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.     

Synthesis and Acid–Base,Absorption, and Fluorescence Properties of Phthalocyanine Derivatives

Russian Journal of General Chemistry - Tetrakis{5,6-bis(4-tert-butylphenyl)pyrazino[2,3-c]}porphyrazine and tetra(4-tert-butyl)phthalocyanine have been synthesized, and their acid–base...     

Esterified porphyrazine complexes: Synthesis,characterization, aggregation behavior,and theoretical study

Magnesium porphyrazine having eight 5-hydroxypentylthio groups at the peripheral positions, was synthesized from 2,3-bis(5-hydroxypentylthio) maleonitrile. By the esterification reaction of octakis(5-hydroxypentylthio) porphyrazinato] Mg(II) with 3,4,5-trimethoxybenzoic acid in dicyclohexylcarbodiimide and toluene-p-sulfonic acid, esterified MgPz appending [5-thiopentyl 2-methoxy-4,6-bis(trifluoromethyl) benzoate] substituent was obtained. Further reaction of the metal-free porphyrazine with Co(II), Cu(II), Zn(II), and Fe(II) acetates have produced the metallo-porphyrazines. By reacting FePzCl with pyridine or pyrazine, the monomeric bis-axial and the oligomeric complexes were synthesized as the novel stable complexes, respectively. Their characterizations were performed by using elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR, mass and UV-Vis spectral data. The aggregation investigations carried out in different concentrations indicate that 3,4,5-trimethoxybenzyloxy-substituted porphyrazine compounds do not have any aggregation behavior in different concentrations. Quantum chemical computations were also done to the structural and electronic properties of target compounds.     

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.     

Palladium Complex of Camphor-Substituted Tetrapyrazinoporphyrazine as a Stationary Phase of Gas Chromatography

Russian Journal of General Chemistry - Surface modification of the diatomite adsorbent Hezasorb AW-HMDS by tetra(1,7,7-trimethylbicyclo[2.2.1]heptane[2,3-b]pyrazino)porphyrazine Pd(II) was...     

Phthalocyanines and Related Compounds: XXXIX. Synthesis of Derivatives of Some Substituted 1-Phenylnaphthalene-2,3-dicarboxylic Acids

Derivatives (dinitriles, anhydrides, imides, N-phenylimides) of substituted 1-phenylnaphthalene-2,3-dicarboxylic and 1-phenylphenanthrene-2,3-dicarboxylic acids were prepared by the reactions of 2-bromomethylbenzophenones with various dienophiles. Starting from these derivatives, gallium complexes of substituted tetra-1-phenyl-2,3-naphthalocyanines and tetra(1-phenyl-2,3-phenanthro)porphyrazine were synthesized.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005, pp. 841–846.Original Russian Text Copyright © 2005 by Donyagina, Luk”yanets.     

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.     

Metal-free,metallo-porphyrazines,monomeric bisaxial complex [FePz(py)2] and the bridged complex [FePz(pyz)]n with eight (4-thiobutyl 4-biphenylcarboxylate) groups

Metal-free and metallo-porphyrazines (M?=?Mg, Co, Cu, Zn, and ClFe) carrying eight hydroxybutylthio groups at peripheral positions were prepared from 2,3-bis(4-hydroxybutylthio) maleonitrile. The hydroxybutyl groups were incorporated by esterification of porphyrazine derivatives with 4-biphenylcarboxylic acid in the presence of dicyclohexylcarbodiimide and p-toluenesulfonic acid. Unlike the parent porphyrazine, the symmetrically functionalized porphyrazines with eight ester units were soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, acetone, and toluene and insoluble in water and n-hexane. Chloro-octakis(4-thiobutyl 4-biphenylcarboxylate) porphyrazinato iron(III) (FePzCl) was prepared by the reaction of metal-free porphyrazine with iron(II) acetate and further treatment with HCl solution. The monomeric bisaxial complex [FePz(py)₂] and the bridged complex [FePz(pyz)]_n were formed as stable complexes by reacting FePzCl with pyridine and pyrazine, respectively. The newly synthesized compounds were characterized by elemental analysis, FT-IR, UV?vis, mass, ¹H and ¹³C NMR spectroscopy.     

Enrichment of solubility by esterification: Metal-free and metallo-porphyrazines with polyfluorinated units

Metal-free and metallo-porphyrazines (M = 2H, Mg, Cu, Zn or Co) carrying eight hydroxypropylsulfanyl units at the peripheral positions were synthesized from 2,3-bis(3-hydroxypropylthio)maleonitrile. The reactivity of the hydroxypropyl units was demonstrated by the esterification of porphyrazine derivatives with 3,5-bis(trifluoromethyl)benzoic acid in the presence of dicyclohexylcarbodiimide and toluene-p-sulfonic acid. The symmetrical porphyrazine derivatives with eight ester units were soluble in common organic solvents such as chloroform, dichloromethane, THF, acetone, and toluene and insoluble in water and n-hexane. The complexes were characterized by several spectroscopic methods.     

