Ronald James Gillespie

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Background of Dr Ronald James Gillespie

Name: Ronald James Gillespie
Birthdate: August 21,1924
Birthplace: London, England
Title: Professor Emeritus
Workplace: Department of Chemistry, McMaster University,Ontario,Canada
Status: Retired
Education:

BSc. University College London, 1945

PhD. University College London, 1949

DSc. University College London, 1957

CHILDHOOD

Figure 1: Ronald Gillespie in his childhood (Source: http://ronaldgillespie.weebly.com/)

Gillespie comes from poor family. Despite so, he is a hardworking and excellent student. At the age of 11, Gillespie received scholarship to the local grammar school. During high school, Gillespie was inspired by his chemistry teacher, Mr. George Cast. Mr. Cast always make chemistry seem to be more exciting compared to textbook by doing lab experiments with his students. Ronald Gillespie specialized in chemistry, physics, and pure and applied mathematics, but did particularly well in chemistry. Gillespie left school in 1942.

UNIVERSITY LIFE

He was awarded a bursary to do a special two year wartime degree at University College London.

During second year, he began to join research group and pursue his studies in sulfuric acid, taking his research in a new innovative direction. This led to the quest to discover other super acid systems of even greater acidity. In 1949,he was already appointed as an assistant lecturer before awarded his Ph.D by University College London. In 1953 Gillespie was awarded a Commonwealth Fund Fellowship. Gillespie moved to McMaster University in Hamilton, Ontario in 1958. The offer from McMaster double his salary and gave him the chance at research funding from the National Research Council of Canada.

WORKING EXPERIENCE

Dr. Ronald J Gillespie had hold numerous faculty positions and are so experienced. The list of working experience can be seen below. (Adapted from: http://ronaldjg.weebly.com/education-and-career.html)

1948 - 1950: Assistant Lecturer, Department of Chemistry, University College London.

1950 – 1958: Lecturer, Department of Chemistry, University College London.

1958 – 1960: Associate Professor, Department of Chemistry, McMaster University, Hamilton, Canada.

1960 – 1989: Professor, Department of Chemistry, McMaster University, Hamilton, Canada.

1962 – 1965: Chairman Department of Chemistry, McMaster University, Hamilton, Canada.

1989 : Present Emeritus Professor, McMaster University, Hamilton, Canada.

Figure 3: McMaster University where Gillespie work and continue his research. (Source: wikimedia.org)

AWARDS

Gillespie recieved many awards for his contribution. Below is the award received according to year. (Adapted from: http://rjgillespie.weebly.com/awards-and-achievements.html)

1953: Fellow of the Royal Institute of Chemistry
1960: Fellow of the Chemical Institute of Canada
1965: Fellow of the Royal Society of Canada
1966: Noranda Award (Chemical Institute of Canada),
1967: Canadian Centennial Medal,
1976: Union Carbide Award (Chemical Institute of Canada) for Chemical Education,
1977: Silver Jubilee Medal,
1977: Chemical Institute of Canada Medal,
1977: Fellow of the Royal Society, London,
1983: Tory Medal (Royal Society of Canada)
2007: Order Of Canada

According to Brian McCarry, chair of the Department of Chemistry, Order of Canada recognizes Ron Gillespie's pioneering research in main-group inorganic chemistry, particularly in the areas of fluorine chemistry, super acid media and concepts of chemical bonding. In addition to his research, Gillespie is also claimed to be popular for his talent as lecturer and educator.

"Dr. Gillespie has made a tremendous impact on science and the Faculty of Science continues to benefit from his contributions and influence in teaching and research within the field of chemistry," said John Capone, dean of the Faculty of Science. "We are proud of him and his accomplishments and are delighted with his appointment to the Order of Canada."(Source: http://dailynews.mcmaster.ca/)

Figure 4: Order of Canada is given to those who make a major difference to Canada through lifelong contributions . (Source: wp.rac.ca)

PUBLICATION

Dr. Ronald J. Gillespie published some books and journal articles. (Source:ttp://www.chemistry.mcmaster.ca/gillespie/)

1. Molecular Geometry, Van Nostrand Reinhold, London, 1972, 226 pages.

German translation: Verlag Chemie 1975

Russian translation: MIR 1975

2. Chemistry, with D.A. Humphreys, N.C. Baird and E.A. Robinson

Allyn and Bacon, 1986, 895 pages. 2nd Edition, 1989, 1132 pages

3. The VSEPR Model of Molecular Geometry (Figure 5) with I. Hargittai Allyn and Bacon, 1991

Russian translation: MIR 1992

Italian translation Zanichelli 1994

Figure 5: The VSEPR Model of Molecular Geometry (Source:http://ronaldjg.weebly.com/)

4. Atoms, Molecules and Reactions: An Introduction to Chemistry (Figure 6) with D.A. Humphreys, E.A. Robinson and D.R. Eaton,

Prentice Hall, 1994, 750 pages.

Figure 6: Atoms, Molecules and Reactions: An Introduction to Chemistry (Source:http://ronaldjg.weebly.com/)

A new book is to be published by Oxford University Press in 2001:

5. The Chemical Bond and Molecular Geometry: from Lewis to Electron Densities.

by Ronald J. Gillespie and Paul L. A. Popelier

Journal Articles

Gillespie has over 370 articles in: The Journal of the American Chemical Society (ACS), Inorganic Chemistry, The Canadian Journal of Chemistry, The journal of the Chemical Society, The Journal of Chemical Education, and many others.

