Department of Chemistry
In the AY2002, the Chemistry Department continued its strong programs in research and undergraduate and graduate education. Associated with the department currently are 241 graduate students, 133 postdoctoral researchers, and 96 undergraduate chemistry majors. As of July 1, 2002, the Chemistry Department faculty will comprise full-time faculty members including seven assistant, one associate, and 22 full professors including one Institute professor and three TBA slots. Alice Ting and Stuart Licht will join the department as assistant professors on July 1, 2002.
Professor Moungi G. Bawendi was awarded the University of Chicago Chemistry Department young alumnus award in August 2001. Professor Sylvia T. Ceyer was elected chairperson of the chemistry section of the National Academy of Sciences for the term May 1, 2002 through April 30, 2005. Professor Christopher C. Cummins received the Humboldt research award for senior US scientists, April 2001 and the 2001 Dannie-Heineman award, November 2001. Professor Catherine L. Drennan was named as a 2001 Searle scholar. Professor Timothy F. Jamison received the National Science Foundation career award and the Boehringer-Ingelheim new investigator award. Professor Stephen J. Lippard was awarded the Theodore W. Richards medal, Northeast Section of the American Chemical Society and was elected to be an honorary member of the Royal Irish Academy. Professor Keith A. Nelson was named the visiting Roentgen lecturer at the University of Wuerzburg in Wuerzburg, Germany, endowed by the Volkswagen Foundation. Professor Peter H. Seeberger received the Robert P. Goldberg grand prize (MIT 50K competition) as team member of Ancora Pharmaceuticals, the Harold E. Edgerton faculty achievement award, the Glaxo-Smith-Kline research scholar award and was named an Alfred P. Sloan research scholar. Professor Richard R. Schrock won the 2002 Royal Society of Chemistry Sir Geoffrey Wilkinson medal. Professor Timothy M. Swager was a principle participant in the competition for the Institute for Soldier Nanotechnologies and will be serving as the associate director. Professor Andre Tokmakoff received a 2002 Alfred P. Sloan research fellowship, the 2002 Coblentz award, and the 2001 National Parkinson Foundation Richard E. Heikkila research scholar award.
In the fall of 2001, 50 students entered the graduate program of the Chemistry Department, and from September 2001 through June 2002 the department awarded 34 PhD degrees. The number of graduate students in our program is expected to continue to increase over the next few years as we rebuild the faculty to its normal level. In 2001, further changes were introduced in our graduate program aimed at reducing stress and improving communication between students and faculty. In particular, several graduate students were appointed to join Professors Essigmann and Imperiali as Chemistry Department mediators. These graduate students are trained and certified by the state of Massachusetts as mediators and serve as a resource for chemistry graduate students, undergraduate students, and faculty/staff as an aid in conflict discussion and resolution. All interaction with the Chemistry REFS program is confidential and voluntary on the part of those requesting assistance.
In the area of undergraduate education, 31 students graduated in June with BS degrees in chemistry, and 22 students completed the requirements for a minor in chemistry. At the annual chemistry majors dinner in May, the recipients of the 2002 undergraduate chemistry awards were announced.
The Merck Index award for outstanding scholarship was presented to Alexandra Ianculescu of Simi Valley, California, and Ryan Zeidan of Kentwood, Michigan. Neal Devaraj of Manhatten Beach, California, and Michael Torrice of Chelmsford, Massachusetts, were joint recipients of the Alpha Chi Sigma award, given in recognition of achievement in research, scholarship and service to the department.
Tet Matsuguchi of Saitama-ken, Japan, received the Hypercube scholar award for outstanding achievement in the area of computational chemistry. The American Institute of Chemists Foundation award, presented in recognition of outstanding achievement, ability, leadership and character, was given to Ahmed Ghazi of Cairo, Egypt. Freshman, Woon Teck Yap of Singapore, received the CRC Press freshman chemistry achievement award for outstanding academic achievement in chemistry.
