Several procedures for the demetalation of silver(III) corrolates have been tested. Acidic conditions induce removal of the silver ion but they can also promote concomitant oxidation of the corrole nucleus to an isocorrole species, the degree of which will depend upon the specific acidic media. This oxidation cannot be completely avoided by addition of hydrazine, particularly in the case of 3-NO2 substituted complexes which are quantitatively converted into the corresponding 3-NO2, 5-hydroxy isocorroles upon silver ion removal. Several beta-nitro isocorrole products were isolated, and one was structurally characterized. Electrochemical and chemical reductive methods for silver(III) corrolates demetalation were then tested with the aim to avoid the formation of isocorroles. While reaction with sodium borohydride was shown to be quite effective to demetalate unsubstituted silver corrolates this was not the case for the beta-nitro derivatives where the peripheral nitro group is reduced by borohydride giving the corresponding 3-amino free base corrole species. For the beta-nitro corrole silver complexes, a successful approach was obtained using DBU/THF solutions which afforded the 3-NO2 corrole free-base compound as a single reaction product in good yield. These conditions were also effective for unsubstituted corroles although longer reaction times were necessary in this case. To study in greater detail the corrole demetalation behavior, selected Ag(III) derivatives were characterized by cyclic voltammetry in pyridine, and the demetalation products spectrally characterized after controlled potential reduction in a thin-layer spectroelectrochemical cell.

Stefanelli, M., Shen, J., Zhu, W., Mastroianni, M., Mandoj, F., Nardis, S., et al. (2009). Demetalation of silver(III) corrolates. INORGANIC CHEMISTRY, 48(14), 6879-6887 [10.1021/ic900859a].

Demetalation of silver(III) corrolates

STEFANELLI, MANUELA;MANDOJ, FEDERICA;NARDIS, SARA;PAOLESSE, ROBERTO
2009-01-01

Abstract

Several procedures for the demetalation of silver(III) corrolates have been tested. Acidic conditions induce removal of the silver ion but they can also promote concomitant oxidation of the corrole nucleus to an isocorrole species, the degree of which will depend upon the specific acidic media. This oxidation cannot be completely avoided by addition of hydrazine, particularly in the case of 3-NO2 substituted complexes which are quantitatively converted into the corresponding 3-NO2, 5-hydroxy isocorroles upon silver ion removal. Several beta-nitro isocorrole products were isolated, and one was structurally characterized. Electrochemical and chemical reductive methods for silver(III) corrolates demetalation were then tested with the aim to avoid the formation of isocorroles. While reaction with sodium borohydride was shown to be quite effective to demetalate unsubstituted silver corrolates this was not the case for the beta-nitro derivatives where the peripheral nitro group is reduced by borohydride giving the corresponding 3-amino free base corrole species. For the beta-nitro corrole silver complexes, a successful approach was obtained using DBU/THF solutions which afforded the 3-NO2 corrole free-base compound as a single reaction product in good yield. These conditions were also effective for unsubstituted corroles although longer reaction times were necessary in this case. To study in greater detail the corrole demetalation behavior, selected Ag(III) derivatives were characterized by cyclic voltammetry in pyridine, and the demetalation products spectrally characterized after controlled potential reduction in a thin-layer spectroelectrochemical cell.
2009
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore CHIM/07 - FONDAMENTI CHIMICI DELLE TECNOLOGIE
English
Con Impact Factor ISI
FREE-BASE CORROLES; REDUCTIVE DEMETALATION; CATALYTIC-REDUCTION; FUNCTIONALIZATION; ELECTROCHEMISTRY; PORPHYRINS
Stefanelli, M., Shen, J., Zhu, W., Mastroianni, M., Mandoj, F., Nardis, S., et al. (2009). Demetalation of silver(III) corrolates. INORGANIC CHEMISTRY, 48(14), 6879-6887 [10.1021/ic900859a].
Stefanelli, M; Shen, J; Zhu, W; Mastroianni, M; Mandoj, F; Nardis, S; Ou, Z; Kadiah, K; Fronczek, F; Smith, K; Paolesse, R
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/26106
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