Metallophthalocyanine Complexes Research Articles

Inducing ring distortions in unsubstituted metallophthalocyanines using axial N-heterocyclic carbenes.

A series of metallophthalocyanine (PcM) complexes with axial N-heterocyclic carbene ligands (NHC; 1,3-diisopropylimidazol-2-ylidene (DIP) and 1,3-dimethylbenzimidazol-2-ylidene (DMB)) were prepared and structurally characterized. PcCoII(DIP), PcZnII(DIP), and PcZnII(DMB) are five-coordinate complexes with mild dome-type Pc-ring distortions, while PcFeII(DIP)2 is six-coordinate and has a very large ruffle-type ring-distortion with respect to typical PcM(L)2 systems. The distortion is induced by the highly steric axial DIP ligands. The distortions were quantified and classified by their bond lengths and torsion angles, and according to the normal-coordinate structural decomposition (NSD) analysis. Upon ligation of the NHC, the insoluble PcM materials were solublized in common organic solvents, with typical UV-visible Q-band maxima observable between 658 and 677 nm; the increased solubility is rationalized in terms of the reduced solid-state aggregation of the complexes, attributable to the axial ligation.

Electrochemical and In-situ spectroelectrochemical properties of novel mononuclear 2,4-di-tert-butyl-6-(3,4-dicyanophenoxy)phenolate substituted metallophthalocyanine compounds

In this study, the synthesis and characterization of a series of novel tetra substituted highly soluble metallophthalocyanines [M = CoII, FeIII, MnIII, NiII and ZnII] derivatives bearing 2,4-di-tert-butyl-6-(3,4-dicyanophenoxy)phenolate groups on the peripheral positions are reported. These phthalocyanine (Pc) compounds can be used as new starting materials for the synthesis of dinuclear ball-type Pcs due to the involvement of four phthalonitrile rings as closable end groups in their molecules. The assignment of the redox processes of these compounds indicated that CoII, FeIII, and MnIII centers into the Pc core increased the redox richness of the complexes, with the addition of metal-based electron transfer processes to the ring-based ones while NiPc and ZnPc show only ring-based electron transfer processes. These ball-type Pc precursor compounds exhibited a unique character also as a result of eight redox-active nitrile end groups on the peripheral tails of the Pc core. Thus, electrochemical and spectroelectrochemical properties of metallophthalocyanine complexes were analysed, also in comparison to their previously reported (5-(tert-butyl)-2-((3,4-dicyanophenoxy)methyl)phenyl)methanolate substituted analogues to determine the influence of metal centers and substituents in the periphery. Altering the metal center of the Pc ring as incorporation of a redox active metal center and changing the positions of the substituents slightly affected the potentials for nitrile and Pc ring redox processes. However, the spectral and color responses of the complexes were significantly influenced by the nature of central metal and peripheral substituents. As an important reflection, the electron transfer processes of the complexes and the connection between the electrochemically generated anionic and cationic species originated distinct spectral and color changes, identified with in-situ spectroelectrochemical measurements in solution medium. These measurements pointed out their potential applicability in the fields of the opto electronic technologies.

Some characteristics of new and innovative COX inhibitor derivatives: Potent hCA‐I and hCA‐II inhibitors supported by molecular docking studies

