The synthesis,using microwave irradiation and characterization of novel,organosoluble metal-free and metallophthalocyanines substituted with flexible crown ether moieties

Cyclotetramerization of a phthalonitrile derivative to the metal-free phthalocyanine was accomplished in n-pentanol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene at reflux under an argon atmosphere. Ni(II), Zn(II), Co(II), Cu(II) phthalocyanines with four, peripheral 4-[methyleneoxy(12-crown-4)] groups were synthesized from 4-[{(12-crown-4)-yl}methyleneoxy]phthalonitrile in the presence of the anhydrous, divalent metal salts (NiCl₂, Zn(CH₃COO)₂, CoCl₂ and CuCl₂). The green phthalocyanines were soluble in common organic solvents such as CHCl₃, CH₂Cl₂, CH₃COCH₃, THF, DMF and DMSO. The structures of the target compounds were confirmed using elemental analysis, IR, ¹H NMR, ¹³C NMR, UV–vis and MS spectral data.     

Electrochemical and spectroelectrochemical characterization of the phthalocyanines with pentafluorobenzyloxy substituents

The solution redox properties and spectroelectrochemical investigation of the novel metal-free, zinc, nickel and cobalt phthalocyanines with tetra-pentafluorobenzyloxy substituents at the periphery were studied using various electrochemical and spectroelectrochemical measurements. Cyclic voltammetry and differential pulse voltammetry studies show that while Ni(II), Zn(II) and free-phthalocyanines give up to two reduction and two oxidation processes having ligand-based diffusion controlled reversible one-electron electron transfer characters, Co(II) phthalocyanine represents one ligand-based oxidation, one metal-based reduction and one ligand-based reduction processes having diffusion controlled reversible one-electron transfer characters. Assignments of the redox couples are also confirmed by spectroelectrochemical measurements. Reduction potentials of all complexes shift to positive potentials due to the electron withdrawing tetra-pentafluorobenzyloxy substituents compared with those of the phthalocyanines bearing phenoxy derivatives. A linear variation of the first reduction and oxidation potentials versus ze/r has been obtained for zinc and nickel phthalocyanines.     

Synthesis of phthalocyanines functionalized by 4-fluorophenoxy moieties and their linear optical properties

Four kinds of phthalocyanines with 4-fluorophenoxy group (H₂Pc, CuPc, Li₂Pc, and FePc) are synthesized by the microwave-assisted method under 15 min. The synthesized phthalocyanines have good solubility in aprotic polar solvents and do not form any new aggregation state with a concentration increase. The phthalocyanine coordinated with Li⁺ ion has a more stable and stronger absorption property in aprotic polar solvents than the phthalocyanine with Cu²⁺ or Fe²⁺ ion. The phthalocyanine coordinated with Fe²⁺ ion is more subject to H-aggregation than other phthalocyanines, especially in polar solvents.     

Conductometric studies of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) tetrafluoroborates in N,N—dimethylacetamide solutions

Results are reported for the molar conductivities at 25°C of N,N—dimethylacetamide (DMA) solutions of Bu₄NBF₄ and Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) tetrafluoroborates. The limiting molar conductivities of [M(DMA)₆]²⁺ (M  MN, Co, Ni, Cu, Zn) and BF^?₄, as well as association constants for Co(BF₄)₂ in DMA solutions have been calculated. The slight differences between conductometric curves of different metal ions are discussed.     

Photokatalytische Systeme. XLVIII. Ungewöhnliche lichtinduzierte Redoxreaktionen von Cobalt(III)-, Eisen(III)- und Kupfer(II)-Komplexverbindungen in Gegenwart von Chromsäureestern

