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Titolo:
Heteroassociation of meso-sulfonatophenylporphyrins with beta- and gamma-cyclodextrin
Autore:
El-Hachemi, Z; Farrera, JA; Garcia-Ortega, H; Ramirez-Gutierrez, O; Ribo, JM;
Indirizzi:
Univ Barcelona, Dept Quim Organ, E-08028 Barcelona, Spain Univ Barcelona Barcelona Spain E-08028 m Organ, E-08028 Barcelona, Spain
Titolo Testata:
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
fascicolo: 5, volume: 5, anno: 2001,
pagine: 465 - 473
SICI:
1088-4246(200105)5:5<465:HOMWBA>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
WATER-SOLUBLE PORPHYRINS; CIRCULAR-DICHROISM; ALPHA-CYCLODEXTRIN; ELECTRON-TRANSFER; AQUEOUS-SOLUTIONS; CRYSTAL-STRUCTURE; COMPLEX; RECOGNITION; ABSORPTION; CHEMISTRY;
Keywords:
cyclodextrin inclusion complexes; water-soluble porphyrins; nuclear Overhauser effect (NOE); rotational nuclear Overhauser effect spectroscopy (ROESY);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
38
Recensione:
Indirizzi per estratti:
Indirizzo: Ribo, JM Univ Barcelona, Dept Quim Organ, C Marti & Franques 1, E-08028 Barcelona, Spain Univ Barcelona C Marti & Franques 1 Barcelona Spain E-08028pain
Citazione:
Z. El-Hachemi et al., "Heteroassociation of meso-sulfonatophenylporphyrins with beta- and gamma-cyclodextrin", J PORPHYR P, 5(5), 2001, pp. 465-473

Abstract

The effect of the addition of beta- and gamma -cyclodextrin (beta -CD, gamma -CD) to water solutions (D2O) of the 4'-sulfonato derivatives of meso-tetraphenylporphyrin (TPPS4, TPPS3, TPPS20 and TPPS2a) was studied by H-1 NMRat several temperatures. In all cases the disaggregation of the porphyrin homoassociates was detected, although in most cases it was only partial. Nuclear Overhauser signals (ROESY) show that cyclodextrin inclusion complexeswere formed with TPPS4, TPPS3, and TPPS20, but not with TPPS2a. These complexes include the sulfonatophenyl groups as guest, but not the hydrophobic phenyl substituents. The geometry of the complexes corresponds to that in which the sulfonatophenyl substituent is introduced through the secondary face of beta -CD and through the primary face of gamma -CD. In the inclusion complexes the polar sulfonato group is inside the cyclodextrin cavity but near to the hydrophilic interface with the bulk water. This explains the absence of complexation in the case of cationic porphyrins such as 5,10,15,20-tetrakis(N-methylpyridin-4-yl)porphyrin (TMPyP), and the decrease in the solubility when the beta -CD complex of 5,15-bis(4-sulfonatophenyl)porphyrin (DPPS20) forms. Complexes of the cyclodextrins with porphyrin homoassociates were also detected. This indicates that the heteroassociation avoids the formation of staggered stacks of porphyrin homoassociates, but has less effect on the association through the hydrophobic region of the phenyl substituents. This last type of aggregation, which is not significantly affected by the addition of alpha -CD, explains why the hydrophobic phenyl substituents are not complexed by the cyclodextrins. Copyright (C) 2001 John Wiley & Sons, Ltd.

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Documento generato il 01/10/20 alle ore 01:24:37