Corrosion resistance of aluminum against acid activation in 1.0 M HCl by symmetrical ball - type zinc phthalocyanine

The inhibition effect of symmetrical Ball - type Zinc Phthalocyanine on Aluminum in 1mol/L hydrochloric acid was analyzed by electrochemical techniques. A novel ball-type zinc phthalocyanine (Zn-Pc) inhibitor has been synthesized and verified utilizing FTIR, nuclear magnetic resonance (1H NMR and 13C NMR), MALDI-TOF MS, and absorption spectroscopy (UV-Vis). In addition, laser-induced breakdown and photoluminescence spectroscopy were employed for additional study. Weight loss technique was employed to investigate the corrosion inhibition effectiveness of the synthesized Zn-Pc on Aluminum in 1mol/L hydrochloric acid at the range of variation temperatures (293-333 K). The inhibition efficiency of Zn-Pc increased with higher concentrations of Zn-Pc and decreased as the temperature increased. Furthermore, Zn-Pc demonstrated outstanding outcomes, achieving 72.9% at a very low inhibitor concentration (0.4 mmol/L) at 298 K. The experimental data for Zn-Pc Aluminum in 1mol/L hydrochloric acid obeys the Langmuir adsorption isotherm. Moreover, the corrosion system's thermodynamic parameters and activation energy were determined. Quantum chemical calculations applying the (DFT) Density Functional Theory method was conducted and applied in this study. These calculations played a pivotal role in elucidating molecular structures and reactivity patterns. Through DFT, numerous reactivity indicators were computed, providing valuable insights into the chemical behavior of the studied compounds. These indicators, such as frontier molecular orbitals, electron density, and molecular electrostatic potential, were subsequently correlated with experimental data.

Synthesis, characterization, third-order non-linear optical properties and DFT studies of novel SUBO bridged ball-type metallophthalocyanines

Novel 4,4'-(((2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropane-2,1-diyl))bis(oxy)) (SUBO) bridged ball-type metallophthalocyanines were synthesized starting from 4,4'-(((2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropane-2,1-diyl))bis(oxy))diphthalonitrile with convenient metal salts in 2-N,N-dimethylaminoethanol. A new bisphthalonitrile compound was obtained from 2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropan-1-ol) and 4-nitrophthalonitrile in acetonitrile at reflux temperature in the presence of potassium carbonate as a catalyst. The structural characterization of the compounds was performed by elemental analysis, and infrared, ultraviolet-visible and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopic methods. Nonlinear absorptions of the phthalocyanine complexes were measured using the Z-scan technique with 7 ns pulse duration at a 532 nm wavelength. It is obvious that ball-type copperphthalocyanine has a high nonlinear absorption coeffıcient and imaginary component of the third-order susceptibility compared to other complexes. Therefore, ball-type copperphthalocyanine can be regarded as a very good candidate for optical limiting applications. Density functional theory was used for geometry optimizations and time-dependent density functional theory calculations of electronic transitions in order to compare with the experimental results. Molecular orbital and nonlinear optical analyses were also performed with density functional theory at the CAM-B3LYP/6-31G(d,p)/LANL2DZ level. The nonlinear optical analyses show that ball-type copperphthalocyanine has significantly better nonlinear optical properties in comparison to a common reference compound, urea.

Synthesis, characterization and electrochemical properties of isoflavone substituted zinc(II), cobalt(II), and metal-free phthalocyanines

In this study, novel tetrasubstituted metallo- and metal-free phthalocyanines containing 7-hydroxy-4′-methoxyisoflavonoxy moieties at peripheral and non-peripheral positions have been prepared by cyclotetramerization of corresponding phthalonitriles. The most obvious feature of these quaternized complexes is their extensive solubility and non-aggregated species (especially non-peripherally substituted) in organic solvents such as chloroform, tetrahydrofuran, dimethylformamide and dimethylsulfoxide, which makes them candidates for use in many applications in different fields. The new compounds have been characterized by elemental analysis, FT-IR, UV-vis, 1H and [Formula: see text]C NMR and MS (Maldi-TOF MS). Voltammetric and in situ spectroelectrochemical measurements have been performed with the aim of characterizing the electron transfer properties of the compounds on Pt in dimethylsulfoxide/tetrabutylammonium perchlorate, compared to those of previously reported corresponding compounds with tetra 6-hydroxyflavonoxy substituents. The effect of aggregation on the redox character of these complexes was also discussed.