Photocatalytic Systems. XLVIII. Unusual Light-Induced Redox Reactions of Cobalt(III), Iron(III) and Copper(II) Complexes in Presence of Chromic Acid Esters The coordination compounds[Co(NH₃)₅H₂O]³⁺,[Co(NH₃)₄(H₂O)₂]³⁺,[Co(en)₂(H₂O)Cl]²⁺ (en = ethylendiamine), [L₂(H₂O)Fe-O-Fe(H₂O)L₂]⁴⁺ (L = 1,10-phenanthroline; 2,2′-bipyridine) and [CuL₂]²⁺ (L = 2,9-dimethyl-1,10-phenanthroline) show no or neglegible photo redox reactions upon irradiation wave-length above 350 nm. However, in the presence of chromate(VI), water, and different alcohols like methanol, ethanol, i-propanol and n-propanol a very efficient light-induced formation of cobalt(II), iron(II) and copper(I) (ϕ = 0,7; Λ^irr = 375 nm) can be observed together with reduced generation of chromium(III). The participation of chromium(V) in the primary step of the photolysis of chromic acid esters was shown to be the reason for these unusual light-induced redox reactions. The coordination compounds under discussion behave as very efficient scavengers for chromium(V) connected with simultaneous reoxidation to chromate(VI) and reduction to the appropriate cobalt(II), iron(II) and copper(I) compounds. The general importance of the participation of chromium(V) in the primary step of the photolysis of chromate(VI) in non-aqueous solvents is also shown by investigations of the photochemical behaviour of the system metal complex/CrO₄—, Cr₂O₇—/dimethylsulfoxide. Possible mechanisms of the light-induced reductions of the metal complexes are discussed.     

Highly soluble phthalocyanines with hexadeca tert-butyl substituents

A phthalonitrile derivative bearing 2,4-di-tert-butylphenoxy substituents at peripheral positions was synthesized; subsequent cyclotetramerization in DMF and hexanol furnished the desired zinc (II), magnesium (II), copper (II) and nickel (II) phthalocyanines. These metallo-phthalocyanines were highly soluble in solvents such as dichloromethane, chloroform, acetone, ethyl acetate, tetrahydrofuran, diethyl ether, n-hexane and DMF. The structures of the compounds were confirmed by elemental analyses, IR, ¹H NMR, ¹³C NMR, electronic spectra and mass spectroscopic methods.     

Synthesis and spectroelectrochemistry of new phthalocyanines with ester functionalities

Metal-free (H₂Pc) and metallophthalocyanines (MPc; M: Co, Zn) with four n-pentyl ester of thioglycolic acid groups have been synthesized by the esterification of the corresponding carboxylic acid derivatives with n-pentanol. The novel phthalocyanine compounds were characterized by elemental analyses, mass, FT-IR and UV-Vis spectral data. The aggregation investigations carried out in different concentrations and solvents indicate that ester substituted metal-free and metallo-phthalocyanine compounds have not shown any aggregation behavior in the concentration range of about 10⁻⁵ M. Electrochemical and in-situ spectroelectrochemical measurements give common MPc based redox behaviors which supported the proposed structure of the complexes. While CoPc gives both metal-based and ring-based redox processes, H₂Pc and ZnPc give only ring-based electron transfer processes. In-situ electrocolorimetric method was applied to investigate the color of the electro-generated anionic and cationic forms of the complexes.     

Synthesis, electrochemical, and photophysical studies of hexadecachlorinatedphthalocyaninato zinc(II)

Synthesis of a new symmetrical 1,4,8,11,15,18,22,25-octahexyloxy-2,3,9,10,16,17,23,24-octa-(3,5-dichlorophenyl)phthalocyaninato zinc(II), ZnPc, has been described and characterized by ¹H NMR, ¹³C NMR, MS, UV-Vis, and IR spectrometry. The newly prepared ZnPc is soluble in organic solvents and is not aggregated in solution. The photophysical properties were studied by steady-state absorption and emission, cyclic voltammetry, and nanosecond transient absorption techniques. The prepared ZnPc absorbs and emits at longer wavelengths compared to that of reported phthalocyanine derivatives. The electron-donating properties of the ZnPc have been examined by mixing it with the electron-accepting dicyanoperylene-3,4,9,10-bis(dicarboximide), PDICN₂. The recorded nanosecond transient spectra in the visible/near-IR region showed clearly the electron-transfer from the triplet-excited state of the ZnPc to PDICN₂ with a rate of 3.40 × 10⁸ M⁻¹ s⁻¹. Light absorption in a wide section of the solar spectrum, favorable redox properties, and the electron-transfer properties suggest usefulness of the ZnPc in light-energy harvesting and developing optoelectronic devices.     

