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How to calculate the value of homo and lumo if the reference...
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LaToya Boggans
How to calculate the value of homo and lumo if the reference...
Please could you explain more clear about your reply? I meant I have seen many papers but most of them mentioned about using ferrocene as internal reference or external reference and calculate them with formular HOMO (LUMO) = -4.8 - (Eonset - E1/2 ferrocene) or second way, tried to measure UV-VIS absorbance and emission spectra and get the Eo-o transition energy from the intersection between them, get the HOMO value from oxidation potential and LUMO=HOMO-Eo-o.
Please could you explain more clear about your reply? I meant I have seen many papers but most of them mentioned about using ferrocene as internal reference or external reference and calculate them with formular HOMO (LUMO) = -4.8 - (Eonset - E1/2 ferrocene) or second way, tried to measure UV-VIS absorbance and emission spectra and get the Eo-o transition energy from the intersection between them, get the HOMO value from oxidation potential and LUMO=HOMO-Eo-o.
Yes, you are right that 4.8 eV is due to the ferrocene redox couple. This could be used as a standard for calibrating the CV curves. You can use any other supporting electrolyte (definitely not ferrocyanide couple) to determine the HOMO-LUMO energy level of your compound.
Yes, you are right that 4.8 eV is due to the ferrocene redox couple. This could be used as a standard for calibrating the CV curves. You can use any other supporting electrolyte (definitely not ferrocyanide couple) to determine the HOMO-LUMO energy level of your compound.
The above equation given by Prof. John is the simplified version of the below equation where the value – 4.8 eV is the HOMO energy level of ferrocene against vacuum. EHOMO (eV) = - (Eox onset - E Fc/Fc+onset) - 4.80 eV and it is found that E Fc/Fc+onset is close to 0.4 V vs Ag/AgCl. where Eox onset and E Fc/Fc+onset are the onset oxidation potentials for the polymer sample and the ferrocene against the Ag/AgCl reference electrode, Ref: (a) M. Kumada and K. Tamao, Adv. Organomet. Chem.1968, 6, 19. (b) J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt, H. Bassler, M. Porsch and J. Daub, Adv. Mater. 1995, 7, 551. (c) B. W. D. Andrade, S. Datta, S. R. Forrest, P. Djurovich, E. Polikarpov and M. E. Thompson, Org. Electron. 2005, 6, 11. (d) Y. Liu, M. S. Liu and A. K.-Y. Jen, Acta Polym., 1999, 50, 105–108.
The above equation given by Prof. John is the simplified version of the below equation where the value – 4.8 eV is the HOMO energy level of ferrocene against vacuum. EHOMO (eV) = - (Eox onset - E Fc/Fc+onset) - 4.80 eV and it is found that E Fc/Fc+onset is close to 0.4 V vs Ag/AgCl. where Eox onset and E Fc/Fc+onset are the onset oxidation potentials for the polymer sample and the ferrocene against the Ag/AgCl reference electrode, Ref: (a) M. Kumada and K. Tamao, Adv. Organomet. Chem.1968, 6, 19. (b) J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt, H. Bassler, M. Porsch and J. Daub, Adv. Mater. 1995, 7, 551. (c) B. W. D. Andrade, S. Datta, S. R. Forrest, P. Djurovich, E. Polikarpov and M. E. Thompson, Org. Electron. 2005, 6, 11. (d) Y. Liu, M. S. Liu and A. K.-Y. Jen, Acta Polym., 1999, 50, 105–108.
Ferrocene is used as a known reference to calculate the energy of the HOMO and LUMO levels. E (HOMO) =-e [Eoxonset + 4.4], E (LUMO) =-e [Ered onset + 4.4] Please check the number: 4.8 eV, it might be 4.4 eV. Please consult this paper. J.L.Bredas, R.Silbey, D.S.Boudreux, R.R.Chance, Chain-length dependence of electronic and electrochemical properties of conjugated systems: polyacetylene, polyphenylene, polythiophene, and polypyrrole, J. Am. Chem. Soc. vol. 105 (1983) p. 6555;
Ferrocene is used as a known reference to calculate the energy of the HOMO and LUMO levels. E (HOMO) =-e [Eoxonset + 4.4], E (LUMO) =-e [Ered onset + 4.4] Please check the number: 4.8 eV, it might be 4.4 eV. Please consult this paper. J.L.Bredas, R.Silbey, D.S.Boudreux, R.R.Chance, Chain-length dependence of electronic and electrochemical properties of conjugated systems: polyacetylene, polyphenylene, polythiophene, and polypyrrole, J. Am. Chem. Soc. vol. 105 (1983) p. 6555;
Please could you explain more clear about your reply? I meant I have seen many papers but most of them mentioned about using ferrocene as internal reference or external reference and calculate them with formular HOMO (LUMO) = -4.8 - (Eonset - E1/2 ferrocene) or second way, tried to measure UV-VIS absorbance and emission spectra and get the Eo-o transition energy from the intersection between them, get the HOMO value from oxidation potential and LUMO=HOMO-Eo-o.
