Faculty

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Prof. Daniel Strasser

Associate Professor of chemistry
Los Angeles 38
02 6585 909

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• Postdoc , 2004-2008, University of California, Berkeley, USA

• Ph.D., 2004, Particle physics department, Weizmann Institute of Science, Rehovot, Israel

• M.Sc., 2000, Particle physics department, Weizmann Institute of Science, Rehovot, Israel

• B.Sc. , 1998, in Physics and Computer Science, Tel Aviv University, Tel Aviv, Israel

 

Research Focus: 
We use intense femtosecond laser pulses to excite and probe ultrafast molecular dynamics. By combining ultrafast laser techniques with advanced fast beam imaging techniques we develop time resolved photo-fragment imaging that allows detection of molecular dissociation events on the relevant ultrafast time scales. Of specific interest are dissociation dynamics of superexcited states that exhibit extremely non-Born-Oppenheimer competition between autoionization and fragmentation decay pathways, multiple fragmentation mechanisms and evolution of molecular dynamics with increasing system complexity.

New: "Ultrafast EUV probe" project is aimed at developing a general technique for time resolved visualization of structural dynamics using the emerging technology of high order

harmonic generation (HHG) of ultrafast EUV pulses for single photon coulomb explosion imaging (CEI).

 

Here are some representative research topics:

 

Ultrafast EUV probe project (HHG based single photon CEI)
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This research is aimed at developing and validating a novel approach for time resolved imaging of structural dynamics, using single photon Coulomb explosion imaging (CEI) with ultrafast extreme UV (EUV) pulses to probe laser initiated ultrafast structural rearrangement and fragmentation dynamics. The emerging field of ultrafast EUV pulses attracts increasing amount of scientific attention, predominantly concentrated on understanding aspects of the generation process itself, as well as on measuring record breaking attosecond pulses at increasingly high photon energies and photon flux. I propose to direct the unique properties of ultrafast EUV pulses towards time resolved studies of molecular reaction dynamics that are inaccessible with conventional ultrafast laser systems. Time resolved single photon CEI will make possible the visualization of complex dynamics in polyatomic systems; specifically, how laser driven electronic excitation couples into nuclear motion in a wide range of molecular systems. In contrast to earlier attempts, in which CEI was driven with intense near-IR pulses that can alter the observed dynamics, the proposed single photon CEI will remove the masking intense field effects and provide a simple and general probe. A comprehensive experimental effort is proposed - to conduct a direct comparison of intense field CEI to the proposed single EUV photon approach. Successful implementation of this research will endow us with a new way to visualize and understand the underlying quantum mechanisms involved in chemical reactions. With this new technology I hope to be able to provide unique insight into molecular fragmentation and rearrangement dynamics during chemical reactions and to resolve long standing basic scientific questions, such as the concerted or sequential nature of double proton transfer in DNA base-pair models. Finally, the "table top" techniques developed in my lab will mature and become applicable to the emerging ultrafast EUV user facilities.

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Intense field interaction with molecular and cluster anions
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By combining fast beam 3D coincidence imaging methods with ultrafast intense laser pulses, we can explore the uncharted regime of intense laser field interactions with molecular anions. After a decade of studies directed at intense field interactions with neutral and cationic species, the resulting insights led to an intuitive understanding of highly non-linear processes such as high order harmonic generation (HHG) opening new research avenues on the attosecond time scale. However, intense field interaction with anionic species can be expected to be very different. For example due to the absence of an attractive Coulomb potential following the removal of the first electron, along with the high contrast between the first electron binding energy and the ionization potential energy required to remove additional electrons. Thus, anionic systems may exhibit new mechanisms of intense field interaction with matter. Our preliminary results indicate a highly efficient non-sequential mechanism for double detachment of molecular anions, which does not rely on rescattering dynamics that dominate intense field interaction with neutral species.

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Selected Publications

1.        Y. Albeck, D.M. Kandhasamy, D. StrasserMoltipule dethachment of the SF6− molecular anion with shaped intense laser pulses. The Journal of Physical Chemistry A, 2014. 118(2): p.388-395. LINK
2.        Y. Albeck, D.M. Kandhasamy, D. StrasserZ-scan method for nonlinear saturation intensity determination, using focused intense laser beams. Physical Review A, 2014. 90(5): p. P053422. LINK
3.        I. Luzon, M. Nagler, O. Heber, D. StrasserSF6- photodetachment near the adiabatic limit. Physical Chemistry Chemical Physics, 2015. LINK
4.        D.M. Kandhasamy, Y. Albeck, K. Jagtap, D. Strasser3D Coincidence Imaging Disentangles Intense Field Double Detachment of SF6−. The Journal of Physical Chemistry A, 2015. 119: p.8076-8082. LINK

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Tshuva Edit

Prof. Edit Tshuva

Professor of Chemistry
Los Angeles 213
02 6586 084

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• Ph.D., 2001, Tel Aviv University

• B.S., 1998, Hebrew University of Jerusalem

 

 

Research Focus:

We are working on original topics in the general area of synthetic bioinorganic chemistry. We investigate biological phenomena that involve transition metal centers, either natural or synthetic, by applying coordination chemistry methodology. We thus combine metal chemistry with biological and medicinal procedures.

