• Ph.D., 2004, Hebrew University of Jerusalem

• M.Sc., 1999, Hebrew University of Jerusalem

• B.Sc., 1997, Hebrew University of Jerusalem

Research Focus:
Catalysis play a central role in the chemical industry and academic research. It is applied in a wide range of fields such as preparation of fine and bulk chemicals, energy production and environmental protection. There are two types of catalysis, homogeneous catalysis and heterogeneous catalysis. The homogeneous catalysts require mild operating conditions and they can usually offer excellent reactivity and high selectivity. However, this type of catalysts has limited application in the chemical industry due to the difficulties in their separation and recovery, which can increase the costs of their application in industrial processes. On the other hand, the heterogeneous catalysts can be separated and recovered easily, but they need harsh operating conditions due to their reduced reactivity and they usually give less selective transformations. Our research aims at developing new catalytic materials by nanotechnology that can bring about bridging between homogeneous and heterogeneous catalysis.

Bridging homogeneous and heterogeneous catalysis is a major challenge in the modern catalysis that requires extensive multidisciplinary studies to achieve it. To address this challenge, we focus on two main strategies. The first relies on the development of new micro- and nano-reactors that contain in their cores non-volatile solvent dissolving or dispersing the desired catalyst. Due to this approach the substrates can react with the catalysts in the core of the micro and nano-reactors under homogeneous or semi-homogeneous conditions. The second strategy is based on the design and construction of nanocatalytic systems with well-defined structures and large surface area.

In the first strategy, we develop methods for preparing catalytic silica and polymeric micro- and nanoreactors. For Example, silica microreactors containing in their core ionic liquids are created by emulsification of ionic liquids in water and then confining the resulted ionic liquid droplets with silica shells by interfacial polycondensation of silane monomer. These silica microreactors containing different types of catalysts are utilized in various organic transformations. The results of this work indicate a unique possibility to tune reactivity and selectivity of catalysts by this approach.

In the second strategy we construct new catalytic nano-materials with large surface area using nanoemulsification methods and sol-gel chemistry. For instance, periodic mesoporous organosilica  (PMO) nanoparticles with a surface area up to 2000 m²/g are prepared by nanoemulsification of different bridged silanes such as 1,2-bis(trimethoxysilyl)ethane and their polycondensation under basic or acidic conditions. These materials are utilized as nanosupports for metal nanoparticles, organometallic complexes or organocatalysts. 

Selected Publications

1.  Immobilization of Palladium Catalyst on Magnetically Separable Polyurea Nanosupport, S. Natour and R. Abu-Reziq, RSC Adv. 2014, 4, 48299-48309.

2. BMIm-PF₆@SiO₂ Microcapsules: Particulated Ionic Liquids as A New Material for the Heterogenization of Catalysts. E. Weiss, B. Dutta, A. Kirschning and R. Abu-Reziq,Chem.                Mater. 2014, 26, 4781-4787        .

3.  Palladium Nanoparticles Encapsulated in Magnetically Separable Polymeric Nanoreactors. E. Weiss, B. Dutta, Y. Schnell, and R. Abu-Reziq, J. Mater. Chem. A 2014, 2, 3971-3977.

4.  Palladium Nanoparticles Supported on Magnetic Organic-Silica Hybrid Nanoparticles. S. Omar, and R. Abu-Reziq, J. Phys. Chem. C 2015, 118, 30045-30056.

5. Homogeneous and semi-heterogeneous magnetically retrievable bis-N-heterocyclic carbene Rh(I) based catalysts for selective hydroaminomethylation reactions.B. Dutta, R. Schwarz, S. Omar, S. Natour, and R. Abu-Reziq, Eur. J. Org. Chem. 2015, 1961-1969.

Ratner Family Chair in Chemistry

Postdoc,1998, Chemistry, University of California, Berkeley, CA.

Ph.D.1996, Chemistry, The Hebrew University of Jerusalem.

M.Sc.1993, Chemistry, Summa Cum Laude, The Hebrew University of Jerusalem.

B.Sc.1982, Mathematics and Physics, The Hebrew University of Jerusalem.

Research Focus:
A theoretical chemist, developing new theories and computational methods to predict the properties of molecules, nanocrystals and in general materials directly from the basic laws of quantum physics. His research focuses on the search of new mathematical and computational ways for describing the molecular processes behind efficient production of sustainable energy, including conversion of sunlight to electricity via solar-cells and production of clean and efficient fuels from natural gas. Baer's recent research involves development of new computational techniques for studying the behavior of charge carriers in nanocrystals and polymers.

Selected Publications

D. Neuhauser, E. Rabani, Y. Cytter and R. Baer "Stochastic Optimally-Tuned Ranged-Separated Hybrid Density Functional Theory", J. Phys. Chem. in press (2016).
DOI: 10.1021/acs.jpca.5b10573

V. Vlček, H. R. Eisenberg, G. Steinle-Neumann E. Rabani, D. Neuhauser and R. Baer, "Spontaneous charge-carrier localization in extended one-dimensional systems", Phys. Rev. Lett. 116, 186401 (2016).DOI:http://dx.doi.org/10.1103/PhysRevLett.116.186401

Q. Feng, A. Yamada, R. Baer & B. D. Dunietz, "Deleterious effects of exact exchange functionals on predictions of molecular conductance", Submitted (2016).

