Possible oxidative polymerization mechanism of 5,6-dihydroxyindole from ab initio calculations.
The reactivity of 5,6-dihydroxyindole and its major dimers has been studied with the use of a recently proposed general-purpose reactive indicator (Anderson et al. J. Chem. Theory Comput. 2007, 3, 358-374) from ab initio density-functional theory calculations. Theoretical prediction has reasonably explained previously isolated oligomers up to tetramers. The oxidative polymerization is governed by the electron-transfer-controlled reaction. The electrostatic interaction plays a regioselective role in the reactant complex and/or intermediates. A monomer-dimer coupling is able to form trimers, while a part of it is prevented by the exchange repulsion, i.e., steric hindrance. Therefore, a dimer-dimer coupling is also able to form tetramers.
Integrative Bioscience and Biomedical Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan. h.okuda@asagi.waseda.jp
Hidekazu
H
Okuda
Kazumasa
K
Wakamatsu
Shosuke
S
Ito
Takayuki
T
Sota
D003198:Computer Simulation; D019281:Dimerization; D007211:Indoles / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D011789:Quantum Theory; D013237:Stereoisomerism
D007211:Indoles; D011108:Polymers; C033871:5,6-dihydroxyindole