Synthesis,characterization, and electrochemical,spectroelectrochemical and electrical measurements of novel ball-type four 1,1′-methylenedinaphthalen-2-ol bridged metal-free,zinc(II) and cobalt(II), and metal-free clamshell phthalocyanines

The new ball-type bisphthalocyanines [metal-free 6, Zn(II) 7 and Co(II) 8] were synthesized from the corresponding 4,4′-[1,1′-methylenebis(naphthalene-2,1-diyl)]bis(oxy)di-phthalonitrile 4, which can be obtained from the reaction of 4-nitrophthalonitrile (2) with 1,1′-methylenedinaphthalen-2-ol 3. A novel clamshell type bisphthalocyanine 5 was synthesized from compound 4 and 4,5-bis(hexylthio)phthalonitrile 1. The novel compounds have been characterized by elemental analysis, UV/Vis, IR, ¹H NMR and MALDI-TOF Mass spectroscopies. The electrochemical and spectroelectrochemical measurements showed the formation of various mixed-valence oxidation and reduction species, due to the strong intramolecular interactions between the two phthalocyanine rings, especially in the ball-type phthalocyanines. The conduction properties of the compounds have been examined by d.c. and impedance spectroscopy measurements as function of temperature and frequency. D.c. conductivity, measured between 290 and 480 K, is thermally activated with the activation energy ranging between 0.62 and 0.84 eV. The a.c. results gave a power law behaviour, σ_a.c. = A(T)ω^s, in which the frequency exponent s decreases with temperature for 6, 7 and 8. The bulk resistance of the samples was derived from complex impedance spectra. It was found that the bulk resistance shows a typical negative temperature coefficient of resistance, decreasing with a rise in temperature, like that of a semiconductor.     

Synthesis and characterization of novel 4-nitro-2-(octyloxy)phenoxy substituted symmetrical and unsymmetrical Zn(II), Co(II) and Lu(III) phthalocyanines

Compounds 3 and 4 have been prepared by the reaction of 4-nitrocatechol 1 and 4-nitrophthalonitrile 2 by a common method, aromatic nucleophilic subtitution of the nitro group in 4-nitrophthalonitrile. Starting from 4 and 1-bromooctane, their alkylation reaction gave compound 5. Zn(II) 8, Co(II) 9 and Lu(III) 10 complexes were synthesized from the corresponding metal salts by the tetramerization of compound 5. Compound 7 was prepared by the statistical condensation of 5 and 4,5-bis(hexylthio)phthalonitrile 6 with CoCl₂ · 6H₂O in dry dimethylformamide. The new compounds were characterized by FT-IR, UV/Vis, NMR and mass spectra. The electrochemical properties of the complexes were also investigated by cyclic voltammetry in non-aqueous medium. The effect of temperature on the dc conductivity and the impedance spectra of spin coated film of the compounds was investigated at temperatures between 295 and 433 K and in the frequency range 40–10⁵ Hz. Thermally activated conductivity dependence on temperature was observed for all compounds.     

Synthesis,characterization, and electrochemical and electrical properties of novel mononuclear and binuclear ball-type Zn(II) and Co(II) phthalocyanines substituted with 1a,8b-dihydronaphtho[b]naphthofuro-[3,2-d]furan-7,10-diyl

New mononuclear phthalocyanines [Zn(II) 4 and Co(II) 6] and ball-type bisphthalocyanines [Zn(II) 5 and Co(II) 7] have been synthesized from the corresponding compound 3, which can be obtained from the reaction of 4-nitrophthalonitrile 1 with 1a,8b-dihydronaphtho[b]naphthofuro[3,2-d]furan-7,10-diol 2. The novel compounds have been characterized by elemental analysis, UV/Vis, IR, ¹H NMR and MASS spectroscopy. The electrochemical measurements show the formation of various mixed-valence oxidized and reduced species, due to intramolecular interactions between the two phthalocyanine units in the ball-type binuclear metallophthalocyanines. Detailed studies of the effect of temperature on the electronic properties of the films were investigated by dc conductivity and impedance spectroscopy techniques at temperatures between 290 K and 460 K. Thermally activated conductivity dependence on temperature was observed from the dc measurements. The ac results give a power law behavior in which the frequency exponent decreases with temperature. It was observed that the impedance spectra consist of a curved line at low temperature. These curved lines transform into a full semicircle with increasing temperature.     

