Metallo Phthalocyanines Research Articles

Ball type (4-(tert-butyl)-1,2-phenylene)dimethanolate bridged dinuclear metallo phthalocyanines: Synthesis, characterization, electrochemistry, and in situ spectroelectrochemistry

In this research, cofacial ball type metallo phthalocyanines (MPcs) with a longer bridge, which by adding a –CH2 group to the oxo bridge, were obtained by working the 4,4′-(((4-(tert-butyl)-1,2-phenylene)bis(methylene))bis(oxy))diphthalonitrile beginning complex. Molecular characterizations of the starting compound and dinuclear ball-type MPcs (Co, Fe, Mn, Zn, Ni) obtained from it were made using elemental analysis, 1H-NMR, 13C-NMR, FT-IR, UV–Vis, and MALDI-TOF mass spectroscopy. In addition, how the macromolecule’s spectral, electrochemical, in situ spectroelectrochemical, and electrochromic properties changed was investigated when the phthalocyanine (Pc) rings moved away from each other due to the increasing linking bridge length. The electrochemical properties of ball-type Pcs were investigated via Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV) in the non-aqueous solvent system on a Pt working electrode (WE). In situ spectroelectrochemical measurements also were carried out to support the electrochemical measurements. In situ electrocolorimetric techniques revealed color changes relevant to the redox processes. Electrochemical and spectroelectrochemical measurements showed that ball type metallo-Pcs form steadfast mixed-valence species based on metal and/or Pc ring on account of the fact that there are forceful and striking intramolecular interactions between the two Pc segments. As a result of the cofacial molecular structure of ball type metallo-Pcs and the split molecular orbitals, the complexes have rich redox properties. They can be utilized as a material in electrochemical technologies since they have plentiful redox behaviors. In situ spectroelectrochemical and in situ electrocolorimetric measurements demonstrated that they also have rich spectral and chromatic features. Due to the apparent color and spectral variations, they are appropriate for electrochromic appliances.

Metallophthalocyanine as ideal antibiotics without light: Mechanisms and applications

The urgent global health problem of antimicrobial resistance (AMR) calls for the discovery of new antibiotics with innovative modes of action while considering the low toxicity to mammalian cells. This paper proposes a novel strategy for designing antibiotics with selective bacterial toxicity by exploiting the positional differences of electron transport chains (ETC) in bacterial and mammalian cells. The focus is on cytochrome c (cyt C) and its maturation system in E. coli. The catalytic oxidative activity of metallophthalocyanine (MPc), which have a distinctive M-N4 structure, is being investigated. Unlike previous applications based on light-activated reactive oxygen species (ROS) generation, this study exploits the ability of MPcs to oxidize Fe2+ to Fe3+ in cyt C and catalyze the formation of disulfide bonds between cysteine residues to interfere with cyt C maturation, disrupt the bacterial respiratory chain and selectively kills bacteria. In contrast, in mammalian cells, these MPcs are located in the lysosomes and cannot access the ETC in the mitochondria, thus achieving selective bacterial toxicity. Two MPcs that showed effective antibacterial activity in a wound infection model were identified. This study provides a valuable reference for the design of novel antibiotics based on M-N4-based metal complex molecules.

Transdermal delivery system to release phthalocyanine photosensitizers for the potential treatment of skin cancer with PDT.

