THEORETICAL STUDY OF THE INFLUENCE OF STERIC EFFECT TO THE ATE CONSTANT OF SOME DIELS- ALDER REACTIONS

Yaman,; Sa, Q.; Dullah,; Shakir,; Saied, M.; Walid,; Yousif, Y.

	THEORETICAL STUDY OF THE INFLUENCE OF STERIC EFFECT TO THE ATE CONSTANT OF SOME DIELS- ALDER REACTIONS
AL-TAQANI
Article 1, Volume 24, Issue 2, 2011, Pages 101-114
Authors
; Q. Sa; ; ; M. Saied; ; Y. Yousif
Abstract
Computational studies with the factors affecting the steric energies of Diels-Alder addition and their correlation with the relevant physical properties of the product and reactant molecules were investigated. A single and multi – parametric linear regression analysis was applied with the rate constant as dependent and independent variables. One of the reactant (Dien or Dienophile) of four series was kept constant and the other reactants were varied. The products and reactants were influenced by all the molecular properties with different extent and different direction for these four serious of reactions. These properties included the total steric energy=E stretching +E bending +E torsion +E over lap +Evdw+E dipole-dipole. The polarity and the values of steric energies were increased due to high electrostatic repulsion power of Dienophile malic unhydride and hexachlorocyclopent-1-ene for series (i) and (ii) respectively. While the rate constants of tetracyanoethylene were increased with decreasing electrons affinity in series (iii) , and the low steric energies of anthracen in series (iv) as determined using MM2 program and this was due to its coplanarity

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