Department of Chemistry, Physics, and Engineering, Chicago State University
Ph.D. Chemistry, University of Notre Dame, 2012

Understanding binding and structural properties of nanostructures that have important implications for increasing storage capacity in molecular electronics, minimizing high temperature destabilizing effects in energy systems, and maintaining bioactivity of bound molecules in biosensors are topics of interest in the group.  DNA origami nano technology, scanning microscopy (SEM and AFM), and electrochemistry are applicable techniques.

Department of Chemistry, University of Pittsburgh
University of Michigan, Ph.D. Chemistry, 2003

Our research involves the design and synthesis of novel hybrid inorganic-organic-biomolecule materials and studying, understanding, and precisely controlling their structures and properties. This research encompasses organic and inorganic synthesis, coordination chemistry, solid-state chemistry, biomolecule assembly, and nanoparticle synthesis and assembly.  We are particular motivated by applications related to the porosity of metal-organic framework materials (e.g. gas storage and separations) and the unique collective plasmonic properties of peptide-nanoparticle assemblies.

Most Cited Publications
  1. "Systematic Design of Pore Size and Functionality in Isoreticular MOFs and Their Application in Methane Storage," Mohamed Eddaoudi, Jaheon Kim, Nathaniel Rosi, David Vodak, Joseph Wachter, Michael  'Keeffe, Omar M. Yaghi, Science295, 469 (2002)
  2. "Nanostructures in Biodiagnostics," Nathaniel L. Rosi and Chad A. Mirkin, Chem. Rev., 105, 1547 (2005)
  3. "Hydrogen Storage in Microporous Metal-Organic Frameworks," Nathaniel L. Rosi, Juergen Eckert, Mohamed Eddaoudi, David T. Vodak, Jaheon Kim, Michael O'Keeffe, Omar M. Yaghi, Science, 300, 1127 (2003)
  4. "Rod Packings and Metal-Organic Frameworks Constructed from Rod-Shaped Secondary Building Units," Nathaniel L. Rosi, Jaheon Kim, Mohamed Eddaoudi, Banglin Chen, Michael O’Keeffe and Omar M. Yaghi, J. AM. CHEM. SOC., 127, 1504 (2005)
  5. "Oligonucleotide-Modified Gold Nanoparticles for Intracellular Gene Regulation,"Nathaniel L. Rosi, David A. Giljohann, C. Shad Thaxton, Abigail K. R. Lytton-Jean, Min Su Han, Chad A. Mirkin, Science,312, 1027 (2006)
Recent Publications
  1. "Programmable topology in new families of heterobimetallic metal-organic frameworks," P.F. Muldoon, C. Liu, C.C. Miller, S.B. Koby, A. Gamble Jarvi, T.Y. Luo, S. Saxena, M. O’Keeffe, and N.L. Rosi, J. Am. Chem. Soc.140, 6194 (2018). 
  2. Systematic adjustment of pitch and particle dimensions within a family of chiral plasmonic gold nanoparticle single helices. S. Mokashi-Punekar, A.D. Merg, and N.L. RosiJ. Am. Chem. Soc., 139, 15043 (2017)
  3. Rare earth pcu metal-organic framework platform based on RE4(m3-OH)4(COO)62+ clusters: rational design, directed synthesis, and deliberate tuning of excitation wavelengths. T.Y. Luo, C. Liu, S.V. Eliseeva, P.F. Muldoon, S. Petoud*, and N.L. Rosi, J. Am. Chem. Soc.139, 9333 (2017).
  4. Peptide-directed assembly of single-helical gold nanoparticle superstructures exhibiting intense chiroptical activity. A.D. Merg, J.C. Boatz, A. Mandal, G. Zhao, S. Punekar, C. Liu, Z. Wang, P. Zhang, P.C.A. van der Wel, N.L. Rosi, J. Am. Chem. Soc.,138, 13655 (2016).
  5. Establishing porosity gradients within metal-organic frameworks using partial postsynthetic ligand exchange. C. Liu, C. Zeng, T.Y. Luo, A.D. Merg, R. Jin, N.L. RosiJ. Am. Chem. Soc.138, 12045 (2016).
Department of Chemistry, Carnegie Mellon University
Ph.D. Chemistry, Northwestern University, Illinois, 2003

