Kinetic characteristics of the destruction of β,β-annelated porphyrazines in a nitrogen-containing base–dimethylsulfoxide system

The state of tetra(1,2,5-thiadiazolo)porphyrazine in a dimethyl sulfoxide medium is investigated. Relatively high stability is observed for the resulting proton-transfer complex, and a chemical structure is proposed for it. It is shown that the nature of the substituent in the porphyrazine macrocycle influences the kinetic parameters of the destruction of tetra(1,2,5-thiadiazolo)porphyrazine, tetra(5-tert-butylpyrazino) porphyrazine, octaethyltetrapyrazinoporphyrazine, and octaphenyltetrapyrazinoporphyrazine in a nitrogen-containing base–dimethylsulfoxide system. The effect the NH acidity of the porphyrazine macrocycle and the nature of the nitrogenous bases have on the reaction rate and activation parameters of the destruction of β,β-annelated porphyrazine proton-transfer complexes is established.     

Solvent effect on the photogeneration of singlet molecular oxygen by copper tetra(tert-butyl)phthalocyanine

The photogeneration of the singlet molecular oxygen (¹O₂) by copper tetra(4-tert-butyl) phthalocyanine in organic solvents of different nature was substantiated. The apparent quantum yields of ¹O₂in benzene and pyridine were determined. The data obtained indicate an influence of the coordinating properties of the solvent on the ¹O₂yield. However, this factor is not “critical” as in the case of photogeneration of ¹O₂by copper tetra(5-tert-butylpyrazino)porphyrazine.     

Metal complexes of tetra(6-<Emphasis Type="Italic">tert</Emphasis>-butyl-2,3-quinolino)porphyrazine: II. Spectral properties

Quanitative spectral characteristics of Cu, Co, Zn, and Ni tetra(6-tert-butyl-2,3-quinolino)porphyrazine complexes prepared for the first time and soluble in hydrophobic liquids were measaured. Analogous spectral data of the protonated forms of complexes dissolved in sulfuric acids were also evaluated.     

Kinetics of proton transfer from tetra(4-nitro-5-tert-butyl)phthalocyanine to nitrogen-containing bases in benzene

The acid-basic interaction between tetra(4-nitro-5-tert-butyl)phthalocyanine and pyridine, 2-methylpyridine, morpholine, piperidine, n-butylamine, diethylamine, and triethylamine in benzene is studied. It is found that the intermolecular transfer of protons of NH groups from tetra(4-nitro-5-tert-butyl)phthalocyanine to morpholine and diethylamine is characterized by unusually low values of the reaction constant rates. The effect of the structure of tetra(4-nitro-5-tert-butyl)phthalocyanine and tetra(3-nitro-5-tert-butyl)phthalocyanine, and of the nature of the base on the kinetic parameters of acid-base interaction is demonstrated. A structure is proposed for complexes with the transfer of displaced phthalocyanines’ protons. It is found that they undergo decomposition over time.     

Synthesis, acid-base properties, and deselenation of 5,6,8,9,11,12-hexakis(4-tert-butylphenyl)[1,2,5]selenadiazolo[3,4-b]porphyrazine

Cross cyclotetramerization of bis(4-tert-butylphenyl)fumaronitrile with 1,2,5-selenadiazole-3,4-dicarbonitrile in the presence of magnesium butoxide as template afforded a mixture of magnesium(II) porphyrazine complexes, from which magnesium complex of 5,6,8,9,11,12-hexakis(4-tert-butylphenyl)[1,2,5]selenadiazolo[3,4-b]porphyrazine was isolated by column chromatography and was subjected to demetalation on treatment with trifluoroacetic acid. The free ligand was found to undergo protonation at one meso-nitrogen atom in acid medium and deprotonation of one pyrrole ring to form monoanion by the action of bases. Reductive deselenation of the title compound with formation of vicinal diamino porphyrazine was studied by spectral and kinetic methods, and a mechanism involving two hydrosulfide ions was proposed.     

Kinetic features of acid-base interaction of tetra(3-nitro-5-tert-butyl)phthalocyanine with nitrogen-containing bases in benzene

The kinetics of the reaction of acid-base interaction of tetra(3-nitro-5-tert-butyl)phthalocyanine with cyclic and acyclic nitrogen-containing bases in benzene was studied. The process is found to proceed with a low rate. The schemes of acid-base interaction are proposed and the probable structure of the proton transfer complexes of tetra(3-nitro-5-tert-butyl)phthalocyanine are discussed. The effect of the nature of the nitrogencontaining base on the kinetic parameters of the process is revealed.     

Metal complexes of tetra(6-tert-butyl-2,3-quinolino)porphyrazine: I. Synthesis

Complexes of tetra(6-tert-butyl-2,3-quinolino)porphyrazine with Cu, Co, Zn, and Ni soluble in hydrophobic liquids were synthesized for the first time by template tetramerization of derivatives of 6-tert-butylquinoline-2,3-dicarboxylic acid formed from the corresponding acid in the course of carbamide synthesis in presence of the bivalent metal ions.     

