TETRAKIS(THIADIAZOLO)PORPHYRAZINES. 3. ACID–BASE PROPERTIES AND STABILITY OF TETRAKIS-3,4-(1,2,5-THIADIAZOLO)PORPHYRAZINE IN SULFURIC ACID SOLUTIONS

Authors

  • П. А. Стужин Ivanovo State University of Chemical Technology, 153460 Ivanovo
  • E. А. Поздышeва Ivanovo State University of Chemical Technology, 153460 Ivanovo
  • О. В. Мальчугина Ivanovo State University of Chemical Technology, 153460 Ivanovo
  • И. А. Попкова Ivanovo State University of Chemical Technology, 153460 Ivanovo
  • К. Эрколани Universita' degli Studi di Roma "La Sapienza", 00185 Rome

DOI:

https://doi.org/10.1007/8383

Keywords:

porphyrazines, 1, 2, 5-thiadiazole, AM1 calculations, basic properties, proton affinity, electronic absorption spectra

Abstract

AM1 calculations gave the proton affinities of different types of donor sites in tetrakis-3,4-(1,2,5-thiadiazolo)porphyrazine, H2{[SN2)4PA}, and protonation of the meso-nitrogen atoms was found to be favored. A spectrometric study showed that the basicity of the meso-nitrogen atoms of the porphyrazine macrocycle is strongly diminished and these atoms in CF3CO2H are involved in an incomplete acid–base interaction (ABI) to give acid solvates, while  a complete ABI (protonation) is found only in the presence of sulfuric acid. The basicity constants of the meso-nitrogen atoms were determined spectrophotometrically in CF3CO2H–H2SO4. The kinetics of decomposition of the macrocyclic chromophore in concentrated sulfuric acid was studied and a possible mechanism for this process was proposed.

How to Cite
Stuzhin, P. A.; Pozdysheva, E. A.; Mal'chugina, O. V.; Popkova, I. A.; Ercolani, C.  Chem. Heterocycl. Compd. 2005, 41, 246. [Khim. Geterotsikl. Soedin. 2005, 278.]

For this article in the English edition, see DOI 10.1007/s10593-005-0136-1


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Published

2023-12-01

Issue

No. 2 (2005)

Section

Original Papers