Singlet Oxygen Quantum Yield Values Research Articles

Photodynamic antibacterial chemotherapy activities of P(V) and Ga(III) triarylcorroles and their silver nanoparticle conjugates

Silver nanoparticle (AgNP) conjugates of two series of P(V) and Ga(III) corroles with 4-thiomethylphenyl- (1-PVCor-AgNPs and 1-GaIIICor-AgNPs), thien-3-yl- (2-PVCor-AgNPs and 2-GaIIICor-AgNPs), thien-2-yl- (3-PVCor-AgNPs and 3-GaIIICor-AgNPs) and 5-bromothien-2-yl- (4-PVCor-AgNPs and 4-GaIIICor-AgNPs) meso-aryl rings have been synthesized and characterized, so that their in vitro photodynamic antimicrobial chemotherapy (PACT) properties could be investigated against S. aureus and E. coli. The 4-PVCor and 4-GaIIICor complexes are reported for the first time in this context, while 1-3-PVCorr and 1-3-GaIIICor were reported previously during a study of the photodynamic therapy (PDT) activity properties of their gold nanoparticle conjugates against MCF-7 breast cancer cells. The heavy atom effects of the bromine atoms result in increases in the singlet oxygen quantum yield values for 4-PVCor and 4-GaIIICor to 0.59 and 0.72, respectively, from 0.47 and 0.69 for 3-PVCor and 3-GaIIICor. Conjugation to the AgNPs results in further slight increases due to an external heavy atom effect and significantly enhances the photostability of the dyes. 1-4-PVCor were found to have higher PACT activities than 1-4-GaIIICor due to lower aggregation effects since there is trans-axial ligation. Complete eradication of the E. coli and a Log[Formula: see text] reduction of 7.04 was achieved with 20μg.mL[Formula: see text] of 3-4-PVCor-AgNPs and 3-4-GaIIICor-AgNPs despite the difficulties that are typically encountered in this context with Gram-([Formula: see text] bacteria.

The photophysical, photobiological, and DNA/HSA-binding properties of corroles containing carbazole and phenothiazine moieties

This study characterized four corrole derivatives, namely Cbz-Cor, MetCbz-Cor, PTz-Cor, and PTzEt-Cor, examining their photophysical, electrochemical, photobiological, and biomolecule-binding properties. Experimental photophysical data of absorption and emission elements correlated with a theoretical analysis obtained through time-dependent density functional theory (TD-DFT). As for the photophysical properties, we observed lower fluorescence quantum yields and discernible differences between the excited and ground states, as indicated by Stokes shift values. Natural Transition Orbit (NTO) plots presented high occupied molecular orbital - low unoccupied molecular orbital (HOMO-LUMO) densities around the tetrapyrrolic macrocycle in all examples. Our findings demonstrate that corroles maintain stability in solution and offer photostability (<20 %), predominantly in DMSO(5 %)/Tris-HCl (pH 7.4) buffer solution. Furthermore, the singlet oxygen (1O2) quantum yield and log POW values underscore their potential application in photoinactivation approaches, as these corroles serve as effective ROS generators with more lipophilic features. We also evaluated their biomolecular binding capacity towards salmon sperm DNA and human serum albumin using spectroscopic techniques and molecular docking analysis for sustenance. Concerning biomolecule interaction profiles, the corrole derivatives showed a propensity for interacting in the minor grooves of the double helix DNA due to secondary forces, which were more pronounced in site III of the human serum protein.

The photodynamic activity properties of a series of structurally analogous tetraarylporphyrin, chlorin and N-confused porphyrin dyes and their Sn(IV) complexes