AbstractIn this study, two novel metallophthalocyanines (ZnPc and CoPc) were synthesized using the corresponding metal salts 4‐(4‐(4‐[4‐chlorophenyl]‐5‐methylisoxazol‐3‐yl)phenoxy)‐phthalonitrile (11), prepared from the reaction of 4‐nitrophthalonitrile and 4‐(4‐[4‐chlorophenyl]‐5‐methylisoxazol‐3‐yl)phenol (9). These metallophthalocyanines (MPcs) showed quite solubility in organic solvents such as dichloromethane (DCM), tetrahydrofuran (THF), dimethyl formamide (DMF), and dimethylsulfoxide (DMSO). The novel compounds 11a and 11b have been characterized using their UV–Vis, FT–IR, 1H NMR, 13C NMR, X‐Ray, and MALDI–TOF mass spectra. Supporting information cocerning with the study has been supplied. Photochemical, photophysical, and cyclic voltagram properties of these novel 4‐(4‐(4‐[4‐chlorophenyl]‐5‐methylisoxazol‐3‐yl)phenoxy substituted metallophthalocyanines (11a and 11b) were determined in DMF. DNA binding, metal chelating effect assay, and DPPH [2,2‐diphenyl‐1‐picrylhydrazyl hydrate] radical scavenging assay and electrochemical studies of MPcs were investigated. Further, the inhibitory effects of the COX‐inhibitor based novel metallophthalocyanines (11a and 11b) and their ligands (10 and 11) were examined on human erythrocyte carbonic anhydrase I (hCA‐I) and II (hCA‐II) isoenzymes, and the synthesized molecules exhibited very strong inhibitory effects on both isoforms. In addition, the hCA‐I and hCA‐II inhibition potential of Zn (II) and Co (II) Phthalocyanine complexes was supported by molecular docking studies. The binding interaction of metallophthalocyanines complexes 11a, 11b enzymes were analyzed in detail.

Spectroscopic, electrochemical and optical properties of non-peripherally (2,2-dimethyl-1,3-dioxolan-4-yl)methoxy groups substituted metal-free and metallophthalocyanines

Metal-free and metallophthalocyanine complexes (M = 2H, InCl, or MnCl) containing (2,2-dimethyl-1,3-dioxolan-4-yl)methoxy groups were synthesized and characterized. The electrochemical properties of the phthalocyanine complexes were investigated by cyclic and square wave voltammetry. Metal-free and indium phthalocyanines give ring-based oxidation and reduction processes, while manganese phthalocyanine gives both metal and ring-based redox processes. Thin films of phthalocyanines were prepared by spin coating technique. The films were investigated as a function of the different metal ions in the inner core, with the transmittance spectrum measured at a wavelength range of 200–1000 nm. The results show that type of metal ions in the phthalocyanine core clearly change the transmittance values of the thin films of phthalocyanine complexes. Surface morphologies of the films were characterized by scanning electron microscopy. It has been observed that metal-free films form a more continuous and non-porous structure, while InPc and MnPc films have a porous surface.

The use of new metallophthalocyanines carrying peripherally 4-methyl-N-(3-morpholinopropyl)benzenesulfonamide moieties for the sensitive fluorimetric determination of banned food dye Sudan II in red chili peppers

The structural elucidation and syntheses methods of new peripherally tetra-substituted MPcs [CuII(6), CoII(7), MnCIIII(8), and NiII(9) phthalocyanines] carrying 4-methyl-N-(3-morpholinopropyl)benzenesulfonamide moieties were reported in the present study. The corroboration of the prepared compounds (3, 5, and 6 to 9) was made by LC–TOF/MS, UV–Vis, Fourier Infrared, 1H NMR, 13C NMR, and MALDI–TOF mass spectral data. Herein, we submit a new procedure that uses metallophthalocyanine complexes for the first time as spectrofluorimetric agents to detect and determine health-threatening food additive, Sudan II dye, with a new simpler, cheaper, and faster spectrofluorimetric method instead of time-consuming and expensive HPLC processes. Furthermore, the sensitivities of the proposed methods are good enough to determine the amount of dye at a concentration of 0.1 mg/L. The methods have LOD values between 0.035 and 0.050 mg/L. The linear ranges are found to be between 0 and 8.3 mg/L. The precision of the methods is determined to be between 1.1 and 2.4 as % RSD. Therefore, this study would make a good contribution to the food industry and phthalocyanine chemistry by detecting and determining the hazardous food colorant Sudan II with metal phthalocyanines.

Computational DFT calculations, photovoltaic properties and synthesis of (2R, 3S)-2, 3, 4-trihydroxybutoxy substituted phthalocyanines

In this study, 4-((2R, 3S)-2, 3, 4-trihydroxybutoxy) phthalonitrile was synthesized and characterized as starting material. This new starting material reacts with cobalt and copper metal salts to obtain metallophthalocyanine complexes. The electronic absorption of cobalt and copper phthalocyanine compounds in different concentrations of THF was investigated. In addition, the solubility and absorption of the compounds in different solvents were investigated. Density functional theory was also performed to support the relevant experimental results of the synthesized copper and cobalt center atomic compound. The photovoltaic performance of compounds was measured as current density–voltage (J–V).

