Electronic Spectral and Electrochemical Behavior of Near Infrared Absorbing Metallophthalocyanines

Spectroscopic and photophysicochemical properties of zinc(II) phthalocyanine substituted with benzenesulfonamide units containing schiff base

In this study, compounds (E)-4-((5-bromo-2-hydroxy-3-methoxybenzylidene)amino)-N-(pyridin-2-yl)benzenesul-fonamide 1, (E)-4-((5-bromo-2-(3,4-dicyanophenoxy)-3-methoxybenzylidene)amino)-N-(pyridin-2-yl)benzenesulfonamide 2 and, complex 2(3),9(10),16(17),23(24)-tetra-[(E)-4-((5-bromo-3-methoxy-2-(λ 1-oxidanyl)benzylidene)amino)-N-(pyridine-2-yl)benzenesulfonamide]phthalocyaninato zinc(II) 3 were synthesized for the first time. Their structures (1 –3) were characterized by spectroscopic methods such as FTIR, 1H NMR,13C NMR, UV–vis, MALDI-TOF mass spectra and elemental analysis. The spectroscopic, aggregation, photophysical and photochemical properties of zinc(II) phthalocyanine 3 in dimethyl sulfoxide were investigated and the effects on the above-mentioned properties were reported as a result of the presence of benzenesulfonamide derivatives containing different bioactive groups, in their peripheral positions. In addition, its above-mentioned properties were also reported by comparing different species with those of their substituted and/or unsubstituted counterparts. The zinc(II) phthalocyanine 3 can be a potential photosensitizer candidate in photodynamic therapy, which is an effective alternative therapy in cancer treatment, due to its good solubility in commonly known solvents and monomeric species, as well as its adequate and favorable fluorescence, singlet oxygen production and photostability.

Amphiphilic Cationic Phthalocyanines for Photodynamic Therapy of Cancer

Effective interaction with biomembranes is essential for activity of photosensitizers; however, majority of them are highly charged symmetrical species. Amphiphilic cationic phthalocyanines differing in bulkiness of substitution on lipophilic part (-H, -SMe, -StBu) were therefore prepared. Compounds had high singlet oxygen production (ΦΔ =0.38-0.46, DMSO), good fluorescence emission (ΦF =0.21-0.26, DMSO), and log P values ranging -0.07-1.1 (1-octanol/PBS). Study of interaction with liposomes revealed that also bulky -StBu derivatives are able to enter biomembranes. Detail in vitro studies (toxicity, subcellular localization, type of cell death, and morphology) were performed. Compounds were characterized by excellent EC50 values in range of dozens of nM (HeLa, EA.hy926, MCF-7, HCT116), which were dependent on drug-light interval and reached plateau after 4 h on HeLa cells. Well-balanced lipophilicity with ability to interact with biomembranes rank these derivatives among perspective photosensitizers, even for vascular-targeted PDT (VTP) since they kill EA.hy926 without any preincubation time.

Tyrosinase-Based Biosensor-A New Tool for Chlorogenic Acid Detection in Nutraceutical Formulations

The purpose of our research was to develop a new enzymatic biosensor, GPH-MnPc-Tyr/SPE, using as a support screen-printed carbon electrode (SPE) modified with graphene, manganese phthalocyanine, and tyrosinase, with the aim of developing sensitive detection of chlorogenic acid (CGA). To immobilise tyrosinase on the sensor surface, crosslinking with the glutaraldehyde technique was used, thus increasing the enzyme bioactivity on this electrode. The modified electrode has a great catalytic effect on the electrochemical redox of chlorogenic acid, compared to the simple, unmodified SPE. The peak current response of the biosensor for CGA was linear in the range of 0.1-10.48 μM, obtaining a calibration curve using cyclic voltammetry (CV) and square-wave voltammetry (SWV). Subsequently, the detection limit (LOD) and the quantification limit (LOQ) were determined, obtaining low values, i.e., LOD = 1.40 × 10^-6 M; LOQ = 4.69 × 10^-6 M by cyclic voltammetry and LOD = 2.32 × 10^-7 M; LOQ = 7.74 × 10^-7 M, by square-wave voltammetry (SWV). These results demonstrate that the method is suitable for the detection of CGA in nutraceutical formulations. Therefore, GPH-MnPc-Tyr/SPE was used for the quantitative determination of CGA in three products, by means of cyclic voltammetry. The Folin-Ciocalteu spectrophotometric assay was used for the validation of the results, obtaining a good correlation between the voltammetric method and the spectrophotometric one, at a confidence level of 95%. Moreover, by means of the DPPH method, the antioxidant activity of the compound was determined, thus demonstrating the antioxidant effect of CGA in all nutraceuticals studied.