A series of tetraarylporphyrin, -chlorin and N-confused porphyrin dyes with 4‑methoxy‑meso-aryl rings (1-Por, 1-Chl and 1-NCP) and their Sn(IV) complexes (1-SnPor, 1-SnChl and 1-SnNCP) have been synthesized and characterized. The heavy atom effect of the Sn(IV) ion results in relatively high singlet oxygen quantum yield values of 0.67, 0.71 and 0.85 for 1-SnPor, 1-SnChl and 1-SnNCP, respectively. The photodynamic activities of 1-Por, 1-Chl, 1-NCP, 1-SnPor, 1-SnChl and 1-SnNCP were determined against MCF-7 breast cancer cells through illumination with Thorlabs 625 or 660 nm (240 or 280 mW.cm−2) light emitting diodes (LEDs) for 20 min. The IC50 values for 1-SnChl and 1-SnNCP lie between 1.4 − 6.1 and 1.6 − 4.8 µM upon photoirradiation with the 660 and 625 nm LEDs, respectively, while higher values of >10 µM were obtained for 1-SnPor and the free base dyes. In a similar manner, 1-SnChl and 1-SnNCP were found to also have significantly higher photodynamic antimicrobial activity against planktonic Gram-(+) Staphylococcus aureus and Gram-(−) Escherichia coli bacteria than the other dyes studied. Upon illumination with Thorlabs 625 and 660 nm LEDs for 75 min, Log10 reduction values of 7.62 and > 2.40−3.69 were obtained with 1 and 5 µM solutions, respectively.

Cobalt(III) dibromo-BODIPY-8-hydroxyquinolinate for mitochondria-targeted red light photodynamic therapy

The photophysical properties of boron-dipyrromethene (BODIPY) dyes have made them suitable for cellular imaging and photodynamic therapy (PDT). The efficacy of these dyes can be augmented by designing their dibromo/diiodo derivatives. Heteroleptic Co(III) complexes of a tetradentate N,N,N,O-donor polypyridyl phenolate (HL) and bidentate N,O-donor 8-hydroxyquinoline (HL1) and its BODIPY (HL2) or dibromo-BODIPY (HL3) pendants, [CoIII(L)(L1−3)]X (1–3) (where X = ClO4 for 1, 2 and Cl for 3) were synthesized and studied. The dibromo-BODIPY ligand HL3 was structurally characterized. The dibromo-BODIPY complex 3, showing singlet oxygen quantum yield (ϕΔ) value of ∼0.25, displayed remarkable apoptotic photo-cytotoxicity in HeLa cancer cells upon red light (600–720 nm) irradiation giving half-maximal inhibitory concentration (IC50) value of 0.36 μM (photocytotoxicity index: >277). It was less toxic in normal cells. Cellular imaging studies revealed mitochondrial colocalization. This work exemplifies Co(III)–dibromo-BODIPY complex as a new class of metal-based PDT agent with higher efficacy than the dyes alone.

Exploring anticancer properties of novel Nano-Formulation of BODIPY Compound, Photophysicochemical, in vitro and in silico evaluations

A new BODIPY complex (C4) composed of meso- thienyl-pyridine substituted core unit diiodinated from 2- and 6- positions and distyryl moieties at 3- and 5- positions is synthesized. Nano-sized formulation of C4 is prepared by single emulsion method using poly(ε-caprolactone)(PCL) polymer. Encapsulation efficiency and loading capacity values of C4 loaded PCL nanoparticles (C4@PCL-NPs) are calculated and in vitro release profile of C4 is determined. The cytotoxicity and anti-cancer activity are conducted on the L929 and MCF-7 cell lines. Cellular uptake study is performed and interaction between C4@PCL-NPs and MCF-7 cell line is investigated. Anti-cancer activity of C4 is predicted with molecular docking studies and the inhibition property on EGFR, ERα, PR and mTOR are investigated for its anticancer properties. Molecular interactions, binding positions and docking score energies between C4 and EGFR, ERα, PR and mTOR targets are revealed using in silico methods. The druglikeness and pharmacokinetic properties of C4 are evaluated using the SwissADME and its bioavailability and toxicity profiles are assessed using the SwissADME, preADMET and pkCSM servers. In conclusion, the potential use of C4 as an anti-cancer agent is evaluated in vitro and in silico methods. Also, photophysicochemical properties are studied to investigate the potential of using Photodynamic Therapy (PDT). In photochemical studies, the calculated singlet oxygen quantum yield (ΦΔ) value was 0.73 for C4 and in photopysical studies, the calculated fluorescence quantum yield ΦF value was 0.19 for C4.

The Photodynamic Anticancer and Antibacterial Activity Properties of a Series of meso-Tetraarylchlorin Dyes and Their Sn(IV) Complexes.

