Volume: 13, Issue: 12(2009)
pp. 1233-1242 DOI: 10.1142/S1088424609001595
|
|
Abstract |
Full Text (PDF, 482KB)
|
References
|
 |
| Title: |
Effect of solvent binding on UV-vis spectra and redox potentials of octaethylporphyrins containing first-row transition metal ions |
| Author(s): |
Weihua Zhu
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, ChinaXiaofeng Zhao
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, ChinaZhongping Ou
Corresponding author, fax: +86 511-88791800.
SPP full member in good standing.
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, ChinaFan Zhou
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, ChinaXiaohong Wang
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, ChinaKarl M. Kadish
Corresponding author, fax: +1 713-743-2745.
SPP full member in good standing.
Department of Chemistry, University of Houston, Houston, TX 77204-5003, USA
|
| History: |
Received 17 February 2009
Accepted 9 March 2009
|
| Abstract: |
The UV-visible spectra and oxidation/reduction potentials for six octaethylporphyrins with first-row transition metal ions were measured in four non-aqueous solvents and then analyzed as a function of the Gutmann solvent parameters, donor number (DN) or acceptor number (AN). The utilized solvents were dichloromethane (CH2Cl2), N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and pyridine (py). The investigated porphyrins were (OEP)M, where OEP = the dianion of octaethylporphyrin and M = CoII, NiII, CuII, ZnII, FeIIICl or MnIIICl. UV-visible spectra upon solvent (S) binding to give (OEP)M(S) or [(OEP)M(S)2]+Cl- were monitored during a titration of the porphyrin in CH2Cl2 and formation constants (logβn, n = 1 or 2) for the ligand addition reactions were determined using standard equations. Five-coordinate (OEP)CoII(S) and (OEP)ZnII(S) are generated in CH2Cl2 solutions containing DMF, DMSO or py while six-coordinate [(OEP)Mn(S)2]+Cl and [(OEP)Fe(S)2]+Cl- are formed under the same solution conditions. The magnitudes of the solvent binding constants are discussed in terms of both the solvent donor/acceptor properties and the electronegativity (EN) or stability index (SI) of the porphyrin central metal ion. A comparison between solvent binding constants measured in this study for (OEP)M and literature data for (TPP)M with the same central metal ions is presented. |
| Keywords: |
UV-vis spectra; electrochemistry; octaethylporphyrins; solvent effect; central metal ion effect; binding constants
|
|
|