This research aims to examine the transdermal release of water-soluble indium and zinc metallo phthalocyanine (InPc and ZnPc) compounds from the poly(vinyl alcohol) (PVA) membrane and the cytotoxicity effect of these Pcs on normal mouse fibroblasts (L929 fibroblast) and human melanoma (SK-MEL-30) cells. For this purpose, the effects of temperature, pH, drug concentration and membrane thickness on transdermal release were investigated in order to obtain the optimum transdermal release profile by preparing PVA membranes with different thicknesses and crosslinked by heat treatment. Optimum drug release was found to be 85.36% using 6 μm thick PVA membrane at 37 ± 0.5 °C, when upper cell pH 1.2 and lower cell pH 5.5, for 3 mg/mL InPc drug concentration. Under the same conditions, the drug release value for ZnPc was found to be 69.78%. In addition, in vitro studies were performed on L929 and SK-MEL-30 cells. under optimized drug (InPc and ZnPc) and membrane conditions. It was found that no significant cytotoxic effect was observed in L929 and SK-MEL-30 cells in the dark. Photodynamic tests were also carried out with InPc and ZnPc. The results show that cell viability decreases in SK-MEL-30 cells at concentrations of 10 μg/mL and above. In addition, while the InPc IC50 value was determined as 4.058 μg/mL, this value was determined as 11.574 μg/mL for ZnPc.

Identification of a Durability Descriptor for Molecular Oxygen Reduction Reaction Catalysts.

The development of durable platinum-group-metal-free oxygen reduction reaction (ORR) catalysts is a key research direction for enabling the wide use of fuel cells. Here, we use a combination of experimental measurements and density functional theory calculations to study the activity and durability of seven iron-based metallophthalocyanine (MPc) ORR catalysts that differ only in the identity of the substituent groups on the MPcs. While the MPcs show similar ORR activity, their durabilities as measured by the current decay half-life differ greatly. We find that the energy difference between the hydrogenated intermediate structure and the final demetalated structure (ΔEdemetalation) of the MPcs is linearly related to the degradation reaction barrier energy. Comparison to the degradation data for the previously studied metallocorrole systems suggested that ΔEdemetalation also serves as a descriptor for the corrole systems and that the high availability of protons at the active site due to the COOH group of the o-corrole decreases the durability.

A3B type asymmetric metallo phthalocyanines bearing carboxylic acid and tert-butyl groups: Photophysical, photochemical and aggregation properties

In this study, A3B type asymmetric magnesium(II), zinc(II) and indium(III)chloro phthalocyanine derivatives bearing carboxylic acid and tert-butyl groups were synthesized and their photochemical, photophysical and aggregation properties for photodynamic therapy (PDT) application were investigated. In the first part of the study; phthalonitriles, which are the starting materials, were synthesized and then different phthalocyanine compounds were obtained from the synthesized phthalonitriles in the second part. The synthesized compounds were characterized using different techniques. At the same time, the photophysical and photochemical properties of the synthesized compounds were also investigated. The calculated singlet oxygen quantum values in DMSO are 0.30 for MgPc, 0.72 for ZnPc, and 0.62 for InPc in and these values in DMF are 0.25 for MgPc, 0.68 for ZnPc, and 0.60 for InPc after photochemical studies. The obtained results proved that the contribution of the substituents increased the therapeutic efficacy. Finally, our results show that all Pc derivatives have displayed desirable singlet oxygen, photodegradation, fluorescence and aggregation properties for PDT studies.

Non-peripheral and peripheral tetrasubstituted metallophthalocyanines having dichlorophenylthio groups as novel biological active materials for antioxidant, DNA cleavage, antimicrobial, and biofilm inhibition activities

We report the preperation of dichlorophenylthio substituted phthalonitrile (2) and its novel non-peripherally tetra sübstituted metallo phthalocyanines {Zn (3), Cu (4) and Mn (5)}. Characterization of newly synthesized compounds was performed by common spectroscopic techniques such as NMR, IR, UV–Vis and mass spectroscopies. The biological properties of the novel non-peripherally dichlorophenylthio substituted Pcs (3–5) and peripherally substituted derivatives (6, 7) were examined for the first time. Comparison of the biological properties of non-peripheral (α- substitution) substituted Pcs with those of peripheral derivatives (β-substution) was made. Among the studied compounds, 3 displayed the highest antioxidant activity as 99.42% at 200 mg/L. DNA cleavage activity of Pcs was also examined and all compounds were found to have DNA cleavage ability. Both peripherally and non-peripherally substituted Pcs showed high antimicrobial activity as tested against pathogenic microorganisms. Microbial cell viability inhibition was also investigated. Additionally, the antimicrobial-photodynamic therapy (APDT) activities of prepared Pcs were performed against Gram-negative bacterium (Escherichia coli) and they exhibited perfect APDT activities as %100. The highest biofilm formation inhibition of S. aureus and P. aeruginosa was 91.28% and 85.74%, respectively, at 250 mg/L with compound 6.