R. E. Hadad and R. Baer "Minimally-corrected partial atomic charges that reproduce the dipole moment", submitted (2015).

E. Rabani, R. Baer, and D. Neuhauser, "Time-dependent Stochastic Bethe-Salpeter Approach", Phys. Rev. B 91, 235302 (2015).

Y. Gao, D. Neuhauser, R. Baer, E. Rabani, "Sublinear scaling for time-dependent stochastic density functional theory", J. Chem. Phys. 142, 034106 (2015).
doi: 10.1063/1.4905568

• Postdoc, 1994-97, University of California, Berkeley

• Ph.D., 1994, Hebrew University of Jerusalem, Summa Cum Laude

• B.Sc., 1989, Hebrew University of Jerusalem, Summa Cum Laude

Research Focus:
Our research concerns the chemistry, physics and applications of nanocrystals focusing on the unique tuning of chemical, optical, electrical and thermodynamic properties afforded by control of size, shape, composition and organization on the nanometer scale. We study colloidal semiconductor nanocrystals that are a class of nanomaterials that manifest the transition from the molecular limit to the solid state, as well as hybrid semiconductor-metal nanoparticles. The tunable properties along with the chemical processibility also lead to significant potential for using nanocrystals as building blocks of nano-devices in diverse applications such as solid state lighting, flat panel displays, solar energy conversion, opto-electronic devices and biomedical applications.

We work on dimensionality effects in semiconductor nanocrystals. Stemming from our ability to control shape of the nanocrystals we study using both ensemble and single nanocrystal based optical spectroscopy, the dependence of nanocrystals optical and electronic properties on the evolution from 0D quantum dots to 1D nanowires as manifested in particular in the intermediate nanorods structure. This is also a basis for applying semiconductor nanocrystals in displays, utilizing their unique emission properties.

An additional focus of our work in recent years concerns hybrid nanoparticles, composed of two components of different material types that represent a frontier area of research in nanomaterials. This addresses a key goal of nanocrystal research in the development of experimental methods to selectively control the composition and shape of nanocrystals over a wide range of material combinations. A particular combination which we pioneered in 2004, concerns the growth of metal (Au) tips onto the apexes of semiconductor (CdSe) nanorods creating ‘nanodumbbells’. Since this discovery, we have been studying hybrid metal-semiconductor nanoparticle systems extensively. The ability to selectively arrange nano-sized domains of metallic, semiconducting and magnetic materials into a single “hybrid” nanoparticle offers an intriguing route to engineer nanomaterials with multiple functionalities or the enhanced properties of one domain. Such semiconductor-metal hybrid nanoparticles manifest a synergistic effect of light induced charge separation opening the path for their application in solar energy harvesting with focus on photocatalysis. Visible light photocatalysis is a promising route for harnessing of solar energy to perform useful chemical reactions and to convert light to chemical energy. Our systems offer possibility for visible light photocatalysis using highly controlled hybrid metal-semiconductor nanoparticles. Under visible light irradiation, charge separation takes place between the semiconductor and metal parts of the hybrid particles. The charge separated state can then be utilized for ensuing oxidation-reduction reactions.

We are also aiming efforts towards development and study of doped nanocrystals. Doping of semiconductors by impurity atoms enabled their widespread technological application in micro and optoelectronics. However, for strongly confined colloidal semiconductor nanocrystals, doping has proven elusive. This arises both from the synthetic challenge of how to introduce single impurities and from a lack of fundamental understanding of this heavily doped limit under strong quantum confinement. We develop methods to dope semiconductor nanocrystals with impurities providing control of the band gap and Fermi energy. Successful control of doping and its understanding provide n- and p-doped semiconductor nanocrystals which greatly enhance the potential application of such materials in the field of printed electronics for solar cells, thin-film transistors, and optoelectronic devices.

Selected Publications 

1.       U. Banin, Y.W. Cao, D. Katz, and O. Millo, “Identification of atomic-like states in InAs nanocrystal quantum dots”, Nature 400, 542-544 (1999).

2.        N. Tessler, V. Medvedev, M. Kazes, S.H. Kan, and U. Banin, “Efficient 1.3m Light Emitting Diodes Based On Polymer-Nanocrystal Nanocomposite”,Science 295, 1506-1508 (20022).

3.       S. Kan, T. Mokari, E. Rothenberg, and U. Banin, “Synthesis and properties of semiconductor quantum rods with cubic lattice”, Nature Materials 2, 155-158 (20033).

4.       T. Mokari, E. Rothenberg, I. Popov, R. Costi and U. Banin, "Selective Growth of Metal Tips Onto Semiconductor Quantum Rods and Tetrapods", Science 304 (5678), 1787-1790 (20044).

5.       T. Mokari, C. G. Sztrum, A. Salant, E. Rabani and U. Banin, "Formation of asymmetric one-sided metal tipped semiconductor nanocrystal dots and rods",Nature Materials 4, 855 (20055).

6.       R. Costi, A.E. Saunders, U. Banin, “Colloidal Hybrid Nanostructures: A New Type of Functional Materials”, Angewandte Chemie International Edition 49, 4878 - 4897 (20100).

7.       J.E. Macdonald, M. Bar Sadan, L. Houben, I Popov, U. Banin, “Hybrid nanoscale inorganic cages”, Nature Materials 9, 810-815 (2010).