Our research focuses on fundamental science and engineering questions motivated by the creation of materials on the nanometer scale (1 nm=10-9 m). Our research themes include the synthesis, characterization, and applications of nanoparticles (typically 1-100 nm in size). We are developing chemical methods for synthesizing well defined nanoparticles, including atomically precise nanoclusters, shape- and size-controlled nanocrystals, hybrid nano-architectures, and inorganic/polymer nanocomposites. In-depth characterizations of the physical and chemical properties of nanoparticles and self-assembled nanomaterials are carried out with microscopy and spectroscopy techniques, such as electron microscopy, atomic force microscopy, X-ray crystallography, steady-state and ultrafast spectroscopies, etc. We also develop applications of nanoparticles in areas of catalysis, optics, chemo- and bio-sensing, and photovoltaics, etc.

Selected Publications: 
  1. “Correlating second harmonic optical responses of single Ag nanoparticles with morphology”, Jin, R.; Jureller, J.E.; Kim, H.Y.; Scherer, N.F. J. Am. Chem. Soc.127, 12482 (2005).
  2. “Synthesis of open-ended, cylindrical Au-Ag alloy nanostructures on a Si/SiOx surface”, Zhang, H.; Jin, R.; Mirkin, C.A. Nano Lett., 4, 1493 (2004).
  3. “Thermally-induced formation of atomic Au clusters and conversion into nanocubes”, Jin, R.; Egusa, S.; Scherer, N.F. J. Am. Chem. Soc.126, 9900 (2004).
  4. “Controlling anisotropic nanoparticle growth through plasmon excitation”, Jin, R.; Cao, Y.W.;  Hao, E.; Metraux, G.S.; Schatz, G.C.; Mirkin, C.A.; Nature425, 487 (2003).
  5. “Raman dye-labeled nanoparticle probes for proteins”, Cao, Y.C.; Jin, R.; Nam, J.M.; Thaxton, C.S.; Mirkin, C.A. J. Am. Chem. Soc.125, 14676 (2003).
Most Cited Publications
  1. "Photoinduced conversion of silver nanospheres to nanoprisms", R Jin, YW Cao, CA Mirkin, KL Kelly, GC Schatz, JG Zheng, science, 294, 1901 (2001).
  2. "Nanoparticles with Raman spectroscopic fingerprints for DNA and RNA detection", YWC Cao, R Jin, CA Mirkin, Science 297, 1536 (2002).
  3. "Controlling anisotropic nanoparticle growth through plasmon excitation", R Jin, YC Cao, E Hao, GS Métraux, GC Schatz, CA Mirkin, Nature 425, 487 (2003).
  4. "Correlating the crystal structure of a thiol-protected Au25 cluster and optical properties", M Zhu, CM Aikens, FJ Hollander, GC Schatz, R Jin, Journal of the American Chemical Society 130 , 5883 (2008).
  5. "What controls the melting properties of DNA-linked gold nanoparticle assemblies?", R Jin, G Wu, Z Li, CA Mirkin, GC Schatz, Journal of the American Chemical Society 125, 1643 (2003).
Recent Publications
  1. "Influence of Atomic-Level Morphology on Catalysis: The Case of Sphere and Rod-Like Gold Nanoclusters for CO2 Electroreduction", Shuo Zhao, Natalie Austin, Mo Li, Yongbo Song, Stephen D. House, Stefan Bernhard, Judith C. Yang, Giannis Mpourmpakis, and Rongchao Jin, ACS Catal., 8, 4996 (2018).
  2. "Sharp Transition from Nonmetallic Au246 to Metallic Au279 with Nascent Surface Plasmon Resonance", T Higaki, M Zhou, K Lambright, K Kirschbaum, MY Sfeir, R Jin, Journal of the American Chemical Society (2018).
  3. "Kernel Tuning and the Resulting Influence on Optical/Electrochemical Gaps of Bimetal Nanoclusters", R JIN, Acta Physico-Chimica Sinca (2018).
  4. "Toward Atomically Precise Nanoclusters and Nanoparticles", R JIN, Acta Physico-Chimica Sinca 34, 737 (2018).
  5. "Excited-State Behaviors of M1Au24 (SR) 18 Nanoclusters: The Number of Valence Electrons Matters", M Zhou, C Yao, MY Sfeir, T Higaki, Z Wu, R Jin, The Journal of Physical Chemistry C (2018).
  6. "Chiral Ag 23 nanocluster with open shell electronic structure and helical face-centered cubic framework", C Liu, T Li, H Abroshan, Z Li, C Zhang, HJ Kim, G Li, R Jin, Nature communications 9, 744 (2018).