Development and application of metallo-phthalocyanines as potent G-quadruplex DNA binders and photosensitizers

Metallo-phthalocyanines (MPc) are common photosensitizers with ideal photophysical and photochemical properties. Also, these molecules have shown to interact with non-canonical nucleic acid structures, such as G-quadruplexes, and modulate oncogenic expression in cancer cells. Herein, we report the synthesis and characterisation of two metallo-phthalocyanines containing either zinc (ZnPc) or nickel (NiPc) in the central aromatic core and four alkyl ammonium lateral chains. The interaction of both molecules with G-quadruplex DNA was assessed by UV–Vis, fluorescence and FRET melting experiments. Both molecules bind strongly to G-quadruplexes and stabilise these structures, being NiPc the most notable G-quadruplex stabiliser. In addition, the photosensitizing ability of both metal complexes was explored by the evaluation of the singlet oxygen generation and their photoactivation in cells. Only ZnPc showed a high singlet oxygen generation either by direct observation or by indirect evaluation using a DPBF dye. The cellular evaluation showed mainly cytoplasmic localization of ZnPc and a decrease of the IC50 values of the cell viability of ZnPc upon light activation of two orders of magnitude.Graphical abstractTwo metallo-phthalocyanines containing zinc and nickel within the aromatic core have been investigated as G-quadruplex stabilizers and photosensitizers. NiPc shows a high G4 binding but negligible photosensitizing ability while ZnPc exhibits a moderate binding to G-quadruplex together with a high potency to generate singlet oxygen and photocytotoxicity. The interaction with G4s and capacity to be photosensitized is associated with the geometry adopted by the central metal core of the phthalocyanine scaffold.

Novel Series of Peripherally Phthalocyanines (Zn, Pd and Cu): Spectroscopic Studies

Abstract:A new series of metallophthalocyanines (MPc) containing metals such as : Zn (II), Cu (II) and, Pd (II) were designed, synthesized, and characterized, using MS, IR and UV-Vis spectroscopy. A Suzuki cross-coupling reaction was investigated by using the Pd(dppf)Cl2 as a catalyst and cesium carbonate as a base to improve the yield of the precursor 2.6-di(pyridin-3-yl)- phenyl benzyl ether. The changes of metals, substituents, and positions increases the Q-band value from the monosubstituted to the octa-substituted macrocycles, and from Pd, to Cu to Zn complexes. All MPc showed quite similar IR spectra.

Construction of Phthalocyanine-Titanium Dioxide/Graphene/Polyaniline Composite Electrodes by Electrochemical Method for Supercapacitor Applications

Supercapacitors (SCs) are the most interesting alternative energy storage and conversion systems to successfully overcome the global energy problem for future generations. A lot of work has been done to improve the capacitive performance of an electrode and to achieve high power and energy density. Herein, for the first time in the literature, we prepared hybrid composite materials consisting of metallo phthalocyanine doped-titanium dioxide (MPc-TiO2) and high conductivity graphene (Gr) and polyaniline (PANI) in a one-step on pencil graphite electrode (PGE) using the cyclic voltammetry method. The microscopic and structural characteristics of the synthesized MPc-TiO2/Gr/PANI/PGE (M=Cu and Co) are analyzed by various spectroscopic and analytical techniques. As a result, the optimized CoPc-TiO2/Gr/PANI/PGE as the electrode shows a highly specific capacitance of 401.5 F g−1 at 5 A g−1 and excellent cyclic stability up to 1000 cycles. The good electrochemical performance could be attributed to the synergistic effect of the high pseudocapacitance and good conductivity of CoPc-TiO2 as well as the capacitive contribution and conductivity of Gr and PANI. Our strategy provides a new avenue to develop high-performance SCs via rational integration of MPc-TiO2 with Gr and PANI.