8.       D. Mocatta, G. Cohen, J. Schattner, O. Millo, E. Rabani, U. Banin, “Heavily Doped Semiconductor Nanocrystal Quantum Dots”, Science 332, 77-81 (2011)

9.       A. Sitt, I. Hadar, and U. Banin “Band-gap engineering, optoelectronic properties and applications of colloidal heterostructured semiconductor nanorods “,Nano Today 8, 494-513 (2013).

10.    G. Jia, A. Sitt, G. B. Hitin, I. Hadar, Y. Bekenstein, Y. Amit, I. Popov, U. Banin, “Colloidal Semiconductor Nanorod Couples Via Self-Limited Assembly”, Nature Materials 13, 301-307 (20144).

Research Focus:
Biofilms are communities of microbial cells that grow on natural and synthetic surfaces. They may be beneficial, for example when protecting plant roots from pathogens. However, in most cases they are related with disease; when they develop on catheters or in the lungs of Cystic Fibrosis patients they most likely lead to death. Irrespective of whether biofilms are beneficial or detrimental to the host, their extracellular matrix is critical to their development and survival. The extracellular matrix is a mesh of biopolymers, mainly polysaccharides, proteins and nucleic acids that connects the biofilm’s cells together. It is also related with an increased resistance of biofilms to antibiotics relative to single cells. Indeed, there has been an immense progress in the study of biofilms’ extracellular matrix from a genetic perspective yet a molecular understanding of the formation, the chemical and the physical properties of this complex 3D network from its components is still lacking.  We study the basic interactions between the biopolymers in the matrix and their interaction with cells. Our model organism for biofilm formation is the soil bacterium, Gram positive Bacillus subtilis (figure 1, shown on an agar plate). A Scanning electron view of a thin section in a B. subtilis biofilm is shown in figure 2, exposing the extracellular material that interconnects the cells.

Selected Publications

1.       Isolation, characterization, and aggregation of a structured bacterial matrix precursor. Chai L, Romero D, Kayatekin C, Akabayov B, Vlamakis H, Losick R, Kolter R. J. Biol. Chem., 288, 175559 - 68 (2013).
2.       Extracellular Signals Regulate Differentiation of Cells in Biofilms.,  Chai L, Vlamakis H,  Kolter R.,  MRS bulletin, 36,  374-379 (2011)
3.       Large area, molecularly smooth (0.2 nm rms) gold films for surface forces and other studies. Chai L, Klein J., Langmuir, 23, 7777 – 83 (2007).
4.       Role of ion ligands in the attachment of poly(ethylene oxide) to a charged surface. Chai L, Klein J., J. Am. Chem. Soc., 127, 1104 - 5 (2005).

• Post-Doctoral fellowship, 2012, at Ecole polythecnique fédérale de Lausanne (EPFL), Dept. of Chemistry and Chemical Engineering. Host: Prof. Michael Grätzel at the laboratory of photonic and interfaces.

• Ph.D., 2009 Nanoscience and Nanotechnology program (A prestige program for which individuals are selected) / Chemistry, Technion–Israel Institute of Technology, Haifa, Israel. Thesis Advisors: Professor Efrat Lifshitz and Professor Rina Tannenbaum. Direct

• B.Sc., 2005, Chemical Engineering, Technion–Israel Institute of Technology, Haifa, Israel. Bachelor of Science in Chemical Engineering, Cum Laude.

Research Focus:

Our research is concentrated on the design and production of new excitonic solar cells, combining radically new materials with novel architectures.



Specific topics related to materials science and photovoltaic cells are:

• Two-dimensional perovskite and its application in solar cells
• Carbon based perovskite solar cells
• Organic-inorganic perovskite nanostructures – synthesis, optical and physical properties
• Inorganic perovskite nanostructures
• Light emitting diode (LED) based on hybrid and inorganic Perovskite
• Semi-transparent perovskite solar cells

More can be found in our website

Semi-transparent perovskite solar cells

Emission from hybrid perovskite nanorods

Flexible perovskite solar cell

Selected publications

1. Bat-El Cohen, Małgorzata Wierzbowska, and Lioz Etgar High efficiency quasi 2D lead bromide perovskite solar cells using various barrier molecules, Sustainable Energy & Fuels, 2017, DOI: 10.1039/C7SE00311K
2. Bat-El Cohen, Małgorzata Wierzbowska, Lioz Etgar. “High efficiency and high open circuit voltage in quasi two-dimensional perovskite based solar cells”, Advanced Functional Materials, 2016, DOI: 10.1002/adfm.201604733.
3. Sigalit Aharon and Lioz Etgar, Two Dimensional Organometal Halide Perovskite Nanorods with Tunable Optical Properties Nano letters, DOI: 10.1021/acs.nanolett.6b00665
4. Ravi K. Misra, Bat-El Cohen, Lior Iagher, and Lioz Etgar, Low-Dimensional Organic–Inorganic Halide Perovskite: Structure, Properties, and Applications, ChemSusChem, 2017, DOI: 10.1002/cssc.201701026.
5. Walleed Abu Laben, . “Depleted hole conductor-free lead halide iodide heterojunctionsolar cell” Energy Environ. Sci., 2013, 6 (11), 3249-3253.
6.  Lioz Etgar, Gao Peng, Zhaosheng Xue, Bin Liu, Md K. Nazeeruddin, Michael Grätzel, “Mesoscopic CH₃NH₃PbI₃/TiO₂ heterojunction solar cell”. Journal of the American Chemical Society, 2012, 134 (42), 17396-17399.