Synthesis, electrochemical and spectroelectrochemical properties of novel soluble peripheral tetra triazole substituted CoII, CuII, MnIIICl and TiIVO phthalocyanines

This paper reports the synthesis, electrochemical and spectroelectrochemical properties of peripherally tetra-substituted metallophthalocyanines (M = CoII, CuII, MnIIICl and TiIVO) which contain 4-(3,4-dimethoxyphenethyl)-5-ethyl-2H-1,2,4-triazol-3(4H)-one. The precursor phthalonitrile compound (3) for the phthalocyanine formation was synthesized in the first step. Subsequently, related metallophthalocyanine complexes of cobalt(II) (3-Co), copper(II) (3-Cu), manganese(III) (3-Mn) and oxo-titanium(IV) (3-Ti) were synthesized. The characterization of all these compounds was accomplished using prevalent spectroscopic techniques. Electrochemical characterization of the metallophthalocyanines (MPcs) bearing redox active Co2+ and Mn3+ metal centers, in addition to the redox inactive Cu2+ ion, were performed to investigate the effects of electron transfer reactions from the metal center on the redox features of the Pc ring. While the CuPc (3-Cu) illustrated three Pc based reduction reactions and one Pc based oxidation reaction, incorporation of redox active Co2+ and Mn3+ metal centers instead of Cu2+ increased the redox richness of the complexes, with additional metal based reduction and oxidation reactions. While the CoPc (3-Co) gave one metal-based reduction and one metal based oxidation reaction, in addition to the redox processes of Pc ring, the MnClPc (3-Mn) gave to two metal-based reduction reactions. All the redox processes had almost chemically and electrochemically reversible character, except those observed at the solvent windows. An in situ spectroelectrochemistry technique was used for the assignment of the redox couples and to determine the optical responses of the electrogenerated species.

Optical and Morphological Properties of New Metallophthalocyanines with Hydroxyethylsulfanyl Substituents

Metallophthalocyanine complexes (M = Pd, FeCl, VO, or MnCl) bearing four hydroxyl-terminated aliphatic groups were prepared by cyclotetramerization 4-(hydroxyethylsulfanyl)phthalonitrile. Aggregation tendencies of these phthalocyanines were investigated in varying concentrations from 4 × 10–5 to 8 × 10–6 M in DMF. Spin coating method was used to prepare thin films of metallophthalocyanines substituted with four hydroxyethylsulfanyl groups. The optical properties of the films were investigated as a function of the different metal ions in the inner core, with the transmittance spectrum measured at a wavelength range of 200–1000 nm. The results show that different metal ions in the inner core clearly change the transmittance values of the thin films of metallophthalocyanine. Morphological results also show that surface of the metallophthalocyanines has changed considerably according to the nature of the metal ion.

Preparation of New Biologically Active and Water Soluble Dyes: Characterization, Aggregation and Extraction of Metal Ions from Solutions

The synthesis of metallo-phthalocyanines complexes (M = Co, Ni, Cu, Zn) containing azo dye were described in this study. The metallophthalocyanines have been supported by elemental analysis, UV-visible, FT-IR and NMR. The aggregation of phthalocyanine compounds was investigated in different solvents and concentrations. The newly synthesized metallophthalocyanines possess modest antibacterial activity against various Gram-positive and Gram-negative bacteria. Moreover, these complexes have been tested as antioxidant and presented remarkable activities by two different in vitro chemical assays. They were able to reduce DPPH % radical with IC50 values ranging from 3.8 to 7.5 μmol L-1 and some of them also reduced ABTS % radical cation.

Aminopyrazole-substituted metallophthalocyanines: Preparation, aggregation behavior, and investigation of metabolic enzymes inhibition properties.