Synthesis and electrochemical characterization of biphenyl-malonic ester substituted cobalt,copper, and palladium phthalocyanines

Phthalocyanines with four biphenyl-malonic ester groups on the periphery were synthesized by cyclotetramerization of 4-(1,1-dicarbethoxy-2-(4-biphenyl)-ethyl)-phthalonitrile. The new compounds were characterized by elemental analyses, FT-IR, ¹H NMR, ¹³C NMR, UV–Vis, and MASS spectral data. Electrochemical behaviors of novel Co(II), Cu(II), and Pd(II) phthalocyanines were investigated by cyclic voltammetry, potential differential pulse voltammetry, and applied potential chronocoulometry techniques. While Cu(II) and Pd(II) phthalocyanines give up to four common phthalocyanine ring reductions, Co(II) phthalocyanine gave two ligand-centered and two metal-centered redox processes. HOMO–LUMO gap of the complexes are comparable with the reported MPc papers.     

Synthesis,characterization and electrochemical properties of amphiphilic axially-disubstituted silicon(IV) phthalocyanines

The new 2-[2-(6-tert-butyl-2H-1,3-benzoxazin-3(4H)-yl)ethoxy]ethanol 1 and 2-[2-(6-pentyl-2H-1,3-benzoxazin-3(4H)-yl)ethoxy]ethanol 2 have been synthesized. Axially disubstituted silicon phthalocyanines 3 and 4 have been synthesized by introducing 2-[2-(6-tert-butyl-2H-1,3-benzoxazin-3(4H)-yl)ethoxy]ethanol and 2-[2-(6-pentyl-2H-1,3-benzoxazin-3(4H)-yl)ethoxy]ethanol at the axial positions of silicon(IV) phthalocyanine, respectively. The electrochemical properties of silicon phthalocyanines 3 and 4 were also investigated by cyclic voltammetry (CV) and square wave voltammetry. Voltammetric studies show that while 3 showed two reversible reduction and one irreversible oxidation couples, 4 showed two quasi-reversible reduction and one irreversible oxidation couples.     

Synthesis, characterization, spectroscopic and electrochemical properties of phthalocyanines substituted with four 3-ferrocenyl-7-oxycoumarin moieties

The synthesis, spectroscopic and electrochemical properties of the tetra-(3-ferrocenyl-7-oxycoumarin)-substituted zinc (II) and cobalt (II) phthalocyanines (3 and 4) are reported for the first time. The synthesis of novel 3-ferrocenyl-7-hydroxycoumarin (1) was performed according to Perkin reaction, and the ligand, 7-(3,4-dicyanophenoxy)-3-ferrocenylcoumarin (2), was synthesized by the reaction of 3-ferrocenyl-7-hydroxycoumarin with 4-nitrophthalonitrile in the presence of K₂CO₃ as the base in dry dimethylformamide. The preparation of the corresponding zinc (II) and cobalt (II) metallo phthalocyanines (3 and 4) substituted with 3-ferrocenyl-7-oxycoumarin moieties at β-positions of the phthalocyanine ring was achieved by the cyclotetramerization of the coumarin ligand (2) with relevant metal(II) acetates in dry 2-dimethylaminoethanol. The new compounds have been characterized by elemental analyses, FT-IR, ¹H NMR, Mass and electronic spectroscopy. The fluorescence property of the zinc metallo phthalocyanine (3) is strongly affected by the presence of ferrocenyl moiety. The ferrocenyl moieties were very efficient in quenching the excited state of 3, which show very poor fluorescent intensity. The electrochemical properties of the complexes were also investigated by cyclic and differential pulse voltammetry techniques in non-aqueous medium. It was found that the redox-active ferrocene substituents are reduced concurrently at one potential.     

Synthesis, characterization and comparative studies on the photophysical and photochemical properties of metal-free and zinc(II) phthalocyanines with phenyloxyacetic acid functionalities

The synthesis and characterization of new peripherally and non-peripherally tetra-substituted metal-free and zinc(II) phthalocyanines with 2-, 3- and 4-phenyloxyacetic acid functionalities are described for the first time in this study. The new compounds have been characterized by elemental analysis, FT-IR, UV-Vis, MALDI-TOF and ¹H-NMR spectra. Photodegradation, singlet oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds are studied in dimethylformamide (DMF). The influence of the substituent position on the phthalocyanine framework (non-peripherally or peripherally), central metal ion (metal-free or zinc) and the position of the COOH group (2-, 3- or 4-position on the phenyloxyacetic acid) on the spectroscopic, photophysical and photochemical properties have been investigated. Non-peripherally zinc(II) phthalocyanines (1b and 2b) and peripherally zinc(II) phthalocyanine (4b) gave good singlet oxygen quantum yields (Φ_Δ) (0.37, 0.39 and 0.38, respectively) which indicate the potential of the complexes as photosensitizers in applications of PDT.     

