Titre du document / Document title
2-Aminopyrimidine directed self-assembly of zinc porphyrins containing bulky 3,5-di-tert-butylphenyl groups
Auteur(s) / Author(s)
BALABAN Teodor Silviu (1) ;
GODDARD Richard (2) ;
LINKE-SCHAETZEL Myriam (1) ;
LEHN Jean-Marie (1 3) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) Forschungzentrum Karlsruhe, Institute for Nanotechnology, Postfach 3640, 76021 Karlsruhe, ALLEMAGNE
(2) Max-Planck-lnstitut für Kohlenforschung, Kaiser-Wilkelm-Platz I, 45470 Mülheim an der Ruhr, ALLEMAGNE
(3) ISIS, Université Louis Pasteur, 8, rue Gaspard Monge, 67000 Strasbourg, FRANCE
Résumé / Abstract
The 2-aminopyrimidin-5-yl ligand is revealed to be a promising candidate for the construction of supramolecular porphyrin arrays with broad absorption bands for efficient light-harvesting. 10-Mono- and 10,20-di(2-aminopyrimidin-5-yl) derivatives of 5,15-bis(3,5-di-tert-butylphenyl)porphyrin have been synthesized in high yield. Their Zn(ll) salts show variable concentration and temperature-dependent UV/vis spectra in solution, consistent with supramolecular aggregation. Whereas the FAB mass spectra of the monosubsituted derivative in toluene suggest the formation of a tetramer at high concentrations and low temperatures (estimated association free enthalpy △H = 220 ± 10 kJ/mol), the larger splitting of the Sorret band (ca. 40 nm) in the variable temperature UV/vis spectra of the disubstituted bis(3,5-di-tert-butylphenyl)porphyrin is indicative of yet higher aggregates involving both 2-aminopyrimidin-5-yl groups. The tetrameric nature of the monosubsituted derivative is confirmed by X-ray analysis, which reveals that two of the 2-aminopyrimidin-5-yl groups are encapsulated by the aggregate and consequently are prevented from undergoing hydrogen bonding. NMR studies show there is no exhange of the 2-aminopyrimidin-5-yl groups, so the tetramer is rigid, which is confirmed by molecular modeling calculations. The tetramer formation is governed by π-π interactions, metal coordination, and hydrogen bonding. The di(2-aminopyrimidin-5-yl) derivative forms strongly scattering solutions, which upon standing form green flocculate precipitates, reminiscent of shaken suspensions of bacteriochlorophyll c.
Revue / Journal Title
Journal of the American Chemical Society
ISSN
0002-7863
CODEN JACSAT
Source / Source
2003, vol. 125, n
o14, pp. 4233-4239 [7 page(s) (article)] (28 ref.)
Langue / Language
Anglais
Editeur / Publisher
American Chemical Society, Washington, DC, ETATS-UNIS
(1879)
(Revue)
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Localisation / Location
INIST-CNRS, Cote INIST : 551, 35400011795607.0500
Nº notice refdoc (ud4) : 14717535
