Influence of metal cation on chromophore properties of complexes of some d metals with α,α-dipyrrolylmethene

Abstract

In complexes of Cu 2+ , Ni 2+ , Co 2+ , Zn 2+ , and Hg 2+ with 3,3`,5,5`-tetramethyl-4,4`-dibutyl-2,2`-dipyrrolylmethene, the d-metal ion exerts an auxochromic effect on the p system of the ligand, manifested in a bathochromic shift of the first absorption band in the spectrum of the complex, compared to the free ligand. Polarization of the chromophore p system in the complexes increases in the order Zn 2+ < Hg 2+ < Co 2+ < Ni 2+ < Cu 2+ . The Hg 2+ ion in the complex with dipyrrolylmethene participates in mercuration of benzene and chloroform; the reaction with chloroform is faster, with the rates of both reactions strongly depending on temperature.Development of studies in the chemistry of polypyrrole compounds is mainly stimulated by their unique biological effect as photoreceptors in the structures of some chromoproteins and intermediate substrates of porphyrin metabolism, and also by their wide use in preparative organic chemistry for synthesis of various manmade and natural porphyrins [1,2]. The efficiency of template synthesis of porphyrins from dipyrrolylmethenes on a metal ion matrix is largely determined by the chelating power of the dipyrrolyl ligand and by the physicochemical properties of the resulting chelates. Therefore, the search for new efficient procedures for template synthesis of porphyrins should be based on systematic data on the reactivity of linear polypyrrole compounds toward various metal ions and on physicochemical properties of the corresponding chelates. Such data are limited [23 4].

Heteroleptic zinc dipyrromethene complexes

“…Using a combination of spectroscopic and calorimetric methods Guseva et al have recently reported on the thermodynamics of dipyrromethene deprotonation and complexation as part of their work towards understanding the metal-template effect in the synthesis of porphyrins [25,[27][28][29]. The data that Guseva uses to calculate equilibrium constants for dipyrromethene complexation with Zn(II), Ni(II), Co(II), Cu(II) and Hg(II) is extracted from the absorption maxima attributed solely to ligand and homoleptic complexes in titrations and does not take into account any intermediates, e.g.…”

Self-assembly of oligomeric linear dipyrromethene metal complexes

“…While the optical spectra, especially fluorescence, have been thoroughly studied for the boron complexes of dipyrromethenes, 8,9 those of simple dipyrromethenes and their metal complexes have not been extensively studied. A. I. V'yugin et al 10 examined solvent effects and showed that l max is determined by the polarization of the p system, which in turn is governed by electronic and steric factors of the metal ions. We have reported 11 that hyperconjugation of peripheral alkyl a Bending angle (y) as shown in Fig.…”

Influence of structural factors on the thermal stability of zinc(II) and boron(III) complexes with iodo- and bromosubstituted 2,2′-dipyrrines

“…Synthesis and elemental analysis, NMR 1 H-, UV-and IR-spectroscopy data for respective dipyrrine hydrobromides HL 1 ·HBr, HL 2 ·HBr and HL 3 ·HBr were described in the previous works [13][14][15].…”

“…For homoleptic zinc (II) dipyrrinates [ZnL2], which by their spectralluminescent and photo-physical properties are not inferior BODIPY [13,14], the systematic study of this effect has not yet been carried out. Important criterion for practical application of phosphors as laser dyes and other fields are their thermal stability.…”