E. D. Jemmis

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E. D. Jemmis
ED-jemmis.jpeg
Born (1951-10-31) 31 October 1951 (age 72)
Nationality Indian
Alma mater Indian Institute of Technology, Kanpur
Princeton University
Cornell University
Known forJemmis ring-cap orbital overlap criteria [1]
Jemmis mno rules
Awards Padma Shri (2014)
Scientific career
Fields Applied theoretical chemistry
Institutions University of Hyderabad

Indian Institute of Science

Indian Institute of Science Education and Research, Thiruvananthapuram
Doctoral advisor Paul von Ragué Schleyer

Eluvathingal Devassy Jemmis (born 31 October 1951) is a professor of theoretical chemistry at the Indian Institute of Science, Bangalore, India. He was the founding director of Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM). His primary area of research is applied theoretical chemistry with emphasis on structure, bonding and reactivity, across the periodic table of the elements. Apart from many of his contributions to applied theoretical chemistry, [2] an equivalent of the structural chemistry of carbon, as exemplified by the Huckel 4n+2 Rule, benzenoid aromatics and graphite, and tetrahedral carbon and diamond, is brought in the structural chemistry of boron by the Jemmis mno rules which relates polyhedral and macropolyhedral boranes to allotropes of boron and boron-rich solids. [3] [4] [5] He has been awarded Padma Shri in Science and Engineering category (year 2014) by the Government of India. [6]

Contents

Education

E. D. Jemmis, after obtaining his BSc from University College, Thiruvananthapuram and St. Thomas College, Thrissur and MSc from IIT Kanpur, joined Princeton University (1973) under the supervision of Profs Paul von Rague Schleyer and John Pople (1998 Nobel laureate). Moving along with his supervisors Jemmis spent one semester at the University of Munich and four semesters at the University of Erlangen-Nuernberg. He was awarded the PhD degree (1978) from Princeton. After a two-year postdoctoral work at Cornell University with Professor Roald Hoffmann (1981 Nobel laureate), he joined the School of Chemistry, University of Hyderabad (1980) rising to the rank of professor (1990) and dean (2002). Jemmis was a visiting fellow at the Australian National University, Canberra (1991) and a visiting professor at the Centre for Computational Quantum Chemistry of the University of Georgia, Athens (2000). Jemmis is an honorary professor at JNCASR and an adjunct professor at ICTS-TIFR. In 2005 he accepted an invitation from the Indian Institute of Science (IISc), Bangalore, and joined the Department of Inorganic and Physical Chemistry. In 2008 Dr. Jemmis moved again, this time on a five-year deputation, accepting the responsibility to start the Indian Institute of Science Education and Research, Thiruvananthapuram and served there till 2013.

Research

Jemmis is engaged in the study of structure and reactivity of molecules, clusters and solids using theoretical methods. A constant attempt is made by his group to find common threads between problems of different areas, viz. between organic and organometallic chemistry; amongst the chemistry of various main group elements; between polymorphs of elements and their compounds; etc. His research group not only gets numbers as an answer to a problem, but also tries to find out why the numbers turn out the way they do, based on overlap of orbitals, perturbation theory and symmetry, and devise transferable models. Significant results have been obtained in understanding the reactions of transition metal organometallics, week H-bond, [7] electronic structure of three-dimensional aromatic compounds, [1] [8] polyhedral boranes, carboranes, silaboranes, electron counting rules for polycondensation, and structure of boron allotropes. [9] [10] [11] [12] [13] The latter involved an extension of the Wade's Rules for polyhedral boranes to macropolyhedral boranes and the Huckel 4n+2 Rule to three dimensions. The Jemmis mno rules for polyhedral boranes have found a place in textbooks [14] [15] [16] [17] [18] [19] [20] and are being taught in Inorganic Chemistry Courses in leading educational institutions around the world. Just as the basic tenets of the structural chemistry of carbon has stood the test of time, and led to major developments in carbon, the edifice of the structural chemistry expounded by Jemmis has already begun to do so for boron. Several of his predictions have been proved experimentally. [21] [22] [23] He has mentored 20 PhD students and several postdoctoral and students and research associates, and published about 200 research articles.