The Frederick D. Greene teaching award for outstanding contributions in the area of teaching was presented to Bogdan Fedeles of Buzau, Romania and Herb Chen of Lexington, Massachusetts. Three seniors received the Chemistry undergraduate service award for significant contributions in the area of service to the department: Neena Kadaba of Capistrano Beach, California; Amy Katz of River Vale, New Jersey; and Amy Tyszkiewicz of Sayreville, New Jersey. The ACS Analytical Chemistry award presented for outstanding achievement by a junior in analytical chemistry, was given to Zhi-Heng Loh of Singapore.
Seniors Gitrada Arjara of Bronx, New York; Adam Silverman of Pomona, New York; and Dylan Stiles of Newton, Massachusetts; were recipients of the Chemistry undergraduate research award for outstanding research in the field of chemistry. Han Sen Soo of Singapore, was also recognized for being awarded the Strem prize for excellence in undergraduate research at the annual Undergraduate Research Symposium.
The department also expressed thanks to the undergraduates who worked this year as educators at MIT as teaching assistants and tutors: Jyoti Agarwal, Herb Chen, Bogdan Fedeles, Alina Feldman, Dina Feith, Melanie Pincus, Michael Torrice, Amy Tyszkiewicz, John Paul Shen, Crystal Shih, Gitanjali Singh, and Siobhan Walshas as teaching assistants; and Gitrada Arjara, Julia Chen, Karen Cheng, Irina Gorodetskaya, Monica Ho, Neena Kadaba, Neal Mankad, Jyoti Tibrewala, Lisa Smith, Sonya Tang, and Gitanjali Singh as tutors.
Professor Moungi G. Bawendi's group showed that nanocrystal DFB lasers could be assembled using soft lithography. These lasers can emit at multiple wavelengths simultaneously. His group also showed, in collaboration with Professor Bulovic (EECS) that monolayers of nanocrystal quantum dots could be made to electroluminesce in a molecular organic layered structure. His group showed that the fluorescence from single nanocrystals could be substantially enhanced by coupling the nanocrystals to a rough metal surface.
Stephen L. Buchwald's work has continued on the development of methods for the formation of aromatic carbon-nitrogen and carbon-oxygen bonds. The latter processes are among the most widely used techniques in the discovery groups of pharmaceutical companies.
Sylvia T. Ceyer's group has demonstrated the decomposition of a vibrationally excited, gas phase molecule (Xe-F) that has been produced as a result of a surface chemical reaction. This observation is the first of its kind and highlights the importance of gas phase processes in understanding the overall chemistry of semiconductor etching reactions.
Current research in the Kit Cummins group has resulted from recent discoveries in the areas of low valent niobium and molybdenum chemistry supported by sterically encumbered amido ligands. Recently, we have successfully synthesized a functional form of a three-coordinate niobium trisamide complex. Research in this area has lead to novel transition metal-containing functional groups including an Nb2P2 bridging diphosphide unit and terminal NbP phosphide anion. Using an analogous molybdenum system, we have uncovered a novel method for coupling highly functionalized alkynes to metal-bound enealkylidynes. Efficient formation of the corresponding enediynes has been ensued by alkyne metathesis routes. In addition, new reductive cleavage and coupling reactions of organic substrates by low valent titanium and molybenum complexes are currently under study.
A new strategy was developed in Rick L. Danheiser's laboratory for the synthesis of azulenes, a class of highly colored aromatic compounds with unusual spectroscopic and electronic properties.
Catherine L. Drennan's laboratory has determined the first structure of a carbon monoxide dehydrogenase/acetyl-CoA synthase and has discovered that this enzyme contains of new type of cofactor. In this cofactor, iron, sulfur, nickel, and copper are combined into one unique metallocenter. In addition, their research on ribonucleotide reductases was featured on the cover of Nature Structural Biology.