Synthesis and spectral properties of 1,2,5-thiadiazolo-, 1,2,5-selenadiazolo-, and benzo-fused β-phenyl-substituted porphyrazines

Cross cyclotetramerization of trans-2,3-diphenylbutanedinitrile with 1,2,5-thia(selena)diazole-3,4-dicarbonitriles or phthalodinitrile in the presence of magnesium butoxide gave mixtures of Mg(II) porphyrazine complexes which were treated with trifluoroacetic acid to isolate unsymmetrical hexaphenyl-substituted 1,2,5-thia(selena)diazolo-and benzo-fused porphyrazines together with diphenyltribenzoporphyrazine. Their ¹H NMR and electronic absorption spectra (in the UV and visible regions) were recorded. The effect of benzene and heteroring fusion on the electronic and steric structure and spectral properties of porphyrazine derivatives was studied in terms of the molecular orbital perturbation theory and semiempirical quantum-chemical calculations (AM1, PM3, ZINDO/S, CNDO/S).     

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.     

ROM polymerization-capture-release: application to the synthesis of unsymmetrical porphyrazinedithiols and peripherally metalated derivatives

Crossover Linstead macrocyclization of a doubly norbornenyl-functionalized dimercaptomaleonitrile with dipropylmaleonitrile gave a crude mixture of porphyrazines containing the hexapropylporphyrazinedithiol magnesium complex. The mixture was subjected to ring-opening metathesis polymerization to yield the insoluble porphyrazinedithiol-functionalized polymers. Cleavage from the polymer backbone using mercury(II) acetate followed by reaction with electrophiles gave access to a range of thioporphyrazinedithiol derivatives including solitaire porphyrazines. Studies into the possible uses of hexapropyl-2,3-di-(carboxymethylthio)porphyrazine in sensing metal cations in solution are described.     

Porphyrazine Structures with Electron-Withdrawing Substituents as the Base for Materials for Photonics and Biomedicine

A survey of the studies dealing with the development of new porphyrazine type tetrapyrrole dyes promising for the application in photonics and biophotonics is presented. An original synthetic approach to the template assembly of the porphyrazine macrocycle at room temperature in high yield has been proposed. A porphyrazine macrocycle containing eight nitrile groups at the periphery has been prepared for the first time. The replacement of four nitrile groups in the macrocycle by aryl groups has been found to generate a unique porphyrazine structure demonstrating a fluorescent molecular rotor behavior, i.e., a strong dependence of fluorescence parameters (quantum yields and lifetimes) on the viscosity of the medium. Some aspects of possible applications of the obtained compounds in biophotonics are described. Good prospects for the use of these compounds as efficient agents for tumor diagnosis, sensitizers for photodynamic therapy, and probes for intracellular viscosity are outlined.     

Synthesis and reactions of aminoporphyrazines with annulated five- and seven-membered rings

The novel five- and seven-membered ring appended aminoporphyrazines 3 and 12 have been prepared via mixed Linstead macrocyclization. The structures of both have been unequivocally established by X-ray crystallographic studies. Reductive deselenation of selenadiazole 3 in the presence of 9,10-phenanthrenequinone or 2,3-butanedione results in the formation of pyrazines 6a,b, whereas oxidation of porphyrazine 12 gave the corresponding seco derivative 14. seco-Porphyrazine 14 mediates the generation of singlet oxygen with a quantum yield of 0.74.     

Structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine investigated using density functional theory

Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculation were adopted to study the structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine (TTPPzH₂ and TTPPzMg) using B3LYP method with the 6–31G(d) basis set. A comparison of the geometrical structures, atomic charges, molecular orbitals, UV-vis spectra and infrared (IR) spectra among tetrathieno[2,3-b]porphyrazine (TTPPzH₂), phthalocyanine (H₂Pc) and porphyrazine (H₂Pz) compounds was performed. The substituent effect of the thiophene heterocycle for electron-donating on the structures and properties of these compounds has been discussed. Compared with other atoms, the charge distribution of C_β atoms adjacent to the sulfur atom is significantly influenced by the thiophene heterocycle substituents. The enlargement of the HOMO-LUMO gaps from H₂Pc and MgPc to TTPPzH₂ and TTPPzMg is at the origin of the observed blue shift of the Q band when moving from H₂Pc to TTPPzH₂ compounds. Special emphasis has been devoted to the strongest B bands for TTPPzH₂ compounds which show red shift due to the large destabilization of the lower lying occupied orbitals compared with the corresponding B bands of H₂Pc compounds. With the assistance of animated pictures produced on the basis of the normal coordinates, the significant peaks and vibration modes in the IR spectra of all the compounds were assigned and analyzed.     

