Henry Rzepa

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Henry Rzepa
Henry Rzepa.jpg
Born
Henry Stephen Rzepa

June 1950 (age 74) [1]
Alma mater Imperial College London (PhD)
Awards Herman Skolnik Award (2012) [2]
Scientific career
Fields Chemistry [3]
Institutions
Thesis Hydrogen Transfer Reactions of Indoles  (1974)
Website

Henry Stephen Rzepa (born 1950) [1] is a chemist and Emeritus Professor of Computational Chemistry at Imperial College London. [4] [ citation needed ]

Contents

Education

Rzepa was born in 1950 and was educated at Wandsworth Comprehensive School in London. He then entered the chemistry department at Imperial College London where he graduated in 1971. He stayed to do a Ph.D. on the physical organic chemistry of indoles supervised by Brian Challis. [5] [6]

Career and research

After spending three years doing postdoctoral research at University of Texas at Austin, Texas with Michael Dewar [7] in the emerging field of computational chemistry, he returned to Imperial College and was eventually appointed as Professor of the college in 2003. As of 2017 he is Emeritus Professor of Computational Chemistry. [8] [9] [ citation needed ]

His research interests [3] directed towards combining different types of chemical information tools for solving structural, mechanistic and stereochemical problems in organic, bioorganic, organometallic chemistry and catalysis, using techniques such as semiempirical molecular orbital methods (the MNDO family), Nuclear Magnetic Resonance (NMR) spectroscopy, X-ray crystallography and ab initio quantum theories. Aware of the complex semantic issues involved in converging different areas of chemistry to address modern multidisciplinary problems, he started investigating the use of the Internet as an information and integrating medium around 1987, focusing in 1994 on the World Wide Web as having the most potential. [10] Peter Murray-Rust and he first introduced Chemical Markup Language (CML) in 1995 as a rich carrier of semantic chemical information and data; and they coined the term Datument as a portmanteau word to better express the evolution from the documents produced by traditional academic publishing methods to the Semantic Web ideals expressed by Tim Berners-Lee. [11] [12] [13]

His contributions to chemistry [14] [15] [16] [17] [18] [19] [20] [21] [22] include exploration of Möbius aromaticity, highlighted by the theoretical discovery of relatively stable forms of cyclic conjugated molecules which exhibit two and higher half-twists in the topology rather than just the single twist associated with Mobius systems. He is responsible for unraveling the mechanistic origins of stereocontrol in a variety of catalytic polymerisation reactions, including that of lactide to polylactide, a new generation of bio-sustainable polymer not dependent on oil. He is also known for the integration of chemistry (in the form of CML) with emergent Internet technologies and trends such as RSS and podcasting, for the introduction of the Chemical MIME types in 1994, and for organizing the ECTOC online conferences in organic chemistry, which ran from 1995-1998. [23]

Awards and honours

Rzepa was awarded the Herman Skolnik Award in 2012 by the American Chemical Society. [2]

Related Research Articles

<span class="mw-page-title-main">Aromaticity</span> Chemical property

In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugation alone. The earliest use of the term was in an article by August Wilhelm Hofmann in 1855. There is no general relationship between aromaticity as a chemical property and the olfactory properties of such compounds.

Chemical Markup Language is an approach to managing molecular information using tools such as XML and Java. It was the first domain specific implementation based strictly on XML, first based on a DTD and later on an XML Schema, the most robust and widely used system for precise information management in many areas. It has been developed over more than a decade by Murray-Rust, Rzepa and others and has been tested in many areas and on a variety of machines.

<span class="mw-page-title-main">Phthalocyanine</span> Chemical compound

Phthalocyanine is a large, aromatic, macrocyclic, organic compound with the formula (C8H4N2)4H2 and is of theoretical or specialized interest in chemical dyes and photoelectricity.

<span class="mw-page-title-main">Borazine</span> Boron compound

Borazine, also known as borazole, is an inorganic compound with the chemical formula B3H6N3. In this cyclic compound, the three BH units and three NH units alternate. The compound is isoelectronic and isostructural with benzene. For this reason borazine is sometimes referred to as “inorganic benzene”. Like benzene, borazine is a colourless liquid with an aromatic odor.

<span class="mw-page-title-main">Thioketone</span> Organic compounds with the structure >C=S

In organic chemistry, thioketones are organosulfur compounds related to conventional ketones in which the oxygen has been replaced by a sulfur. Instead of a structure of R2C=O, thioketones have the structure R2C=S, which is reflected by the prefix "thio-" in the name of the functional group. Thus the simplest thioketone is thioacetone, the sulfur analog of acetone. Unhindered alkylthioketones typically tend to form polymers or rings.

<span class="mw-page-title-main">Michael J. S. Dewar</span> American chemist

Michael James Steuart Dewar was an American theoretical chemist.

<span class="mw-page-title-main">Open Babel</span>

Open Babel is computer software, a chemical expert system mainly used to interconvert chemical file formats.