Aggregation of slipped-cofacial phthalocyanine J-type dimers: Spectroscopic and AFM study

Direct metallation of 2-hydroxyphthalocyanine J-type slipped-cofacial dimeric ligand by Mg, Zn, Cu, Ni and Co salts has been carried out to obtain corresponding metal complexes selectively without any noticeable dissociation or polymerization of the starting ligand. Integrated analysis of aggregation properties in the synthesized series has been conducted with the involvement of AFM microscopy, UV/Vis spectroscopy and theoretical assessment. As a result, a nonlinear relationship between absorption and concentration was found, with aggregation beginning to appear at concentrations above 3.3 × 10^-5 mol L^-1 with predominant formation of trimers from the dimeric molecules in THF solutions.

Redox-Switchable New Phthalocyanines Containing Hydrazono-Thiazole-Carboxylate Fragments: Synthesis, Electrochemical, Spectroelectrochemical and Electrocolorimetric Investigation

New phthalonitrile compound with Schiff base, carbothioamide and thiazole moieties as substituents and its corresponding metal-free and metallophthalocyanines (Zn(II), Ni(II), Co(II), and Cu(II)) were synthesized and characterized for the first time. The solubilities of these novel phthalocyanines were high in organic solvents. The redox properties of the compounds have been researched by cyclic voltammetry, square wave voltammetry, controlled-potential coulometry and in situ spectroelectrochemistry in dimethylsulfoxide. The compounds displayed metal and/or phthalocyanine ring-based, generally reversible or quasi-reversible reduction and oxidation processes. The effect of aggregation on the redox behavior of these complexes was also discussed. In general, decreased intensity and broadening in the main Q absorption band and the appearance of a new blue-shifted band confirmed the presence of H-type aggregates in the solutions of the complexes 4, 6 and 8 in DMSO/TBAP. The color changes associated with the redox processes and electrogenerated anionic and cationic redox species were also recorded with in situ electrocolorimetric measurements. In situ UV-vis spectral and associated color changes monitored during the reduction processes of the complexes suggested their applicability in the fields of the electrochemical technologies.

Novel 4,4′-{(diphenylmethylene) bis(4,1-phenylene)bis(oxy)}-bridged ball-type phthalocyanines: Electrochemical, electrocatalytic oxygen reducing and heavy metals ions sensing properties

Novel 4,4′-{(diphenylmethylene)bis(4,1-phenylene)bis(oxy)} bridged ball-type metal-free, zinc(II), cobalt(II) and iron(II) ball-type metallophthalocyanines were achieved by the reaction of the bisphthalonitrile derivative in 2-dimetylaminoethanol. The isolation of the metal-free and metallophthalocyanines were carried out by both planar and column chromatography and also by hot soxhalet extraction. Their structures have been characterized by infrared, ultraviolet-visible,1H nuclear magnetic resonance and matrix assisted laser desorption/ionization mass spectroscopies. The redox characters of the ball-type metallophthalocyanines have been investigated by cyclic voltammetry, square wave voltammetry, controlled potential coulometry and spectroelectrochemistry in nonaqueous media. The investigation suggested that the ball-type complexes form ring-based and/or metal-based mixed-valence species as a result of the remarkable interaction between the two Pc rings and/or metal centers. Furthermore, these species were found to be stable as evidenced by the splitting of the relevant redox processes. The electrocatalytic oxygen reducing performances of the dinuclear ball-type complexes were also studied. The compound involving Fe(II) centers at the phthalocyanine cores displayed higher catalytic performance towards oxygen reduction than those of other ones. By using these compounds as sensing materials, a flow type quartz crystal microbalance sensor was developed for the detection of small concentrations of heavy metal ions. A cadmium ion sensitivity of 2.85 × 104Hz/mg.L[Formula: see text] was observed with ball-type iron(II) phthalocyanine coated quartz crystal microbalance sensor. Detection of other metal ions including Fe[Formula: see text], Zn[Formula: see text], Ag[Formula: see text] and Sn[Formula: see text] were also performed. The results indicated that 1– 4 functionalized quartz crystal microbalance sensors can be used for the detection of heavy metal ions in aqueous solution. Partition coefficients obtained from the linear response regimes of the calibration curves are in the 8.6 × 104–5.4 × 105range. Results show that the minor structural difference between metal free and metallophthalocyanine poses significant impact on metal ion partitioning.