Highly Efficient Strategy for Constructing New Types of Peptide Macrocycles

  • By Burcu Ozden
  • 10 April 2018

Peng Liu and his colleagues report a highly efficient and generally applicable strategy for constructing new types of peptide macrocycles using palladium-catalyzed intramolecular C(sp3)–H arylation reactions on their newly published paper in Nature Chemistry. 

This strategy provides a powerful tool to address the long-standing challenge of size- and composition-dependence in peptide macrocyclization, and generates novel peptide macrocycles with uniquely buttressed backbones and distinct loop-type three-dimensional structures.

Department of Chemistry
PhD, Chemistry, Harvard University

Raúl Hernández Sánchez's research group is interested in combining supramolecular, inorganic, and materials chemistry to synthesize functional systems that bridge the gap between nanoscale materials and molecular chemistry. Their research is focused on developing new synthetic methodologies to access well-defined nanometer-sized clusters where they can investigate surface structure-function relationships relevant in catalytic and magnetic materials. Other efforts in the Hernández Sánchez (HS) group are aimed at designing and synthesizing structural analogues of carbon nanotubes where exquisite control of the resulting framework allows for properties manipulation.

Students in the HS group will engage in synthetic chemistry and develop familiarity with a range of spectroscopic, electrochemical, crystallographic and magnetic techniques. While rooted in synthetic chemistry, research in the HS group will interface with materials, organic, theory, and physical chemistry.

Most Cited Publications
  1. "High total proton conductivity in large-grained yttrium-doped barium zirconate," Y Yamazaki, R Hernandez-Sanchez, SM Haile, Chemistry of Materials 21, 2755 (2009
  2.  "Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure, and proton conductivity," Y Yamazaki, R Hernandez-Sanchez, SM Haile, Journal of Materials Chemistry 20, 8158 (2010)
  3. "Ligand Field Strength Mediates Electron Delocalization in Octahedral [(HL)2 Fe6 (L')m]n+ Clusters," Hernández Sánchez, R., Zheng, S.-L., Betley, T.A. Journal of the American Chemical Society 137(34), 11126-11143 (2015)
  4. "Synthesis of open-shell, bimetallic Mn/Fe trinuclear clusters," Powers, T.M., Gu, N.X., Fout, A.R., Hernández Sánchez, R., (...). Journal of the American Chemical Society 135(38), 14448-14458 (2013)
  5. "Single-Walled Carbon Nanotubes: Mimics of Biological Ion Channels," 
    Amiri, H., Shepard, K.L., Nuckolls, C., Hernández Sánchez, R. Nano Letters 17(2), 1204-1211 (2017)
Recent Publications
  1. "Defying strain in the synthesis of an electroactive bilayer helicene." Milton, Margarita, Nathaniel J. Schuster, Daniel W. Paley, Raúl Hernández Sánchez, Fay Ng, Michael L. Steigerwald, and Colin Nuckolls. Chemical Science (2018).
  2. "Thermally persistent high spin ground states in octahedral iron clusters." Hernández Sánchez, Raúl, and Theodore A. Betley. Journal of the American Chemical Society (2018).
  3. "Molecular Materials for Nonaqueous Flow Batteries with a High Coulombic Efficiency and Stable Cycling," Margarita Milton, Qian Cheng, Yuan Yang, Colin Nuckolls, Raúl Hernández Sánchez, Thomas J Sisto, Nano Letters, 17, 7859 (2017)
  4. "Towards Catalytic Ammonia Oxidation to Dinitrogen: A Synthetic Cycle Using a Simple Manganese Complex,"Megan Keener, Madeline Peterson, Raúl Hernández Sánchez, Victoria F Oswald, Guang Wu, Gabriel Menard, Chemistry-A European Journal 23, 11479 (2017)
  5. "Single-Walled Carbon Nanotubes: Mimics of Biological Ion Channels,"Hasti Amiri, Kenneth L Shepard, Colin Nuckolls, Raúl Hernández Sánchez, American Chemical Society, 17, 1204 (2017)
Department of chemistry, University of Pittsburgh
Ph.D. in Chemistry: Cornell University,1997

Saxena Group is focused on developing Fourier Transform electron spin resonance and its application to otherwise inaccessible problems in biophysics. The coupling of electron spin angular momentum to its environment—as revealed by the ESR spectrum—provides rich information about the electronic, structural and dynamical properties of the molecule. Saxena group creates the methods that measure the precise distance between two units in a protein, in order to determine their folding patterns and conformational dynamics. These ESR Spectroscopic Rulers— based on multiple quantum coherences and double resonance experiments—are unique in that they resolve distances in the 1-16 nm length scale even on bulk amorphous materials. Much of this work is based on the use of first-principles theory to develop new experimental protocols and to analyze experimental results.