Synthesis of peripheral and non-peripheral substituted metallophthalocyanines containing (E)-3-(5-bromo-2-hydroxphenyl)-1-o-tolyprop-2-en-1-one: Investigation of the photophysical and photochemical properties

In this study, the novel peripherally (5-7) and non-peripherally (9-11) metallo (zinc, magnesium and lead) phthalocyanine derivatives were synthesized from their (E)-4-(4-bromo-2-(3-oxo-3-o-tolyprop-1-enyl)phenoxy) substituted phthalonitrile precursors (4 and 8). These novel phthalocyanine derivatives including chalcone groups were characterized by spectroscopic techniques such as FT-IR, UV-vis, ¹H NMR, ¹³C NMR and MALDI-TOF mass spectra. In the next stage, the photophysical and photochemical properties of synthesized compounds were searched in DMSO which is not cause toxic effects at a certain concentration in biological applications. As a result of investigations, it was determined that phthalocyanine complexes did not demonstrate aggregation in DMSO solutions.

Electrodeposited Benzothiazole Phthalocyanines for Corrosion Inhibition of Aluminium in Acidic Medium

Tetrakis[(benzo[d]thiazol-2-yl-thio) phthalocyaninato] gallium(III)chloride (1) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. The aim of this study was to compare the corrosion resistance of electrodeposited metallated phthalocyanines. Scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy (EIS), and polarization confirmed the aluminium corrosion inhibition potentials of complexes 1 and 2. EIS and polarization techniques showed that complex 2 performed better than complex 1, with values from EIS measurements of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution. The importance of electrodeposition in industries and a dearth of research on the use of electrodeposited metallated phthalocyanines necessitated this study, and results show that coatings formed by electrodeposition of 1 and 2 onto aluminium reduced its susceptibility to corrosion attack.

Applications of Photoinduced Phenomena in Supramolecularly Arranged Phthalocyanine Derivatives: A Perspective

This review focuses on the description of several examples of supramolecular assemblies of phthalocyanine derivatives differently functionalized and interfaced with diverse kinds of chemical species for photo-induced phenomena applications. In fact, the role of different substituents was investigated in order to tune peculiar aggregates formation as well as, with the same aim, the possibility to interface these derivatives with other molecular species, as electron donor and acceptor, carbon allotropes, cyclodextrins, protein cages, drugs. Phthalocyanine photo-physical features are indeed really interesting and appealing but need to be preserved and optimized. Here, we highlight that the supramolecular approach is a versatile method to build up very complex and functional architectures. Further, the possibility to minimize the organization energy and to facilitate the spontaneous assembly of the molecules, in numerous examples, has been demonstrated to be more useful and performing than the covalent approach.

Octa-substituted metallophthalocyanines bearing (2,3-dihydrobenzo-1,4-benzodioxin-2-yl)methoxy and chloro groups: Synthesis, characterization and photophysicochemical studies

In this study, the synthesis and characterization of novel 4-chloro-5-((2,3-dihydrobenzo-1,4-benzodioxin-2-yl)methoxy)phthalonitrile (1) and its peripherally octa-substituted Zn(II) (Pc-Zn), In(III) (PcInCI) and Mg(II) (Pc-Mg) phthalocyanine (Pc) derivatives are reported for the first time. FT-IR, elemental analysis, UV-vis, NMR and MS techniques were used for characterization studies of the compounds. Aggregation properties of the compounds were evaluated in DMF, DMSO and THF solvents in different concentrations, and the compounds did not tend to aggregate in these solvents. In addition, photophysicochemical properties such as fluorescence, photodegradation and singlet oxygen quantum yield of the compounds were examined in DMSO, DMF and THF solvents to show the potential use of these novel compounds as photosensitizers for photodynamic therapy (PDT). The effects of zinc, indium and magnesium metals, octa substitutions in peripheral positions and different types of solvents on photophysicochemical properties were investigated. The singlet oxygen quantum yield values of compounds ranged from 0.27 to 0.77 in different solvents. As a result of the photophysicochemical properties, these compounds can be considered as potential candidates for PDT, applications.

The peripheral and non-peripheral 2H-benzotriazole substituted phthalocyanines: Synthesis, characterization, photophysical and photochemical studies of zinc derivatives

In this study, the novel 3-(1H-benzo[d][1,2,3]triazol-1-yl)methoxy substituted novel phthalonitrile compounds (2 and 6) were synthesized. Their non-peripheral and peripheral zinc (II) (3 and 7), manganese (III) (4 and 8) and copper (II) (5 and 9) phthalocyanine complexes were synthesized for the first time. These novel compounds were characterized by elemental analysis and different spectroscopic techniques such as FT-IR, UV-Vis, ¹H NMR, ¹³C NMR and MALDI-TOF mass. Also, photochemical and photophysical properties of non-peripheral and peripheral substituted zinc (II) phthalocyanines (3 and 7) were investigated for determination of photodynamic therapy applications of these phthalocyanines.

Recent advances in chemistry of phthalocyanines bearing electron-withdrawing halogen, nitro and N-substituted imide functional groups and prospects for their practical application

Herein, we present an overview of the approaches for the synthesis of phthalocyanines bearing electron-withdrawing halogen-, nitro- and N-substituted imide functional groups in different positions of the phthalocyanine macrocycle.

