmaceutical industries, including highly efficient carbon-carbon bond formation. A new approach towards catalysis based on the ordering of metal complexes in thin films was demonstrated (with Meir Lahav, Materials and Interfaces). The use of metals for the generation, stabilization and controlled release of biologically relevant, unstable organic transients is being studied. New ligands and complexes for MRI imaging, which are receptor specific, are being developed (with Hadassa Degani, Biological Regulation).

Biological activity of visual pigments and bacteriorhodopsin is related to a photocycle during which both the retinal and the opsin moieties undergo a series of structural changes. The molecular changes and their correlation with the corresponding biological functions are of primary importance. The use of artificial pigments, model compounds and spectroscopic methods by Mudi Sheves has resulted in the clarification of the role that single and double bonds play in the photocycle; protein-chromophore interactions in the binding site; the role of water and light in retinal protein activity; cations-protein interaction in bacteriorhodopsin; and the mechanism of rhodopsin light activation.

In Abraham Shanzer's group the principles of Biomimetic Chemistry are being applied to mimic bioactive molecules with emphasis on natural iron-carriers that are recognized by microbial receptors and consequently transported into the living cells. When labeled with fluorescent markers, these carriers proved to be useful diagnostic kits. When linked to a cytotoxic agents, they are envisioned as a new generation of anti microbial agents. Molecular electronics is being persued, including: (a) Preparation of molecules with desired optical, electronic and magnetic properties, and their assembly on gold surfaces (with Israel Rubinstein, Materials and Interfaces); (b) Sensors based on imidazolyl ligands capable of axial coordination of metalloporphyrins in a predetermined location above the conductive surfaces have been developed and used as sensors for oxygen, NO and CO; (c) Design and preparation of devices acting as static and dynamic molecular switches for memory storage and Molecular Logic-Gates for executing algebraic operations.

The structure, function and thermal stability of thermophilic enzymes are being studied by Yigal Burstein, aiming at understanding the mechanisms of adaptation of enzymes to extreme environment and for designing novel enzymes for biotransformations in organic chemistry. A family of highly homologous alcohol dehydrogenases that span the phenotypic range of temperature in microorganisms, is investigated. Structural elements conferring thermal stability were identified and analyzed employing genetic engineering methods.

Chemical, biological and clinical studies of modulatory peptides including immunomodulator antibacterial anticancer and neuroactive compounds are being carried out by Mati Fridkin. Novel technologies for drug delivery and stabilization have been developed and applied to several proteins (e.g. insulin, growth hormone, interferon), peptides (e.g. GnRH ,exendin ) and small molecules ( antibiotics and anticancer drugs ). The clinical-pharmaceutical potential of several compounds are being evaluated. A novel approach toward Fe- chelation in relation to neuroprotection is being developed. En route to anti-Alzheimer and anti-Parkinson drugs.

Design, synthesis, structure and function of aminoglycoside-arginine conjugates (AACs), novel HIV-1 inhibitors of viral entry and transactivation of the viral transcripts by Tat protein, are being studied by Aviva Lapidot aiming at understanding the mechanisms of inhibition of the diversity functions of Tat protein, which might be critical for anti-AIDS strategies.

DNA organization and survival under stress is being studied by Avi Minsky. Morphological changes that occur within living cells, following their exposure to various stress conditions are being studied by electron microscopy and X-ray scattering. Under such conditions, genomic DNA undergoes either a spontaneous or a protein-promoted phase transition into highly packed and ordered structures in which the DNA molecules are sequestered and effectively protected. A new and general mode of protection through biocrystallization is indicated. The structural properties of stress-induced DNA-binding proteins that are involved in these structural transitions are being studied. Ultrasensitive calorimetrical methods are used to assess the effects of the large intracellular crowding and viscosity upon the thermodynamic features of interactions between macromolecules, such as DNA and proteins.

