9,10-Anthraquinone, molecular orbitals

Indigo is the most important vat dye, dating back to ancient times and produced on an industrial scale since 1880. To replace the indigo dyes, the indanthrone (21) class of dyes was developed. Indanthrone has superior characteristics as a vat dye and became a key material for further development of anthraquinoid vat dyes. There exist a variety of anthraquinone vat dyes differing in the chromophoric system. The color-structure relationship of vat dyes have been rationalized by the Pariser-Parr-Pople molecular orbital (PPP MO) method. Some examples of commercialized anthraquinoid vat dyes are shown in Scheme 6.14... 

Fabian, W.M., Timofei, S. and Kurunczi, L. (1995). Comparative Molecular Field Analysis (CoMFA), Semiempirical (AMI) Molecular Orbital and Multiconformational Minimal Steric Difference (MTD) Calculations of Anthraquinone Dye Fiber Affinities. I.MoLStruct.(Theo-chem), 340, 73-81. 

Alternative pulping catalysts have also been addressed through molecular orbital calculations on anthraquinone and its various reactive forms and adducts. Shevchenko and Zarubin [40] interpret the reactivity of the C-10 position and the reduced form of anthraquinone in terms of the atomic orbital contributions to the HOMO. Elder et al. 

Elder, T. J., D. J. Gardner, M. L. McKee, and S. D. Worley. 1989. The application of molecular orbital calculations to wood chemistry. VI. The reactions of anthraquinone under pulping conditions. J. Wood Chem. Technol. 9(3) 277-292. 

CNDO molecular orbital calculations [11] were performed to calculate the 7t charge distribution in substituted anthraquinones. Geometry optimization through energy minimization was prohibited by the size of the anthraquinones, and thus standard molecular bond distances and angles [12] were employed. CNDO calculations were also performed on tautomeric structures of hydroxy-substituted anthraquinones and resonance structures of amino-substituted anthraquinones. 

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