His group continues to develop applications of these spectroscopic rulers that range from capturing the essence of structural changes - such as misfolding - in proteins, to measuring the atomic-level details of ion-permeation in a ligand gated ion-channel. The main projects of his group include:

  • Pulsed ESR methods to measure distance constraints in systems containing paramagnetic metals
  • Measurement of structural and dynamical determinants of the protein-DNA interactions and functional dynamics in pentameric ligand gated ion-channels.
  • Application of the spectroscopic ruler to measure and predict global structures of nanostructured materials.
  • Role of metals in aggregation of Amyloid-β peptide.
Most Cited Publications
  1. "Nonlinear-least-squares analysis of slow-motion EPR spectra in one and two dimensions using a modified Levenberg–Marquardt algorithm," D. E. Budil, S. Lee, S. Saxena, J. H. Freed, Journal of Magnetic Resonance, Series A 120, 155 (1996)
  2. "Amplification of xenon NMR and MRI by remote detection," A. J. Moulé, M. M. Spence, S. I. Han, J. A. Seeley, K. L. Pierce, S Saxena, A. Pines. Proceedings of the National Academy of Sciences 100, 9122 (2003)
  3. "Double quantum two-dimensional Fourier transform electron spin resonance: distance measurements," S. Saxena, J. H. Freed, Chemical physics letters 251,102 (1996)
  4. "Theory of double quantum two-dimensional electron spin resonance with application to distance measurements," J Freed, S. Saxena, Jounal of Chemiical Physics 107, 1317-1340 (1997).
  5. "Direct evidence that all three histidine residues coordinate to Cu (II) in amyloid-β1− 16," B. Shin, S. Saxena, Biochemistry 47, 9117 (2008)
Recent Publications
  1. “ESR shows that the C-terminus of Ligand Free Human Glutathione S-Transferase A1-1 exists in two conformations,” M. J. Lawless, J. R. Pettersson, G. S. Rule, F. Lanni, S. SaxenaBiophysical Journal 114, 592 (2018)
  2. “The Cu(II)-nitrilotriacetic acid complex improves loading of a-helical double-histidine sites for precise distance measurements by pulsed ESR,” S. Ghosh, M. J. Lawless, G. S. Rule, S. SaxenaJ. Magn. Reson., 286, 163 (2018)
  3. “On the use of Cu(II)-iminodiacetic acid complex in double-Histidine based distance measurements by pulsed electron spin resonance,” M. J. Lawless, S. Ghosh, T. F. Cunningham, A. Shimshi, and S. SaxenaPhys. Chem. Chem. Phys., 19, 20959 (2017)
  4. “An analysis of nitroxide based distance measurements by pulsed ESR spectroscopy in cell-extract and in-cell,” M. J. Lawless, A. Shimshi, T. F. Cunningham, M. Kinde, P. Tang, and S. SaxenaChemPhysChem., 18, 1653 (2017)
  5. “Nucleotide-independent Cu(II)-based distance measurements in DNA by pulsed ESR,” M. J. Lawless, J. L. Sarver, S. Saxena, Angew Chem, 56, 2115 (2017)

Molecular Phenotypes of Structurally Homologous ETS Transcriptions Factors

Gregory Poon
Thursday, September 28, 2017 - 4:30pm

 ETS transcription factors comprise an evolutionarily related family of genetic regulators that are ubiquitous in animals and control a myriad of physiologically critical processes. ETS proteins are united by a highly conserved DNA-binding domain, with overlapping target DNA preferences on the one hand, but are functionally diverse and non-redundant on the other. This so-called ìspecificity conundrumî besets not only our understanding of ETS homologs but also the structure-activity relationships of eukaryotic transcription factors in general. Translationally, it hampers efforts to develop...

