Unsymmetrical Pentoxy-Substituted Porphyrazines

The reactions of 3,6-dipentoxyphthalonitrile (A) in the 1-pentanol - magnesium pentylate medium with phthalonitrile, 2,3-di(methylsulfanyl)-2-butenedinitrile, and 2,3-dihydro-1,4-dithiin-5,6-dicarbonitrile (B) were performed. Unsymmetrically substituted porphyrazines A₃B were prepared and studied. The influence of the structure of fragment B on the spectral characteristics of the porphyrazines was examined.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005, pp. 504–508.Original Russian Text Copyright © 2005 by Nikolaev, Kudrik, Kulinich, Shaposhnikov.     

Porphyrazines as molecular scaffolds: flexible syntheses of novel multimetallic complexes

Reductive deselenation of selenodiazole-fused porphyrazines, followed by acylation of the resultant labile porphyrazinediamines, was used to prepare macrocycles bearing two Collins ligands, two oxamido residues, or two quinoline-2-carboxamido units. Peripheral coordination of copper(II) to the di-(quinoline-2-carboxamido)-porphyrazine gave a metal-linked face-to-face porphyrazine dimer array. Sequential derivatization of the two amino groups in the porphyrazinediamines was used to prepare mixed peripheral ligand systems including a dimetallic picolinamido-Schiff base porphyrazine. Such systems exhibit strong metal-metal spin coupling and are anticipated to be of value in the synthesis of novel electronic and magnetic materials.     

Porphyrazines with tosylamine functional groups

Metal-free (3b) and metallo-porphyrazines (3a, 3c, 3d) (M  Mg, Ni and Co) carrying eight functional tosylaminoethylthia-groups on peripheral positions have been synthesised for the first time from cyclotetramerization of 1,2-bis(2-tosylaminoethylthia)maleonitrile (2) in the presence of magnesium propoxide; the metal-free derivative 3b was obtained by treatment of 3a with trifluoroacetic acid and it was further converted into Co(II) (3c) and Ni(II) (3d) derivatives by using acetate salts of corresponding metal ions. The reactivity of tosylamino-groups was verified by its alkylation to yield octakis[(tosyl)(hexyl)amino- ethylthia]porphyrazinatomagnesium(II) (4a).The new compounds were characterised by elemental analysis, IR, NMR and UV-vis spectra.     

Cobalt Porphyrazines with Heterocyclic Substituents

Reactions of 4,5-diaminophthalodinitrile with thionyl chloride, sodium nitrite in concentrated sulfuric acid, and phenanthrenequinone gave, respectively, 5,6-dicyano-2,1,3-benzothiadiazole, 5,6-dicyano- 1H-benzotriazole, and 6,7-dicyano-2,3-(9,10-phenanthro)quinoxaline, from which the corresponding cobalt porphyrazines were prepared. The effect of the heterocyclic moiety on the physicochemical and spectral properties of porphyrazines was elucidated.     

Chiral bis-Acetal Porphyrazines as Near-infrared Optical Agents for Detection and Treatment of Cancer

We report the preparation of chiral oxygen atom-appended porphyrazines (pzs) as biomedical optical agents that absorb and emit in the near-IR wavelength range. These pzs take the form M[pz(A_4-nB_n)], where “A” and “B” represent moieties appended to the pz’s pyrrole entities, A = (2R,3R) 2,3-dimethyl-2,3-dimethoxy-1,4-diox-2-ene, B = β,β′-di-isopropoxybenzo, M is the incorporated metal ion (M = H₂, Zn), and n = 0, 1, 2 (-cis/-trans) and 3 ( Scheme 1 ). When dissolved in polar media, H₂[pz(trans-A₂B₂)] 5a does not fluoresce and has a negligible quantum yield for singlet oxygen generation (Ф_Δ = 0.074 ± 0.001, methanol), as measured by the photo-oxidation of DMA. However, when sequestered in the nonpolar environment of a liposome, it displays strong NIR emission (λ _max = 705 nm, Ф _f = 0.087) and an extremely high singlet oxygen quantum yield (Ф_Δ→1). Of this series, H₂[pz(trans-A₂B₂)] 5a is attractive as a potential optical probe, showing strongly fluorescent uptake by cells in culture, while 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide measurements of cell viability show no evidence of dark toxicity. This agent does show significant photoinduced toxicity suggesting that pzs such as 5a have promise as “theranostic” optical agents that can be visualized with fluorescence imaging while acting as a sensitizer for photodynamic therapy.

Figure Scheme 1. Open in figure viewer PowerPoint Synthesis of Porphyrazines 3a – 7a , 3b – 7b .     