Synthesis and electrochemical and in situ spectroelectrochemical characterization of manganese, vanadyl, and cobalt phthalocyanines with 2-naphthoxy substituents

Metallo (Mn, Co, VO) phthalocyanines bearing peripheral 2-naphthoxy groups were synthesized by cyclotetramerisation of the corresponding phthalonitrile derivative. The phthalocyanine compounds were characterized by elemental analyses, mass, FT-IR and UV–vis spectral data. Three intense bands in the electronic spectra clearly indicate the absorptions resulting from naphthyl groups along with the Q and B bands of the phthalocyanines. Electrochemical and spectroelectrochemical measurements exhibit that incorporation of redox active metal ions, Co^II and Mn^III, into the phthalocyanine core extends the redox capabilities of the Pc ring including the metal-based reduction and oxidation couples of the metal. Presence of molecular oxygen in the electrolyte system affects the voltammetric and spectroelectrochemical responses of the cobalt and manganese phthalocyanines due to the interaction between the complexes and molecular oxygen. Interaction reaction of oxygen with CoPc occurs via an “inner sphere” chemical catalysis process. While CoPc gives the intermediates [O₂⁻–Co^IIPc⁻²]⁻ and [O₂²–Co^IIPc⁻²]²⁻, MnPc forms μ-oxo MnPc species. An in situ electrocolorimetric method has been applied to investigate the color of the electro-generated anionic and cationic forms of the complexes for possible electrochromatic applications.     

The microwave-assisted synthesis and structural characterization of novel,dithia-bridged polymeric phthalocyanines containing a substituted thiophenylamine Schiff base

Novel polymeric metal-free and metallo(Cu(II), Co(II), Ni(II), Zn(II) and Pb(II))–phthalocyanine complexes were synthesized using microwave irradiation and the products were purified by several (crystallization and preparative thin layer) techniques. The newly prepared compounds were characterized by a combination of elemental analyses, IR, ¹H/¹³C NMR, ¹H–¹H COSY, MS and UV–Vis spectroscopy. In order to better understand the spectroscopy data (especially for ¹H/¹³C NMR and ¹H–¹H COSY techniques), computational calculations were used for characterization at DFT/6-31G(d) level. The electronic spectra exhibited an intense π → π* transition with characteristic Q and B bands of the phthalocyanine core.     

Synthesis, characterization, and properties of polychelates of poly(maleic acid-co-olefin) with Cu(II), Co(II), Ni(II), and Zn(II)

SUMMARY Polychelates of poly(maleic acid-co-olefin) with Cu(II), Co(II), Ni(II), and Zn(II) metal ions are synthesized. These compounds are characterized by FT IR, UV-vis spectroscopy, and thermal analysis. The electrical conductivity measurements are carried out. These demonstrate that at temperature close to 130°C the electrical conductivity increased to values near to the semiconductor range. The PM3 calculations are also carried to study the geometry of the polychelates. Received: 1 November 2000/Revised version: 20 March 2001/Accepted: 21 March 2001     

Electrical properties of macromolecular complexes of coordinated polymers with mixed valence of Co(II), Co(III) and Co(II–III)

Electrical properties of bis‐ethylenediamine Co(II), Co(III) and Co(II–III) mixed valence complexes and polyethylenediaminecarbosilazane (PEDCSZ) [Co(II), Co(III) and Co(II–III)] macromolecules were measured at room temperature in a frequency range between 1 Hz and 10⁶ Hz. Electrical modulus, permittivity and ac conductivity were calculated using ac impedance and phase‐angle measurements. It was found that the overall conductivity of PEDCSZ macromolecules with Co is much higher than that for Co monomers. In addition, the conductivity of PEDCSZ Co(III) and Co(II–III) mixed valence compounds are higher than those containing Co(II) where the electronic conduction is dominant. The relaxation time increases from about 2.7 × 10^?6 s for Co(II) chloride to a value of 2.9 × 10^?4 s for Co(II–III) chloride monomers. Copyright © 2003 Society of Chemical Industry     

Bio active mixed ligand complexes of Cu(II), Ni(II) and Zn(II): Synthesis,spectral, XRD,DNA binding and cleavage properties