Synthesis, characterization and some properties of novel bis(pentafluorophenyl)methoxyl substituted metal free and metallophthalocyanines

The preparation of some new tetrakis[bis(pentafluorophenyl)methoxyl] substituted metal free and metallophthalocyanine (MPcs) complexes were achieved by the tetramerization of 4-[bis(pentafluorophenyl)methoxy]phthalonitrile with Li metal in pentan-1-ol or metal [Co(II) or Zn(II)] acetates in DMAE, respectively. The structures of the target compounds were confirmed by elemental analysis, IR, UV–vis, ¹H NMR, ¹⁹F NMR and mass spectroscopic methods. MPcs are soluble only in strong and medium polar solvents while the metal free one is soluble in weakly, medium and strong polar solvents. The temperature and frequency dependence of the electrical conductivities were studied on spin coated films of the compounds using dc and impedance spectroscopy techniques in the frequency range from 40 to 10⁵ Hz and within the temperature range from 290 to 440 K. The temperature dependence of the exponent s and conductivity, σ_ac, were completely in agreement with the prediction of the hopping model. The redox properties of the complexes were determined by cyclic voltammetry. The nature of the redox processes was also confirmed using spectroelectrochemical measurements.     

Synthesis of novel alkylamino zinc(II) phthalocyanines

The synthesis of tetramethyl‐tetraphthalimidomethyl‐phthalocyaninato zinc(II) ( 6 ) and tetramethyl‐tetraaminomethyl‐phthalocyaninato zinc(II) ( 7 ) is described.     

Synthesis, characterization and photophysical properties of novel tetrasubstituted phthalocyaninato zinc derivatives

Peripherally tetraimido-substituted phthalocyaninato zinc compounds 1-3 were synthesized through the reaction of tetraamino-substituted phthalocyaninato zinc with 4-Br-1,8-naphthalic anhydride, 4-hexahydropyridine-1,8-naphthalic anhydride and 4-morpholine-1,8-naphthalic anhydride, respectively. The compounds were characterized by MS, ¹H NMR, UV-vis, IR and elemental analysis, the results of which were consistent with the proposed structures. The effects of substitutes, acid/base and solvents on the UV-vis spectra of the new complexes were discussed in detail.     

Synthesis and electrochemical properties of crown ether functionalized coumarin substituted cobalt and copper phthalocyanines

The synthesis of novel 6,7-[15-crown-5]-3-[p-(3,4-dicyanophenoxy)phenyl]coumarin (1)/6,7-[15-crown-5]-3-[p-(2,3-dicyanophenoxy)phenyl]coumarin (2) and their peripherally/non-peripherally cobalt and copper phthalocyanine complexes (3-6) have been prepared and characterized by elementel analysis, ¹H-NMR, MALDI-TOF, FT-IR and UV-Vis spectral data. Fluorescence intensity changes of compound 1 and 2 have been determined by addition of Na⁺ or K⁺ ions at 25 °C in THF. The effect of substitution type on the redox and aggregation behaviour of the compounds was investigated by voltammetry and in situ spectroelectrochemistry.     

Synthesis,spectroscopic, electrochemical and spectroelectrochemical properties of metal free,manganese, and cobalt phthalocyanines bearing peripherally octakis-[4-(thiophen-3-yl)-phenoxy] substituents

Metal free (2), manganese (3), and cobalt (4) phthalocyanines, which are octa-substituted at the peripheral positions with [4-(thiophen-3-yl)-phenoxy] moieties, were synthesized and electrochemical properties were reported for the first time. The complexes were characterized by elemental analysis, IR, ¹H NMR, mass spectroscopy, and electronic spectroscopies. Electrochemical and spectroelectrochemical measurements exhibit that incorporation of the redox active metal ions, Co^II and Mn^IIIOAc, into the phthalocyanine core extends the redox richness of the Pc ring with the reversible metal-based reduction and oxidation couples in addition to the common Pc ring-based electron transfer processes. Presence of molecular oxygen in the electrolyte system causes to form π-oxo MnPc complexes, which alter the voltammetric and spectroelectrochemical responses of the complex. 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.     