A series of tetraarylchlorins with 3-methoxy-, 4-hydroxy- and 3-methoxy-4-hydroxyphenyl meso-aryl rings (1-3-Chl) and their Sn(IV) complexes (1-3-SnChl) were synthesized and characterized so that their potential utility as photosensitizer dyes for use in photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT) can be assessed. The photophysicochemical properties of the dyes were assessed prior to in vitro PDT activity studies against MCF-7 breast cancer cells through irradiation with Thorlabs 625 or 660 nm LED for 20 min (240 or 280 mW·cm-2). PACT activity studies were performed against both planktonic bacteria and biofilms of Gram-(+) S. aureus and Gram-(-) E. coli upon irradiation with Thorlabs 625 and 660 nm LEDs for 75 min. The heavy atom effect of the Sn(IV) ion results in relatively high singlet oxygen quantum yield values of 0.69-0.71 for 1-3-SnChl. Relatively low IC50 values between 1.1-4.1 and 3.8-9.4 µM were obtained for the 1-3-SnChl series with the Thorlabs 660 and 625 nm LEDs, respectively, during the PDT activity studies. 1-3-SnChl were also found to exhibit significant PACT activity against planktonic S. aureus and E. coli with Log10 reduction values of 7.65 and >3.0, respectively. The results demonstrate that the Sn(IV) complexes of tetraarylchlorins merit further in depth study as photosensitizers in biomedical applications.

Combination of Light and Ultrasound: Exploring Sono–Photochemical Activities of Phthalocyanine-Based Sensitizers

Recently, there has been increasing interest in photodynamic therapy (PDT) compared to traditional methods (immunotherapy, surgery, chemotherapy, or radiotherapy) in the treatment of cancer. Also, sonodynamic therapy (SDT) is a non-invasive therapeutic modality that enables high tissue penetration by triggered ultrasound (US). Phthalocyanines (Pcs) are known as one of the most important classes of sensitizers used in PDT and SDT. Motivated by these facts, in this study, to assess potentials for sono-PDT (SPDT), the preparation of peripherally substituted metal-free (2), zinc (3), and indium (4) Pcs was completed by 3-methoxybenzyloxy substituents. The resulting compounds were characterized by applying spectroscopic techniques including 1H NMR, FT-IR, UV–vis, and MS. In sono–photochemical studies, the calculated singlet oxygen quantum yield (ΦΔ) values were 0.68 for ZnPc (3) and 0.83 for InPc (4) after light irradiation; these values increased to 0.81 for 3 and 0.94 for 4 after combination US and light irradiation. The obtained data proved that the singlet oxygen production increased considerably by changing the method from light irradiation to US/light. This research will enrich the literature on increasing singlet oxygen production by the SPDT method. Theoretical calculations based on density functional theory (DFT) give further explanations of the optical and (photo)chemical processes behind the singlet oxygen generation. Our calculations are able to provide the energy of the excited states with excellent agreement with the experimental results, and they also allow us to understand and predict the activity of these Pcs based on their excited states and a clear enhancement of the spin–orbit coupling (SOC) when a metal center is included in the Pcs. This work thus exploits new insights into the advanced sono-photodynamic properties of potential sensitizers for efficient SPDT applications.

Lysosome directed red light photodynamic therapy using glycosylated iron-(III) conjugates of boron-dipyrromethene

To overcome the drawbacks associated with chemotherapeutic and porphyrin-based photodynamic therapy (PDT) agents, the use of BODIPY (boron-dipyrromethene) scaffold has gained prominence in designing a new generation of photosensitizers-cum-cellular imaging agents. However, their poor cell permeability and limited solubility in aqueous medium inhibits the in-vitro application of their organic form. This necessitates the development of metal-BODIPY conjugates with improved physiological stability and enhanced therapeutic efficacy. We have designed two iron(III)-BODIPY conjugates, [Fe(L1/2)(L3)Cl] derived from benzyl-dipicolylamine and its glycosylated analogue along with a BODIPY-tagged catecholate. The complexes showed intense absorption bands (ε ∼ 55,000 M−1 cm−1) and demonstrated apoptotic PDT activity upon red-light irradiation (30 J/cm2, 600–720 nm). The complex with singlet oxygen quantum yield value of ∼0.34 gave sub-micromolar IC50 (half-maximal inhibitory concentration) value (∼0.08 μM) in both HeLa and H1299 cancer cells with a photocytotoxicity index value of >1200. Both the complexes were found to have significantly lower cytotoxic effects in non-cancerous HPL1D (human peripheral lung epithelial) cells. Singlet oxygen was determined to be the prime reactive oxygen species (ROS) responsible for cell damage from pUC19 DNA photo-cleavage studies, 1,3-diphenylisobenzofuran and SOSG (Singlet Oxygen Sensor Green) assays. Cellular imaging studies showed excellent fluorescence from complex 2 within 4 h, with localization in lysosomes. Significant drug accumulation into the core of 3D multicellular tumor spheroids was observed within 8 h from intense in-vitro emission. The complexes exemplify iron-based targeted PDT agents and show promising results as potential transition metal-based drugs for ROS mediated red light photocytotoxicity with low dosage requirement.