Memberships and honors

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In chemistry, the Jemmis mno rules represent a unified rule for predicting and systematizing structures of compounds, usually clusters. The rules involve electron counting. They were formulated by E. D. Jemmis to explain the structures of condensed polyhedral boranes such as B20H16, which are obtained by condensing polyhedral boranes by sharing a triangular face, an edge, a single vertex, or four vertices. These rules are additions and extensions to Wade's rules and polyhedral skeletal electron pair theory. The Jemmis mno rule provides the relationship between polyhedral boranes, condensed polyhedral boranes, and β-rhombohedral boron. This is similar to the relationship between benzene, condensed benzenoid aromatics, and graphite, shown by Hückel's 4n + 2 rule, as well as the relationship between tetracoordinate tetrahedral carbon compounds and diamond. The Jemmis mno rules reduce to Hückel's rule when restricted to two dimensions and reduce to Wade's rules when restricted to one polyhedron.

<span class="mw-page-title-main">Carborane acid</span> Class of chemical compounds

Carborane acidsH(CXB
11
Y
5
Z
6
)
(X, Y, Z = H, Alk, F, Cl, Br, CF3) are a class of superacids, some of which are estimated to be at least one million times stronger than 100% pure sulfuric acid in terms of their Hammett acidity function values (H0 ≤ –18) and possess computed pKa values well below –20, establishing them as some of the strongest known Brønsted acids. The best-studied example is the highly chlorinated derivative H(CHB
11
Cl
11
)
. The acidity of H(CHB
11
Cl
11
)
was found to vastly exceed that of triflic acid, CF
3
SO
3
H
, and bistriflimide, (CF
3
SO
2
)
2
NH
, compounds previously regarded as the strongest isolable acids.

Borane, also known as borine, is an unstable and highly reactive molecule with the chemical formula BH
3
. The preparation of borane carbonyl, BH3(CO), played an important role in exploring the chemistry of boranes, as it indicated the likely existence of the borane molecule. However, the molecular species BH3 is a very strong Lewis acid. Consequently, it is highly reactive and can only be observed directly as a continuously produced, transitory, product in a flow system or from the reaction of laser ablated atomic boron with hydrogen. It normally dimerizes to diborane in the absence of other chemicals.

