engleski

Ab Initio RHF investigation of mono- and dihalogenated indole-3-acetic acid (IAA) phytohormones.

The potential energy surfaces of 5-Cl-IAA, 6-Cl-IAA, 7-Cl-IAA, and 5,6-Cl2-IAA show a high similarity with that of unsubstituted IAA: the positions of the local minima are almost identical with differences of the torsion angle values within a few degrees, and the same is true for the transition states and the reaction paths. Furthermore the relative energy of corresponding stationary points is within a range of 1 kJ/mol, except for the increased energy gap between the global minimum (which is displayed above) and the respective minimum of second lowest energy, if a chlorine atom is substituted in position 5. In unsubstituted IAA, 6-Cl-IAA, and 7-Cl-IAA this energy gap is below 0.7 kJ/mol, whereas in 5-Cl-IAA and 5,6-Cl2-IAA it is more than 1.9 kJ/mol.

Auxin; halogenated indole-3-acetic acid; Ab inito; conformational serach

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