<span class="mw-page-title-main">Peter Murray-Rust</span> Chemist and open-access research activist

Peter Murray-Rust is a chemist currently working at the University of Cambridge. As well as his work in chemistry, Murray-Rust is also known for his support of open access and open data.

<span class="mw-page-title-main">Möbius aromaticity</span>

In organic chemistry, Möbius aromaticity is a special type of aromaticity believed to exist in a number of organic molecules. In terms of molecular orbital theory these compounds have in common a monocyclic array of molecular orbitals in which there is an odd number of out-of-phase overlaps, the opposite pattern compared to the aromatic character to Hückel systems. The nodal plane of the orbitals, viewed as a ribbon, is a Möbius strip, rather than a cylinder, hence the name. The pattern of orbital energies is given by a rotated Frost circle (with the edge of the polygon on the bottom instead of a vertex), so systems with 4n electrons are aromatic, while those with 4n + 2 electrons are anti-aromatic/non-aromatic. Due to incrementally twisted nature of the orbitals of a Möbius aromatic system, stable Möbius aromatic molecules need to contain at least 8 electrons, although 4 electron Möbius aromatic transition states are well known in the context of the Dewar-Zimmerman framework for pericyclic reactions. Möbius molecular systems were considered in 1964 by Edgar Heilbronner by application of the Hückel method, but the first such isolable compound was not synthesized until 2003 by the group of Rainer Herges. However, the fleeting trans-C9H9+ cation, one conformation of which is shown on the right, was proposed to be a Möbius aromatic reactive intermediate in 1998 based on computational and experimental evidence.

The Barton reaction, also known as the Barton nitrite ester reaction, is a photochemical reaction that involves the photolysis of an alkyl nitrite to form a δ-nitroso alcohol.

<span class="mw-page-title-main">Blue Obelisk</span>

Blue Obelisk is an informal group of chemists who promote open data, open source, and open standards; it was initiated by Peter Murray-Rust and others in 2005. Multiple open source cheminformatics projects associate themselves with the Blue Obelisk, among which, in alphabetical order, Avogadro, Bioclipse, cclib, Chemistry Development Kit, GaussSum, JChemPaint, JOELib, Kalzium, Openbabel, OpenSMILES, and UsefulChem.

Organogold chemistry is the study of compounds containing gold–carbon bonds. They are studied in academic research, but have not received widespread use otherwise. The dominant oxidation states for organogold compounds are I with coordination number 2 and a linear molecular geometry and III with CN = 4 and a square planar molecular geometry.

<span class="mw-page-title-main">Birch reduction</span> Organic reaction used to convert arenes to cyclohexadienes

The Birch reduction is an organic reaction that is used to convert arenes to 1,4-cyclohexadienes. The reaction is named after the Australian chemist Arthur Birch and involves the organic reduction of aromatic rings in an amine solvent with an alkali metal and a proton source. Unlike catalytic hydrogenation, Birch reduction does not reduce the aromatic ring all the way to a cyclohexane.

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<span class="mw-page-title-main">Antony John Williams</span> British chemist

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Proline organocatalysis is the use of proline as an organocatalyst in organic chemistry. This theme is often considered the starting point for the area of organocatalysis, even though early discoveries went unappreciated. Modifications, such as MacMillan’s catalyst and Jorgensen's catalysts, proceed with excellent stereocontrol.

Parisa Mehrkhodavandi is a Canadian chemist and Professor of Chemistry at the University of British Columbia (UBC). Her research focuses on the design of new catalysts that can effect polymerization of sustainably sourced or biodegradable polymers.

<span class="mw-page-title-main">Jordi Burés</span> Spanish chemist

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Concerted metalation-deprotonation (CMD) is a mechanistic pathway through which transition-metal catalyzed C–H activation reactions can take place. In a CMD pathway, the C–H bond of the substrate is cleaved and the new C–Metal bond forms through a single transition state. This process does not go through a metal hydride species that is bound to the cleaved hydrogen atom. Instead, a carboxylate or carbonate base deprotonates the substrate. The first proposal of a concerted metalation deprotonation pathway was by S. Winstein and T. G. Traylor in 1955 for the acetolysis of diphenylmercury. It was found to be the lowest energy transition state in a number of computational studies, was experimentally confirmed through NMR experiments, and has been hypothesized to occur in mechanistic studies.

