A novel fluorescein-porphyrinatozinc(II) hybrid: synthesis and its supramolecular self-assembly with imidazolyl-linked porphyrinatomanganese(III) by coordinative bonding

Abstract

A novel fluorescein-porphyrinatozinc(II) hybrid, Zn(Fl-PPTPP), was synthesized and characterized by u.v.-vis., i.r., 1 H-n.m.r, ESMS and elemental analyses. The supramolecular self-assembly of Zn(Fl-PPTPP) with an imidazolyl-linked porphyrinatomanganese(III), Mn (III) ( p-ImBPTPP)Cl, complex has been studied by fluorescence spectroscopic titration, VPO measurements and ESMS, which indicates that the formation of the Zn(Fl-PPTPP)-Mn (III) ( p-ImBPTPP)Cl. supramolecular complex is driven by coordinative bonding formed by the coordination of imidazolyl group in Mn (III) ( p-ImBPTPP)Cl to Zn(II) in Zn(Fl-PPTPP). The association constant of the supramolecular complex was calculated from the fluorescence spectroscopic titration data. It was found that the conformation of the Zn(Fl-PPTPP)-Mn (III) ( p-ImBPTPP)Cl supramolecular complex, the steric hindrance and the electronic effect of the fluorescein group linked to porphyrin through a flexible long alkoxy chain are all acting on the association constant of the Zn(Fl-PPTPP)-Mn (III) ( p-ImBPTPP)Cl supramolecular complex. It seems that the steric hindrance and the electronic effect of the fluorescein group are the primary factors effecting the association constant of Zn(Fl-PPTPP)-Mn (III)

Synthesis of a fluorescein–porphyrin hybrid and its supramolecular self-assembly with amino-porphyrinatocopper(II) by hydrogen bonding

“…CHCl 3 , CH 2 Cl 2 and other chemicals used in the synthesis and physical measurements were analytical reagents and were purified by published methods prior to use [15][16][17][18].…”

“…The yield of Fl-PTPP was 40%. Anal APTPP and its copper(II) complex, CuAPTPP, were prepared according to the literature method [17,18]. All these compounds were characterized by elemental analysis, IR, 1 H NMR, ES-MS and UV/Vis.…”

“…UV/vis and 1 H NMR spectra As far as we are aware, the formation of a ground-state complex between electron donor and acceptor molecules usually results in a change of their UV/vis spectra [18,19]. UV/vis spectra for 1:1 mixtures of Fl-PTPP and CuAPTPP in CH 2 Cl 2 at 298 K are shown in Fig.…”

“…The isolated complex CuAPTPP has no fluorescent emission in any range of concentration, which relates to the paramagnetic of Cu 2? ion [16][17][18][19]. We Absorbance(a.u.)…”

“…Much effort has therefore been directed toward the study of porphyrin supramolecular systems assembled by non-covalent weak interactions including hydrogen bonding, coordinate bonding, p-p stacking, hydrophobic interactions and so on [15][16][17]. There are several examples in the literature of model dimeric structures that involve conjugated bridges in the context of the donor-acceptor model system of porphyrin-fluorescein with diad-chromophores [16][17][18][19]. Various fluorescence quenching phenomena caused by photoinduced electron transfer from porphyrins or porphyrinatozinc to an electron acceptor have been observed in these systems [20][21][22][23][24][25][26].…”