Showing papers by "N. Zh. Mamardashvili published in 2008"
TL;DR: The published data on self-assembling systems based on porphyrin macrocycles are surveyed in this article, where the key principles, mechanisms and driving forces of intermolecular complexation are discussed.
Abstract: The published data on self-assembling systems based on porphyrin macrocycles are surveyed. The key principles, mechanisms and driving forces of intermolecular complexation are discussed. Examples of supramolecular assemblies and factors that allow an efficient control over their formation are considered.
48 citations
TL;DR: In this article, a bisporphyrinocalixarene was prepared and its basicity was examined spectrophotometrically, and the ionization constants and the concentration intervals of the formation of the mono-and dicationic forms of the bispora were determined.
Abstract: A bisporphyrinocalix[4]arene was prepared, and its basicity was examined spectrophotometrically. The protonation of tetrapyrrole fragments of the porphyrinocalixarene conjugate in the ethanol-sulfuric acid system occurs in two steps and is described by the Hammett equation. The ionization constants and the concentration intervals of the formation of the mono-and dicationic forms of the bisporphyrinocalixarene were determined.
32 citations
TL;DR: Palladium 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrinate (I) and its 5,15-diaza (II), diphenyl (III), and di(4-bromophenyl) (IV) derivatives were synthesized by the complex formation reaction of palladium(II) chloride with corresponding tetrapyrrole ligands in dimethylformamide, and their spectral properties were studied as mentioned in this paper.
Abstract: Palladium 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrinate (I) and its 5,15-diaza (II), diphenyl (III), and di(4-bromophenyl) (IV) derivatives were synthesized by the complex formation reaction of palladium(II) chloride with corresponding tetrapyrrole ligands in dimethylformamide, and their spectral properties were studied.
10 citations
TL;DR: In this article, the effect of diamine structure on the formation of porphyrinate-ligand complexes of the composition 1 :1 and 1 :2 was established and the stability constants of the complexes obtained were calculated and the concentration intervals of their formation were determined.
Abstract: The complex formation of zinc 2,8,12,18-tetramethyl-3,7,13,17-tetraethylporphyrinate, 5,17-bis(zinc 2,8,12,18-tetramethyl-3,7,13,17-tetraethyl-10-phenylporphyrinate)-25,27-dimethoxy-26,28-dihydroxycalic-[4]-arene, and 5,17-bis(zinc 2,8,12,18-tetramethyl-3,7,13,17-tetraethyl-10-phenylporphyrinate)-25,27-dimethoxy-26,28-crwon-[6]-calix-[4]-arene with 1,2-diaminoethane, 1,3-diaminopropane, and 1,2-di-(dimethylamino)ethane in toluene was studied by spectrophotometric molar ratio method and 1H NMR. The effect of the diamine structure on the formation of “internal” and “external” porphyrinate-ligand complexes of the composition 1 :1 and 1 :2 was established. The stability constants of the complexes obtained were calculated and the concentration intervals of their formation were determined.
9 citations
01 Jan 2008
TL;DR: In this paper, the titration of the diprotonated form of 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrin with the series of halide ions has been done in the acetonitrile solution.
Abstract: @The titration of the diprotonated form of 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrin with the series of halide ions has been done in the acetonitrile solution. It was shown that the stable complexes of 1:1 and 1:2 structures with halide ions have been formed. The influence of complexation with halide ions on the porphyrin fluorescent properties has been studied. The strong quenching of the porphyrin fluorescence has been found. It was established that both static quenching upon the nonfluorescent complex formation due to internal heavy atom effect and dynamic diffusioncontrolled quenching took place. Based on the analysis of dependencies of fluorescence intensity and lifetime on the iodide ions concentration in solution, it was proposed to use the diprotonated form of the porphyrin as a basic compound for design of the fluorescent molecular receptor for the halide ions.
9 citations
TL;DR: In this article, the basic properties of azaporphyrin were studied by means of spectrophotometric titration and the ionization constants and the concentration ranges of existence of mono-and dicationic forms were evaluated.
Abstract: 5-Aza-2,3,7,8,12,13,17,18-octamethylporphyrin was synthesized and its basic properties were studied by means of spectrophotometric titration. Protonation of nitrogen atoms in the tetrapyrrolic macrocycle with the ethanolic sulfuric acid is found to be a two-step process. Corresponding ionization constants and the concentration ranges of existence of mono-and dicationic forms of the azaporphyrin under investigation are evaluated.
4 citations
4 citations
3 citations
TL;DR: In this article, it was shown that the distance between the reaction centers of the porphyrin fragments of the macrocycle can be controlled by varying the solution acidity of the solution.
Abstract: pH-Dependent conformational changes in bisporphyrincalixarene in which the calix[4]arene core fixes the tetrapyrrole chromophores in the cyclophane orientation relative to each other were studied by spectrophotometric titration and 1H NMR spectroscopy. It was shown that the distance between the reaction centers of the porphyrin fragments of the macrocycle can be controlled by varying the solution acidity. The ranges of reagent concentrations where functionally significant reversible conformational changes of the dimeric porphyrin occur were determined.
1 citations
TL;DR: In this article, three cyclophane-like calixarene-bis-porphyrins were synthesized and their spectral properties were studied, and their stability constant was determined by spectrophotometric titration.
Abstract: Three new cyclophane-like calixarene-bis-porphyrins were synthesized, and their spectral properties were studied. Zinc complex of meso-(aminophenyl)-substituted calixarene-bis-porphyrin was found to form a stable 1:1 complex with dimethyl maleate in toluene. Its stability constant was determined by spectrophotometric titration.
TL;DR: In this article, a meso-aryl substituent was synthesized and its complexation with zinc and potassium cations in the system toluene-methanol (5:1) was studied by spectrophotometric titration and 1H NMR spectroscopy.
Abstract: 2,8,12,18-Tetrabutyl-3,7,13,17-tetramethyl-5-{3-[11-(pyridin-4-yloxy)-3,6,9-trioxaundecyloxy] phenyl}porphyrin was synthesized, and its complexation with zinc and potassium cations in the system toluene-methanol (5:1) was studied by spectrophotometric titration and 1H NMR spectroscopy. Spatial preorganization of the meso-aryl substituent due to complex formation of potassium cation with the polyether fragment accelerates the reaction of zinc with the title compound approximately threefold. A probable scheme of the interaction was proposed, and formation constants of the corresponding complexes were determined.
TL;DR: In this article, a conformationally labile polyether fragment with a terminal pyridine ring was synthesized and its spectral and physicochemical properties were studied, and the relation between the spectral parameters of the tetrapyrrole chromophore and acid-base equilibria and complex formation with alkali metal cations was found.
Abstract: meso-Phenylporphyrins containing at the benzene ring a conformationally labile polyether fragment with a terminal pyridine ring were synthesized, and their spectral and physicochemical properties were studied. The relations found between the spectral parameters of the tetrapyrrole chromophore, on the one hand, and acid-base equilibria and complex formation with alkali metal cations, on the other, showed the possibility for design of porphyrin-based molecular ensembles possessing useful properties.