• Ph.D, 2000, the Hebrew University of Jerusalem

• B.Sc., 1994, the Hebrew University of Jerusalem

Research Focus:

Protein-Protein Interactions (PPI) mediate most of the vital processes in cells and are involved in numerous diseases. However, it is extremely challenging to make PPI drug targets. This becomes even more difficult when the interactions involve disordered protein domains.

The research in our lab focuses on using peptides for the quantitative biophysical and structural analysis of PPI in health and disease. Based on this, we develop lead peptides that modulate PPI for therapeutic purposes. We are looking at PPI in biological systems that are affected in disease, such as cancer-related pathways.

Our research strategy is:

1. Studying the molecular mechanisms of protein-protein interactions in health, to understand how the particular biological system works at the molecular level
2. Understanding what goes wrong at the molecular level in disease
3. Developing peptide-based drugs that target protein-protein interactions to restore the biological system to its healthy conditions

We are using an interdisciplinary approach combining:

1. Peptide chemistry: developing new methods for the synthesis of peptides and modified peptides
2. Protein biochemistry: new methods for protein expression and purification
3. Biophysical and biochemical studies of structure, interactions and activity of peptides and proteins

Our specific research Topics are:

1. Interactions of apoptosis-related proteins as a basis for drug design (Katz et al., J. Biol. Chem., 2012; Rotem-Bamberger S. et al., PLoS ONE, 2013; Iosub-Amir et al., Sci. Rep., 2015; Iosub-Amir et al., Chem Sci., 2019; Mayer et al., Chem. Eur. J., 2020)
   
   (Rotem-Bamberger et al., 2013)
2. Intrinsically disordered proteins: the interplay between structured and disordered domains in proteins (Amartely et al., ChemComm, 2013; Faust et al., Chem. Comm., 2014; Reingewertz et al., Biochemistry, 2015; Amartely et al., Chem. Sci., 2016; Faust et al., Chembiochem, 2018)
   
   (Amartely et al., 2016)
3. Intrinsically disordered proteins as drug targets (Mayer et al., Chem. Eur. J., 2020)
   
   (Mayer et al., 2020)
4. Developing new synthetic methods for efficient synthesis of modified peptides such as cyclic peptides (Hayouka et al., J Biol. Chem., 2012; Chandra et al., Angew. Chem. Int. Ed., 2014; Chandra et al., Org. Biomol. Chem., 2014; Chandra et al., ChemMedChem, 2016; Mamidi et al., Front. Chem., 2020) and multiphosphorylated peptides (Mamidi et al., Org. Biomol. Chem., 2019; Grunhaus et al., Eur. J. Org. Chem., 2021)
   
   (Mamidi et al., 2019)
   ​​​​​​​
5. Developing PPI-based biosensors (Amit et al., Chem. Sci., 2015; Solomon et al., Chem. Eur. J., 2022; Joshi et al., Biosens. Bioelectron., 2022)
   
   (Joshi et al., 2022)

Selected Publications

1. Hayouka Z, Rosenbluh J, Levin A, Loya S, Lebendiker M, Veprintsev DB, Kotler M, Hizi A, Loyter A and Friedler A (2007) “Inhibiting HIV-1 integrase by shifting its oligomerization equilibrium”, Proc Natl Acad Sci USA, 104(20):8316-21
2. Katz C, Benyamini H, Rotem S, Lebendiker M, Danieli T, Dines M, Bronner V, Bravman T, Rudiger S and Friedler A (2008) “Molecular Basis of the Interaction Between the Anti-Apoptotic Bcl-2 Family Proteins and the Pro-Apoptotic Protein ASPP2”, Proc Natl Acad Sci USA, 105(34):12277-82
3. Katz C, Levy-Beladev L, Rotem-Bamberger S, Rito T, Rüdiger SG and Friedler A (2011) “Studying protein-protein interactions using peptide arrays”, Chem Soc Rev, 40(5):2131-45                 
4. Chandra K, Roy TK, Shalev DE, Loyter A, Gilon C, Gerber RB and Friedler A (2014) “A Tandem In Situ Peptide Cyclization through Trifluoroacetic Acid Cleavage”, Angew Chem Int Ed Engl, 53(36):9450-5
5. Iosub-Amir A, Van Rosmalen M, Mayer G, Lebendiker M, Danieli T and Friedler A (2015) “Highly homologous proteins exert opposite biological activities by using different interaction interfaces”, Sci Rep, 5, 11629
6. Amartely H, David A, Shamir M, Lebendiker M, Izraeli S and Friedler A (2016) “Differential effects of zinc binding on structured and disordered regions in the multidomain STIL protein”, Chem Sci, 7(7), 4140-4147
7. Samarasimhareddy M, Mayer D, Metanis N, Veprintsev D, Hurevich M and Friedler A (2019) “A targeted approach for the synthesis of multi-phosphorylated peptides: a tool for studying the role of phosphorylation patterns in proteins”, Org Biomol Chem, 17(42):9284-9290
8. Iosub-Amir A, Bai F, Sohn Y, Song L, Tamir S, Marjault H, Mayer G, Karmi O, Jennings P, Mittler R, Onuchic J, Friedler A and Nechushtai R (2019) “The anti-apoptotic proteins NAF-1 and iASPP interact to drive apoptosis in cancer cells” Chem Sci, 10, 665-673
9. Mayer D, Damberger FF, Samarasimhareddy M, Feldmueller M, Vuckovic Z, Flock T, Bauer B, Mutt E, Zosel F, Allain FHT, Standfuss J, Schertler GFX, Deupi X, Sommer ME, Hurevich M, Friedler A and Veprintsev DB (2019) “Distinct G protein-coupled receptor phosphorylation motifs modulate arrestin affinity and activation and global conformation”, Nat Commun, 10(1):1261.
10. Mayer G, Shpilt Z, Bressler S, Marcu O, Schueler-Furman O, Tshuva EY and Friedler A (2020) “Targeting an interaction between two disordered domains using a designed peptide”, Chem Eur J, 26(45):10156
11. Joshi PN, Mervinetsky E, Solomon O, Chen YJ, Yitzchaik S and Friedler A (2022) “Electrochemical biosensors based on peptide-kinase interactions at the kinase docking site”, Biosens Bioelectron, 207:114177
12. Solomon O, Sapir H, Mervinetsky E, Chen YJ, Friedler A and Yitzchaik S (2022) “Kinase Sensing Based on Protein Interactions at the Catalytic Site”, Chem Eur J, 28(17):e202200655