The group of Yossi Sperling is studying the structure and function in pre-mRNA processing of supraspliceosomes. These huge macromolecular assemblies contain, in addition to pre-mRNAs, all known components required for their post-transcriptional processing (capping, polyadenylation, editing and splicing). Hence, they can be regarded as representing the nuclear RNA processing machinery. A new mechanism that regulates splicing by affecting splice site selection has been discovered. This discovery implies that the reading frame of mRNAs can be recognized in the nucleus prior to splicing. A model derived from structural studies of supraspliceosomes by electron microscopy is being developed to explain this unexpected finding.

http://www.weizmann.ac.il/Organic_Chemistry/ 

Research Staff, Visitors and Students

Professors

Gershom (Jan) Martin, Ph.D., University of Antwerp, Wilrijk, Belgium
       The Margaret Thatcher Professorial Chair of Chemistry
David Milstein, Ph.D., The Hebrew University of Jerusalem, Jerusalem, Israel
       The Israel Matz Professorial Chair of Organic Chemistry
Abraham Minsky, Ph.D., The Hebrew University of Jerusalem, Jerusalem, Israel
       The Professor T. Reichstein Professorial Chair
Ronny Neumann, Ph.D., The Hebrew University of Jerusalem, Jerusalem, Israel
       The Rebecca and Israel Sieff Professorial Chair of Organic Chemistry
Abraham Shanzer, Ph.D., Virginia Polytechnic Institute, Charlotsville, United States (on extension of service)
       The Siegfried and Irma Ullmann Professorial Chair
Mordechai Sheves, Ph.D., Weizmann Institute of Science, Rehovot, Israel
       The Ephraim Katzir-Rao Makineni Professorial Chair of Chemistry

Professors Emeriti

Mario D. Bachi, Ph.D., The Hebrew University of Jerusaelm, Jerusalem, Israel
Yigal Burstein, Ph.D., Weizmann Institute of Science, Rehovot, Israel
Matityahu Fridkin, Ph.D., Weizmann Institute of Science, Rehovot, Israel
Valeri A. Krongauz, Ph.D., L.Y. Karpov Physical Chemistry Institute, Moscow, Russian Federation
Aviva Lapidot, Ph.D., The Hebrew University of Jerusalem, Jerusalem, Israel
Abraham Patchornik, Ph.D., The Hebrew Univesity of Jerusalem, Jerusalem, Israel
Joseph Sperling, Ph.D., Weizmann Institute of Science, Rehovot, Israel

Associate Professor

Milko Van Der Boom, Ph.D., Weizmann Institute of Science, Rehovot, Israel

Senior Scientists

Michael Bendikov, Ph.D., Technion - Israel Institute of Technology, Haifa, Israel
       Incumbent of the Recanati Career Development Chair of Energy Research
Rafal Klajn, Ph.D., Northwestern University, Evanston, United States
       Incumbent of the Robert Edward and Roselyn Rich Manson Career Development Chair
David Margulies, Ph.D., Weizmann Institute of Science, Rehovot, Israel
       Incumbent of the Judith and Martin Freedman Career Development Chair
Boris Rybtchinski, Ph.D., Weizmann Institute of Science, Rehovot, Israel
       Incumbent of the Abraham and Jennie Fialkow Career Development Chair

Senior Staff Scientist

Alexander M. Khenkin, Ph.D., Academy of Science, Russian Federation

Associate Staff Scientists

Irena Efremenko, Ph.D., Kazakh National Academy of Science, Alma-Ata, Russian Federation
Edward E. Korshin, Ph.D., Kazan State University, Russian Federation

Assistant Staff Scientists

Yaniv Barda, Ph.D., The Hebrew University of Jerusalem, Jerusalem, Israel
Yana Sheynin, Ph.D., Moscow State University, Moscow, Russian Federation
Haim Weissman, Ph.D., Weizmann Institute of Science, Rehovot, Israel

Interns

Moran Feller, Ph.D., Weizmann Institute of Science, Rehovot, Israel
Eyal Kamhi, Ph.D., Weizmann Institute of Science, Rehovot, Israel