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References

  1. 1 2 Jemmis, E. D. (1982). "Overlap control and stability of polyhedral molecules. closo-Carboranes". J. Am. Chem. Soc. 104 (18): 7017–7020. doi:10.1021/ja00382a008.
  2. Prasad V. Bharatam; Gernot Frenking; G. Narahari Sastry (2012). "Research expedition of Prof. Eluvathingal D. Jemmis". Theor Chem Acc. 131 (3): 1–2. doi: 10.1007/s00214-012-1164-4 .
  3. Jemmis, E. D.; Balakrishnarajan M. M; Pancharatna P. D. (2002). "Electronic Requirements for Macropolyhedral Boranes". Chem. Rev. 102 (1): 93–114. doi:10.1021/cr990356x. PMID   11782130.
  4. Jemmis, E. D.; Jayasree E. G. (2003). "Analogies between Boron and Carbon". Acc. Chem. Res. 36 (11): 816–824. doi:10.1021/ar0300266. PMID   14622028.
  5. Prasad, D. L. V. K.; Balakrishnarajan M. M; Jemmis E. D. (2005). "Electronic structure and bonding of β-rhombohedral boron using cluster fragment approach". Phys. Rev. B. 72 (19): 195102. Bibcode:2005PhRvB..72s5102P. doi:10.1103/PhysRevB.72.195102.
  6. "Padma Shri Award Recipients 2014".
  7. Jorly, J.; Jemmis E. D. (2007). "Red-, Blue-, or No-Shift in Hydrogen Bonds: A Unified Explanation". J. Am. Chem. Soc. 129 (15): 4620–4632. doi:10.1021/ja067545z. PMID   17375920.
  8. Jemmis, E. D.; Schleyer P. v. R. (1982). "Aromaticity in three dimensions. 4. Influence of orbital compatibility on the geometry and stability of capped annulene rings with six interstitial electrons". J. Am. Chem. Soc. 104 (18): 4781–4788. doi:10.1021/ja00382a008.
  9. Jemmis, E. D.; Balakrishnarajan M. M. (2001). "Polyhedral Boranes and Elemental Boron: Direct Structural Relations and Diverse Electronic Requirements". J. Am. Chem. Soc. 123 (18): 4324–4330. doi:10.1021/ja0026962. PMID   11457199.
  10. Jemmis, E. D.; Balakrishnarajan M. M.; Pancharatna P. D. (2001). "A Unifying Electron-Counting Rule for Macropolyhedral Boranes, Metallaboranes, and Metallocenes". J. Am. Chem. Soc. 123 (18): 4313–4323. doi:10.1021/ja003233z. PMID   11457198.
  11. Prasad, D. L. V. K.; Jemmis E. D. (2000). "Stuffing Improves the Stability of Fullerene-like Boron Clusters". Phys. Rev. Lett. 100 (16): 165504. Bibcode:2008PhRvL.100p5504P. doi:10.1103/PhysRevLett.100.165504. PMID   18518216.
  12. Shameema, O.; Jemmis E. D. (2008). "Orbital Compatibility in the Condensation of Polyhedral Boranes". Angew. Chem. Int. Ed. 47 (30): 5561–5564. doi:10.1002/anie.200801295. PMID   18567034.
  13. Prasad, D. L. V. K.; Jemmis E. D. (2010). "Stuffed fullerenelike boron carbide nanoclusters". Appl. Phys. Lett. 96 (2): 023108. Bibcode:2010ApPhL..96b3108P. doi:10.1063/1.3280369.
  14. Gary L. Miessler; Donald A. Tarr (2011). Inorganic Chemistry. Prentice Hall. ISBN   978-0136128663.
  15. Wai-Kee Li; Gong-Du Zhou; Thomas Mak (2008). Advanced Structural Inorganic Chemistry (International Union of Crystallography Texts on Crystallography). Oxford University Press. ISBN   978-0199216956.
  16. Thomas Fehlner, Jean-François Halet, Jean-Yves (2007). Molecular clusters : a bridge to solid-state chemistry. Cambridge: Cambridge University Press. ISBN   978-0521852364.{{cite book}}: CS1 maint: multiple names: authors list (link)
  17. Matthias Driess; Heinrich Nöth (2004). Molecular clusters of the main group elements (1. Aufl. ed.). Weinheim: Wiley-VCH. ISBN   978-3527306541.
  18. Bd Gupta; Anil J. Elias (2010). Basic organometallic chemistry : concepts, syntheses, and applications of transition metals. Hyderabad: Universities Press. ISBN   978-1439849682.
  19. Grimes, Russell N. (24 March 2011). Carboranes (2nd ed.). London: Academic Press. ISBN   978-0123741707.
  20. Comba, Peter, ed. (5 October 2011). Modeling of molecular properties. Weinheim: Wiley-VCH. ISBN   978-3527636419.
  21. Bin, Li; John D. Corbett (2005). "Phase Stabilization through Electronic Tuning: Electron-Poorer Alkali-Metal−Indium Compounds with Unprecedented In/Li Clusters". J. Am. Chem. Soc. 127 (3): 926–932. doi:10.1021/ja0402046. PMID   15656631.
  22. Bernhardt, E.; Brauer D. J.; Finze M.; Willner H. (2007). "closo-[B21H18]−: A Face-Fused Diicosahedral Borate Ion". Angew. Chem. Int. Ed. 46 (16): 2927–2930. doi:10.1002/anie.200604077. PMID   17366499.
  23. Pediaditakis, A.; Schroeder M.; Sagawe V; Ludwig T.; Hillebrecht H. (2010). "Binary Boron-Rich Borides of Magnesium: Single-Crystal Investigations and Properties of MgB7 and the New Boride Mg5B44". Inorg. Chem. 49 (23): 10882–10893. doi:10.1021/ic1012389. PMID   21043472.
  24. "Prizes and Awards". The World Academy of Sciences. 2016.