Synthesis and photochromism of a new binuclear porphyrazinato magnesium(II)

The synthesis, characterization and photochromism of a new coplanar binuclear porphyrazine bearing six bis-(trimethylthiophenyl) photochromic functionalities at the periphery are described. The synthetic route is concise and the near-infrared luminescence changes of this binuclear porphyrazine can be regulated in a reversible manner by the photoisomerization of the bisthienylethene moiety.     

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.     

Tetra-2,3-pyrazinoporphyrazines with externally appended pyridine rings. 1. Tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine: a new macrocycle with remarkable electron-deficient properties

A new pyrazinoporphyrazine macrocycle carrying externally appended pyridine rings, tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine (hydrated), [Py(8)TPyzPzH(2)].2H(2)O, was prepared in high yield by direct cyclotetramerization of the precursor, 2,3-dicyano-5,6-di(2-pyridyl)-1,4-pyrazine, [(CN)(2)Py(2)Pyz], in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The single-crystal X-ray structure of [(CN)(2)Py(2)Pyz] shows a noncoplanar positioning of the pyrazine and pyridine rings in the two slightly different independent molecular units present in the crystal. UV-vis spectra of [Py(8)TPyzPzH(2)] were measured in two nondonor solvents (CHCl(3), CH(2)Cl(2)), a slightly basic solvent (pyridine), and an acidic solvent (CH(3)COOH). In all cases, the spectral changes are consistent with the occurrence of molecular aggregation and colloidal dispersions which break up with time to give clear solutions containing exclusively the monomeric form of the macrocycle, either neutral [Py(8)TPyzPzH(2)] (in CHCl(3), CH(2)Cl(2), and CH(3)COOH) or dianionic [Py(8)TPyzPz](2)(-) (in pyridine). A spectrally monitored titration of [Py(8)TPyzPzH(2)] in CH(2)Cl(2) with TBA(OH) shows the loss of two protons from the macrocyclic core and quantitative conversion of [Py(8)TPyzPzH(2)] to [Py(8)TPyzPz](2)(-). Cyclic voltammetry and thin-layer spectroelectrochemical measurements show that [Py(8)TPyzPzH(2)] is present in CH(2)Cl(2) while [Py(8)TPyzPz](2)(-) is present in pyridine, but both forms of the compound exhibit identical electrochemical behavior, consistent with a conversion of the dianion to the neutral porphyrazine in pyridine prior to electroreduction via four reversible one-electron transfer steps. No oxidations of the macrocycle are observed in either solvent containing 0.1 M tetrabuthylammonium perchlorate (TBAP). A comparison of the electrochemical behavior for [Py(8)TPyzPzH(2)] with what is reported for related phthalocyanine and porphyrazine analogues highlights the remarkable electron-accepting properties of the presently investigated free-base macrocycle.     

Synthesis and Characterisation of Unsymmetrical Porphyrazines Containing Bis(hydroxyethylthio) Substituents

Unsymmetrical porphyrazines bearing a single peripheral bis(hydroxyethylthio) moiety were synthesised by mixed condensation of bis(2-hydroxyethylthio)maleonitrile and phthalonitrile. Complexation of the thioether groups of metal-free porphyrazine with PdCl₂ further lowered the intensity of the Q-band absorption of the porphyrazine core. The new compounds were characterised by elemental analyses, IR, ¹H NMR, UV-Vis, and mass spectra.     

Profiling energetics and spectroscopic signatures in prototropic tautomers of asymmetric phthalocyanine analogues

Density functional theory (DFT) and time-dependent density functional theory (TDDFT) were used to explain discrepancies in UV-vis and MCD spectra of the metal-free tribenzo[b,g,l]thiopheno[3,4-q]porphyrazine (1), substituted tribenzo[b,g,l]porphyrazine (2), and 2,3-bis(methylcarboxyl)phthalocyanine (3). On the basis of gas-phase and polarized continuum solvation model (PCM) DFT and TDDFT calculations, it was suggested that both NH tautomers contribute to the spectroscopic signature of 1, whereas the Q-band region of 2 and 3 is dominated by a single NH tautomer. For all tested compounds, it was found that the combination of the BP86 exchange-correlation functional, 6-31G(d) basis set, and TDDFT-PCM approach provides the best accuracy in energies of the Q(x)- and Q(y)-bands of the individual NH tautomers as well as correctly describes their relative energy differences, which are important in understanding of experimental spectroscopy of the target systems.