TY - JOUR TT - A Theoretıcal Study On Proton-Loss Behavıor Of Some Monoazo Derıvatıves AU - Öğretir, Cemil PY - 2007 DA - June Y2 - 2006 JF - Eskişehir Osmangazi Üniversitesi Mühendislik ve Mimarlık Fakültesi Dergisi JO - ESOGÜ Müh Mim Fak Derg PB - Eskişehir Osmangazi University WT - DergiPark SN - 2630-5712 SP - 113 EP - 136 VL - 20 IS - 1 KW - Proton-verme KW - yarı-empirik hesaplamalar KW - PM3 metodu. . N2 - The deprotonation acidity constants, (pKa) of five monoazo derivatives were calculated by using the semi-empirical PM3 method and the obtained pKa values were compared with the experimental ones. Taking into account of the best fit results, the deprotonation centers and deprotonation patterns were determined. Using the calculated acidity constants the equlibrium constants, for keto-enol tautomerizm KT, were calculated. The evaluation of the toutomeric equlibrium constant volues revealed that the enol forms are more stable. It was observed that both deprotonation takes place on the aromatic ring which has two phenolic hydroxy groups. Whith the exception two molecules which deprotonates at phenolic hydroxy group located at ortho position of the other aromatic ring. The first deprotonation for all seems to take place at the para positioned phenolic hydroxyl group.  CR - [1] H., Zolinger, “Synthesis, Properties and Applications of Organic Dyes and Pigments, Color chemistry” 2 nd ed., VCH, Weinheim, 1991. CR - [2] G.S., Kumar, “Azo Functional Polymers: Functional Group Approach in Macromolecular Design”, Tecnomic Publishing Co. Inc.: Lancaster, Basel, 1993. CR - [3] Z.F., Liu, K., Hashimoto, and A., Fujishima, “Photoelectrochemical information storage using an azobenzene derivative”, Nature, Vol.347, 658660, 1990. CR - [4] H.W., Russ, and H., Tappe, Eur. Pat. Appl., EP. 629, 667, 1994. CR - [5] X.J., Peng, and J.Z., Yang, Chin. Image Sci. Practise, 4, 5, 1998. 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