个人简介

B.S., Purdue University, 1998 Ph.D., California Institute of Technology, 2004 NIH Postdoctoral Fellow, University of Wisconsin-Madison, 2004-2007

研究领域

Lanthanide chemistry/contrast agents for magnetic resonance imaging/catalysis/molecular imaging/coordination chemistry

Research in the Allen laboratory explores the chemistry of magnetic resonance imaging (MRI) and asymmetric catalysis. We are at the frontier of inorganic chemistry intersecting with organic synthesis, analytical chemistry, and biology. Because of the multidisciplinary approach to science in the laboratory, group members are exposed to a wide variety of synthetic and analytical techniques from chemical and biological disciplines. Specifically, projects in the group require the synthesis of inorganic and organic molecules; characterization of these compounds using a variety of techniques including multinuclear NMR spectroscopy, mass spectrometry, fluorescence spectroscopy, and cyclic voltammetry; and compound testing through catalytic transformations or in vitro and in vivo imaging experiments. Two major aims in the group are (1) to overcome critical barriers to the advanced use of lanthanide-based contrast agents for MRI and (2) to elucidate mechanistic details of water-tolerant lanthanide-catalyzed organic reactions with the goal of generating improved catalysts. (1) Magnetic Resonance Imaging: MRI can be used to noninvasively visualize the inside of living organisms. This property of MRI has greatly advanced the ability to diagnose disease and evaluate medical conditions. Lanthanide complexes can enhance inherent contrast in MR images through interactions with solvent molecules. Through the selective enhancement of contrast, MRI can be converted into an even more powerful tool for imaging biological events on the molecular level (molecular imaging); however, there are major limitations to the use of existing rare earth complexes in improving the diagnostic capabilities of MRI and in the study of complicated biological systems. To overcome these limitations, our laboratory uses novel coordination chemistry to manipulate the properties of lanthanide ions. Specifically, we are interested in controlling the magnetic and electronic interactions of lanthanide ions with their surrounding environment and in stabilizing unstable oxidation states. These projects will illuminate fundamental properties of lanthanides. Additionally, they are an inroad toward greatly enhancing the molecular imaging and diagnostic capabilities of MRI. (2) Asymmetric Catalysis: The use of water-tolerant catalysts is of great consequence in synthesizing organic molecules in a more environmentally benign manner. The Allen laboratory is interested in the study of lanthanide-based, water-tolerant, asymmetric catalysts for organic transformations including aldol, Mannich, and Diels-Alder reactions. Over the last decade, the use of lanthanide triflates as water-tolerant catalysts for organic transformations has been developed; however, mechanistic details of these reactions are largely unknown. During the development of these catalysts, the field of MRI inspired the generation of advanced techniques for characterizing and manipulating the properties of lanthanide ions. Our group is working at the intersection of these two fields to design and study lanthanide triflate-based catalysts with high enantioselectivity and water-stability. By studying and improving lanthanide-based catalysts, we hope to increase the quality and number of more environmentally benign catalysts for the synthesis of organic molecules.

