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Synthesis, spectroscopic and crystallographic analysis of the Zn-complex of a di(β,β'-sulfoleno)pyrrin: model for Zn-complexes of bilirubin and of phylloxanthobilins.

Li C, Wurst K, Feng Y, Kräutler B - Monatsh. Chem. (2016)

Bottom Line: In the brightly green fluorescent Zn-complex of the hardly luminescent di(β,β'-sulfoleno)pyrrin, the metal ion is bound by two di(β,β'-sulfoleno)pyrrin ligands, as revealed first by its mass spectra.The crystal structure of this Zn-complex of the di(β,β'-sulfoleno)pyrrin confirmed a regular 2:1 composition of the bidentate di(β,β'-sulfoleno)pyrrin ligand and the metal ion.The latter was coordinated in a distorted tetrahedral fashion, as found in other dipyrrin Zn-complexes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria ; School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People's Republic of China.

ABSTRACT

Abstract: A high yield preparation, spectroscopic and crystallographic investigation of the crystalline Zn-complex of a di(β,β'-sulfoleno)pyrrin are reported here. In the brightly green fluorescent Zn-complex of the hardly luminescent di(β,β'-sulfoleno)pyrrin, the metal ion is bound by two di(β,β'-sulfoleno)pyrrin ligands, as revealed first by its mass spectra. The crystal structure of this Zn-complex of the di(β,β'-sulfoleno)pyrrin confirmed a regular 2:1 composition of the bidentate di(β,β'-sulfoleno)pyrrin ligand and the metal ion. The latter was coordinated in a distorted tetrahedral fashion, as found in other dipyrrin Zn-complexes. The here studied Zn-complex of a designed di(β,β'-sulfoleno)pyrrin ligand provides insights into the coordination properties of the proposed (2:1)- and (2:2)-complexes of phylloxanthobilin and bilirubin, respectively, which are two abundant natural bilin-type tetrapyrroles.

No MeSH data available.


1H NMR spectra of the dipyrrin 2 (bottom) and of its Zn(II)-complex 3 (Zn-(2)2) (top) in CDCl3 (300 MHz, 25 °C, × = solvent signals)
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Fig2: 1H NMR spectra of the dipyrrin 2 (bottom) and of its Zn(II)-complex 3 (Zn-(2)2) (top) in CDCl3 (300 MHz, 25 °C, × = solvent signals)

Mentions: Our synthetic route to di(β,β′-sulfoleno)pyrrin 2 relied on the earlier made corresponding di(β,β′-sulfoleno)pyrromethane (1), available, in turn, from condensation of 3,5-di-tert-butylbenzaldehyde and β,β′-sulfolenopyrrole [13]. Dipyrromethane 1 was oxidized with dicyanodichlorobenzoquinone (DDQ) to furnish bright yellow 2 in 76 % yield, after crystallization in CH2Cl2/n-C6H14 (see Scheme 1). The UV/Vis spectrum of the dipyrrin 2, displayed in Fig. 1, exhibits characteristic maxima at 436.5 and 327 nm, comparable to the one of bilirubin [14, 15], or of a recently described yellow chlorophyll catabolite (YCC, a phylloxanthobilin) [16, 17]. A FAB-mass spectrum featured a strong pseudo-molecular ion at m/z = 513.1 [M + H]+, confirming its molecular formula as C27H32N2O4S2. Fragments at m/z = 448.2 and 384.2 indicated consecutive loss of the two SO2-groups. The 1H NMR spectrum of 2 exhibited two singlets at intermediate field of the two pairs of symmetry equivalent β-methylene groups, a singlet at 7.58 ppm of the pyrrole-α positions, the signals of aryl o- and p-protons at low field, and a broad signal of an NH at 12.76 ppm (see Fig. 2, bottom).Fig. 1


Synthesis, spectroscopic and crystallographic analysis of the Zn-complex of a di(β,β'-sulfoleno)pyrrin: model for Zn-complexes of bilirubin and of phylloxanthobilins.

Li C, Wurst K, Feng Y, Kräutler B - Monatsh. Chem. (2016)

1H NMR spectra of the dipyrrin 2 (bottom) and of its Zn(II)-complex 3 (Zn-(2)2) (top) in CDCl3 (300 MHz, 25 °C, × = solvent signals)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4863038&req=5

Fig2: 1H NMR spectra of the dipyrrin 2 (bottom) and of its Zn(II)-complex 3 (Zn-(2)2) (top) in CDCl3 (300 MHz, 25 °C, × = solvent signals)
Mentions: Our synthetic route to di(β,β′-sulfoleno)pyrrin 2 relied on the earlier made corresponding di(β,β′-sulfoleno)pyrromethane (1), available, in turn, from condensation of 3,5-di-tert-butylbenzaldehyde and β,β′-sulfolenopyrrole [13]. Dipyrromethane 1 was oxidized with dicyanodichlorobenzoquinone (DDQ) to furnish bright yellow 2 in 76 % yield, after crystallization in CH2Cl2/n-C6H14 (see Scheme 1). The UV/Vis spectrum of the dipyrrin 2, displayed in Fig. 1, exhibits characteristic maxima at 436.5 and 327 nm, comparable to the one of bilirubin [14, 15], or of a recently described yellow chlorophyll catabolite (YCC, a phylloxanthobilin) [16, 17]. A FAB-mass spectrum featured a strong pseudo-molecular ion at m/z = 513.1 [M + H]+, confirming its molecular formula as C27H32N2O4S2. Fragments at m/z = 448.2 and 384.2 indicated consecutive loss of the two SO2-groups. The 1H NMR spectrum of 2 exhibited two singlets at intermediate field of the two pairs of symmetry equivalent β-methylene groups, a singlet at 7.58 ppm of the pyrrole-α positions, the signals of aryl o- and p-protons at low field, and a broad signal of an NH at 12.76 ppm (see Fig. 2, bottom).Fig. 1

Bottom Line: In the brightly green fluorescent Zn-complex of the hardly luminescent di(β,β'-sulfoleno)pyrrin, the metal ion is bound by two di(β,β'-sulfoleno)pyrrin ligands, as revealed first by its mass spectra.The crystal structure of this Zn-complex of the di(β,β'-sulfoleno)pyrrin confirmed a regular 2:1 composition of the bidentate di(β,β'-sulfoleno)pyrrin ligand and the metal ion.The latter was coordinated in a distorted tetrahedral fashion, as found in other dipyrrin Zn-complexes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria ; School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 People's Republic of China.

ABSTRACT

Abstract: A high yield preparation, spectroscopic and crystallographic investigation of the crystalline Zn-complex of a di(β,β'-sulfoleno)pyrrin are reported here. In the brightly green fluorescent Zn-complex of the hardly luminescent di(β,β'-sulfoleno)pyrrin, the metal ion is bound by two di(β,β'-sulfoleno)pyrrin ligands, as revealed first by its mass spectra. The crystal structure of this Zn-complex of the di(β,β'-sulfoleno)pyrrin confirmed a regular 2:1 composition of the bidentate di(β,β'-sulfoleno)pyrrin ligand and the metal ion. The latter was coordinated in a distorted tetrahedral fashion, as found in other dipyrrin Zn-complexes. The here studied Zn-complex of a designed di(β,β'-sulfoleno)pyrrin ligand provides insights into the coordination properties of the proposed (2:1)- and (2:2)-complexes of phylloxanthobilin and bilirubin, respectively, which are two abundant natural bilin-type tetrapyrroles.

No MeSH data available.