• PhD (2003) The Hebrew University.

• BSc (1996) The Hebrew University.

Research Focus: 
Generally, research in my group is focused on synthetic and mechanistic organometallic chemistry. The core of the work is the interplay between the structures and reactivity of organometallic compounds relevant to catalysis. We use a wide range of synthetic and spectroscopic methods for the manipulation and characterization of our targets: air-free techniques, NMR spectroscopy, X-ray crystallography, etc.

The major current direction of our studies include: the design of new carbometalated transition metal complexes-based catalysts towards activation/formation of polar and nonpolar bonds.

•   Synthesis and organometallic chemistry of new 3-dimensional PC(sp³)P complexes

Over the past 30 years of extensive research, the chemistry and applications of PCP pincer-like complexes have been well documented. These compounds are widely used as homogeneous catalysts and stoichiometric promoters for the challenging chemical transformations, as well as building blocks for the construction of advanced materials. However, the research activity in the field mainly focuses C(sp²)- rather than C(sp³)-based compounds. Recently, we described a new family of C(sp³)-metalated pincer complexes based on dibenzobarrelene scaffold. Unlike most of known PC(sp³)Ps, our compounds are perfectly stable even under very harsh condition, while remain catalytically active. In addition, the suggested scaffold is very modular and three-dimensional. Both these characteristics are remarkably important for diversification of available pincer ligands and fine-tuning chemical/steric/physical properties of the resulting complexes, which makes this class of compounds very attractive for practical applications in many research areas.

•   Applications of the 3-dimensional PC(sp³)P complexes in ligand-metal cooperative catalysis

Molecular complexity of these systems along with coordination versatility of the 3-D sp³-hybridized pincer complexes opens new practical reactivity patterns in non-oxidative (i.e. alternative to the conventional oxidative addition/reductive elimination sequence) activation and formation of polar and non-polar bonds via metal-ligand metal cooperating mechanism. For example, pincer complexes possessing functional sidearm capable of interacting with the catalytic site were identified as practical catalysts in acceptorless dehydrogenation of polar and nonpolar substrates, hydrogenation, hydroformylation, etc.

•   Chemistry of formic acid

​We are interested in the design of novel catalytic systems for dehydrogenation of formic acid/hydrogenation of carbon dioxide and in the development of new generic transformations involving structural modification of functionalized hydrocarbon substrates using formic acid as a source of H₂ and CO₂. This goal was motivated by the economic and ecological sustainability of formic acid, as well as by importance of fundamental understanding of carbon dioxide interactions with transition metal catalysts. In particular, the catalysts focused in this proposal belong to the family of 3-D bifunctional PC(sp³)P pincer complexes developed in our group in the recent years.

Selected Publications

1.       Musa, S.; Ghosh, A.; Vaccaro, L.; Ackermann, L. and Gelman, D. (2015) "Efficient E-Selective Transfer Semihydrogenation of Alkynes by Means of Ligand-Metal Cooperating Ruthenium catalyst" Adv. Synth. Catal. 357: 2351-2357.
2.       Ismalaj, E.; Strappaveccia, G.; Ballerini, E.; Elisei, F.; Piermatti, O.; Gelman, D. and Vaccaro, L. (2014) “γ-​Valerolactone as a Renewable Dipolar Aprotic Solvent Deriving from Biomass Degradation for the Hiyama Reaction” ACS Sustainable Chem. Eng., 2: 2461-2497.
3.       Musa, S.; Filippov, O. A.; Belkova, N. V.; Shubina, E. S.; Silantyev, G. A.; Ackermann L. and Gelman, D. (2013) "Ligand-Metal Cooperating PC(sp3)P Pincer Complexes as Catalysts in Olefin Hydroformylation" Chem. – Eur. J. 19:16906-16909.
4.       Musa, S. and Gelman, D. (2012) Coordination Versatility of sp3-Hybridized Pincer Ligands toward Ligand-Metal Cooperative Catalysis ACS Catalysis 2:2456-2466.
5.       Musa, S.; Shaposhnikov, I.; Cohen, S. and Gelman, D. (2011) Ligand-Metal Cooperation in PCP Pincer Complexes: Rational Design and Catalytic Activity in Acceptorless Dehydrogenation of Alcohols.  Angew. Chem., Int. Ed. 50: 3533-3537.
6.       Azerraf, C. and Gelman, D. (2010) New Shapes of PC(sp3)P Pincer Complexes. Organometallics 28: 6578-6584.    
7.       Azerraf, C.; Shpruhman, A. and Gelman, D. (2009) Diels-Alder Cycloaddition as a New Approach Toward Stable PC(sp3)P-Metalated Compounds. Chem. Commun. 466-468.
8.       Azerraf, C. and Gelman, D. (2008) Exploring the Reactivity of C(sp3)-Cyclometalated Ir(III) Compounds in Hydrogen Transfer Reactions. Chem. – Eur. J. 14:10364-10368.