The synthesis, characterization, aggregation behavior, theoretical studies, and investigation of antimicrobial, antidiabetic, and anticholinergic properties of 4-(2-(5-amino-4-(4-bromophenyl)-3-methyl-1H-pyrazol-1-yl)ethoxy)phthalonitrile (2) and its soluble aminopyrazole-substituted peripheral metallo (Mn, Co, and Ni)-phthalocyanine complexes (3-5) are reported for the first time. The synthesized compounds and phthalocyanine complexes were characterized spectroscopically. The new phthalonitrile derivative (2) and its peripheral metallophthalocyanine complexes (3-5) were found to be effective inhibitors of α-glycosidase, acetylcholinesterase (AChE), human carbonic anhydrase I and II isoforms (hCA I and II), and butyrylcholinesterase (BChE) with Ki values in the range of 1.55 ± 0.47 to 10.85 ± 3.43 nM for α-glycosidase, 8.44 ± 0.32 to 21.31 ± 7.91 nM for hCA I, 11.73 ± 2.82 to 31.03 ± 4.81 nM for hCA II, 101.62 ± 26.58 to 326.54 ± 89.67 nM for AChE, and 68.68 ± 11.15 to 109.53 ± 19.55 nM for BChE. This is the first study of peripherally substituted phthalocyanines containing an aminopyrazole group as potential carbonic anhydrase enzyme inhibitor. Also, the antimicrobial activities of the synthesized compounds were evaluated against six microorganisms (four bacteria and two Candida species) using the broth microdilution method. The gram-positive bacteria were detected to be more sensitive than gram-negative bacteria and yeasts in the synthesized compounds.

Study of interaction of CoPcF16 within poly 4-vinylpyridine matrix using UV/Vis spectroscopy

Metallophthalocyanine (MPc) complexes based on abundant transition metals has greatly interest as catalyst due to their attractive features including a rich redox behaviour, the potential to bind with metals or non-metals in the central cavity. Among the transiton metal, cobalt complexes as electrocatalyst are preferable due to their efficient catalytic activity. Immobilisation of the catalyst onto surface may improve with the poly 4-vinylpyridine (P4VP) as polymer backbone. However, aggreagation of MPc is the challenge to overcome. This study aims to investigate the interaction behaviour of cobalt(II) hexadecfluorophthalocyanine (CoPcF16) within poly 4-inylpyridine (P4VP) using UV/Vis spectroscopy. Two solutions of CoPcF16 and P4VP were mixed and the interaction of CoPcF16-P4VP was observed through the time using UV/Vis spectroscopy at wavelength 500 to 750 nm. The outcome suggests that coordination of the electrocatalysts is favoured by the comportment of a high concentration of 4VP. Subsequently, this CoPcF16-P4VP electrocatalyst has a potential for water splitting or hydrogen evolution.

Catalytic selectivity of metallophthalocyanines for electrochemical nitric oxide sensing

The catalytic properties of metallophthalocyanine (MPc) complexes have long been applied to electrochemical sensing of nitric oxide (NO) to amplify sensitivity and reduce the substantial overpotential required for NO oxidation. The latter point has significant ramifications for in situ amperometric detection, as large working potentials oxidize biological interferents (e.g., nitrite, l-ascorbate, and carbon monoxide). Herein, we sought to isolate and quantify, for the first time, the selectivity benefits of MPc modification of glassy carbon electrodes. A series of the most catalytically active MPc complexes towards NO, including Fe(II)Pc, Co(II)Pc, Ni(II)Pc, and Zn(II)Pc, was selected and probed for NO sensing ability under both differential pulse voltammetry (DPV) and constant potential amperometry (CPA). Data from DPV measurements provided information with respect to MPc signal sensitivity amplification (∼1.5×) and peak shifting (100–200 mV). Iron-Pc exerted the most specific catalytic activity towards NO over nitrite. Catalyst-enabled reduction of the working potential under CPA was found to improve selectivity for NO over high potential interferents, regardless of MPc. However, impaired selectivity against low potential interferents was also noted.