Electrochemical and spectroelectrochemical characterizations of phthalocyanines bearing peripherally tetra-4-carboxyethylenephenoxy anchoring groups and usage as photosensitizers of dye-sensitized solar cell

A series of metal-free and metallo phthalocyanines (MPc) peripherally substituted with tetra-4-carboxyethylenephenoxy (M = 2H+ (H2Pc), Co2+ (CoPc), Zn2+ (ZnPc), and TiO2+ (TiOPc)) are used as dyes in the dye-sensitized solar cells (DSSCs). To predict the feasibility of MPcs as photosensitizers, electrochemical and in-situ spectroelectrochemical characterizations are first carried out since their redox mechanisms and optical responses under electrochemical excitations are the key factor for the requirement of the photosensitizers in DSSCs. The redox activities and opto-electrochemical responses of the compounds make them promising dye candidates with electrochemically reversible and multi-electron electron transfer reactions and suitable HOMO-LUMO band positions. The DSSCs using TiO2 film modified with these MPcs are developed and characterized. DSSC analyses indicate that especially H2Pc and TiOPc among the MPcs illustrate better photovoltaic performances than the others. The increase in efficiency of DSSC consisting of H2Pc and TiOPc is mainly associated with their suitable band positions and high electron lifetimes. When compared with the Pc bearing various substituents, ethylenephenoxy linkers between the Pc ring and the carboxyl anchoring groups significantly enhance the push-pull features between the dyes and TiO2 semiconductor, which results in 1.15, 2.98, 3.17 and 3.97 % power conversion efficiencies with CoPc, ZnPc, H2Pc, and TiOPc based DSSCs respectively.

Synthesis, characterization, in vitro cytotoxicity of novel metallo phthalocyanines with four methylpropiophenonyl clusters and their effects on Caenorhabditis elegans thermotolerance

Synthesis, characterization, in vitro cytotoxicity of novel metallo phthalocyanines with four methylpropiophenonyl clusters and their effects on Caenorhabditis elegans thermotolerance

Hybrid materials based on pyrene-substituted metallo phthalocyanines as sensing layers for ammonia detection: Effect of the number of pyrene substituents

In this work, the effect of the number of pyrene substituents in zinc(II) phthalocyanine molecules on the sensor properties of their hybrid materials with single-walled carbon nanotubes (SWCNT) is studied. For this purpose, hybrid materials of SWCNTs modified with five different trioxyethylenethio substituted zinc(II) phthalocyanines containing 0, 1, 2, and 4 methoxypyrene substituents in the phthalocyanine ring were prepared and characterized by Raman spectroscopy, scanning electron microscopy and inductively coupled plasma atomic emission spectrometry. The chemiresistive sensor response of the prepared hybrids toward low concentrations of ammonia (1–100 ppm) was studied to reveal the effect of the number of pyrene substituents in the phthalocyanine ring on the sensor performance of the hybrid materials. It was demonstrated that the hybrids with zinc(II) phthalocyanine bearing four methoxypyrene substituents exhibited the maximal sensor response to ammonia with the limit of detection of 0.4 ppm. The sensitivity of the hybrid materials to ammonia was shown to be much higher than to CO2, H2, H2S, CH4, ethanol, acetone, and dichloromethane vapors, however, an oxidizing gas such as NO2 was an interfering compound in the determination of ammonia. 1 ppm NO2 show the same absolute value of the response than 10 ppm NH3. The quantum-chemical calculations were performed to explain this effect as well as the dependence of the binding energy of substituted zinc(II) phthalocyanines with carbon nanotubes on the number of pyrene substituents.