VSEPR THEORY

Valence Shell Electron Pair Repulsion or VSEPR Theory is a method to determine the geometry of a molecule based on the idea that electron pairs are as far apart as possible. It is also known as Gillespie-Nyholm theory as it was developed by the two great chemist. Firstly, the idea of correlation between molecular geometry and number of valence electrons (both shared and unshared) was originally proposed in 1939 by Ryutaro Tsuchida in Japan. In 1957, Gillespie done extensive work on expanding the idea of the Valence Shell Electron Pair Repulsion (VSEPR) model of Molecular Geometry, which he developed with Ronald Nyholm, and setting the rules for assigning numbers. Their contribution defined VSEPR theory in more detailed concept and we are able to choose between alternative geometry.

Video1: Brief explanation on VSEPR theory. (Source: Youtube.com)

Electron pairs in the valence shell of a central atom can be determined by drawing the Lewis structure of the molecule, and expanding it to show all bonding groups and lone pairs of electrons

Figure 1: Drawing Lewis structure can determine the shape of the molecule according to VSEPR theory. (Source:http://chemed.chem.purdue.edu/)

AXE notation also used when applying VSEPR theory. A is the central atom which always has 1 subscript. X is the number of sigma bond between central and outside atoms. E is the number of lone electron pairs surrounding the central atom. Sum of X and E is known as steric number. VSEPR theory uses steric number and distribution of X's and E's to predict molecular geometric shape as figure 2 below.

Figure 2: AXE method annotation, geometry and example for each shape. (Source: https://www.boundless.com/)

Limitation of VSEPR Theory

Like other theory, VSEPR theory also has exceptions and limitations. The limitations are for:

Isoelectronic species.

Isoelectronic species are elements, ions and molecules that share same number of electrons. Although two isoelectronic compound have the same number of electrons, but it has different geometry shape. For example, VSEPR predict the shape of IF7 and [TeF7]- that have 56 electrons to be pentagonal bipyramidal. However, the equatorial of F atoms in [TeF7]- are not coplanar according to X-ray diffraction. Thus, VSEPR fails to predict it shape.

Transition metal compounds.

As VSEPR theory does not take relative sizes of the substituents and stereochemically inactive lone pairs into account, it fails to predict structure of certain compound. For example,[TeCl6]2-is predicted to have pentagonal bipyramidal geometries according to VSEPR since the central atom can have seven electron pairs. However, due to the stereochemical inert pair effect, these molecules are found to be regular octahedral because one of the electron pairs is stereochemically inactive. The shape can be seen in figure 3 below.

Figure 3: Transition metal that disobey VSEPR theory. (Source: http://chemwiki.ucdavis.edu/)

REASONS CONTRIBUTION IS CRUCIAL

VSEPR theory can determine the shape of molecule. This is important to understand the reaction and properties. Properties like smell, taste and proper targeting of drugs are all possible because of knowing the shapes of molecule. VSEPR theory also a great predictive tool that make it simple for student to understand element's molecular geometry. Scientist no longer need to depends on X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy to know the 3-D structure of molecule.

Figure 4: X-ray crystallography determine the atom arrangement(Source: http://chemwiki.ucdavis.edu/)

MODIFICATION ON THE CONTRIBUTION

Kepert Model is the modification of VSEPR theory. It able to predict the molecular geometry shape of transition metal. Since transition metal have partially filled d-subshells, VSEPR theory doesn't work for them. The different between Kepert model and VSEPR theory is Kepert model does not account for non-bonding electrons and it considered ligands attached to the metal repel each other like point charges repel each other in VSEPR theory. Here is the coordination numbers and geometries of Kepert model. (click to enlarge)

Figure 5: Shape of molecule is determined by the coordination number in Kepert model. (Source:http://www.unf.edu/)

Example, the d8 metals like Ni(II), Pd (II), Pt (II), Au (III) and d9 metals like CU(II) has square planar shape. Figure below shows the geometry of Platinum transition metal.

Figure 6: The isomer of platinum (II) which has the shape of square planar. (Source:http://www.unf.edu/)

Here is the geometry of Rhenium, Re a third row transition metal in group 7 according to Kepert model. Rhenium has 6 coordination number with geometry of trigonal prismatic.

Figure 7: The less common arrangement of rhenium. (Source:http://www.unf.edu/)

The limitation for Kepert Model is it cannot explain the formation of square planar complexes or distorted structures.

IS IT WIDELY ACCEPTED?

VSEPR theory is widely accepted. This is obvious in medical field. For example, shape of Aspirin is important to be determined as the shape affect the pain. Aspirin act as inhibitor that will bind at the reactant side to block the substrate which cause pain from binding. If the molecular shape of the medicine does not portable, the medicine will not be effective to the pain. This is explained in figure 4 below.

Figure 8: Aspirin blocking substrate from binding to enzyme which consequently avoid inflammation. (Source:www.sjaweb.org )

FUTURE CHEMISTRY

VSEPR theory is important whether now or in the future. If a chemists found a new element, they can simply determine it properties by analyzing the shape. This can be done with the present of VSEPR theory. In the future, VSEPR theory need to be modified until there is no limitation. VSEPR theory should be modified to become better than the current model. So that, the VSEPR model can predict for the entire element including for transition metal compound and isoelectronic compound.