New peripherally tetra-[trans-3,7-dimethyl-2,6-octadien-1-ol] substituted metallophthalocyanines: synthesis, characterization and catalytic activity studies on the oxidation of phenolic compounds

In this paper, we elucidated the synthesis, characterization, and investigation of catalytic activity studies of new metallophthalocyanines 4 and 5 as the catalyst for phenolic compounds oxidation by trying different types of oxygen sources. The structural characterization of the products was made by a combination of elemental analysis, FT-IR, LC-MS/MS (for phthalonitrile derivative 3), MALDI-TOF mass spectral data (for metallophthalocyanines 4–7), UV–vis spectroscopy (for metallophthalocyanines 4–7), 1H NMR and 13C NMR spectroscopies (for compounds 3 and 6). The synthetic routes for the (trans-3,7-dimethyl-2,6-octadien-1-ol) substituted phthalonitrile derivative 3 and corresponding metallophthalocyanines 4–7 are outlined in Scheme 1. The MPc complexes 4–7 were synthesized via cyclotetramerization of compound 3 in the presence of the corresponding anhydrous metal salts (CoCl2 for 4, CuCl2 for 5, Zn(CH3COO)2 for 6 and MnCl2 for 7) in dry n-pentanol as solvent and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as strong base at reflux temperature under nitrogen gas. Phthalocyanines and their metal complexes, in general, display poor solubility in most of the organic solvents, however, the synthesized metallophthalocyanine complexes 4–7 were highly soluble in common organic solvents because of the introduction of the methyl groups on alkyl chains of peripheral arms. The catalytic activity of compounds 4 and 5 was evaluated for the oxidation of phenolic compounds such as 4-nitrophenol, o-chlorophenol, 2,3-dichlorophenol, and p-methoxyphenol. CoPc 4 displayed good catalytic performance with a full oxidation of 4-nitrophenol into the corresponding benzoquinone and hydroquinone with the highest TON and TOF values within 3 h.

Synthesis and antioxidant, aggregation, and electronic properties of 6-tert-butyl-1,4-benzodioxine substituted phthalocyanines

As a starting material, 7-tert-butyldibenzo [b,e] [1,4] dioxine-2,3-dicarbonitrile was prepared by the reac- tion of 4-tert-butylcatechol with 4,5-dichlorophthalonitrile. Metallophthalocyanine complexes 4-7 were obtained by cyclotetramerization of 7-tert-butyldibenzo [b,e] [1,4] dioxine-2,3-dicarbonitrile. All compounds were characterized by elemental analysis and other spectroscopic methods (IR, UV/Vis, and $^{1}$H NMR). Phthalocyanine compounds remained nonaggregated in tetrahydrofuran at the studied concentration ranges. Metallophthalocyanines 4-7 were tested for their antioxidant activities. The antioxidant activity processes included evaluation of radical-scavenging activity, chelat- ing activity, and reducing power. These compounds were compared to standard antioxidant ascorbic acid. The electronic data of the new compounds were obtained by computational calculations at the B3LYP/6-31G (d,p) level of theory.

Comparative studies of photophysical and electrochemical properties of sulfur-containing substituted metal-free and metallophthalocyanines

The synthesis, photophysical and electrochemical properties of soluble sulfur-containing 4-(methylthio) benzenethiol substituted, non-peripherally metal-free and metallo (Zn, Ga, Co, and Mn) phthalocyanine complexes (2–6) are reported for the first time. The new phthalocyanines have been characterized by FT-IR spectroscopy, 1H-NMR, 13C-NMR, mass and UV–Vis spectroscopy techniques. Spectroscopic properties of these compounds were investigated in different solvents. Spectral and photophysical (fluorescence quantum yield) properties of metal free (2), zinc(II) (3), and gallium(III) phthalocyanines (4) were reported in different solvents toluene, tetrahydrofuran, and dimethyl sulfoxide. These results suggest that the solvents play role on the fluorescence quantum yields Φ F of the synthesized complexes (2–4). The electrochemical studies exhibit that while complexes (3) and (4) give only Pc ring-based redox processes, complexes (5) and (6) give both metal and ring-based redox reactions due to the energy level of metal in the Pc core lie between the HOMO and the LUMO of the ring.