Synthesis and spectral parameters of tetra(6-<Emphasis Type="Italic">tert</Emphasis>-butyl-2,3-quinoxalino)porphyrazine and its metal complexes

Tetra(6-tert-butyl-2,3-quinoxalino)porphyrazine and its complexes with bivalent metals were synthesized for the first time by template tetramerization of 6-tert-butylquinoxaline-2,3-dicarbonitrile. The obtained macrocyclic compounds are soluble in hydrophobic solvents. Their electronic absorption spectra in organic solvents and the spectra of the corresponding protonated forms in sulfuric acid were studied.     

Spectral properties and solubility of the lanthanide complexes with substituted and annelated porphyrazines

An analysis of the electronic optical properties and solubility in chloroform and DMF of the erbium and ytterbium complexes with porphyrazine and its octaphenyl- and octa(p-alkylsulfamoylphenyl)-substituted derivatives and tetrapyrazinoporphyrazine and its octaethyl-, tetra(tert-butyl)-, and octaphenyl-substituted derivatives is presented. The dependence of the electronic optical properties and solubility on the composition of the macrocycle of the studied complexes, namely, on the nature of the extraligand and peripheral environment of the porphyrazine macrocycle, is shown.     

Kinetic characteristics of intermolecular proton transfer from NH groups of tetra(3-nitro-5-tert-butyl)phthalocyanine in nitrogen base-benzene systems

The kinetics of acid-base interaction between tetra(3-nitro-5-tert-butyl)phthalocyanine and cyclic and acyclic nitrogen bases in benzene was studied. The reaction was found to occur with a low rate. The structure and reactivity of protolytes were shown to be interrelated. The structure and stability of the proton-transfer complexes formed are considered.     

Synthesis and spectroscopic study of tert-butyl-substituted benzoporpyrazines with fused 1,2,5-thiadiazole fragments

Cross cyclotetramerization of 1,2,5-thiadiazole-3,4-dicarbonitrile and 4-tert-butylphthalodinitrile in the presence of magnesium butoxide gave a mixture of symmetric and asymmetric porphyrazine magnesium(II) complexes. One of these, (2²⁽³⁾,7²⁽³⁾,12²⁽³⁾-tri-tert-butyltribenzo[b,g,l][1,2,5]thiadiazolo[3,4-q]-5,10,15,20-tetraazaporphyrinato)magnesium(II) (MgSBBB), was isolated by column chromatography and was treated with trifluoroacetic acid to obtain the corresponding free ligand (H₂SBBB). The effect of the mode of heteroring fusion on the electronic absorption spectra of tribenzoporphyrazines was studied.     

Synthesis and properties of tetra-(4-<Emphasis Type="Italic">tert</Emphasis>-butyl-5-nitro)phthalocyanines

The interaction of 4-tert-butyl-5-nitrophthalonitrile with a series of metal acetates has yielded the corresponding metal phthalocyaninates. The treatment of magnesium tetra(4-tert-butyl-5-nitro)phthalocyaninate with hydrochloric acid has afforded tetra(4-tert-butyl-5-nitro)phthalocyanine. Spectral properties of the prepared macrocycles have been studied. The nature of the organic solvent and the complex forming metal marginally affect the position of the Q band in the electron absorption spectra of the studied compounds. It has been demonstrated that the prepared phthalocyanines can dye polymer materials and are catalytically active towards oxidation of a model sulfur-containing compound.     

Synthesis of tetra(1,4-dithiacyclohexene)porphyrazine and its metal complexes

The syntheses of tetra, 1, 4-dithiacyclohexene)porphyrazine and its lithium salt, obtained by reaction of 3,6-dithiahexene-1,2-dicarbonitrile with lithium amylate, are described. A series of metal complexes of tetra(1,4-dithiacyclohexene)porphyrazine has been synthesized starting from 3,6-dithiacyclohexene-1,2-dicarbonitrile and the salts of the corresponding metals as well as from the free ligand and metal chlorides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 603–606, May, 1986.     

Acid-base properties of thianaphthene-annulated porphyrazine and tetra(pyrazino)porphyrazine complexes with aluminum group metals

Acid-base properties of Al(III), Ga(III), and In(III) complexes with tert-butyl-substituted thianaphthene-annulated porphyrazine and tetra(2,3-pyrazino)porphyrazine in proton-donor medium (CH₂Cl₂-CF₃COOH) were studied by spectrophotometric titration. The concentration stability constants of the singly protonated complexes were determined. The effects of the metal nature and aromatic heterocyclic fragment on the basicity of meso-nitrogen atoms were analyzed. Negative inductive effect of the sulfur atom in the thianaphthene fragment reduces the basicity of the meso-nitrogen atoms as compared to analogous porphyrazine and phthalocyanine complexes. Acid-base transformations of the thianaphthene-annulated tetra(2,3-pyrazino)porphyrazine involve both meso-nitrogen atoms and those in the pyrazine rings.     