Ph.D., 2012, Weizmann Institute of Science

M.Sc., 2007, Weizmann Institute of Science

B.Sc., 2004, Ben Gurion University

Research Focus: 
The main goal of our research is to discover new electronic and optical properties of conjugated organic molecules and polymers. In particular, we are interested in various aspects of conjugated molecules with axial chirality and in their application as chiral organic semiconductors. We also study low bandgap polymers bearing fused heterocycles, aiming for strong fluoresce in the near infrared (NIR) spectral region. In addition, we explore various aspects related to the interface between supramolecular chemistry and organic electronics.

While the main part of our work involves organic synthesis of new materials, we also use computational tools to predict the properties of these materials. In addition, we investigate the photophysical, chiroptical and electronic properties of our materials (both in solution and in the solid state) with various characterization techniques, such as electrochemistry, UV-Vis-NIR absorption and fluorescence spectroscopy, and circular dichroism, to gain deeper understanding of their structure-property relation. We also collaborate with several groups for the purpose of testing our materials as the active layer in optical and electronic devices, such as organic field-effect transistors (OFETs), and organic light-emitting diodes (OLEDs) and light-emitting transistors (OLETs).

Selected Publications

-          O. Gidron, M. Jirasek, N. Trapp, M-O. Ebert, X. Zhang and F. Diederich, Homochiral [2]Catenane and Bis[2]catenane from Alleno-Acetylenic Helicates - A Highly Selective Narcissistic Self-Sorting Process. J. Am. Chem. Soc. 2015, 137, 12502.
-          O. Gidron, M-O. Ebert, N. Trapp and F. N. Diederich, Chiroptical Detection of Non-Chromophoric, Achiral Guests by Enantiopure Alleno-Acetylenic Helicages. Angew. Chem. Int. Ed. 2014, 53, 13614.
-          O. Gidron and M. Bendikov, Oligofurans – An Emerging Class of Conjugated Oligomers for Organic Electronics. Angew. Chem. Int. Ed. 2014, 53, 2546.
-          O. Gidron, N. Varsano, L. J. W. Shimon, G. Leitus and M. Bendikov, Study of Bifuran Linker vs. Bithiophene Linker for Rational Design of π-Conjugated Systems. What Have We Learned? Chem. Commun. 2013, 49, 6256. Selected for the front cover page.
-          O. Gidron, Y. Diskin-Posner and M. Bendikov, High Charge Delocalization and Conjugation in Oligofuran Molecular Wires. Chem. Eur. J. 2013, 19, 13140.
-          O. Gidron, A. Dadvand, E. W.-H. Sun, I. Chung, L. J. W. Shimon, M. Bendikov and D. F. Perepichka, Oligofuran-Containing Molecules for Organic Electronics, J. Mater. Chem. C 2013, 1, 4358
-          O. Gidron, L. J. W. Shimon, G. Leitus and M. Bendikov, Reactivity of Long Conjugated Systems: Selectivity of Diels-Alder Cycloaddition in Oligofurans. Org. Lett. 2012, 14, 502.
-          O. Gidron, A. Dadvand, Y. Sheynin, M. Bendikov, and D. F. Perepichka, Towards "Green" Electronic Materials. a-Oligofurans as Semiconductors. Chem. Commun. 2011, 47, 1976. Selected for the front cover page.
-          O. Gidron, Y. Diskin-Posner and M. Bendikov, α-Oligofurans. J. Am. Chem. Soc. 2010, 132, 2148.
·         Selected as a research highlight by Chemical & Engineering News, 2010, 88.
·         Selected for highlighting in SYNFACTS 2010, 5, 0536.
·         Research highlight (U. H. F. Bunz, Angew. Chem. Int. Ed. 2010, 49, 5037).

Our group studies the chemistry, material science, and application of solar energy conversion materials. The research focuses on plasma-enhanced growth processes, combinatorial approaches, advanced characterization, and fundamental studies of novel functional materials, primarily hetero-anionic semiconductors, for solar energy-driven conversion of cheap, abundant resources (such as water and CO₂) into chemical fuels.

Hetero-anionic materials consist of metal cation(s) and at least two anionic species (e.g., O^2-, N^3-, S^2-, and H^-) in a single phase, offering a broader avenue to tune properties than homo-anionic materials due to differences in anions properties. Plasma-enhanced growth processes can increase the stability of hetero-anionic materials, unlocking new chemical spaces inaccessible through conventional solid-state reactions and accelerated by combinatorial approaches.

Discovering new semiconductor materials with enhanced physicochemical properties and stability in aqueous solutions is an age-old task in photoelectrochemical water-splitting research. Oxynitrides are predicted to contain such desired material compositions. We investigate pioneering synthesis routes, physicochemical properties, and working mechanisms of oxynitride perovskite model systems and fully assembled photoelectrochemical devices for water splitting.