John M. Essigmann's group designed two prospective anticancer drugs. In one case a molecule was constructed that has activity against prostate cancer cells in mouse xenografts. In the other, a molecule was designed that has activity against a mouse model of breast cancer. In both cases a ligand for a steroid receptor was linked to a DNA damaging nitrogen mustard. The compounds inhibited DNA repair specifically in tumor cells.
Gregory C. Fu's group has developed more efficient methods for carbon-carbon bond formation using palladium catalysts. Furthermore, we have discovered a variety of new catalytic asymmetric processes, including the addition of amines to ketenes, the hydrosilylation of ketones, the cyclization of alkynals to form cyclopentenones, and the synthesis of beta-lactams.
Research in Robert W. Field's group continues in three areas of intramolecular dynamics: intramolecular vibrational redistribution (IVR) and unimolecular isomerization, intersystem crossing (ISC), and energy transfer between electronic and nuclear motions. Anharmonic interactions in the S1 state of acetylene permit the experimental realization of a "local bender pluck" by which the acetylene<->vinylidene S0 transition state may be selectively illuminated. In our first venture into time-domain spectroscopy, a one-color, phase coherent pump/probe scheme is being set up to determine the quadrupole moment of a molecular ion-core by measuring the precession period of the Rydberg electron orbital angular momentum.
Robert G. Griffin's group has completed the first de novo structure determination of a molecule with solid state NMR. The structure is of the peptide f-MLF-OH which does not crystallize. The distance (±0.3 Å) and torsion angle (±5°∫) constraints from the NMR experiments are high precision and therefore the structure is quite high resolution (backbone RMSD = 0.02 Å). This will appear shortly in PNAS.
Robert G. Griffin's group has also performed dynamic nuclear polarization (DNP)/NMR experiments on proteins and achieved signal enhancements of 50. These increases in signal intensity are larger that are observed with FT spectroscopy and with 1H detection (HSQC). Therefore, they could have a significant impact on future directions in solid state and solution NMR. A report describing this work will appear shortly in JACS. The group has received a grant from the NIH to purchase and operate a 900 MHz NMR spectrometer. The instrument will be part of the MIT/Harvard Center for Magnetic Resonance.
In research targeted at the development of multitasking tools for structural and functional proteomics, Barbara Imperiali's group has recently developed small peptides as lanthanide binding tags (LBTs). Because the LBTs are composed exclusively of encoded amino acids they can be introduced as co-expression tags at the DNA level to create fusion proteins. The LBT sequence imparts on the fusion protein a built-in and site-specific fluorophore that can be used for monitoring protein expression and function. The bound lanthanide also provides excellent x-ray scattering power; therefore co-expression of a target protein with an LBT will accelerate the determination of protein x-ray structures by providing an intrinsic, ordered heavy atom for phase determination.
Timothy F. Jamison's group has developed several novel organic reactions that assemble useful molecules efficiently from simple "building blocks" Under continuing development are catalytic coupling reactions of alkynes with aldehydes, imines, and epoxides and catalytic cycloadditions and epoxide-opening cascades that yield oxygen heterocycles. These methods are also the centerpieces of several current projects directed toward the synthesis of natural products with important biological functions such inhibition of HIV infection and cancer treatment.
Stephen J. Lippard's work in synthetic chemistry yielded a carboxylate-bridged non-heme diiron catalyst for the oxidation of substrates using O2 as the terminal oxidant. This work was based on our understanding of the mechanism of action of a related diiron center in methane monooxygenase. Application of recently designed and synthesized fluorescent sensors for zinc in neuroscience afforded unprecedented views of cells damaged by zinc release following drug-induce epileptic seizure in rats. These same sensors have identified previously unknown zinc-loaded cells in brain.
Keith A. Nelson's research resulted in unique advances in control and characterization of coherent terahertz-frequency vibrational waves, called polaritons, that move at light-like speeds through crystal lattices. An prototype integrated "polaritonics" platform for THz-frequency spectroscopy and THz-bandwidth signal processing has been developed on the basis of these results.