 

Early Transition Metal Complexes for Anti-Tumor Applications

Titanium(IV) and vanadium(V) complexes represent attractive alternatives to platinum-based anti-cancer drugs due to their wider activity range and reduced toxicity. Titanium is a biologically friendly metal; titanium dioxide is often found in food products and cosmetics, and is known to be a safe non-toxic material with no side-effects. Vanadium is also a naturally occurring element, which was previously implemented successfully in various therapeutics. The main drawback of both metals is their potentially rich aquatic chemistry and decomposition in biological environment. Thus, we produce hydrolytically stable titanium and vanadium compounds based on costume-designed ligands, and explore their medicinal applications.

The complexes developed in our laboratory rely on strongly binding phenolato ligands. Such complexes demonstrate substantially higher activity than those known compounds including cisplatin towards various cancer cells, with activity also toward drug-resistant cells and in vivo efficacy. Moreover, the strongly binding phenolato ligands afford particularly high stability for weeks in water, contributing further to the promise of these complexes. Various aspects of the complexes mechanism in the cells are under investigations, as well as structure activity studies to direct the design and development of improved derivatives.

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Copper Complexes: Models for Copper Metallochaperones

Copper ions are essential for the well maintenance of living systems; however, their high redox activity may also lead to harmful formation of toxic radicals. Therefore, copper ions in biological environment are protected by binding proteins at all times, and metallochaperone proteins are responsible for copper trafficking in the cell. We are studying metallochaperone model complexes and their reactivity towards relevant oxygen-based species, inspired by the potential therapeutic application of a copper binding unit, with structural characteristics and redox reactivity similar to the natural system. Various model peptides analyzed exhibit unexpected structural motifs as well as promising in vitro anti-oxidative reactivity.

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Selected Publications

1.      Ganot, N., Redko, B., Gellerman, G., and Tshuva, E. Y. (2015) Anti-proliferative Activity for the Combination of Salan Ti(IV) Complexes with other Organic and Inorganic Anticancer Drugs against HT-29 and NCL-H1229 Cells: Synergism with Cisplatin. RSC. Adv. 5:7874.

2.      Meker, S., Margulis-Goshen, K., Weiss, E., Magdassi, S., and Tshuva, E. Y. (2012) High Antitumor Activity of Highly Resistant Salan–Titanium(IV) Complexes in Nanoparticles: An Identified Active Species. Angew. Chem. Int. Ed. 51:10515. Selected for Cover; Selected as "HOT PAPER”

3.      Manna, C. M. , Braitbard, O. , Weiss, E. , Hochman, J. , and Tshuva, E. Y.  (2012) Cytotoxic Salan-Titanium(IV) Complexes: High Activity Towards A     Range of Sensitive and Drug Resistant Cell Lines and Mechanistic Insights. Chem. Med. Chem. 7:703.

4.       Glasner, H.  and Tshuva, E. Y.  (2011) A Marked Synergistic Effect in Antitumor Activity of Salan Titanium(IV) Complexes Bearing Two Differently Substituted Aromatic Rings. J. Am. Chem. Soc. 133:16812

5.       Shoshan, M. S., Shalev, D. E., Adriaens, W., Merkx, M. , Hackeng, T. M. and Tshuva, E. Y. (2011)  NMR Characterization of a Cu(I)-Bound Peptide Model of Copper Metallochaperones: Insights on the Role of Methionine.       Chem. Commun. 47: 6407

6.       Peri, D., Meker, S.,  Shavit, M., and Tshuva, E. Y. (2009) Synthesis, Characterization, Cytotoxicity, and Hydrolytic Behavior of C2- and C1-Symmetrical Ti(IV) Complexes of Tetradentate Diamine Bis(phenolato) Ligands: A New Class of Anti-tumor Agents. Chem. Eur. J. 15:2403

7.       Tshuva, E. Y. and Peri, D. (2009) Modern Cytotoxic Ti(IV) Complexes; Insights on the Enigmatic Involvement of Hydrolysis. Coord. Chem. Rev. 253:2098

8.       Shavit, M., Peri, D., Manna, C. M., Alexander, J. S., and Tshuva, E. Y. (2007) Active Cytotoxic Reagents Based on Non-Metallocene Non-Diketonato Well-Defined C2-Symmetrical Titanium Complexes of Tetradentate Bis(phenolato) Ligands. J. Am. Chem. Soc. 129:12098. 

