| 1. |
- MURRAY, JS, et al.
(författare)
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CORRELATIONS BETWEEN MOLECULAR ELECTROSTATIC POTENTIALS AND SOME EXPERIMENTALLY-BASED INDEXES OF REACTIVITY
- 1992
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Ingår i: Journal of Molecular Structure. - UNIV NEW ORLEANS, DEPT CHEM, NEW ORLEANS, LA 70148 USA. : ELSEVIER SCIENCE BV. - 0166-1280. ; 88, s. 29-45
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Tidskriftsartikel (refereegranskat)abstract
- The key role that electrostatics plays in molecular reactive behavior is demonstrated in this work, which surveys and further explores correlations that we found between the molecular electrostatic potential V(r) calculated by an ab initio SCF-MO approach (a gas-phase property) and experimentally-based indices of reactivity (derived from solution studies). In our relationships involving negative V(r), we find in all cases that spatial minima (V(min)) provide correlations of higher quality than surface minima (V(S,min)). Relationships between V(min) and the hydrogen-bond-acceptor parameter-beta, and V(S,max) and the hydrogen-bond-donor parameter-alpha, confirm the physical validity of the empirically-derived solvatochromic parameters-alpha and beta. Correlations between the V(min) of NH2-X molecules and the substituent constants sigma(I), and sigma(I) + sigma(R) (when sigma(R) > 0) for the substituents X show how electrostatic properties reflect the electron-attracting tendencies of substituent groups. Whereas good relationships exist between the pK(a) values of some limited groups of molecules and their conjugate base V(min), we find that the average local ionization energy IBAR-(r) is better suited as a general measure of aqueous acidity.
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| 2. |
- MURRAY, JS, et al.
(författare)
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RELATIONSHIPS OF CRITICAL CONSTANTS AND BOILING POINTS TO COMPUTED MOLECULAR-SURFACE PROPERTIES
- 1993
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Ingår i: JOURNAL OF PHYSICAL CHEMISTRY. - UNIV NEW ORLEANS,DEPT CHEM,NEW ORLEANS,LA 70148. : AMER CHEMICAL SOC. - 0022-3654 .- 1541-5740. ; 97:37, s. 9369-9373
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Tidskriftsartikel (refereegranskat)abstract
- It is shown, for a large number of organic compounds of a variety of types, that their critical constants (T(c), V(c), and P(c)) and normal boiling points can be related to computed properties of the respective molecular surfaces. One of these is the surface area; the other is a measure of the molecule's tendency for electrostatic interactions. These properties are obtained by ab initio SCF computations at the STO-5G* level, using STO-3G* optimized geometries.
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| 3. |
- POLITZER, P, et al.
(författare)
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RADIAL BEHAVIOR OF THE AVERAGE LOCAL IONIZATION ENERGIES OF ATOMS
- 1991
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Ingår i: Journal of Chemical Physics. - : AMER INST PHYSICS. - 0021-9606 .- 1089-7690. ; 95:9, s. 6699-6704
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Tidskriftsartikel (refereegranskat)abstract
- The radial behavior of the average local ionization energy IBAR(r) has been investigated for the atoms He-Kr, using ab initio Hartree-Fock atomic wave functions. IBAR(r) is found to decrease in a stepwise manner with the inflection points serving effectively to define boundaries between electronic shells. There is a good inverse correlation between polarizability and the ionization energy in the outermost region of the atom, suggesting that IBAR(r) may be a meaningful measure of local polarizabilities in atoms and molecules.
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