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Synthesis and Spectral Characterization of Some New Aromatic Schiff Bases Derivated from 2,4- Dinitrophenylhydrazine
تحضير وتشخيص طيفي لبعض قواعد شف الاروماتية الجديدة المشتقة من 4,2 -ثنائي نيتروفنيل هيدرازين

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Abstract

Four novel Schiff bases SB1 to SB4 as new aromatic compound not hydrolysed under ordinaryconditions were synthesized in this study by condensation reactions between2,4-dinitrophenylhydrazine: firstly with 2,4,4`-trihydroxybenzophenone to give SB1, secondly with 4-hydroxybenzophenone to give SB2, thirdly with 4-dimethylaminobenzaldhyde to give SB3 andfourthly with 4-aminobenzaldehyde to give SB4. The molecular structures of these aromatic Schiffbases obtained were identified and characterized based on melting points, elemental analysis(CHN),FT-IR and UV-Visible spectra. The electronic absorption spectra of Schiff bases obtained were studiedin the solvents of ethanol, DMF, water, chloroform, carbon tetrachloride and cyclohexane. Therecorded absorption bands in ethanol solvent were assigned to corresponding electronic transitionswere discussed. The absorption bands at 291 to 411 nm obtained in electronic spectra of thesynthesized new aromatic Schiff bases were assigned to (π→π*) transition which originates fromsubstituted benzophenone or benzaldehyde rings and directed along of molecule in Schiff bases. Thesetransitions are assumed to represent the intramolecular charge-transfer complexes bands in which thesubstituted two moieties of benzophenone and benzaldehyde rings are the charge donors and thesubstituted phenylhydrazine ring is the charge acceptor. Also, the effect of polar, non-polar solventson the electronic transitions of charge-transfer bands have measured and discussed.The physical-spectroscopic parameters in molecular structural shapes of intra CT complexesmolecules such as transition energies, molar extinction coefficients, molecular oscillate strength;transition molecular dipole moment and molecular resonance have been calculated and discussed.

حضرت اربع قواعد شف اروماتية جديدة لا تتحلل مائيا بالظروف الاعتيادية في هذه الدراسة بتفاعلاتالتكاثف بين 2وثانيامع 4-هيدروكسي SB 4- ثلاثي هيدروكسي بنزوفينون ليعطي 1 ′, 4ثنائي نيتروفينل هيدرازين:اولا مع 4,2 ,.SB ورابعا مع 4-امينوبنزالدهايد ليعطي 4 SB و, ثالثا مع 4- ثنائي مثيل امينوبنزالديهايد ليعطي 3 SB بنزوفينون ليعطي 2لقد شۥخصت التراكيب الجزيئية لقواعد شف الاروماتية هذه على اساس تعيين درجات انصهارها وتحليل العناصر الدقيقوتسجيل اطيافها تحت الحمراء وفوق البنفسجية-المرئية. ان الانتقالات الالكترونيه التي تم الحصول عليها درست فيمذيبات الايثانول وثنائي مثيل فورمايد والماي والكلورفورم ورابع كلوريد الكاربون والهكسان الحلقي, وتعود حزمالامتصاص المسجلة في مذيب الايثانول الى انتقالتها الالكترونيه المناظره.تعود حزم الامتصاص التي تم الحصول عليها)

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