Infrared Spectral Study of Crown Ether Molecular Complexes with 4-Nitroaniline |
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| Authors: | B I El-Eswed M B Zughul G AW Derwish |
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| Institution: | Department of Chemistry, Faculty of Science , University of Jordan , Amman, 11942, Jordan |
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| Abstract: | Abstract The IR spectra of the crystalline complexes of 4-nitroaniline with crown ethers were studied, viz., 18-crown-6, benzo-18-crown-6, dibenzo-18-crown-6, dicyclohexano-18-crown-6 and dibenzo-24-crown-8. The hydrogen bonding interaction was found to be predominant in these complexes. The strongest among them was the one formed with the most flexible crown ether dicyclohexano-18-crown-6, in which both the N-H bonds of 4-nitroaniline were shown to be equivalently hydrogen bonded to the crown ether oxygens. The shift of the NO2 absorption bands indicated that the resonance form (?C2N-C6H4=N+H2) is favored upon complexation with the larger ring size dibenzo-24-crown-8, while for the other complexes, the resonance form (C2N-C6H4-NH2) is favored; a fact which was attributed to geometrical factors. |
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