Synthesis,characterization, antioxidant and antibacterial properties of non-peripherally and peripherally tetra-substituted phthalocyanines

abstract

This study focuses on the synthesis, spectral, antioxidant and antibacterial properties of the metal-free, zinc and cobalt phthalocyanines (3–8) bearing 4-methoxy-phenoxy substituents on the nonperipheral [(1(4), 8(11), 15(18), 22(25)] or peripheral [2(3), 9(10), 16(17), 23(24)] positions. The new synthesized complexes 7 and 8 have been characterized by elemental analysis, FT-IR, MALDI-MS, and UV-vis spectral data. The antioxidant activities of all tested compounds were investigated by applying three different antioxidant methods such as radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl, chelating ability to ferrous ions and reducing power activity methods. In addition, the antibacterial activities of the compounds were screened by disc diffusion method against one gram-negative and four gram-positive bacteria. The tested phthalocyanine compounds showed very good antioxidant activity and promising antibacterial properties.     

Synthesis and characterization of liquid crystalline tetra- and octa-substituted novel phthalocyanines

Methylene-bridged tetra- and octa-(13,17-dioxa nonacosane-15 sulfanyl)-substituted metal free- and Ni(II) phthalocyanines were synthesized from the corresponding phthalonitrile (3, 4) derivatives in the presence of the anhydrous metal salt (NiCl₂) or a strong organic base. The new compounds were characterized by elemental analyses, UV/Vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry (DSC), optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirm that tetra- and octa-substituted compounds (3a–b, 4a–b) form hexagonal columnar mesophases (Col_h). We indicated that addition of the methylene-bridged phthalocyanine (Pc) core can either decrease the liquid crystal phase transition temperatures or extend the liquid crystal temperature range to include room temperature. Also, the Pc compounds (3a, 3b, 4a and 4b) are liquid crystals at room temperature. These properties of the Pc complexes provide some advantages such as easily obtaining an ordered film for sensor applications. Computational modelling work was combined with X-ray diffraction investigation to validate the diameter of the phthalocyanine molecule (3b).     

Synthesis,spectroscopy and electrochemical properties of highly soluble fluoro containing phthalocyanines

2(3),9(10),16(17),23(24)-Tetrakis-4′-[3,5-bis-(trifluoromethyl)-phenoxy]-phthalocyanines, {M[Pc-β(OBz-(CF₃)₂)₄]}, (M = Zn(II), Cu(II), Co(II) and Ni(II)) were synthesized and characterized by elemental analysis, FTIR, ¹H NMR, UV–Vis and MS (Maldi-TOF) spectral data. It is shown that the 4-(3,5-bis(trifluoromethyl)-phenoxy) moieties on the periphery affect the solubility, spectroscopic data and electrochemistry of the tetrakis metallophthalocyanines. The cyclic voltammetry and differential pulsed voltammetry of the complexes give well-defined redox couples in harmony with common metallophthalocyanine complexes. Electrochemical studies show that the complexes exhibit stable monoanionic M{Pc-β-[(OBz-(CF₃)₂)₄]}¹⁻, dianionic M{Pc-β-[(OBz-(CF₃)₂)₄]}²⁻ and monocationic M{Pc-β-[(OBz-(CF₃)₂)₄]}¹⁺ species during the reduction and oxidation processes. When compared with the unsubstituted analogues, the redox potentials of the complexes shifted to more positive potentials due to the electron-withdrawing fluorine groups.     

Synthesis,characterization and electrochemical properties of new phthalocyanines

The chemical synthesis and characterization with spectroscopic and electrochemical properties of [bis(4-fluorophenyl)-methoxy]-substituted metallo-phthalocyanines were reported for the first time. The new phthalocyanines have been characterized by elemental analysis, UV-Vis, FT-IR, and mass spectroscopies. The aggregation behavior of the phthalocyanine compounds was investigated in different solvents and concentrations. It is found that the fluoro substituents of peripherally Co and Cu complexes are examined and induce a shift to the redox processes toward the negative potentials and formed more reversible processes. Metal-based reduction and oxidation reactions were obtained for the Co(II) complex, whereas Cu(II) complexes exhibited Pc-ring-based electron-transfer reactions. The voltammetric measurements supported the proposed structure of the complexes.     