B.Sc. 2003 The Hebrew University of Jerusalem

Research Focus: 
Heterogeneous catalysis is an essential technology for the formation of environmentally friendly, alternative feedstock. We are a multidisciplinary group aims at elucidating the mechanisms that governs catalytic processes in order to prepare highly controllable catalysts suited for energy-needs of the 21st century society. To uncover the full potential of heterogeneous catalysis for energy applications, we employ a bottom-up approach in which we design the properties of catalysts in order to activate designated bonds within a reactant molecule. Structure-reactivity correlations within the catalytic systems are analyzed with advanced in-situ spectroscopy in order to unfold the dynamic processes that shape the catalytic reaction.

Selected Publications

1. E. Gross, F. D. Toste and G. A. Somorjai “Polymer-Encapsulated Metallic Nanoparticles as a Bridge between Homogeneous and Heterogeneous Catalysis” Catal Lett 145 (2015) 126.

2. E. Gross , X. Z. Shu, S. Alayoglu, H. A. Bechtel, M. C. Martin, F. D. Toste and G. A. Somorjai “In Situ IR and X-ray High Spatial-Resolution Microspectroscopy Measurements of Multistep Organic Transformation in Flow Microreactor Catalysed by Au Nanoclusters" J. Am. Chem. Soc. 126, (2014), 3624.

3. E. Gross, J. H. C. Liu, S. Alayoglu, F. D. Toste and G. A. Somorjai “Asymmetric catalysis at the Mesoscale: Gold nanoclusters embedded in hydrogen-bonded chiral self-assembled-monolayer as heterogeneous catalyst for asymmetric reactions” J. Am. Chem. Soc. 135, (2013), 3881.

4. E. Gross, J. H. C. Liu, F. D. Toste and Gabor A. Somorjai “Selectivity control in heterogeneous catalysis by tuning nanoparticles properties and flow-reactor’s residence time” Nature Chemistry 4, (2012), 947.

• B.Sc., 1995, The Hebrew University of Jerusalem

Research Focus: 
We study how biologically complex solvation environments direct macromolecular association and lead to formation of complexes that can carry specific functions in cells. Examples include receptors that bind ligands or pass signals across cell membranes, and proteins that fold and unfold in solution, and can further missfold to form aggregates such as amyloid fibers. We have been following such biologically relevant molecular complexes, as well as related systems, including granular materials that sometimes behave as collections of assembling “macromolecules” governed by similar physical forces.

Specifically, we have been studying systems where not only strong and specific interactions are important, but where the presence of many weak, and often non-specific interactions are crucial, too. These include: screened electrostatics and specific-ion effects, properties of hydrogen bonding networks and their modulation by cosolvents such as osmolytes, or by entropically driven depletion forces exerted by “crowders” that act through excluded volume interactions.

The main emphasis is on developing theoretical approaches and computational tools to help dissect the different contributing forces involved in these important interactions, while maintaining close contact to experimental findings. The research group uses atomic-scale computer simulations, as well as several levels of coarse-grained methodologies based on statistical thermodynamic formulations. Where possible, we have been collaborating closely with experimentalists to test our theoretical predictions. In other studies, we have performed our own directed experiments to extend the scope of our theories.

Some current investigations include:

Modeling the impact of osmolytes and ions on protein association, folding, misfolding, and aggregation

Nature has developed many strategies to ensure that protein folding occurs in vivo with efficiency and fidelity. Among the most widely employed strategies is the use of small solute molecules called osmolytes that most often confer stability to folded proteins by preferential exclusion from macromolecular surfaces. Recent evidences indicate that modest changes in environmental conditions set by osmolytes and other cosolutes, such as salts, can have profound effects on protein and peptide conformation and aggregation. Such aggregation processes constitute a hallmark of neurodegenerative pathologies, including Alzheimer's, Huntington's, and Parkinson's diseases.

We have been examining the effect of natural osmolytes and ions on model compounds, including peptides and carbohydrate-protein channel interactions. Insights into the molecular mechanisms by which osmolytes control the macromolecular structure and thermodynamic stability were gained by performing Molecular Dynamic (MD) simulations. Experimentally, we used a range of techniques, including fluorescence, electron microscopy, and circular dichroism measurements of folding peptides, as well as single ion channel measurements.

We find that excluded osmolytes such as sugars and polyols drive peptides to favor a more compact (folded or aggregated) structure relative to more extended (unfolded) conformations. Contrary to common wisdom, we showed that this stabilization is often enthalpically driven. Using MD simulations we have been able to show that osmolytes impact water structuring in close proximity to peptide surfaces, as well as near osmolytes, thereby crucially affecting the peptide folding and aggregation processes. Understanding the role of osmolytes and ions in cellular regulation has not only allowed us to begin to predict the action of osmolytes on macromolecular interactions in stressed and crowded environments typical of cellular conditions, but will also provide insights on how osmolytes may be involved in pathologies or in their prevention.

