Page 265 - Academic Press Encyclopedia of Physical Science and Technology 3rd Organic Chemistry

P1: LDK/GJK P2: GQT/Final Pages Qu: 00, 00, 00, 00
Encyclopedia of Physical Science and Technology EN012G-576 July 28, 2001 12:44

Physical Organic Chemistry

Charles L. Perrin
University of California, San Diego

I. Molecular Structure: Bonding
II. Molecular Structure: Stereochemistry
III. Chemical Reactivity
IV. Methodology of Mechanistic Studies
V. Illustrative Examples
VI. Quantitative Relationships

GLOSSARY Linear free energy relationship Logarithmic linearity
between rate and equilibrium constants.
Aromaticity Unusual stability of cyclic conjugated sys- Nucleophile Atom or reactant that uses an electron pair
tems containing 4n + 2 pi electrons. to form a bond to an electrophile.
Brønsted relationship Linearity between logarithms Orbital One-electron wave function.
of the catalytic constants for acid or base and Order (kinetic order) Power of the concentration of a
pK. chemical species entering into a rate equation.
Chiral Not superimposable upon its mirror image. Pericyclic reaction Reorganization of electrons around a
Cis/trans isomerism Isomerism arising from sidedness cycle of nuclei, with simultaneous bond breaking and
on a double bond or ring. bond making.
Conformations Structures interconvertible by rotation Product-development control Predominant formation
about single bonds. of the more stable product because its transition state
Diastereomers Stereoisomers that are not mirror images partakes of that stability.
of each other. Racemic mixture A 50:50 mixture of two enantiomers.
Enantiomers Stereoisomers that are (nonsuperimpos- Reactioncoordinate Geometricparameterthatmeasures
able) mirror images of each other. progress from reactants to products.
General acid catalysis Catalysis where each acid present Stereoisomers Different molecules with the same con-
+
functions as a catalyst, rather than H 3 O alone. nectivity (bonding relationships between atom pairs).
Hammett equation Quantitative comparison with sub- Torsional strain Destabilization of eclipsed conforma-
stituent effects in benzoic acid dissociation. tions.
Intermediates Energy minina between reactant and Transition state Position of maximum energy along
product on a reaction coordinate. reaction coordinate.

211