The paper presents the synthesis of complex combinations of Cu(II), Zn(II) and Ni(II) with Schiff bases obtained by the condensation reaction of diphenylglyoxal with 1-amino-4-nitrobenzene (L¹)/1-amino-4-chlorobenzene (L²)/p-anisidine (L³) as the main ligand and 1,10-phenanthroline as the co-ligand respectively. The characterization of newly formed complexes has been done by spectral and molar conductivity studies. The bioefficacy of the ligands and their complexes have been examined against the growth of bacteria and fungi in vitro to evaluate their antimicrobial potential. The in vitro antibacterial and antifungal assay indicates that these complexes are good antimicrobial agents against various pathogens. X-ray powder diffraction illustrates that the complexes have crystalline nature. The effect of the metal complexes on DNA is carried out by pUC19 DNA agarose gel electrophoresis at 50 V for 2 h. The results indicate that the complexes bind to DNA through intercalation and act as efficient cleaving agents.     

Preparation,characterization and comparative electrochemical studies of MgMXMn2-XO4 (x=0, 0.5; M= Ni/Co)

In this study, the structural, electrical and electrochemical properties of the compounds MgM_xMn_2-xO₄ [M = Ni/Co: x = 0,0.5] were investigated by preparing the materials by the citric acid assisted simple, cost effective sol-gel method. X-ray Diffraction (XRD) confirmed that Ni/Co doping created a phase transition of MgMn₂O₄ from tetragonal spinel-structure with a space group of I4₁/amd to a cubic spinel structure with a space group of Fd-3m. HRTEM and SAED analysis showed the bare compound to be polycrystalline and doped compounds to be single crystalline in nature. SEM analysis showed the agglomerated submicron sized particles for all the three compounds. The electrical properties of the compounds have been investigated through AC impedance spectroscopy. The electrical conductivity of the bare compound MgMn₂O₄ was found to be 5.09 × 10⁻⁶ S/cm at 583 K. Cyclic Voltammetry (CV) and Galvanostatic Charge-Discharge (GCD) studies made by the three electrode system shows that all the samples under study could undergo reversible redox reactions in the aqueous magnesium nitrate solution. MgMn₂O₄ sample exhibited highest specific discharge capacity of 263 mAh/g at the current density of 30 mA/g.     

Solvent directed assembly of two zinc(II)-2-(4-pyridyl)-4,5-imidazoledicarboxylate frameworks

Two zinc(II)-2-(4-pyridyl)-4,5-imidazoledicarboxylate frameworks, formulated as {[Zn₃(HPIDC)₃(DMF)₂](DMF)₂(H₂O)₂}_n (1) and {[Zn₄(HPIDC)₄(DMF)₄](DMF)₂(FMA)₂(H₂O)}_n (2) (H₃PIDC = 2-(4-pyridyl)-1H-4,5-imidazoledicarboxylic acid, DMF = N,N′-dimethylformamide, FMA = formamide) have been solvothermally synthesized depending on whatever solvents are used. In both structures, the HPIDC^2 − anions act as tripodal connectors to chelating with three zinc(II) cations while the zinc(II) cations coordinate with three HPIDC^2 − anions, to form the T-shape molecular building blocks [Zn_n(HPIDC)_n], which further connect in interdigitating or alternating fashion to result in the assembly of two different 3,3-connected networks. The luminescence behaviors and solvent effect were also discussed.     

Synthesis and characterization of new monomeric and polymeric phthalocyanines

Monomeric (M = 2Li or 2H) and polymeric (M = 2H, Zn, Cu, Co, or Ni), where M is metal or hydrogen, phthalocyanines were prepared by the tetramerization reaction of bisphthalonitrile monomer with appropriate materials. The electrical conductivities of the polymeric phthalocyanines, which were measured as gold sandwiches, were found to be 10⁻¹⁰–10⁻⁷ S/cm in vacuo and in air. The binding property of a Co‐containing polymeric phthalocyanine ( 10 ) toward alkali, alkaline‐earth, and some heavy cations was studied in tetrahydrofuran. The extraction affinity of 10 for K⁺ was found to be the highest in the heterogeneous phase extraction experiments. The disaggregation property of a Ni‐containing polymeric phthalocyanine ( 11 ) was investigated with K⁺, Na⁺, and NH₄⁺ cations. The intrinsic viscosities of all polymers were also measured by means of viscometry. All the novel compounds were characterized with elemental analysis, ultraviolet–visible, Fourier transform infrared, NMR, and mass spectrometry spectral data, and differential thermal analysis/thermogravimetry. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and photodynamic properties of amphiphilic A3B-phthalocyanine derivatives bearing N-heterocycles as potential cationic phototherapeutic agents