Consultants

Eyal Ben-Ari, Agan-Aroma, Ashdod, Israel
Alexander Berchansky
Yigal Burstein
Virginia Buchner
Shlomo Dukler
Noga Friedman
Amiram Hirshfeld
Boris Kraiz
Yisrael Parment, Ben-Gurion University of the Negev, Beer-Sheva, Israel (left February 2010)
Joseph Sperling
Edna Schechtman, Ben-Gurion University of the Negev, Beer-Sheva, Israel

Visiting Scientists

Amir Karton
Eugene Khaskin, University of Maryland, U.S.A.
Amir Korton
Peter Maitlis
Gershom Martin
Dmitri Perepichka, McGill University, Canada
Tamar Schlick
Yossi Weizmann, MIT, Mass. Inst. of Tech., U.S.A.
Yossi Weizmann, Mass. Gal. Hospital, Boston, U.S.A.
Sanjio Zade, Indian Inst. of Sci., Bangalore, India

Postdoctoral Fellows

Marc Altman, Weizmann Institute of Science, Israel
Rigoberto Barrios, Universidad Nacional Autonoma De Mexico
Gnanaprakasam Boopathy, Ph.D., Bhavnagar University
Joyanta Choudhury, Indian Institute of Technology Kharagpur
Sanjib Das, Indian Institute of Technology Kanpur
Iraklii Ebralidze, Weizmann Institute of Science, Israel
Balaraman Ekambaram, University of Hyderabad, Hyderabad.
Joseph Englander, Ph.D., Weizmann Institute of Science, Israel
Moran Feller, Weizmann Institute of Science, Israel
Santosh Ganapathysubramanian, Ph.D., Indian Institute of Technology Bombay
Eyal Kamhi, Weizmann Institute of Science, Israel
Viktoria Koltunov, Hebrew University of Jerusalem, Israel
Elizaveta Kossoy, Weizmann Institute of Science, Israel
Sebastian Kozuch, Hebrew University of Jerusalem, Israel
Robert Langer, University of Karlsruhe (Th)
Vered Lev-Goldman, Ph.D., Weizmann Institute of Science, Israel
Maya Mani-Hazan, Bar-Ilan University, Israel
Michael Montag, Weizmann Institute of Science, Israel
Takafumi Nakagawa, The University of Tokyo
Snehangshu Patra, Indian Institute of Science
Dana Peled, Weizmann Institute of Science, Israel
Emanuel Perugia, Weizmann Institute of Science, Israel
Elena Poverenov, Weizmann Institute of Science, Israel
Joseph Renny, University of Bristol
Bhimsen Rout, Indian Institute of Technology Kanpur
Ujjal Kanti Roy, Indian Institute of Technology Kharagpur
Sagar Sharma, Indian Institute of Technology Bombay
Dennis Sheberla, Technion - Israel Institute of Technology, Israel
Madhu Vedichi, Ph.D., University of Hyderabad
Yair Haim Wijsboom, Weizmann Institute of Science, Israel
Nathan Zauberman, Weizmann Institute of Science, Israel
Olena Zenkina, Weizmann Institute of Science, Israel

Research Students

Jonathan Baram Graham de Ruiter
Delina Dematov Jessica Ettedgui
Eran Fogler Moti Gargir
Ori Gidron Hila Goldberg- Azoulay
Revital Kaminker Amir Karton
Jenny Kolsenik Elizaveta Kossoy
Elisha Krieg Alexandr Laskavy
Noam Levi Eldad Marom
Anat Milo Leila Motiei
Yael Mutsafi Evgenia Olshvang
Meital Orbach Ronny Peri - Naor
Rinat Rozin Amir Rubinstein
Leonid Schwartsburd Hen Shahar
Yamit Sharaabi Naor Nelia Shechter
Elijah Shirman Tanya Shirman
Elena Smolensky Natalia Szenkier-Garcia
Yaron Tidhar Alona Ustinov
Yair Haim Wijsboom Natalia Zamoshchik
Nathan Zauberman Olena V. Zenkina

Administrator

Galit Zemel Saig