Department of Chemistry, University of Pittsburgh
Ph.D., Physical Chemistry, University of Wisconsin-Madison, 2013

In the Laaser Lab, we are interested in developing a physical understanding of how changes at the molecular level translate to the macroscopic properties of responsive polymeric materials. For example, how does a change in charge spacing affect the interactions between charged polymers, and at what point do the polymers stop behaving like isolated chains in solution and start behaving like part of a bulk material? How do orientational changes in single polymer chains propagate through a material to achieve macroscopic ordering? And how do polymeric networks transduce force, to achieve things like mechanochemical responses?

We explore these questions by a number of optical and spectroscopic methods, such as light scattering and Raman and infrared spectroscopy, along with classical materials characterization methods like rheology and electron microscopy. Together, these methods allow us to develop new understanding of the structure and dynamic properties of responsive polymeric materials, and offer students the opportunity to gain broad experience in both physical chemistry and polymer science.

Most Cited Publications
  1. "Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sum-frequency generation (HD 2D SFG) spectroscopy," Wei Xiong, Jennifer E. Laaser, Randy D. Mehlenbacher, and Martin T. Zanni, PNAS 108, 20902 (2011)
  2. "Time-Domain SFG Spectroscopy Using Mid-IR Pulse Shaping: Practical and Intrinsic Advantages," Jennifer E. Laaser, Wei Xiong, and Martin T. Zanni, J. Phys. Chem. B 115, 2536 (2011)
  3. "Transient 2D IR Spectroscopy of Charge Injection in Dye-Sensitized Nanocrystalline Thin Films," Wei Xiong, Jennifer E. Laaser, Peerasak Paoprasert, Ryan A. Franking, Robert J. Hamers, Padma Gopalanand Martin T. Zanni, J. Am. Chem. Soc. 131,18040 (2009)
  4. "Bridge-Dependent Interfacial Electron Transfer from Rhenium−Bipyridine Complexes to TiO2 Nanocrystalline Thin Films," Peerasak Paoprasert, Jennifer E. Laaser, Wei Xiong, Ryan A. Franking, Robert J. Hamers, Martin T. Zanni, J. R. Schmidt and Padma Gopalan, J. Phys. Chem. C 114, 9898 (2010)
  5. "Two-Dimensional Sum-Frequency Generation Reveals Structure and Dynamics of a Surface-Bound Peptide," Jennifer E. Laaser, David R. Skoff, Jia-Jung Ho, Yongho Joo, Arnaldo L. Serrano, Jay D. Steinkruger, Padma Gopalan, Samuel H. Gellman, and Martin T. Zanni, J. Am. Chem. Soc. 136, 95 (2014)
Recent Publications
  1. "Equilibration of Micelle–Polyelectrolyte Complexes: Mechanistic Differences between Static and Annealed Charge Distributions," Jennifer E. Laaser, Michael McGovern, Yaming Jiang, Elise Lohmann, Theresa M. Reineke, David C. Morse, Kevin D. Dorfman, and Timothy P. Lodge, J. Phys. Chem. B, 121, 4631 (2017)
  2. "Architecture-Dependent Stabilization of Polyelectrolyte Complexes between Polyanions and Cationic Triblock Terpolymer Micelles," Jennifer E. Laaser, Elise Lohmann, Yaming Jiang, Theresa M. Reineke, and Timothy P. Lodge, Macromolecules 49, 6644 (2016)
  3. "Tuning Cationic Block Copolymer Micelle Size by pH and Ionic Strength," Dustin Sprouse, Yaming Jiang, Jennifer E. Laaser, Timothy P. Lodge, and Theresa M. Reineke, Biomacromolecules 17, 2849 (2016)
  4. "Interpolyelectrolyte Complexes of Polycationic Micelles and Linear Polyanions: Structural Stability and Temporal Evolution," Jennifer E. Laaser, Yaming Jiang, Shannon R. Petersen, Theresa M. Reineke, and Timothy P. Lodge, J. Phys. Chem. B 119, 15919 (2015)
  5. "Probing Site-Specific Structural Information of Peptides at Model Membrane Interface In Situ," Bei Ding, Afra Panahi, Jia-Jung Ho, Jennifer E. Laaser, Charles L. BrooksIII, Martin T. Zanni, and Zhan Chen, J. Am. Chem. Soc. 137, 10190 (2015)