Novel phenyl-substituted pyrazinoporphyrazine complexes of rare-earth elements: optimized synthetic protocols and physicochemical properties

Novel synthetic protocols based on both template and direct methods were developed for phenyl-substituted pyrazinoporphyrazine complexes of rare-earth elements.

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

Manganese phthalocyanine (MnPc) is a member of the family of transition-metal phthalocyanines, which combines interesting electronic behavior in the fields of organic and molecular electronics with local magnetic moments. MnPc is characterized by hybrid states between the Mn 3d orbitals and the π orbitals of the ligand very close to the Fermi level. This causes particular physical properties, different from those of the other phthalocyanines, such as a rather small ionization potential, a small band gap and a large electron affinity. These can be exploited to prepare particular compounds and interfaces with appropriate partners, which are characterized by a charge transfer from or to MnPc. We summarize recent spectroscopic and theoretical results that have been achieved in this regard.

Photophysical and nonlinear optical study of benzothiazole substituted phthalocyanines in solution and thin films

In this study, the photophysical, nonlinear absorption and nonlinear optical limiting properties of zinc and gallium phthalocyanine complexes: tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato]zinc(II) (3), tetrakis[(benzo[d]thiazol-2-yl phenoxy)phthalocyaninato] gallium(III) chloride (4), tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] zinc(II) (5), tetrakis[(benzo[d]thiazol-2-ylthio)phthalocyaninato] gallium(III) chloride (6), were investigated both in solution and when embedded in polystyrene thin films using 532 nm laser excitation at 10 ns pulses. It was also observed that complexes that have higher triplet state absorption also possessed enhanced nonlinear and optical limiting behavior. Superior optical performance was observed when the complexes were embedded in thin films compared to when they are in solution. Complex 6 in thin films gave the highest imaginary third-order susceptibility (I[Formula: see text][X[Formula: see text]]) and hyperpolarizability ([Formula: see text] at 4.61 × 10[Formula: see text] esu and 3.44 × 10[Formula: see text] esu, respectively, with a low I[Formula: see text] value of 0.06 J.cm[Formula: see text]

Phthalocyanine Doped Metal Oxide Nanoparticles on Multiwalled Carbon Nanotubes Platform for the detection of Dopamine

The electrocatalytic properties of metal oxides (MO = Fe₃O₄, ZnO) nanoparticles doped phthalocyanine (Pc) and functionalized MWCNTs, decorated on glassy carbon electrode (GCE) was investigated. Successful synthesis of the metal oxide nanoparticles and the MO/Pc/MWCNT composite were confirmed using UV-Vis, EDX, XRD and TEM techniques. Successful modification of GCE with the MO and their composite was also confirmed using cyclic voltammetry (CV) technique. GCE-MWCNT/ZnO/29H,31H-Pc was the best electrode towards DA detection with very low detection limit (0.75 μM) which compared favourably with literature, good sensitivity (1.45 μA/μM), resistance to electrode fouling, and excellent ability to detect DA without interference from AA signal. Electrocatalytic oxidation of DA on GCE-MWCNT/ZnO/29H,31H-Pc electrode was diffusion controlled but characterized with some adsorption of electro-oxidation reaction intermediates products. The fabricated sensors are easy to prepare, cost effective and can be applied for real sample analysis of dopamine in drug composition. The good electrocatalytic properties of 29H,31H-Pc and 2,3-Nc were related to their (quantum chemically derived) frontier molecular orbital energies and global electronegativities. The better performance of 29H,31H-Pc than 2,3-Nc in aiding electrochemical oxidation of DA might be due to its better electron accepting ability, which is inferred from its lower E_LUMO and higher χ.

One-pot three-component Biginelli-type reaction to synthesize 3,4-dihydropyrimidine-2-(1H)-ones catalyzed by Co phthalocyanines: Synthesis, characterization, aggregation behavior and antibacterial activity

The synthesis of a novel phthalonitrile derivative with pyridine-2-thiol and 2,4,6-trimethylphenylamine substituents functionalized groups and its peripherally tetrasubstituted cobalt phthalocyanine and cationic phthalocyanines complexes were reported. The aggregation investigations carried out in different concentrations indicate that Co Phthalocyanines compounds 3,4 do not have any aggregation behavior for the concentration range of 6×10(-4)-14×10(-6)M in DMSO. The ion binding properties of Co Phthalocyanines compounds 3,4 show the formation of stable complex with Co(2+). In addition 3,4-Dihydropyrimidin-2(1H)-one derivatives were synthesized by modified Biginelli cyclocondensation reaction catalyzed by MPc as Lewis base. The structures of the synthesized compounds have been successfully characterized by the spectroscopic methods (IR, (1)H NMR, (13C)NMR, UV-Vis, mass spectrometry, elemental analysis and NMR 2D). The influence of substrate/catalyst ratio, solvent was also investigated to find optimal reaction on this synthesis for getting the highest conversion. Different parameters were examined for finding optimal conditions of catalysis. In addition; the compounds 3-11 were investigated for antimicrobial activity. Most of them exhibited important antimicrobial activity.