Improvement in metrological performances of phthalocyanine-based QCM sensors for BTX detection in air through substituent’s effect

Molecular engineering in macrocyclic materials like metallophthalocyanines (MPc) is a powerful strategy to tune the thin film properties that can be relevant to develop high performance gas sensors. In this context, the present work reports the enhancement in BTX sensing properties of MPc-based quartz crystal microbalance (QCM) sensors through exploiting the large surface area of tertiary-butyl (ttb) substituent grafted at the periphery of CuPc. Thin films of CuPc and ttb-CuPc reveal distinct morphologies and microstructures, in which the former presents a locally organized columnar structure, while the latter has an amorphous structure, containing agglomeration of molecular clusters. Such structural variation of the MPc films has huge implications on benzene, toluene and xylenes (BTX) sensing properties of the QCM sensors, utilizing these materials as sensing layers. Responses of ttb-CuPc-based QCM sensor are amplified by ca. 4-times and response time is reduced, compared to CuPc-based sensor. Moreover, ttb-CuPc-based QCM sensor displays high repeatability, resolution better than 20 ppm, negligible hysteresis and high sensitivity with limit of detection to 2 ppm, 1 ppm and 0.7 ppm for benzene, toluene and xylenes, respectively. Such favorable metrological characteristics combined with negligible interference from other gases make this microsensors suitable for BTX detection in real environment at concentrations below the recommended guidelines.

Synthesis, characterization, electrochemical, spectroelectrochemical and dye-sensitized solar cell properties of Phthalocyanines Containing Carboxylic Acid Anchoring Groups as photosensitizer

Peripherally tetra-4-carboxyethylphenoxy substituted oxotitanium (IV), cobalt(II), zinc(II) and metal free phthalocyanines were synthesized to research the sensitizing abilities of these dye molecules in standard dye-sensitized solar cells (DSSCs). All the synthesized phthalocyanine complexes have been characterized by using elemental analyses, UV–Vis, FT-IR, 1H NMR and MALDI-TOF MS spectroscopic techniques. Electrochemistry of metallo phthalocyanines (MPcs) were studied with electrochemical and in-situ spectroelectrochemical measurements. H2Pc (7) and ZnPc (5) illustrated similar Pc based electron transfer reactions. Differently, CoPc (6) and TiOPc (4) illustrated metal based redox reactions, which enhanced the redox functionality of these complexes. Metal based reductions for CoPc (6) and TiOPc (4) were recorded in addition to the Pc based one. In-situ spectroelectrochemical measurements supported the proposed voltametric mechanism. Moreover, the color and spectra of the electrogenerated species were determined with the in-situ spectroelectrochemical analyses to predict possible optoelectrochemical application of the complexes. Pronounced optical and color changes during the electrolysis of the complexes indicated electrooptical and possible solid state electrochemical functionality of the complexes. TiO2 semiconductor on the fluoride doped indium tin oxide coated glass electrode (FTO) was decorated with H2Pc (7) and TiOPc (4) bearing four carboxyl anchoring groups and they were first of all tested as possible dye for the DSSC. H2Pc (7), TiOPc (4), CoPc (6) and ZnPc (5) dyes used in DSSCs showed 2.9%, 3.3%, 1.02% and 2.2% of power conversion efficiencies respectively.

