کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1238452 | 968936 | 2007 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Solvent effects on spectrophotometric titrations and vibrational spectroscopy of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin in aqueous DMF
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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![عکس صفحه اول مقاله: Solvent effects on spectrophotometric titrations and vibrational spectroscopy of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin in aqueous DMF Solvent effects on spectrophotometric titrations and vibrational spectroscopy of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin in aqueous DMF](/preview/png/1238452.png)
چکیده انگلیسی
The spectrophotometric titration by sodium hydroxide of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin ((OH)1PH2) is studied as a function of solvent composition of DMF-H2O binary solvent mixture ([OHâ]Â =Â 0.04Â M). Combining the structure changes of the porphyrin and the “four orbital” model of Gouterman, many features of the optical spectra of this deprotonated para-hydroxy-substituted tetraphenylporphyrin in different composition of binary solvent mixtures can be rationalized. In highly aqueous solvents, the changes of the titration curves are shown to be mainly due to hydrogen-bonding of the oxygen of the phenoxide anion group by the hydroxylic solvent, Which decreases the energy of the phenoxide anion Ï orbital. Thus the phenoxide anion Ï orbital cannot cross over the porphyrin Ï orbital being a different HOMO. However, its energy is close to that of the porphyrin Ï orbitals. As a result, in the visible region, no charge-transfer band is observed, while in the visible-near region, the Soret peak split into two components. In nonaqueous solvents, the changes are mainly attributed to further deprotonation of pyrrolic-Hs of (OH)1PH2 by NaOH and coordination with two sodium ions to form the sodium complex of (OH)1PH2, which turns hyperporphyrin spectra of deprotonated of phenolic-H of (OH)1PH2 into three-banded spectra of regular metalloporphyrin.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 67, Issue 1, May 2007, Pages 166-171
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 67, Issue 1, May 2007, Pages 166-171
نویسندگان
Hongwei Guo, Junguang Jiang, Yingyan Shi, Yuling Wang, Shaojun Dong,