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Prof. Roie Yerushalmi

Associate Professor of chemistry
Los Angeles 218
02 6585 608

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Research Focus: 

We focus in studying nanomaterials and functional nano architectures. Design and synthesis of hybrid nanostructures for photocatalysis, sensing, optical applications, and energy harvesting. Development of new surface chemistries, synthesis and surface modification of Hybrid nanostructures, ex-situ doping of nanostructures, nanostructure array assembly. Our work include synthesis and comprehensive characterization of complex nanosystems by application of analytical methods.

 

Our research interests are focused on several directions:

Bottom-up synthesis and assembly of nano architectures

New bottom-up synthesis concepts enabling the production of new semiconducting and hybrid metal-semiconducting nanosystems with controlled dimensions and composition. Our research focuses on utilizing non-lithographic methods for symmetry breaking and tailoring the structural details of complex nanosystems featuring unique optical and electronic properties utilized in chemical sensing, plasmonics, and more.

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Hybrid Nanosystems enabling electrical and optical sensing

We develop new methods utilizing vapor phase and condensed phase chemistry for the synthesis of new nanoscale hybrid materials with unique physical properties. Specifically, the formation of hybrid nanomaterials consisting of inorganic and organic parts that are well suited for sensing applications. We study the reactivity, optical, plasmonic, and electronic properties of the Hybrid Nanosystems.

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Catalytic properties of nanostructure arrays

Nanomaterials exhibit unique catalytic properties that are very different from the bulk material properties. The distinct reactivity at the nanoscale enables new pathways for designing novel materials with tailored chemical reactivity. Our research focuses on the study of surface interactions at nanostructure interfaces in the context of photo-catalysis and electro-catalysis.

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Development of advanced nanocomposite materials

We develop novel gas-phase and condensed phase methods for achieving high performance carbon-based nano composites used in the car and aerospace industries. We focus on both synthesis and advanced characterization of the nanocomposite materials.

 

 

Selected Publications

1-D Metal Nanobead Arrays within Encapsulated Nanowires via a Red-Ox-Induced Dewetting: Mechanism Study by Atom-Probe Tomography. Zhiyuan Sun, Avra Tzaguy, Ori Hazut, Lincoln J. Lauhon, Roie Yerushalmi, and David N. Seidman. Nano Lett., 2017, 17 (12), pp 7478–7486. DOI: 10.1021/acs.nanolett.7b03391

 

Self-formed nanogap junctions for electronic detection and characterization of molecules and quantum dots. Amir Ziv, Avra Tzaguy, Ori Hazut, Shira Yochelis, Roie Yerushalmi and Yossi Paltiel. RSC Adv., 2017, 7, 25861. DOI: 10.1039/C7RA04600F

 

Direct Dopant Patterning by a Remote Monolayer Doping Enabled by a Monolayer Fragmentation Study. Ori Hazut and Roie Yerushalmi. Langmuir, 2017, 33 (22), 5371–5377. DOI: 10.1021/acs.langmuir.7b01085

 

Semiconductor-Metal Nano-Floret Hybrid Structures by Self-Processing Synthesis. Ori Hazut, Sharon Waichman, Thangavel Subramani, Debabrata Sarkar, Sthitaprajna Dash, Teresa Roncal-Herrero, Roland Kroger, and Roie Yerushalmi. J. Am. Chem. Soc., 2016, 138 (12), 4079–4086. DOI: 10.1021/jacs.5b12667

 

Sustainable photocatalytic production of hydrogen peroxide from water and molecular oxygen. Niv Kaynan, Binyamin Adler Berke, Ori Hazut, and Roie Yerushalmi. J. Mater. Chem. A, 2014, 2, 13822-13826. DOI:10.1039/C4TA03004D

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Prof. Shlomo Yitzchaik

Professor of Chemistry
Los Angeles 320
02 6586 971

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Ph.D., 1992, Weizmann Institute of Science

M.Sc., 1987, The Hebrew University of Jerusalem

B.Sc., 1984, The Hebrew University of Jerusalem

 

 

Research Focus:

We have set an multifaceted platform for the study of molecular layers-solid substrate interactions, covering Organic Chemistry, Surface Science, Molecular and Biomolecular Electronics and Photonics.