Determining membrane elastic properties from relatively small simulations

Many proteins that peripherally adsorb on lipid membranes contain structured domains that target the protein to the bilayer, and act to restructure the membrane; examples include the C2, PH, FERM and BAR domains. Many of these domains act by specifically binding to a particular lipid species, like the PH domain that binds PIP₂ lipids, or receptors that function in cholesterol rich domains. Membrane remodeling is therefore an essential part of cellular processes, and understanding the interplay between membrane elasticity and the influence of guest molecules is an important current challenge. And yet, determining material properties of lipid membranes based on composition, particularly from simulations, is a complex task. A major obstacle towards this goal is the lack of robust methodologies able to reliably quantify elastic parameters, such as the bending rigidity, K_C, for membranes of different lipid compositions and in different fluidity states (i.e., thermodynamic phases). We have recently established a general computational approach to determine K_C for multicomponent membranes over the entire biologically relevant range of rigidities (in different thermodynamic phases) and have illustrated its advantage over currently existing computational methodologies used to extract bending modulii from molecular simulations. Moreover, we have shown that our computational approach can extract the bending modulus, KC, for lipid membranes from relatively small-scale molecular simulations. Fluctuations in the splay of individual pairs of lipids faithfully inform on K_C in multicomponent membranes over a large range of rigidities in different thermodynamic phases. Predictions are validated by experiments even where the standard spectral analysis-based methods that have been used for almost two decades fail. The local nature of this method potentially allows its extension to calculations of K_C in protein-laden membranes.

Selected Publications 

Is the depletion force entropic? Molecular crowding beyond steric interactions. 
Sapir, L.; Harries D.
Curr. Opin. Colloid Interface Sci. 20 3-10 (2015) 

Calculating the bending modulus for multicomponent lipid membranes in different thermodynamic phases 
Khelashvili, G.; Kollmitzer, B.; Heftberger, P. Pabst, G.; Harries, D.
J. Chem. Theo. Comp. 9, 3866–3871 (2013)

Modeling Membrane Deformations and Lipid Demixing upon Protein-Membrane Interaction: The BAR Dimer Adsorption
Khelashvili, G; Harries, D; Weinstein, H
Biophysical Journal Volume: 97 Issue: 6 Pages: 1626-1635 (2009) 
 

Enthalpically driven peptide stabilization by protective osmolytes
Politi, R; Harries D
Chemical Communications 46 (35), 6449-6451 (2010)
 

Cholesterol Orientation and Tilt Modulus in DMPC Bilayers
Khelashvili, G; Pabst, G; Harries, D
Journal of Physical Chemistry B Volume: 114 Issue: 22 Pages: 7524-7534 (2010)

1997-2000: B.Sc. in Chemistry The Hebrew University of Jerusalem, Israel.

2000-2002: M.Sc. The Hebrew University of Jerusalem, Israel

2003-2010: Ph.D in Chemistry The Hebrew University of Jerusalem, Israel

2010-2014: Minerva postdoctoral fellowship at the Max Planck Institute of Colloids and Interfaces Berlin, Germany

Research Focus:
Carbohydrates are major components of biological systems and have many functions that ranges from purely structural ones to elusive fine-tuned communication ones. Carbohydrates (glycans), that is oligo- and poly-saccharides, are assembled from a monosaccharide building blocks that have multiple alcohol functional groups but vary in their structural features. This amazing variety accounts for the many roles of carbohydrates but makes their synthesis a very complex task because it requires the functionalization of a specific functional moiety in a sea of very similar groups. Chemical oligosaccharide synthesis suffers from many limitations that prevents it from reaching the same level of popularity associated with synthetic oligopeptides and oligonucleotides in which the protecting group removal is performed using simple and well established protocols

Our group develops synthetic strategies to facilitate the procurement of oligosaccharides. We exploit the use of photochemical reactions for the synthesis of oligosaccharides in a very mild conditions and use of photo labile protecting groups (PPGs) that can be liberated using LED irradiation as attractive solution for oligosaccharide synthesis.

We specialize in the state-of-the-art Automated Glycan Assembly (AGA) platform that enables fast and easy synthesis of complex glycans from simple monosaccharide building blocks. Our group develop explore the use of flow chemistry, solid phase chemistry, photochemistry and automation and their combination for oligosaccharide synthesis.

Selected publications

Mamidi Samarasimhareddy, Israel Alshanski, Evgeniy Mervinetsky, and Mattan Hurevich. 2018. “Photodeprotection of up to Eight Photolabile Protecting Groups from a Single Glycan.” Synlett, EFirst.

J. N. Naoum, K. Chandra, D. Shemesh, R. B. Gerber, C. Gilon, and M. Hurevich. 2017. “DMAP-assisted sulfonylation as an efficient step for the methylation of primary amine motifs on solid support.” Beilstein Journal of Organic Chemistry, 13: 806-816. Publisher's Version

H. S. Hahm, M. K. Schlegel, M. Hurevich, S. Eller, F. Schuhmacher, J. Hofmann, K. Pagel, and P. H. Seeberger. 2017. “Automated glycan assembly using the Glyconeer 2.1 synthesizer.” Proceedings of the National Academy of Sciences of the United States of America, 17, 114: E3385-E3389.Publisher's Version

H. S. Hahm, M. Hurevich, and P. H. Seeberger. 2016. “Automated assembly of oligosaccharides containing multiple cis-glycosidic linkages.” Nature Communications, 7. Publisher's Version

M. Hurevich and P. H. Seeberger. 2014. “Automated glycopeptide assembly by combined solid-phase peptide and oligosaccharide synthesis.” Chemical Communications, 15, 50: 1851-1853.Publisher's Version

M. Hurevich, J. Kandasamy, B. M. Ponnappa, M. Collot, D. Kopetzki, D. T. McQuade, and P. H. Seeberger. 2014. “Continuous Photochemical Cleavage of Linkers for Solid-Phase Synthesis.” Organic Letters, 6, 16: 1794-1797. Publisher's Version