Organic steep-slope nano-FETs: A rational design based on two-dimensional covalent-organic frameworks

We report a strategy to design organic steep-slope nanoscale field-effect transistors (nano-FETs) with subthreshold swing (SS) breaking the thermionic limit of 60 mV/dec at room temperature. The devices are based on a family of two-dimensional (2D) covalent-organic frameworks (COFs) with a square lattice and building blocks of metallophthalocyanine (MPc). Our first-principles calculations reveal that lattice mismatch-free metal/semiconductor monolayer heterojunctions, which serve as both electrodes and channel of the devices, can be obtained by modulating monolayer 2D MPc-COFs with suitable MPc. The cold-source mechanism and the interplay between electrodes and channel are of critical importance for realizing doping-free organic steep-slope nano-FETs, of which the SS can reach as small as 37.2 mV/dec at 300 K. Our findings offer a route to overcome the “Boltzmann tyranny” in low-power nanoelectronic devices by rational design of organic 2D materials, which are much more diverse and flexible in material design than their inorganic counterparts. • Organic nano-FETs with subthreshold swing breaking the thermionic limit of 60 mV/dec at room temperature were proposed. • The devices are based on two-dimensional covalent-organic frameworks of metallophthalocyanine. • The cold-source mechanism and the interplay between electrodes and channel are the underlying mechanism for the devices.

Non-covalent functionalization of single walled carbon nanotubes with Fe-/Co-porphyrin and Co-phthalocyanine for field-effect transistor applications

This work reports the non-covalent functionalization of SWNTs with Fe-porphyrin, Co-porphyrin and Co-phthalocyanine molecules. The functionalized SWNTs were first characterized using Raman and X-ray photoelectron spectroscopies. Observations down to nanoscale resolution were also performed by atomic force microscopy, as well as scanning and transmission electron microscopies. The spectroscopic methods evidenced an electronic interaction between the metal-centered molecules and the SWNTs, ensuring the robustness of the functionalization. High resolution microscopy characterizations reveal that the porphyrin and phthalocyanine molecules are adsorbed on the surface of SWNTs. The electrical characterizations show a weak charge transfer between those grafted molecules and the SWNTs, confirming the electronic interaction between the molecules and the SWNTs. Density functional theory (DFT) supports experimental data and helps understanding the experimental results of selective interaction of metal complexes with one type of semiconducting SWNTs. • The non-covalent assembly of metalloporphyrin (MPo) and metallophthalocyanines (MPc) onto CNTFETs. • These molecules strongly bind to the side walls of SWNTs via physi-adsorption and п-п interactions. • The theoretical study evidences that the molecules are electron donors and the SWNTs are n-doped. • The electrical measurements showed a charge transfer between the metal-centered molecules and SWNTs.

Tuning the Electrical and Thermoelectric Properties of Phthalocyanine and Metallo-Phthalocyanine Molecular Junction

In this work, a comparative study is presented that analyses the electrical and thermoelectrical properties of free base-Phthalocyanine (Bare-Pc) and Metallo-Phthalocyanine (MPc) molecule sandwiched between gold electrodes. The study investigates the transmission and conductance characteristics of Bare-Pc without central metal ion and with different transition metal ions at the centre of (Pc) such as (Mn, Co, Ni, and Zn) in two different molecular configurations, cis and trans. The results reveal that the conductance changed by varying the transition metal-centre in the order of Co > Ni > Zn in trans, and closely similar pattern Co > Ni > Mn in cis with higher values in trans configuration. This reflects the correlation between the spin-dependent transport properties with the transition metal-centre type and the molecular structure. Further, thermoelectrical properties such as thermal conductance (k), Seebeck coefficient (S) and figure of merit (ZT) are investigated. It was found that (k), (S) and (ZT) have higher values in case of trans configuration for Co-Pc, Ni-Pc and Zn-Pc structures. Thus, by varying the transition metal-centre type and the molecular configuration of (Pc) molecule, transport properties can be tuned to produce a good value of the transmission and electrical conductance, thermal conductance, Seebeck coefficient, and figure of merit of the (Pc) molecular junction for potential high conductance and efficient thermoelectric applications.