References

  1. 1 2 Anon (2017). "Henry Stephen RZEPA, June 1950". companieshouse.gov.uk. London: Companies House. Archived from the original on 25 April 2017.
  2. 1 2 Anon (2011). "CCL Archives". ccl.net.
  3. 1 2 Henry Rzepa publications indexed by Google Scholar OOjs UI icon edit-ltr-progressive.svg
  4. "A Royal Society of Chemistry interview with Henry Rzepa". Archived from the original on 19 October 2012.
  5. Rzepa, Henry Stephen (1974). Hydrogen transfer reactions of indoles. ethos.bl.uk (PhD thesis). University of London. doi:10.5281/zenodo.18777. hdl:10044/1/20860. OCLC   930651784.
  6. Challis, Brian C.; Rzepa, Henry S. (1975). "Heteroaromatic hydrogen exchange reactions. Part VIII. The ionisation of 1,3-dimethylindolin-2-one" (PDF). Journal of the Chemical Society, Perkin Transactions 2 (15): 1822. doi:10.1039/p29750001822. hdl:10044/1/21275. ISSN   0300-9580.
  7. Dewar, M. J. S.; Mckee, M. L.; Rzepa, H. S. (1978). "ChemInform Abstract: MNDO Parameters for third period elements". Chemischer Informationsdienst. 9 (34). doi:10.1002/chin.197834001. ISSN   0009-2975.
  8. "Information on conference speakers". ukoln.ac.uk.
  9. "Rzepa Biography". rzepa.net.
  10. Rzepa, Henry S.; Whitaker, Benjamin J.; Winter, Mark J. (1994). "Chemical applications of the World-Wide-Web system". Journal of the Chemical Society, Chemical Communications (17): 1907. doi:10.1039/c39940001907. ISSN   0022-4936. S2CID   95897719.
  11. ACS Publications News
  12. Professor Henry Rzepa discusses the launch of Imperial College London's iTunes U on YouTube, Imperial College London
  13. Chemical Science and Data Repository Design with Prof. Henry Rzepa on YouTube, Science & Engineering South
  14. O'Boyle, N. M.; Guha, R.; Willighagen, E. L.; Adams, S. E.; Alvarsson, J.; Bradley, J. C.; Filippov, I. V.; Hanson, R. M.; Hanwell, M. D.; Hutchison, G. R.; James, C. A.; Jeliazkova, N.; Lang, A. S. D.; Langner, K. M.; Lonie, D. C.; Lowe, D. M.; Pansanel, J. R. M.; Pavlov, D.; Spjuth, O.; Steinbeck, C.; Tenderholt, A. L.; Theisen, K. J.; Murray-Rust, P. (2011). "Open Data, Open Source and Open Standards in chemistry: The Blue Obelisk five years on". Journal of Cheminformatics . 3 (1): 37. doi: 10.1186/1758-2946-3-37 . PMC   3205042 . PMID   21999342.
  15. Guha, R.; Howard, M. T.; Hutchison, G. R.; Murray-Rust, P.; Rzepa, H.; Steinbeck, C.; Wegner, J.; Willighagen, E. L. (2006). "The Blue Obelisk - Interoperability in Chemical Informatics". Journal of Chemical Information and Modeling . 46 (3): 991–998. doi:10.1021/ci050400b. PMC   4878861 . PMID   16711717.
  16. Rzepa, H. S. (2005). "A Double-Twist Möbius-Aromatic Conformation of [14]Annulene". Organic Letters . 7 (21): 4637–4639. doi:10.1021/ol0518333. PMID   16209498.
  17. Fowler, P. W.; Rzepa, H. S. (2006). "Aromaticity rules for cycles with arbitrary numbers of half-twists". Physical Chemistry Chemical Physics . 8 (15): 1775–7. Bibcode:2006PCCP....8.1775F. doi:10.1039/b601655c. PMID   16633661.
  18. Marshall, E. L.; Gibson, V. C.; Rzepa, H. S. (2005). "A computational analysis of the ring-opening polymerization of rac-lactide initiated by single-site beta-diketiminate metal complexes: Defining the mechanistic pathway and the origin of stereocontrol". Journal of the American Chemical Society . 127 (16): 6048–51. doi:10.1021/ja043819b. PMID   15839705.
  19. Murray-Rust, P; Rzepa, H. S.; Williamson, M. J.; Willighagen, E. L. (2004). "Chemical markup, XML, and the World Wide Web. 5. Applications of chemical metadata in RSS aggregators". Journal of Chemical Information and Modeling . 44 (2): 462–9. CiteSeerX   10.1.1.477.524 . doi:10.1021/ci034244p. PMID   15032525.
  20. H. S. Rzepa and M. E. Cass (May–June 2006). Progress towards a Holistic Web: Integrating OpenSource programs, Semantic data, Wikis and Podcasts. Spring ConfChem.
  21. Allan, C. S. M.; Rzepa, H. S. (2008). "A computational investigation of the structure of polythiocyanogen". Dalton Transactions (48): 6925–6932. doi:10.1039/b810147g. PMID   19050778.
  22. Rzepa, H. S. (2009). "Wormholes in chemical space connecting torus knot and torus link π-electron density topologies". Physical Chemistry Chemical Physics . 11 (9): 1340–1345. Bibcode:2009PCCP...11.1340R. doi:10.1039/b810301a. PMID   19224034.
  23. Rzepa, Henry S. (13 March 1998). "Electronic Conferences on Trends in Organic Chemistry". www.ch.ic.ac.uk. Retrieved 15 January 2024.