Phenalenone derivatives: The voyage from photosensitizers to push-pull fluorescent molecules

Phenalenone and several phenalenone derivatives have the remarkable capacity to produce singlet oxygen (1O2), via photosensitization, with singlet oxygen quantum yield values close to unity in most solvents. Considerable efforts have been made to obtain phenalenones that red-shifted their absorption but maintaining the high capacity of generation of singlet oxygen.The presence of electron donors on specific positions of the aromatic ring promotes important changes. Herein, with the presence of a dimethylamino substituent in position 3 or 6, we were able to modulate singlet oxygen generation capacity and fluorescence. Both, 3DMAPNF and 6DMAPNF show red-shifted absorption (compared with phenalenone) associated with ππ* transitions. Solvent effect in absorption and emission properties were observed for 6DMAPNF, while that for 3DMAPNF no fluorescence response was observed. Both, show a decrease in singlet oxygen quantum yield with polarity of solvent, always with 3DMAPNF singlet oxygen quantum yield values greater than for 6DMAPN. No singlet oxygen generation was observed for both compounds in H2O.

Participation of fractional charge transfer on the efficiency of singlet oxygen production: Heteroleptic ruthenium (II) bipyridine derivatives

The photophysical properties of some synthesized heteroleptic polypyridyl ruthenium(II) complexes of the form [Ru(bpy)2L](PF6)2 where L = 2,2′-bipyridine, 4,4′-dimethoxy-2,2′-bipyridine, 1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine, 4,7-diphenyl-1,10-phenanthroline and 3,4,7,8-tetramethyl-1,10-phenanthroline, are investigated in acetonitrile. The excited state lifetime of the metal to ligand charge transfer (3MLCT) states of these complex ions are found to be ligand dependent and were found to be in the range 0.56 μs to 1.5 μs. Oxygen quenching of the excited states rate constants, kq, were found to be in the range 1.50–2.24 × 109 M−1s−1. Singlet oxygen quantum yield values, ΦΔ, are found to vary from 0.40 to 0.60 and the efficiency, fΔT, with which excited singlet oxygen, O2 (1Δg), is thereby produced was found to be in the range 0.55–0.85. Treatment of the data with charge transfer and non-charge transfer pathways using Schmidt’s model shows that partial charge transfer parameter was in the range of 0.18 to 0.58. It has also been found that fΔT decreases and oxygen quenching rate constants, kq, increases as pCT increases.

Photodynamic Antitumor and Antimicrobial Activities of Free-Base Tetra(4-methylthiolphenyl)chlorin and Its Tin(IV) Complex.

Meso-tetra(4-methylthiolphenyl)chlorin (3) and its Sn(IV) complex (3-Sn) have been synthesized and characterized. The heavy atom effects of the Sn(IV) ion and sulfur atoms result in relatively high singlet oxygen quantum yield values of 0.40 and 0.48. The photodynamic activities against MCF-7 breast cancer cells were determined through irradiation with a Thorlabs 660 nm LED for 30 min (280 mW.cm-2 ). IC50 values of 7.8 and 3.9 μM were obtained, respectively. 3-Sn was found to have significant photodynamic antimicrobial activity against both gram-(+) S. aureus and gram-(-) E. coli bacteria upon irradiation with a Thorlabs 660 nm LED for 75 min.

Red light active Pt(iv)-BODIPY prodrug as a mitochondria and endoplasmic reticulum targeted chemo-PDT agent.

