Structure-property relationships in polycyclic aromatics

Conference · Mon Sep 01 04:00:00 EDT 1986 · Am. Chem. Soc., Div. Pet. Chem., Gen. Pap., Prepr.; (United States)

OSTI ID:6772215

Herndon, W C; Szentpaly, L V

The theoretical characterization of the molecular structure of polycyclic benzenoid aromatic hydrocarbons (PBAH) and the relationship of structure to PBAH physical and chemical properties are problems that continue to be of interest. In general, quantum chemical procedures are used to correlate kinetic and thermodynamic data for PBAH. These procedures are usually restricted to the pi systems of the PBAH, and seem to yield normally very good results because the pi system properties are described accurately by quantum mechanical calculations. In fact, the PBAH have served as the testing systems for many of the approximations used in molecular orbital calculations. Quantum chemical pencil and paper procedures have proved to be quite useful in the PBAH field. The methods that have been developed are widely applicable, easy to use and they give quantitatively good results for correct physical reasons. The authors feel that reactivity indices obtained from Huckel MO calculations lie in the pencil and paper category. Actual HMO calculations are seldom necessary since there are comprehensive tabulations of eigenvalues, eigenvectors and derived indices for nearly all common ..pi..-systems with less than thirty rho-orbitals. However, the correlative ability of HMO calculations is generally worse than results from SCF-..pi.. or all-valence-electron SCF methods. Rates of protedetritiation of aromatic hydrocarbons are compared with several types of localization energy calculations. Correlation coefficients with the log of the rate constant are 0.979, 0.970 and 0.893 for localization energies calculated by CNDO/2, SCF and HMO methods, respectively.

• Research Organization: Dept. of Chemistry, Univ. of Texas at El Paso, El Paso, TX
• OSTI ID: 6772215
• Report Number(s): CONF-860911-
• Conference Information: Journal Name: Am. Chem. Soc., Div. Pet. Chem., Gen. Pap., Prepr.; (United States) Journal Volume: 31:3
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
CALCULATION METHODS
CHARGED-PARTICLE REACTIONS
CHEMICAL PREPARATION
CHEMICAL PROPERTIES
CHEMICAL REACTION KINETICS
CORRELATIONS
ELECTRON REACTIONS
HYDROCARBONS
KINETICS
LEPTON REACTIONS
MECHANICS
MOLECULAR STRUCTURE
NUCLEAR REACTIONS
ORBITS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
POLYCYCLIC AROMATIC HYDROCARBONS
QUANTUM MECHANICS
REACTION KINETICS
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
VALENCE