Photocatalytic Efficiency of Metallo Phthalocyanine Sensitized TiO2 (MPc/TiO2) Nanocomposites for Cr(VI) and Antibiotic Amoxicillin

Dye sensitization on semiconductor catalyst TiO2 was performed with four different metallophthalocyanine (MPc) derivates (M: Zn, Cu, Co, and Si) using a modified sol-gel method. MPc derivatives were loaded on TiO2 at 1% mass ratio aiming to increase its photocatalytic action and to shift the light absorption to higher UV region (365 nm). Non-ionic surfactant Triton X-100 (TX-100) was used to obtain a homogenous and mesa pore catalyst structure. The prepared catalysts were characterized by FT-IR, XRD, and SEM to determine the crystal and surface structural properties of nanocomposites. The nanocomposites were used for photocatalytic removal and degradation of Cr(VI) and amoxicillin (AMX) as model pollutants. Photocatalytic reduction capacities of the catalysts were tested for Cr(VI) (10 mg/L) and AMX (20 mg/L) aqueous solutions. ZnPc-TiO2 catalyst was successful for Cr(VI) photoreduction since all Cr(VI) ions in the solution were successfully removed. Presence of TX-100 in the sol-gel synthesis of ZnPc-TiO2 had a positive effect by increasing the Cr(VI) removal rate to 97.93% after 150 min exposure period. Prepared catalysts were also tested for photodegradation of AMX, applying similar procedures. In general, all catalysts exhibited low degradation rates under the studied condition but more effective with 254 nm UV light (50.38%). Neither surface modification with TX-100 nor MPc sensitization provided significant degradation of AMX.

Design, synthesis of novel peripherally tetra-chalcone substituted phthalocyanines and their inhibitory effects on acetylcholinesterase and carbonic anhydrases (hCA I and II)

In this work, phthalocyanine precursor (3), tetra-chalcone substituted metal-free (4) and metallo phthalocyanines (5, 6, 7) were synthesized for the first time and surveyed interactions against acetylcholinesterase (AChE, which are associated with Alzheimer's disease) and human CA isoenzymes I and II (hCA I and hCA II, which are ubiquitous cytosolic isoforms). The structures of the novel phthalonitrile (3) and phthalocyanines (4-7) were designated by FT-IR, NMR, UV-Vis, and mass spectroscopy. These phthalocyanines inhibited hCA I with inhibition constants in the range of 0.5621-0.6413 μM and hCA II with inhibition constants in the range of 0.4823-0.6117 μM. On the other hand, these phthalocyanines indicated notable inhibitory effect against AChE.

Sulfur bridged new metal-free and metallo phthalocyanines carrying 1,2,4-triazole rings and their photophysicochemical properties

The novel metal-free (4) zinc(II) (5) and lead(II) (6) phthalocyanines containing 1,2,4-triazole groups connected to the phthalocyanine ring by S-bridge were synthesized and characterized. For this purpose, the original 2-(4-chlorobenzoyl)-N-(4-fluorophenyl)hydrazinecarbothioamide (1) was synthesized as a result of the reaction of 4-chlorobenzyl hydrazide and 4-fluorophenyl isothiocyanate. It was obtained 5-(4-chlorophenyl)-4-(4-fluorophenyl)-4H-1,2,4-triazole-3-thiol (2), which is a new compound by the ring closure reaction of 1. The other original compound 4-[5-(4-chlorophenyl)-4-(4-fluorophenyl)-4H-[1,2,4]triazol-3-yl sulfanyl]-phthalonitrile (3) was synthesized by the nucleophilic aromatic substitution reaction of 4-nitrophthalonitrile and compound 2. Starting from the new phthalonitrile (3), the metal-free (4), zinc(II) (5) and lead(II) (6) phthalocyanines (Pcs) were prepared. Six new compounds were synthesized, and their structures were characterized by elemental analysis and 1H NMR, 13C NMR, FT-IR, MALDI-TOF MS and UV–vis spectral data in this work. The photophysical and photochemical properties of the synthesized phthalocyanines were investigated for determination of their usability as photosensitizers (PS) for photodynamic therapy (PDT) applications.© 2021 Elsevier Ltd. All rights reserved.