New developments in porphyrin-like macrocyclic chemistry: a novel family of dibenzotetraaza[14]annulene-based cofacial dimers

The first known cofacial dimers, based on covalently linked dibenzotetraaza[14]annulenes, were synthesized in reasonable 35–40% yields, without recourse to high-dilution techniques.

Coumarin-substituted manganese phthalocyanines: synthesis, characterization, photovoltaic behaviour, spectral and electrochemical properties

The synthesis and spectroscopic characterization of novel manganese(III) phthalocyanines bearing 7-oxy-4-(4-methoxyphenyl)-8-methylcoumarin or/and chloro groups have been achieved. The effect of alpha and beta substitution on the ligand- and metal-based reduction processes of the manganese phthalocyanine complexes and their interaction with dioxygen were investigated. The more effective interaction of the central metal of the beta coumarin substituted complex with dioxygen than that of its alpha substituted analogue was attributed to the hindrance of the interaction by the nonplanarity in the case of alpha substitution. Similarly, the aggregation tendency was lower in the case of alpha substitution. Among the fabricated coumarin-substituted manganese phthalocyanine donor layer and fullerene (C60) acceptor based photovoltaic heterojunction devices, the one containing 8 exhibited the best performance. The effect of the thickness of the active Pc layer on solar cell parameters has also been investigated. A nearly thickness independent open circuit voltage was observed.

Self-assembly of tetrakis (3-trifluoromethylphenoxy) phthalocyaninato cobalt(II) on multiwalled carbon nanotubes and their amperometric sensing application for nitrite

In this work, the soluble cobalt phthalocyanine functionalized multiwalled carbon nanotubes (MWCNTs) are synthesized by π-π stacking interaction between tetrakis (3-trifluoromethylphenoxy) phthalocyaninato cobalt(II) (CoPcF) complex and MWCNTs. The physical properties of CoPcF-MWCNTs hybrids are evaluated using spectroscopy (UV-vis, XPS, and Raman) and electron microscopy (TEM and SEM). Subsequently, an amperometric nitrite electrochemical sensor is designed by immobilizing CoPcF-MWCNTs hybrids on the glassy carbon electrode. The immobilized CoPcF complex shows the fast electron transfer rate and excellent electrocatalytic activity for the oxidation of nitrite. Under optimum experimental conditions, the proposed nitrite electrochemical sensor shows the fast response (less than 2 s), wide linear range (9.6 × 10(-8) to 3.4 × 10(-4) M) and low detection limit (6.2 × 10(-8) M) because of the good mass transport, fast electron transfer rate, and excellent electrocatalytic activity.

Synthesis and Antimicrobial Activity of New Phthalocyanine Complexes and Electrochemical and Spectroelectrochemical Behaviour of Cobaltphthalocyanine

A novel phthalocyanine bearing oxygen donor atoms on the peripheral positions has been synthesised by cyclotetramerisation of ( E)-4-(4-cinnamoylphenoxy) phthalonitrile and its nickel, zinc, cobalt, copper and lead derivatives prepared. The thermal stabilities of the phthalocyanine compounds have been determined and their possible biological activities (antibacterial, anticandidal and antifungal) studied. The effects of substituent on the electrochemical and in situ spectroelectrochemical behaviour of cobaltphthalocyanine have been investigated and an in situ electrocolorimetric method was applied to investigate the colour of the electrogenerated anionic and cationic forms of the complex.