Kinetic stability of tetra(3-nitro-5-<Emphasis Type="Italic">tert</Emphasis>-butyl)phthalocyanine in the system nitrogen-containing base-DMSO

The state of tetra(3-nitro-5-tert-butyl)phthalocyanine in DMSO medium was studied. Sufficiently high stability of the obtained proton transfer complex is established, and its structure is suggested. It is shown that this complex is kinetically unstable in the highly basic media. Effect of the nature of cyclic and acyclic nitrogen-containing bases on the rate and activation parameters of destruction of the proton transfer complex of tetra(3-nitro-5-tert-butyl)phthalocyanine was found     

Synthesis and coordination properties of the zinc complex of dimeric porphyrin in reactions with imidazole, 2-methylimidazole, and the pyridine in benzene

Dimeric porphyrin(2,6-bis[15′-(3″,5″-di-tert-butylphenol)-3′,7′,13′,17′-tetramethyl-2′,8′,12′,18-tetraethylporphin-5′-yl]-4-tert-buthylphenol) and its binuclear zinc complex were obtained from 4,4′-dimethyl-3,3′-diethyldipyrrolylmethane, 2,6-diformyl-4-tert-butylphenol and 3,5-di-tert-buthylbenzaldehyde. Coordina-tion properties of dimeric zincporphyrin in the intermolecular reaction with nitrogen-containing bases (imidazole, 2-methylimidazole, and pyridine) in benzene were studied. Geometry and electronic structure of the zincporphyrin and its molecular complexes were calculated by a quantum-chemical method. Energy characteristics of the intermolecular reaction of the dimeric zincporphyrin with bases were determined. The calculated energies of the central metal atom interaction with the nitrogen atom of an extra-ligand agree well with the stability of the Zn-porphyrin molecular complexes. The influence of the deformation distortions of the porphyrin ligand on the strength of the metal-extra-ligand σ-bond was established.     

Kinetics of the Acid-Base Interaction between Tetra(4-<Emphasis Type="Italic">tert</Emphasis>-butyl)phthalocyanine and Nitrogen-Containing Bases in Dimethyl Sulfoxide

Specific features of the acid-base interaction of tetra(4-tert-butyl)phthalocyanine with cyclic and acyclic nitrogen-containing bases in dimethyl sulfoxide are studied. The effect of pK _a of proton-withdrawing molecules, basicity of a medium, and steric screening of acidic NH centers on the kinetic parameters of formation of proton-transfer complexes stable in time is shown.     

Study of basic properties of tert-butyl-substituted tribenzo(1,2,5-thiadiazolo)porphyrazines

Basic properties of tri(4-tert-butylbenzo)[b,g,l](1,2,5-thiadiazolo)[3,4-q]porphyrazine and its Cu complex in the H₂SO₄-CH₃COOH medium were studied by means of spectrophotometric titration. It was found that in going from an acetic acid solution 100% H₂SO₄ the complete acid-base interaction consecutively involves all the four meso-nitrogen atoms of the porphyrazine macroring, as well as one of the nitrogen atoms of the 1,2,5-thiadiazol fragment. The stability constants of the resulting acid forms were determined and compared with the gas-phase proton affinities calculated by the AM1 method. Annulation of a 1,2,5-thiadiazole fragment to the porphyrazine macroring increases the basicity of the 1,2,5-thiadiazole nitrogen atoms and decreases the basicity of macroring meso-nitrogen atoms.     

Dipole moments of some metal complexes of five new monothio-β-diketones

Dipole moments have been determined for Co(III), Ni(II), Pd(II), Pt(II), Cu(II) and Zn(II) complexes of the fluorinated monothio-β-diketones RC(SH)CHCOCF₃ [R  5′-methyl-2′-thienyl, 5′-chloro-2′-thienyl, 4′-isopropylphenyl, 4′-tert-butylphenyl and 3′-fluoro-4′-methoxyphenyl] from static-polarization measurements. The moments clearly indicate cis-square-planar configurations for the nickel, palladium and platinum complexes. The zinc complexes have tetrahedral structure and copper complexes have distorted cis-square-planar structure. The cobalt complexes perhaps have facial-octahedral structure. The values of dipole moment for the complexes varies with R: 5′-methyl-2′-thienyl > 3′-fluoro-4′-methoxyphenyl > 4′-isopropylphenyl ≈ 4′-tert-butylphenyl > 5′-chloro-2′-thienyl.     

Synthesis and spectral properties of unsymmetrical benzoporphyrins containing phenoxy groups or quinoxaline fragments

Condensation of phthalimide and 4-tert-butylphthalimide with zinc(II) acetate gave 3-(3-oxo-2,3-dihydro-1H-isoindol-1-ylidenemethyl)-1H-isoindol-1-one and 5-tert-butyl-3-(5-tert-butyl-3-oxo-2,3-dihydro-1H-isoindol-1-ylidenemethyl)-1H-isoindol-1-one, respectively. Their reactions with 4-phenoxyphthalimide and quinoxaline-2,3-dicarboximide in the presence of Zn(OAc)₂ led to the formation of zinc complexes of cis-4,4′-diphenoxytetrabenzoporphyrin and cis-di(4-tert-butylbenzo)diquinoxalinoporphyrin. The complexes were converted into the free bases by treatment with sulfuric acid. Spectral properties of the obtained porphyrin derivatives were studied.