Please could you explain more clear about your reply? I meant I have seen many papers but most of them mentioned about using ferrocene as internal reference or external reference and calculate them with formular HOMO (LUMO) = -4.8 - (Eonset - E1/2 ferrocene) or second way, tried to measure UV-VIS absorbance and emission spectra and get the Eo-o transition energy from the intersection between them, get the HOMO value from oxidation potential and LUMO=HOMO-Eo-o.
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what should be value instead 4.8 if we are using KOH as an electrolyte?
what should be value instead 4.8 if we are using KOH as an electrolyte?
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I have one question regarding this:
Why not ferro ferri cyanide??
I have one question regarding this:
Why not ferro ferri cyanide??
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Yes, you are right that 4.8 eV is due to the ferrocene redox couple. This could be used as a standard for calibrating the CV curves. You can use any other supporting electrolyte (definitely not ferrocyanide couple) to determine the HOMO-LUMO energy level of your compound.
Yes, you are right that 4.8 eV is due to the ferrocene redox couple. This could be used as a standard for calibrating the CV curves. You can use any other supporting electrolyte (definitely not ferrocyanide couple) to determine the HOMO-LUMO energy level of your compound.
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If cyclic voltammogram shows multiple reductions, can I calculate LUMO+1, LUMO+2 etc from potential values? If not, what is the reason behind it?
If cyclic voltammogram shows multiple reductions, can I calculate LUMO+1, LUMO+2 etc from potential values? If not, what is the reason behind it?
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The above equation given by Prof. John is the simplified version of the below equation where the value – 4.8 eV is the HOMO energy level of ferrocene against vacuum.
EHOMO (eV) = - (Eox onset - E Fc/Fc+onset) - 4.80 eV
and it is found that E Fc/Fc+onset is close to 0.4 V vs Ag/AgCl.
where Eox onset and E Fc/Fc+onset are the onset oxidation potentials for the polymer sample and the ferrocene against the Ag/AgCl reference electrode,
Ref:
(a) M. Kumada and K. Tamao, Adv. Organomet. Chem.1968, 6, 19.
(b) J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt, H. Bassler, M. Porsch and J. Daub, Adv. Mater. 1995, 7, 551.
(c) B. W. D. Andrade, S. Datta, S. R. Forrest, P. Djurovich, E. Polikarpov and M. E. Thompson, Org. Electron. 2005, 6, 11.
(d) Y. Liu, M. S. Liu and A. K.-Y. Jen, Acta Polym., 1999, 50, 105–108.
The above equation given by Prof. John is the simplified version of the below equation where the value – 4.8 eV is the HOMO energy level of ferrocene against vacuum.
EHOMO (eV) = - (Eox onset - E Fc/Fc+onset) - 4.80 eV
and it is found that E Fc/Fc+onset is close to 0.4 V vs Ag/AgCl.
where Eox onset and E Fc/Fc+onset are the onset oxidation potentials for the polymer sample and the ferrocene against the Ag/AgCl reference electrode,
Ref:
(a) M. Kumada and K. Tamao, Adv. Organomet. Chem.1968, 6, 19.
(b) J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt, H. Bassler, M. Porsch and J. Daub, Adv. Mater. 1995, 7, 551.
(c) B. W. D. Andrade, S. Datta, S. R. Forrest, P. Djurovich, E. Polikarpov and M. E. Thompson, Org. Electron. 2005, 6, 11.
(d) Y. Liu, M. S. Liu and A. K.-Y. Jen, Acta Polym., 1999, 50, 105–108.
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VOTE
Ferrocene is used as a known reference to calculate the energy of the HOMO and
LUMO levels.
E (HOMO) =-e [Eoxonset + 4.4],
E (LUMO) =-e [Ered onset + 4.4]
Please check the number: 4.8 eV, it might be 4.4 eV. Please consult this paper.
J.L.Bredas, R.Silbey, D.S.Boudreux, R.R.Chance, Chain-length dependence of electronic and electrochemical properties of conjugated systems: polyacetylene, polyphenylene, polythiophene, and polypyrrole, J. Am. Chem. Soc. vol. 105 (1983) p. 6555;
Ferrocene is used as a known reference to calculate the energy of the HOMO and
LUMO levels.
E (HOMO) =-e [Eoxonset + 4.4],
E (LUMO) =-e [Ered onset + 4.4]
Please check the number: 4.8 eV, it might be 4.4 eV. Please consult this paper.
J.L.Bredas, R.Silbey, D.S.Boudreux, R.R.Chance, Chain-length dependence of electronic and electrochemical properties of conjugated systems: polyacetylene, polyphenylene, polythiophene, and polypyrrole, J. Am. Chem. Soc. vol. 105 (1983) p. 6555;
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