Synthesis, interface (Au/M2Pc2/p-Si), electrochemical and electrocatalytic properties of novel ball-type phthalocyanines

The phthalodinitrile derivative (3) was prepared by the reaction of 4,4'-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol (1) and 4-nitrophthalonitrile (2) with dry DMF as the solvent in the presence of the base K(2)CO(3) by the method of nucleophilic substitution of an activated nitro group in an aromatic ring. The template reaction of 3 with the corresponding metal salts gave the novel bi-nuclear ball-type metallophthalocyanines, MPcs {M = Co (4), Cu (5), Zn (6)}. Newly synthesized compounds were characterized by elemental analysis, UV-vis, FT-IR (ATR), MALDI-TOF mass and (1)H-NMR spectroscopy techniques. The electronic spectra exhibit an intense π→π* transition of characteristic Q and B bands of the Pc core. The dielectric properties and interface between the spin coated films of 4-6 and a p-type silicon substrate have been studied by fabricating metal-insulator-semiconductor capacitors. The results indicated that the frequency dependence of the dielectric permittivity, ε'(ω), exhibits non-Debye type relaxation for all the temperatures investigated. The ac conductivity results indicated that the conduction mechanism can be explained by a hopping model at low temperatures (<430 K) and a free band conduction mechanism at high temperatures (≥430 K). The density of interface state calculations on these novel compounds showed that the combination of Au/4/p-Si is a promising structure with a high dielectric constant and a low interface trap density suitable for metal-oxide-semiconductor devices. The electrochemical properties of the Pc complexes were examined by cyclic voltammetry, differential voltammetry and controlled potential coulometry on platinum in non-aqueous media. The complexes showed ring-based and/or metal-based mixed-valence behaviours as a result of the remarkable interaction between the two Pc rings and/or metal centres. The mixed-valence splitting values for the complexes suggested that the mixed valence species are considerably stable. The Vulcan XC-72(VC)/Nafion(Nf)/4 modified glassy carbon electrode showed much a higher catalytic performance towards oxygen reduction than those of VC/Nf/5 and VC/Nf/6 modified ones.

Synthesis and characterization, novel across adjacent ring formed phthalocyanine

Novel mononuclear Zn(ii) 4, Co(ii) 5 and Cu(ii) 6 metallophthalocyanines have been synthesized from 4,4'(ethane-1,1-p-phenol-2,2-p-phenoxy)phthalonitrile 3, which can be obtained by the reaction of 4-nitrophthalonitrile 1 with 1,1,2,2-tetrakis(p-hydroxy-phenyl)-ethane 2. The target water-soluble derivatives of 7-9 were acquired from a boiling suspension of the compounds in aqueous 20% KOH solution. The synthesized complexes have been characterized by UV-vis, IR, (1)H NMR and MALDI-TOF-mass spectroscopies. In addition, the geometric and electronic structures of 2-6 were investigated by ab initio/DFT quantum mechanical calculations using the Gaussian 03 program with HF theory at the B3LYP/3-21G level. The redox properties of the complexes 4-6 were examined by cyclic voltammetry on platinum in DMSO/TBAP. These complexes displayed one-electron metallophthalocyanine-based and multi-electron hydroxyphenyl-based redox processes. The effect of temperature on the d.c. conductivity and impedance spectra of spin coated films of compounds were investigated at the temperatures between 300-452 K and in the frequency range of 40-105 Hz. Thermally activated conductivity dependence on temperature was observed for all compounds. A.c. results indicated that conduction mechanism can be explained by classical hopping barriers mechanism for all films.