近期论文

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Ekanger, L. A.; Polin, L. A.; Shen, Y.; Haacke, E. M.; Allen, M. J.* In Vivo Differentiation of Relative Oxygen Levels and Tumor Necrosis Using Divalent Europium. submitted Kuda-Wedagedara, A. N. W.; Wang, C.; Martin, P. D.; Allen, M. J.* Aqueous Eu(II)-Containing Complex with Bright Yellow Luminescence. J. Am. Chem. Soc. in press Lutomski, C. A.; El-Baba, T. J.; Siriwardena-Mahanama, B. N.; Weidner, S. M.; Falkenhagen, J.; Allen, M. J.; Trimpin, S.* Characterization of a Europium-Containing 2-Arm Polymer Conjugate by Matrix-Assisted Ionization-Ion Mobility Spectrometry-Mass Spectrometry. submitted Ekanger, L. A.; Allen, M. J.* Overcoming Concentration-Dependence in Responsive Contrast Agents for Magnetic Resonance Imaging. Metallomics 2015, 7, 405–421. DOI Kochi, A.; Lee, H. J.; Vithanarachchi, S. M.; Padmini, V.; Allen, M. J.*; Lim, M. H.* Inhibitory Activity of Curcumin Derivatives toward Metal-Free and Metal-Induced Amyloid-Beta Aggregation. Curr. Alzheimer Res. in press Averill, D. J.; Allen, M. J.* Tools for Studying Aqueous Enantioselective Lanthanide-Catalyzed Mukaiyama Aldol Reactions. Catal. Sci. Technol. 2014, 4, 4129–4137. DOI Wu, X.; Dawsey, A. C.; Siriwardena-Mahanama, B. N.; Allen, M. J.*; Williams, T. J.* A (Fluoroalkyl)Guanidine Modulates the Relaxivity of a Phosphonate-Containing T1-Shortening Contrast Agent. J. Fluorine Chem. 2014, 168, 177–183. DOI Hopper, L. E.; Allen, M. J.* Synthesis of 1,7-Bis(t-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane (DO2A-t-Bu Ester). Tetrahedron Lett. 2014, 55, 5560–5561. DOI Ekanger, L. A.; Ali, M. M.; Allen, M. J.* Oxidation-Responsive Eu(2+/3+)–Liposomal Contrast Agent for Dual-Mode Magnetic Resonance Imaging. Chem. Commun. 2014, 50, 14835–14838. DOI Lin, Z.; Shelby, M. L.; Hayes, D.; Fransted, K. A.; Chen, L. X.; Allen, M. J.* Water-Exchange Rates of Lanthanide Ions in an Ionic Liquid. Dalton Trans. 2014, 43, 16156–16159. DOI Kuda-Wedagedara, A. N. W.; Allen, M. J.* Enhancing Magnetic Resonance Imaging with Contrast Agents for Ultra-High Field Strengths. Analyst 2014, 139, 4401–4410. DOI Averill, D. J.; Allen, M. J.* Synthesis, Spectroscopic Characterization, and Reactivity of Water-Tolerant Eu(3+)-Based Precatalysts. Inorg. Chem. 2014, 53, 6257–6263. DOI Lin, Z.; Allen, M. J.* Luminescence as a Tool to Study the Lanthanide-Catalyzed Formation of Carbon–Carbon Bonds. Dyes Pigments 2014, 110, 261–269. DOI Pierre, V. C.*; Allen, M. J.*; Caravan, P.* Contrast Agents for MRI: 30+ Years and Where Are We Going? J. Biol. Inorg. Chem. 2014, 19, 127–131. DOI Siriwardena-Mahanama, B. N.; Allen, M. J.* Strategies for Optimizing Water-Exchange Rates of Lanthanide-Based Contrast Agents for Magnetic Resonance Imaging. Molecules 2013, 18, 9352–9381. DOI Siriwardena-Mahanama, B. N.; Allen, M. J.* Modulating Water-Exchange Rates of Lanthanide(III)-Containing Polyaminopolycarboxylate-Type Complexes Using Polyethylene Glycol. Dalton Trans. 2013, 42, 6724–6727. DOI Vithanarachchi, S. M.; Allen, M. J.* A Multimodal, Beta-Amyloid-Targeted Contrast Agent. Chem. Commun. 2013, 49, 4148–4150. DOI Moore, J. D.; Lord, R. L.; Cisneros, G. A.; Allen, M. J.* Concentration-Independent pH Detection with a Luminescent Dimetallic Eu(III)-Based Probe. J. Am. Chem. Soc. 2012, 134, 17372–17375. DOI Garcia, J.; Allen, M. J.* Interaction of Biphenyl-Functionalized Eu(2+)-Containing Cryptate with Albumin: Implications to Contrast Agents in Magnetic Resonance Imaging. Inorg. Chim. Acta 2012, 393, 324–327. DOI Mei, Y.; Averill, D. J.; Allen, M. J.* Study of the Lanthanide-Catalyzed, Aqueous, Asymmetric Mukaiyama Aldol Reaction. J. Org. Chem. 2012, 77, 5624–5632. DOI Vithanarachchi, S. M.; Allen, M. J.* Strategies for Target-Specific Contrast Agents for Magnetic Resonance Imaging. Current Molecular Imaging 2012, 1, 12–25. (review article) DOI