A cisplatin-based platinum(iv) prodrug, [Pt(NH3)2Cl2(OH)(L 1 )], having L 1 as a red-light active boron-dipyrromethene (BODIPY) pendant, was synthesized and characterized and its application as a chemo-cum-photodynamic therapy agent was studied. Me-L 1 as the ligand precursor is structurally characterized. The complex displayed an intense absorption band near 650 nm (ε ∼ 8.8 × 104 dm3 mol-1 cm-1) in 1 : 1 (v/v) DMSO/DPBS. It showed an emission band at 674 nm (λ ex = 630 nm) with a fluorescence quantum yield (Φ F) value of 0.37. In red light (600-720 nm), it generated singlet oxygen as evidenced from the 1,3-diphenylisobenzofuran (DPBF) titration experiment giving a singlet oxygen quantum yield (Φ Δ) value of 0.28 in DMSO. The mechanistic pUC19 DNA photocleavage study and singlet oxygen sensor green (SOSG) assay ascertained its ability to generate singlet oxygen in both extracellular and intracellular media by a type-II photo-process. The complex exhibited high stability in the dark, but on red-light irradiation, it displayed rapid activation in the presence of a reducing environment. It displayed remarkable apoptotic photocytotoxicity with half-maximal inhibitory concentration (IC50) ranging from 0.58 to 0.76 μM in human cervical cancer (HeLa) and breast cancer (MCF-7) cells with a respective photo-cytotoxicity index value of >172 and >131. The photodynamic activity was significantly less in non-cancerous human peripheral lung epithelial (HPL1D) cells. The emissive complex showed localization in the mitochondria and endoplasmic reticulum (ER) with a similar Pearson's correlation coefficient value, making it a dual organelle-targeted therapeutic agent. JC-1, fluo-4-AM and annexin V-FITC/propidium iodide assays in HeLa cells showed cellular apoptosis by arresting cells in the sub-G1 phase via mitochondrial dysfunction and ER stress.

BODIPY-Ruthenium(II) Bis-Terpyridine Complexes for Cellular Imaging and Type-I/-II Photodynamic Therapy.

A series of multichromophoric ruthenium(II) complexes with the formulation [Ru(tpy-BODIPY)(tpy-R)]Cl2 (1-4), having a heteroleptic Ru(II)-bis-tpy (tpy = 4'-phenyl-2,2':6',2″-terpyridine) moiety covalently linked to a boron-dipyrromethene (BODIPY) pendant, have been prepared and characterized and their application as a phototherapeutic and photodetection agent in cancer therapy has been explored. Ligand L1 with a terpyridine-BODIPY moiety and complex 1 as its PF6 salt (1a) have been structurally characterized by a single-crystal X-ray diffraction study. Complex 1a has a distorted-octahedral RuN6 core with a Ru(II)-bis-terpyridine unit that is covalently linked to one photoactive BODIPY unit. The complexes exhibit strong absorbance near 502 nm (ε ≈ (3.7-7.8) × 104 M-1 cm-1) and high singlet oxygen sensitization ability, giving singlet oxygen quantum yield (ΦΔ) values ranging from 0.57 to 0.75 in DMSO. An emission-based study using complex 4 and Singlet Oxygen Sensor Green (SOSG) displays the formation of singlet oxygen inside the cells and also in the buffer medium upon light irradiation. DNA (pUC19) photocleavage experiments using ROS scavengers/stabilizers reveal photoinduced generation of singlet oxygen by a type-II process and of the superoxide anion radical by a type-I process. Complex 4 having a pendant biotin moiety as a cancer cell targeting group shows high photocytotoxicity with a remarkable phototherapeutic index (PI) value of >1400 in HeLa cancer cells with a low light dose activation (400-700 nm, 2.2 J cm-2). The complexes display reduced activity in noncancerous HPL1D cells. The emission property of the complexes is used for cellular imaging, thus making them suitable as next-generation theranostic PDT agents.

Monocyclometalated (C N) Gold(III) Metallacycles: Tunable Emission and Singlet Oxygen (1 O2 ) Generation Properties.