Porphyrazines peripherally functionalized with hybrid ligands as molecular scaffolds for bimetallic metal-ion coordination

We report the synthesis and physical characterization of a new family of peripherally functionalized porphyrazine (pz) compounds, denoted 1[M1, M2], where metal ion M1 is incorporated into the pz core and metal ion M2 is bound to a salicylidene/picolinamide "hybrid" chelate built onto two nitrogen atoms attached to the pz periphery. The complexes 1[MnCl, Cu], 1[VO, Cu], and 1[Cu, Cu] have been prepared, and crystal structures show 1[MnCl, Cu] and 1[VO, Cu] to be isostructural. These complexes have been subjected to electron paramagnetic resonance and temperature-dependent magnetic susceptibility measurements. The variation of the ligand-mediated exchange splittings (delta) in these complexes is striking: delta/k(B) values for 1[MnCl, Cu] and 1[VO, Cu] are 22 and 40 K, respectively, while delta/k(B) for 1[Cu, Cu] is only 1 K. These coupling results are explained in terms of the relative orientation of the M1 and M2 orbitals and reflect the fact that the ligand set of M2 in the periphery is rotated in-plane by 45 degrees relative to the effectively coplanar pz ligand set of M1. The exchange couplings are essentially the same as those we determined for the Schiff base porphyrazines (pzs). Thus, the hybrid ligand has eliminated the dimerization found to occur when Cu(II) is bound to the periphery of bis(picolinamido) pzs and has created a more robust ligand system than the Schiff base pzs while retaining the ability they show to promote spin coupling between M1 and M2.     

Synthesis and Properties of Unsymmetrical Phenyl-substituted Porphyrazines

3-Amino-1,1-dichloro-5/6-phenyl-1H-isoindole hydrochloride was reacted with 5-amino-2-imino-3,4-diphenyl-2H-pyrrole or 5-amino-2-imino-3,4-ethylenedithio-2H-pyrrole to obtain unsymmetrical phenyl-substituted porphyrazines.     

A Cyclic Voltammetric Study of Some Porphyrazines

Summary.  Some porphyrazines with dimethylamino- or trimethylammoniumethylsulfanyl substituents were studied in dichloromethane or dimethylsulfoxide solution by cyclic voltammetric methods. The cyclic voltammogram of metal free octakis-(dimethyl-aminoethylsulfanyl)-porphyrazine is characterized by three one-electron reduction waves which show quasi-reversible behaviour at all sweep rates observed; the same holds for its cobalt(II) derivative. The quaternized octacationic derivative, however, exhibits four one-electron reduction waves which are reversible at all sweep rates. The reaction mechanisms and diffusion coefficients were investigated. Received October 17, 2000. Accepted (revised) December 11, 2000     

Porphyrazines: synthesis,properties, application

The data on the synthesis, properties, and practical application of porphyrazines (tetraazaporphines), the nearest structural analogs of porphyrins and phthalocyanines, have been systematized.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2320–2336, December, 1995.This work was financially supported by the Russian Government and the International Science Foundation (Grant No. MEY300).     

Electrochemical Investigation on Porphyrazines with Peripheral Crown-Ether Groups

Summary.  In this study, the electrochemical properties of novel porphyrazines with eight crown ether substituents appending on the periphery through flexible chains were investigated by using cyclic voltammetry and controlled potential coulometry. Cyclic voltammetry measurements showed that the metal free porphyrazine gave all of the six possible redox reactions of common porphyrazine derivatives. Cobalt porphyrazine exhibited a metal-based reduction and a metal-based oxidation processes followed by two ligand-based reduction and two oxidation processes. I _p vs. ν^1/2 plots of redox processes of the two compounds indicated the diffusional mass transfer mechanism of the complexes. Copper porphyrazine gave an oxidation process having adsorption properties and three reduction reactions. The variations of peak current ratios of electrochemical reactions for all three complexes with scan rate showed that electron transfer processes of complexes were followed by reversible or irreversible chemical reactions. Aggregation and sandwich adduct formation properties of complexes were determined by CV measurements. Peak potentials of redox processes for all complexes were shifted towards positive potentials by addition of alkali metal cations. Addition of K⁺ formed sandwich type adducts with 15-crown-macrocycles diminishing aggregation of planar molecules by intramolecular rather than intermolecular complexation. Corresponding author. E-mail: ahmetg@itu.edu.tr Received May 23, 2002; accepted (revised) May 31, 2002     

Electrochemical Investigation on Porphyrazines with Peripheral Crown-Ether Groups

 In this study, the electrochemical properties of novel porphyrazines with eight crown ether substituents appending on the periphery through flexible chains were investigated by using cyclic voltammetry and controlled potential coulometry. Cyclic voltammetry measurements showed that the metal free porphyrazine gave all of the six possible redox reactions of common porphyrazine derivatives. Cobalt porphyrazine exhibited a metal-based reduction and a metal-based oxidation processes followed by two ligand-based reduction and two oxidation processes. I _p vs. ν^1/2 plots of redox processes of the two compounds indicated the diffusional mass transfer mechanism of the complexes. Copper porphyrazine gave an oxidation process having adsorption properties and three reduction reactions. The variations of peak current ratios of electrochemical reactions for all three complexes with scan rate showed that electron transfer processes of complexes were followed by reversible or irreversible chemical reactions. Aggregation and sandwich adduct formation properties of complexes were determined by CV measurements. Peak potentials of redox processes for all complexes were shifted towards positive potentials by addition of alkali metal cations. Addition of K⁺ formed sandwich type adducts with 15-crown-macrocycles diminishing aggregation of planar molecules by intramolecular rather than intermolecular complexation.     