Novel dopant-free metallophthalocyanines based hole transporting materials for perovskite solar cells: The effect of core metal on photovoltaic performance

Abstract Two novel asymmetric metallophthalocyanines with different metal core (2,9,16-triphenoxy-23-nitrophthalocyaninatozinc, ZnPcNO 2 -OPh and 2,9,16-triphenoxy-23-nitrophthalocyaninatocopper, CuPcNO 2 -OPh) are synthesized and employed as hole transporting materials (HTMs) for perovskite ((FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 ) solar cells (PSCs), reaching high power conversion efficiency ( PCE ). Both of the two metallophthalocyanines show particular solubility, absorption, thermal stability and suitable energy levels. Results confirm that the photovoltaic performance is strongly influenced by the core metals. The optimized devices based on ZnPcNO 2 -OPh exhibit a maximum power conversion efficiency ( PCE ) of 14.35% with a high open-circuit voltage ( V OC ) of 1.071 V under standard global 100 mW cm −2 AM 1.5G illumination, while devices based on CuPcNO 2 -OPh show a lower PCE of 12.72% with a V OC of 1.064 V. This newly developed perovskite solar cells demonstrated dramatically enhanced durability under ambient atmosphere. This study provides a promising prospect for an alternative approach based on the highly stable asymmetric metallophthalocyanine complexes to enhance the stability of perovskite solar cells.

Synthesis, characterization and investigation of electrochemical and spectroelectrochemical properties of peripherally tetra 4-phenylthiazole-2-thiol substituted metal-free, zinc(II), copper(II) and cobalt(II) phthalocyanines

In this study novel peripherally tetra 4-phenylthiazole-2-thiol substituted metal-free phthalocyanine (4) and its zinc(II) (5), copper(II) (6) and cobalt(II) (7) derivatives were synthesized and characterized by a combination of various spectroscopic techniques such as FT-IR, 1H-NMR, UV–vis and MALDI-TOF mass. Electrochemical characterizations of metallo-phthalocyanine complexes were conducted by voltammetric and in situ spectroelectrochemical measurements. CoIIPc went [CoIIPc−2]/[CoIPc−2]1-, [CoIPc−2]1-/[CoIPc−3]2-, [CoIPc−3]2-/[CoIPc−4]3- and [CoIIPc−2]/[CoIIPc−2]1+ reduction and oxidation processes respectively. Differently ZnIIPc only showed four ligand-based reductions and two ligand based oxidation processes.

Quantitative methylene blue decolourisation assays as rapid screening tools for assessing the efficiency of catalytic reactions

Identifying the most efficient oxidation process to achieve maximum removal of a target pollutant compound forms the subject of much research. There exists a need to develop rapid screening tools to support research in this area. In this work we report on the development of a quantitative assay as a means for identifying catalysts capable of decolourising methylene blue through the generation of oxidising species from hydrogen peroxide. Here, a previously described methylene blue test strip method was repurposed as a quantitative, aqueous-based spectrophotometric assay. From amongst a selection of metal salts and metallophthalocyanine complexes, monitoring of the decolourisation of the cationic dye methylene blue (via Fenton-like and non-Fenton oxidation reactions) by the assay identified the following to be suitable oxidation catalysts: CuSO4 (a Fenton-like catalyst), iron(II)phthalocyanine (a non-Fenton oxidation catalyst), as well as manganese(II) phthalocyanine. The applicability of the method was examined for the removal of bisphenol A (BPA), as measured by HPLC, during parallel oxidation experiments. The order of catalytic activity was identified as FePc > MnPc > CuSO4 for both BPA and MB. The quantitative MB decolourisation assay may offer a rapid method for screening a wide range of potential catalysts for oxidation processes.

Topological phases of metallophthalocyanine complexes

The presence of edge dissipationless currents generated by the emergence of molecular Frenkel excitons in metallophthalocyanine complexes in a constant magnetic field increases the fluorescence intensity for such samples. The consequences of the Frenkel exciton model are discussed from the viewpoint of the observables, which have applications in novel molecular spintronics.

Substituted phthalocyanines and their electropolymerization properties

In this study, new metal-free and metallo-phthalocyanine complexes (Co, TiO) were synthesized using a piperazine-substituted phthalonitrile derivative. All proposed structures were supported by instrumental methods. Electrochemical studies of H2-Pc, TiIVOPc, and CoIIPc were examined using cyclic voltammetry (CV) and square-wave voltammetry (SWV) techniques. Voltammetric analyses of phthalocyanines supported the proposed structure of the synthesized complexes. All studied phthalocyanines were oxidatively electropolymerized on the working electrode during the repetitive anodic potential scans.