Synthesis,characterization, conduction,and dielectric properties of tetra tert-butylsulfanyl substituted phthalocyanines

The tert-butylsulfanylphthalonitrile has been prepared with optimized synthetic procedure. Metal free (H₂Pc) and metallo phthalocyanines (Pcs) (ZnPc, CoPc, CuPc, PbPc) have been synthesized by cyclotetramerization of tert-butylsulfanylphthalonitrile in the presence of DBU and metal salts. Thus, tert-butylsulfanyl groups enhance the solubility, shift the Q band absorption to the red visible region, and inhibit efficient cofacial interaction of the Pcs (2–6) as evaluated by UV–vis spectra. The electrical conduction and dielectric properties of the synthesized Pc thin films sandwiched between indium tin oxide and aluminum electrodes (ITO–Pc–Al) were investigated from 300 to 500 K. At low bias voltage the conduction is ohmic while at high bias voltage the conduction becomes space charge limited with an exponential distribution of traps. The measured ac conductivity data are discussed in terms of classical models based on pair approximation. It was found that the ac conductivity obeys the power law given by σ_ac = σ₀ω^s, in which the frequency exponent s decreases with temperature. The real and imaginary parts of the impedance are found to be dependent on both frequency and temperature.     

Synthesis,characterization, and optical studies of pentoxy-substituted tetrakis(pentafluorobenzyloxy)phthalocyanines

Abstract

The synthesis and characterization of peripherally 2′,3′,5′,6′-tetrafluoro-4′-pentoxy-benzyloxy-substituted metal-free and metallo (Zn(II) and Co(II)) phthalocyanines are described in this study. Aggregation properties of these phthalocyanines were studied in the concentration range of 1 × 10^?5?1 × 10^?6 M in tetrahydrofuran. Thin films of phthalocyanines were prepared by spin-coating technique. The spectrophotometric measurements of transmittance spectra were carried out in the wavelength range of 200–1000 nm. Optical band gaps of phthalocyanine thin films were also calculated. Surface morphologies and thickness of the films were examined by Scanning Electron Microscopy. Results show that film thickness can be changed significantly depending on the type of metal in the phthalocyanine.     

Synthesis,characterization, crystal structures,enzyme inhibition,DNA binding,and electrochemical studies of zinc(II) complexes

Five zinc(II) complexes, [Zn(L¹)₂] (1), [Zn(L¹)₂(phen)H₂O]·H₂O (2), [Zn(L¹)₂(bipy)] (3), [Zn(L²)₂] (4), and [Zn(L²)₂(phen)] (5) (where L¹?=?4-nitrophenylacetate, L²?=?phenylacetate, phen?=?1,10-phenanthroline and bipy?=?2,2′-bipyridine), have been synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR. Complexes 2, 3, and 4 have been confirmed by single-crystal X-ray diffraction. In 2 and 3, zinc is bonded monodentate to two carboxylates exhibiting distorted trigonal bipyramidal and tetrahedral geometries, respectively, whereas in 4, the carboxylates are bridging bidentate in distorted tetrahedral geometry. The complexes have been screened for electro- and biological activities, including DNA interaction and enzyme inhibition studies. The effect of concentration of 1–5 on the activity of enzyme, alkaline phosphatase, showed that an increase in concentration of complex decreased the activity of the enzyme. Electrochemical behavior of HL¹, 2, and 3 was investigated by cyclic voltammetry and it was observed that ligand-centered electro-activity exhibits a proportionate change on complexation. The UV–visible spectroscopic and viscometric data indicate electrostatic and groove binding of the complexes with DNA. The binding constant and Gibb’s free energy values indicate the feasibility of the complex–DNA interaction and show potent biological activity of the complexes.     

“Pinwheel-like” phthalocyanines with four non-peripheral chiral menthol units: Synthesis,spectroscopy, and electrochemistry

Chiral side chains have been incorporated onto the non-periphery moiety of phthalocyanine ring, resulting in a pair of chiral phthalocyanines, (D)-and (L)-1,8,15, 22-tetrakis(2-isopropyl-5-methylcyclohexoxyl)phthalocyanine.