The synthesis, characterization and photoluminescent properties of four cyclometalated (C N)-type gold(III) complexes bearing a bidentate diacetylide ligand, tolan-2,2'-diacetylide (tda), are reported. The complexes exhibit highly tunable excited state properties and show photoluminescence (PL) across the entire visible spectrum from sky-blue (λPL =493 nm) to red (λPL =675 nm) with absolute PL quantum yields (PLQY) of up to 75 % in solution, the highest PLQY found for any monocyclometalated Au(III) complex in solution. As a consequence of the use of the strongly rigidifying diacetylide bidentate ligand, a significant increase in the excited state lifetimes (τ0 =16-258 μs) was found in solution and in thin films. The complexes showed remarkable singlet oxygen generation in aerated solution with absolute singlet oxygen quantum yield (ϕ1Δ ) values reaching up to 7.5×10-5 and singlet oxygen lifetimes (τ0 1Δ ) in the range of 66-95 μs. Furthermore, the radiative and non-radiative rates of singlet oxygen were determined using the ϕ1Δ and τ0 1Δ values and correlations are drawn between the formation of singlet oxygen and its interaction with cyclometalated (C N) gold(III) complexes.

Unveiling the photophysical, biomolecule binding and photo-oxidative capacity of novel Ru(II)-polypyridyl corroles: A multipronged approach

Two fluorinated corrole derivatives, namely H3MebpyCor and RuMebpyCor, were synthesized and characterized in terms of their photophysical, electrochemical, and photooxidation behavior. Their biomolecular binding capacity toward Human Serum Albumin (HSA) and calf thymus DNA (CT-DNA) was also evaluated. The experimental data were correlated with theoretical analysis via Time Dependent Density Functional Theory (TDDFT) and Molecular Docking calculations. We found an extremely low fluorescence quantum yield for both corroles dissolved in acetonitrile (CH3CN) and dimethyl sulfoxide (DMSO), which suggests a relaxation pathway through nonradiative processes, such as internal conversion. However, the internal conversion channel in RuMebpyCor competes with the energy transfer to the Ru(II) moiety, placing triplet state formation as a second mechanism of relaxation for this structure. Both corroles showed no aggregation and good photostability. The singlet oxygen (1O2) quantum yield (ΦΔ) values also highlight their potential application in photoinactivation approaches. Theoretical analysis suggests that the introduction of Ru(II) ion coordinated in the bipyridyl unit significantly alters the optically induced electronic transitions, and that the solvents play an important role in defining the optical spectra of the two corroles. Additionally, they interact spontaneously and moderate to strong via ground-state association (static process) with HSA and CT-DNA. However, for the HSA binding assays the dynamic fluorescence quenching mechanism can also occur at high corrole concentrations. Finally, in silico calculations suggest that the main binding region into CT-DNA is the minor groove, while subdomain IIA (site I) is the main binding region for HSA:H3MebpyCor (experimental proportion 1:1) and both subdomains IIA and IB (sites I and III, respectively) for HSA:RuMebpyCor (experimental proportion 1:2).

Dual-purpose both peripheral and non-peripheral triazole substituted ZnII, MgII and PbII phthalocyanines: Synthesis, characterization, photophysicochemical and acetylcholinesterase inhibitory properties

Both peripheral and non-peripheral 4-(3,4-dimethoxyphenethyl)-5-ethyl-2H-1,2,4-triazol-3(4H)-one substituted zinc(II), magnesium(II) and lead(II) phthalocyanines were synthesized in this paper. Techniques used to illuminate the structure of these phthalocyanines included FT-IR, MALDI TOF, UV–Vis, NMR spectroscopy. The ZnIIPcs (p/np-ZnPcs), MgIIPcs (p/np-MgPcs) and PbIIPcs (p/np-PbPcs) exhibited outstanding solubility in common organic solvents such as 1,4-Dioxane, acetonitrile, chloroform, dichloromethane, dimethylformamide, dimethylsulphoxide, ethyl acetate and tetrahydrofurane. The photophysicochemical properties of ZnIIPcs, MgIIPcs and PbIIPcs were researched in DMSO. The positions of the substituents (peripheral or non-peripheral) and the effects of the central metal ions (Zn2+, Mg2+, Pb2+) on the photophysicochemical properties were reported by comparison. The singlet oxygen quantum yield values of ZnIIPcs, MgIIPcs and PbIIPcs ranged from 0.11 to 0.78 in DMSO. The newly synthesized peripherally tetra substituted zinc(II) phthalocyanine (p-ZnPc) exhibited high singlet oxygen generation in DMSO compared to unsubstituted zinc(II) phthalocyanine used as standard. These results indicate that the (p-ZnPc) can be a candidate as photosensitizer for PDT. Besides, the inhibitory properties of the compounds were determined using the spectrophotometric method on AChE and α-glucosidase. IC50 values showed that np-MgPc has highest inhibitory actions among the tested compounds on AChE and α-glucosidase.