Computational study of aza-adamantanes as multivalent bases

Structure and bonding characteristics, and gas phase stepwise basicities of proposed multivalent bases 1,3,5,7-tetraazatricyclo[3.3.1.1(3,7)]decane, 1,3,5,7,9,10-hexaazatricyclo[3.3.1.1(3,7)]decane and tricyclo[3.3.1.1(3,7)]azadecane, named and abbreviated here respectively as tetra-aza-adamantane (TAA), hexa-aza-adamantane (HAA) and deca-aza-adamantane (DAA), have been studied using B3LYP/6-311++G** method. Effects of protonation on the bond lengths and angles, and atomic charges, and on their correlations are studied in detail. Results show that the most affected characteristics by protonation are the N–H bond lengths and the charge of the hydrogen atoms. It is found, interestingly, that in the protonation of DAA, electric charges of the unprotonated nitrogen atoms are increased more than that of the protonated nitrogen atoms. Because of very small effects of protonation on the skeletal C–N and N–N bond lengths, it can be said that the aza-adamantane cage volume is not changed significantly upon protonation. The protonation energies approve multivalent nature of these bases with the order of TAA ≈ HAA > DAA. Different isomers for the unprotonated and protonated HAA and DAA are also studied.     

含四硫富瓦烯结构单元的酞菁和四氮杂卟啉衍生物的研究概况

综述了含四硫富瓦烯(TTF)结构单元的酞菁和四氮杂卟啉衍生物的合成、光物理和电化学性质以及聚集和自组装性能的研究概况.     

One- and Two-Photon-Induced Photochemistry of Modified Palladium Porphyrazines Involving Molecular Oxygen

Abstract— Octaphenyltetraanthraporphyrazinato palladium undergoes a self-sensitized photoreaction in the presence of oxygen to form a substituted palladium phthalocyanine with four endoperoxide bridges. This compound exhibits photophysical behavior similiar to palladium tetra-tert- butyl-phthalocyanine. The phthalocyanine-palladium complex with four endoperoxide bridges ejects molecular oxygen when excited by consecutive two-photon absorption in the Q-band region at 662 nm. This photocyclo-reversion, which produces palladium porphyrazines bearing a diminished number of endoperoxide bridges, can occur up to four times per initial molecule. Irradiation of these photoproducts in the presence of oxygen produces substituted palladium phthalocyanine containing four endoperoxide groups.     

Electrochemical Investigation of Metal-Free and Nickel-Containing Porphyrazines Carrying Eight Tosylaminoethylthia Groups

Summary.  In this study, the electrochemical properties of metal-free and nickel-containing porphyrazines with eight tosylaminoethylthia groups were investigated using cyclic voltammetry, double potential step chronoamperometry, double potential step chronocoulometry, and controlled potential coulometry. Cyclic voltammetry measurements showed that both compounds exhibit two quasi-reversible and an irreversible reduction waves. The first electron transfer reaction was followed by an irreversible chemical reaction, the second one by a reversible chemical reaction for both species. The electrode processes of metal-free and nickel-containing porphyrazines are diffusion controlled, but the double potential step chronocoulometry measurements indicated that the nickel porphyrazine is adsorbed at the electrode. However, a small adsorption current has no significant effect on the mass transport mechanism of the system. Diffusion coefficients of both compounds were determined by both cyclic voltammetric and chronocoulometric measurements. The diffusion coefficients of the reduced forms of the porphyrazines were found to be smaller than those of the neutral forms. Received October 29, 2001. Accepted (revised) December 17, 2001     

Electrochemical Investigation of Metal-Free and Nickel-Containing Porphyrazines Carrying Eight Tosylaminoethylthia Groups

 In this study, the electrochemical properties of metal-free and nickel-containing porphyrazines with eight tosylaminoethylthia groups were investigated using cyclic voltammetry, double potential step chronoamperometry, double potential step chronocoulometry, and controlled potential coulometry. Cyclic voltammetry measurements showed that both compounds exhibit two quasi-reversible and an irreversible reduction waves. The first electron transfer reaction was followed by an irreversible chemical reaction, the second one by a reversible chemical reaction for both species. The electrode processes of metal-free and nickel-containing porphyrazines are diffusion controlled, but the double potential step chronocoulometry measurements indicated that the nickel porphyrazine is adsorbed at the electrode. However, a small adsorption current has no significant effect on the mass transport mechanism of the system. Diffusion coefficients of both compounds were determined by both cyclic voltammetric and chronocoulometric measurements. The diffusion coefficients of the reduced forms of the porphyrazines were found to be smaller than those of the neutral forms.     

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

Summary. 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.