Spin frustration, the focus of Daniel G. Nocera's group's work, represents an extensively studied phenomenon in contemporary condensed matter physics. Of the various lattices displaying spin frustration, layered antiferromagnets with a kagomé-type arrangement of magnetic ions has received the most attention. The jarosite family of compounds has been especially prominent as an ideal model for studying frustrated magnetism in layered kagomé-type antiferromagnets. In the past 30 years, however, these materials, so attractive to systematic magnetic study, have proven extremely difficult to prepare in pure and single crystalline form, rendering the precise determination of their magnetic properties impossible. The group has developed new synthetic methods that yield a perfect kagomé lattice, allowing them to unambiguously characterize for the first time the magnetism derived from spin frustration in this lattice type. The project has evolved to one that is vigorously collaborative, involving this group and the groups of P. Lee, Y. Lee, and M. Kastner in the Department of Physics.
Joseph P. Sadighi's group has developed new, highly electrophilic complexes of late transition metals, using heavily fluorinated supporting ligands. These complexes react with air to generate highly active oxidizing agents. The group is also exploring the metal-catalyzed incorporation of carbon dioxide into organic molecules.
Richard R. Schrock's group has continued to synthesize and test a large number of new catalysts of the type Mo(CHR)(NR')(chiral diolate) and test them in a variety of asymmetric olefin metathesis reactions. This chemistry is expected to have a significant impact in the synthesis of drugs and pharmaceuticals. The group has also expanded this considerable chemistry to tungsten. They have developed sterically crowded cationic complexes of hafnium that will polymerize ordinary olefins such as 1-hexene in a living manner (at 0°C up to 600 equiv). They are now studying the effects of various anions, solvents, and olefins themselves on the kinetics and mechanistic details of this well-behaved polymerization reaction. The group has discovered how to prepare molybdenum complexes that contain extremely bulky arylated triamidoamine ligands and have found that they are catalysts for the reduction of molecular nitrogen in the presence of protons and a reducing agent. They have now demonstrated that dinitrogen can be reduced catalytically under some conditions, and are working to optimize that catalytic reaction by varying the ligand structure and the nature of the reducing agent and proton source.
In the past year Peter H. Seeberger's laboratory has utilized their automated oligosaccharide synthesizer to rapidly assemble a malaria toxin carbohydrate. In collaboration with a group at WEHI in Australia this molecule has been used as a highly effective anti-toxin malaria vaccine in mice. In the near future this malaria vaccine will be tested in primates.
Jeffrey I. Steinfeld's work has employed high sensitivity cavity enhanced spectroscopic techniques to detect trace vapors and short-lived reactive species. Cavity RingDown Spectroscopy has been used to detect a variety of trace vapors in atmospheric mixtures. The IntraCavity Laser Absorption Spectrometer has been modified to measure reaction kinetics of free radicals and other short-lived reactive species.
Timothy M. Swager's research group has discovered a new reversible resistance based method for the detection of nitric oxide, has demonstrated (with Vladimir Bulovic, EECS) that semiconductor polymer laser sensors can provide an additional 100 fold sensitivity over the best previously devised sensors (breaking their own record) and had developed a novel approach to the problem of interlayer dielectrics that are necessary for achieving optimal performance in small (0.13 micron) feature size semiconductor devices.
Andrei Tokmakoff's group has developed new methods for two-dimensional infrared spectroscopy, which can be applied to study transient molecular structure and molecular dynamics in solution. A new femtosecond mid-infrared laser source was constructed, which will be used to study the molecular dynamics of the hydrogen bond network of liquid water. Additionally, new methods for acquiring two-dimensional infrared spectra are now being applied to study the infrared spectroscopy of protein secondary structure.
More information about the Department of Chemistry can be found online at http://web.mit.edu/chemistry/.