In Vitro Anti-Leishmanial Effect of Metallic Meso-Substituted Porphyrin Derivatives against Leishmania braziliensis and Leishmania panamensis Promastigotes Properties.

In this study, a family of porphyrins based on 5,10,15,20-Tetrakis(4-ethylphenyl)porphyrin (1, Ph) and six metallo-derivatives (Zn2+(2, Ph-Zn), Sn4+(3, Ph-Sn), Mn2+ (4, Ph-Mn), Ni2+ (5, Ph-Ni), Al3+ (6, Ph-Al), and V3+ (7, Ph-V)) were tested as photosensitizers for photodynamic therapy against Leishmania braziliensis and panamensis. The singlet oxygen quantum yield value (ΦΔ) for (1–7) was measured using 1,3-diphenylisobenzofuran (DPBF) as a singlet oxygen trapping agent and 5,10,15,20-(tetraphenyl)-porphyrin (H2TPP) as a reference standard; besides, parasite viability was estimated by the MTT assay. After metal insertion into the porphyrin core, the ΦΔ increased from 0.76–0.90 and cell viability changed considerably. The ΦΔ and metal type changed the cytotoxic activity. Finally, (2) showed both the highest ΦΔ (0.90) and the best photodynamic activity against the parasites studied (IC50 of 1.2 μM).

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.

Novel phthalocyanines bearing 1,2,4 triazole substituents: Synthesis, characterization, photophysical and photochemical properties

4-(4,5-Diphenyl-4H-1,2,4-triazol-3-ylthio)phthalonitrile (3) and its non-peripherally tetra substituted zinc(II) phthalocyanine (4) and magnesium(II) phthalocyanine (5) derivatives were prepared. The novel compounds 3–5 were characterized spectroscopically. To determine the photodynamic therapy potential of 4 and 5, their photophysical and photochemical properties were investigated. The magnesium(II) phthalocyanine (5) showed the highest fluorescence quantum yield. In addition, non-peripheral substitution of the 4-(4,5-diphenyl-4H-1,2,4-triazol-3-ylthio) groups on the phthalocyanine ring did not affect the fluorescence properties of the phthalocyanines. The zinc(II) phthalocyanine (4) exhibited the highest singlet oxygen quantum yield value. The 4 and 5 exhibited lower photostability than Std-ZnPc. These results show that the zinc(II) phthalocyanine (4) can be used in photodynamic therapy applications with its singlet oxygen production and photostability.

Design and Synthesis of New Porphyrin Analogues as Potent Photosensitizers for Photodynamic Therapy: Spectroscopic Approach.

New porphyrin analogues have been designed and synthesized using pyrrole, various aldehydes and propionic acid. The formation of desired compounds was analyzed by utilizing the spectral analysis such as IR, NMR and Mass spectroscopy. The studies on absorption and fluorescence emission of synthesized porphyrins were used to evaluate photophysical characteristics such as molar excitation coefficient and Stokes shift. The estimated values of fluorescence lifetime and fluorescence quantum yield of synthesized porphyrins were found to be variable due to thepresence of change in the electron donating and withdrawing characters. The efficiency of generation of singlet oxygen by each synthesized porphyrin as photosensitizer was measured in terms of singlet oxygen quantum yield through photooxidation of 9,10-dimethylantharacene. The obtained singlet oxygen quantum yield values were found to be higher in case of porphyrins those have more electron withdrawing characters rather than donating characters as compared to reference 5,10,15,20-tetraphenylporphyrin (H2TPP). The singlet oxygen quantum yield values of synthesized porphyrins varied from 0.52 to 0.66. Pleasingly, some of synthesized porphyrins are found to be photostable and competent to discover as PDT agents as compared to reference H2TPP.