Unsymmetrically substituted A₃B-phthalocyanine derivatives bearing annulated 6-membered N-heterocycles, pyridine and pyrazine rings, were synthesized by the ring expansion reaction of boron(III) subphthalocyanine chloride. A geometrically constrained subphthalocyanine unit was reacted with a range of 1,2-phthalonitrile derivatives in presence of 8-diazabicyclo[5.4.0]undec-7-ene to form the A₃B-phthalocyanine. The reactions were carried out in DMSO/1-chloronaphthalene at 130-140 °C for 15 h. This synthetic strategy resulted in phthalocyanines in 37-42% yield that required only simple purification. Annulated 6-membered N-heterocycles were methylated to obtain cationic Zn(II)phthalocyanine derivatives. The spectroscopic and photodynamic properties of these photosensitizers were studied in N,N-dimethylformamide solution. Antifungal activity photoinduced by these compounds was evaluated in Candida albicans cellular suspensions. The results indicate that amphiphilic cationic phthalocyanines represent interesting agents with potential applications in photodynamic inactivation of microorganisms.     

Preparation of Co-Sn alloys by electroreduction of Co(II) and Sn(II) in molten LiCl-KCl

Co-Sn alloys were prepared by an electrochemical route in molten LiCl-KCl between 400 and 550 °C. The Sn(IV)/Sn(II), Sn(II)/Sn(0) and Co(II)/Co(0) redox couples were studied by cyclic voltammetry and/or chronopotentiometry over the temperature range. The diffusion coefficient values of Co(II) ions were measured. For example, it was found that the D_Co(II) values deduced from chronopotentiometry range from D_Co(II) = 1.65 × 10⁻⁵ cm² s⁻¹ at 400 °C to 4.95 × 10⁻⁵ cm² s⁻¹ at 550 °C. The standard potential of the Co(II)/Co(0) redox couple in molten LiCl-KCl was measured at 400 °C: vs Cl₂/Cl⁻. Finally, Co-Sn alloys were prepared in potentiostatic mode. The influence of the temperature of molten LiCl-KCl, the applied potential and the deposition time on the morphology and the composition of the Co-Sn alloys were also investigated. For T > 450 °C, the following tendency has been observed: the more negative the potential, the higher the Sn content in the deposited alloy. Thus, depending on the operating conditions, pure CoSn or CoSn₂ can be prepared.     

Synthesis and characterization of a novel alkoxy substituted gold(III) phthalocyanine

Gold(III) compounds have long been investigated for anti-cancer treatment. However, clinical use has often been hampered by their poor stability in solution. In the design of physiologically stable anticancer gold (III) complexes, promising tetrapyrrole derivatives such as phthalocyanines are rarely studied. In this work, a novel soluble symmetrical gold-(III) phthalocyanine (AuPc) complex bearing four pentyloxy terminal moieties was prepared from metal-free phthalocyanine precursor in dioxane in the presence of K[AuCl₄] and sodium acetate/acetic acid buffer. The new gold(III) complex obtained from this metallation was characterized by using elemental analyses, UV–Vis, FTIR, ¹H NMR and mass spectroscopic data. The aggregative properties of the novel compound were also investigated in a concentration range of 2 × 10^− 6 M to 3.1 × 10^− 5 M and no aggregation was observed.     

Separation of Co(II) and Mn(II) from sulphate media via a HFSLM: Reaction flux model and experimental verification

Separation of Co(II) and Mn(II) from sulphate media through triple HFSLM in series using D2EHPA was explored. Mn(II) was extracted preferentially over Co(II) at the pH value of 5, 100 ppm of Co(II) and Mn(II), 5% (v/v) of D2EHPA, 0.2 M HCl. The highest extraction percentage of Mn(II) was 98.14%, and Co(II) remained at 94.05% in the raffinate stream. The reaction order (n) and the reaction rate constant (k_f) were found to be 1.00 and 0.0180 min⁻¹, respectively. Furthermore, the reaction flux model proved to be in good agreement with the experimental data at an average deviation of 2.24%.