Our research group is exploring the role of surface science in assembling novel classes of functional nanolayers and their implementation in molecular and biomolecular electronics and photonics.  We investigate fundamental issues related to nanolayers structural organization and growth dictating rational design of a variety of new technologies. Our research is highly interdisciplinary and offers opportunities to advantageously combine principles of synthetic chemistry and materials science to build well defined architectures. The latter are helping us address key issues related to biomedical diagnosis, environmental sensors, unconventional computing, molecular electronics and photoactive materials. While design of new molecules and materials is at the core of our activities, the group is actively involved in a variety of state-of-art characterization studies, including advanced electrochemical methods, spectroscopic ellipsometry, nanoscale electrical measurements, and fabrication of prototype devices.

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Our team investigates various routes influencing the surface potential of semiconductors through an oxide layer for the molecular tuning of semiconductors including Si and ITO. Our understanding of the molecular shielding and depolarization effects is implemented in silicon-based transistors and metallic electrodes used in biosensing and neuroelectronic applications.

We study the assembly of monomers on template surfaces containing different dimensionality. These ensembles are then polymerized by chemical or electrochemical or enzymatic methods yielding low dimensionality conducting polymers. Typical templates include 2D substrates, pseudo 3D - pours inorganic semiconductors and 1D biopolymers such as DNA and oligopeptides. The hybrids are examined in biomedical detectors and electrical p-n junctions.

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Our interest in self-assembled peptidic monolayers has led us to investigate a new sensing paradigm that is based on structural ordering-disordering transition accompanying enzymatic reactions on molecular layers.  Highly selective and sensitive electrochemical biosensor for kinases was designed enabling monitoring variety of enzymatic phosphorylation and dephosphorylation reactions. These biosensors are implemented for lung cancer biomarkers monitoring. Anticancer drugs leads are evaluated based on their kinase inhibitory activity. Additionally, post-translation modification derived biomarkers for autoimmune diseases including multiple sclerosis are studied.  We also investigate neuroelectronic hybrids for neurons electrical and chemical signaling. Realization of electrical coupling between neurons and MOS transistors and CNTs derived devices are investigated in relation to chemical and topological ques.  Electronic and photonic neurotransmitters detectors containing artificial receptors are investigated in light of optimized affinity and novel signal transduction schemes. 

 

Selected Publications

1.       E. Amit, O. Rofeamor, Y-T. Wang, R. Zhuravel, A.J.F. Reyes, S. Elbaz, D. Rotem, D. Porath, A. Friedler, Yu-Ju Chen, S. Yitzchaik Integrating proteomics with electrochemistry for identifying kinase biomarkers Chem. Sci., 2015, 6, 4756 – 4766.
2.       Nahor, A.; Shalev, I.; Sa’ar,  A.; Yitzchaik S. Optical and Electrooptical Properties of Porous Silicon- Conjugated Polymers Composite Structures Eur. J. Inorg. Chem. 2015, 7, 1212–1217.
3.       Snir, E.; Joore, J.; Timmerman, P.; Yitzchaik, S.Monitoring selectivity in kinase-promoted phosphorylation of peptidic substrates using label-free electrochemical detection methods Langmuir, 2011, 27, 11212-11221.
4.       Bardavid, Y.; Goykhman, I.; Nozaki, D.; Cuniberti, G.; Yitzchaik, S.Dipole Assisted Photo-Gated Switch in Spiropyran Grafted Polyaniline Nanowires J. Phys. Chem. C 2011, 115, 3123–3128.
5.       Vaganova, E.; Wachtel, E.; Leitus, G.; Danovich, D.; Lesnichin, S.; Shenderovich, I.G.; Limbach, H.-H.; Yitzchaik, S. Photoinduced Proton Transfer in a Pyridine Based Polymer Gel J. Phys. Chem. B 2010, 114, 10728-10733.
6.       Goykhman, I.; Korbakov, N.; Bartic, C.; Borghs, G.; Spira , M.E.; Shappir, J.; Yitzchaik  S.Direct Detection of Molecular Bio-Recognition by Dipole Sensing Mechanism J. Am. Chem. Soc., 2009, 131, 4788-4794.
7.       Peor, N.; Sfez, R.; Yitzchaik, S. Variable Density Effect of Self-Assembled Polarizable Monolayers on the Electronic Properties of Silicon J. Am. Chem. Soc. 2008, 130, 4158-4165.
8.       Sfez, R.; De-Zhong, L.; Turyan, I.; Mandler, D.; Yitzchaik, S. Polyaniline Monolayer Self-Assembled on Hydroxyl-Terminated Surfaces Langmuir 2001, 17, 2556-2559.
9.       Burtman, V.; Zelichenok, A.; Yitzchaik S. Organic Quantum-Confined Structures via Molecular Layer Epitaxy Angew. Chem. Int. Eng. Ed. 1999, 38, 2041-2045.
10.   Cohen, R.; Zenou, N.; Cahen, D.; Yitzchaik, S. Molecular Electronic Tuning of Si Surfaces Chem. Phys. Lett. 1997, 279, 270-274.

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