Fluorinated porphyrinoids and their biomedical applications

Singlet oxygen generation on a superhydrophobic surface: Effect of photosensitizer coating and incident wavelength on 1O2 yields

Photochemical generation of singlet oxygen (1O2) often relies on homogenous systems; however, a dissolved photosensitizer (PS) may be unsuitable for some applications because it is difficult to recover, expensive to replenish, and hazardous to the environment. Isolation of the PS onto a solid support can overcome these limitations, but implementation faces other challenges, including agglomeration of the solid PS, physical quenching of 1O2 by the support, photooxidation of the PS, and hypoxic environments. Here, we explore a superhydrophobic polydimethylsiloxane (SH-PDMS) support coated with the photosensitizer 5,10,15,20-tetrakis(pentafluorophenyl)-21H,23H-porphyrin (TFPP). This approach seeks to address the challenges of a heterogeneous system by using a support that exhibits low 1O2 physical quenching rates, a fluorinated PS that is chemically resistant to photooxidation, and a superhydrophobic surface that entraps a layer of air, thus preventing hypoxia. Absorbance and fluorescence spectroscopy reveal the monomeric arrangement of TFPP on SH-PDMS surfaces, a surprising but favorable characteristic for a solid-phase PS on 1O2 yields. We also investigated the effect of incident wavelength on 1O2 yields for TFPP in aqueous solution and immobilized on SH-PDMS and found overall yields to be dependent on the absorption coefficient, while the yield per absorbed photon exhibited wavelength independence, in accordance with Kasha-Vavilov's rule.

Refining antimicrobial photodynamic therapy: effect of charge distribution and central metal ion in fluorinated porphyrins on effective control of planktonic and biofilm bacterial forms

Antibiotic resistance represents a pressing global health challenge, now acknowledged as a critical concern within the framework of One Health. Photodynamic inactivation of microorganisms (PDI) offers an attractive, non-invasive approach known for its flexibility, independence from microbial resistance patterns, broad-spectrum efficacy, and minimal risk of inducing resistance. Various photosensitizers, including porphyrin derivatives have been explored for pathogen eradication. In this context, we present the synthesis, spectroscopic and photophysical characteristics as well as antimicrobial properties of a palladium(II)-porphyrin derivative (PdF2POH), along with its zinc(II)- and free-base counterparts (ZnF2POH and F2POH, respectively). Our findings reveal that the palladium(II)-porphyrin complex can be classified as an excellent generator of reactive oxygen species (ROS), encompassing both singlet oxygen (Φ△ = 0.93) and oxygen-centered radicals. The ability of photosensitizers to generate ROS was assessed using a variety of direct (luminescence measurements) and indirect techniques, including specific fluorescent probes both in solution and in microorganisms during the PDI procedure. We investigated the PDI efficacy of F2POH, ZnF2POH, and PdF2POH against both Gram-negative and Gram-positive bacteria. All tested compounds proved high activity against Gram-positive species, with PdF2POH exhibiting superior efficacy, leading to up to a 6-log reduction in S. aureus viability. Notably, PdF2POH-mediated PDI displayed remarkable effectiveness against S. aureus biofilm, a challenging target due to its complex structure and increased resistance to conventional treatments. Furthermore, our results show that PDI with PdF2POH is more selective for bacterial than for mammalian cells, particularly at lower light doses (up to 5 J/cm2 of blue light illumination). This enhanced efficacy of PdF2POH-mediated PDI as compared to ZnF2POH and F2POH can be attributed to more pronounced ROS generation by palladium derivative via both types of photochemical mechanisms (high yields of singlet oxygen generation as well as oxygen-centered radicals). Additionally, PDI proved effective in eliminating bacteria within S. aureus-infected human keratinocytes, inhibiting infection progression while preserving the viability and integrity of infected HaCaT cells. These findings underscore the potential of metalloporphyrins, particularly the Pd(II)-porphyrin complex, as promising photosensitizers for PDI in various bacterial infections, warranting further investigation in advanced infection models.

A Comparative Evaluation of the Photosensitizing Efficiency of Porphyrins, Chlorins and Isobacteriochlorins toward Melanoma Cancer Cells

Skin cancer is one of the cancers that registers the highest number of new cases annually. Among all forms of skin cancer, melanoma is the most invasive and deadliest. The resistance of this form of cancer to conventional treatments has led to the employment of alternative/complementary therapeutic approaches. Photodynamic therapy (PDT) appears to be a promising alternative to overcome the resistance of melanoma to conventional therapies. PDT is a non-invasive therapeutic procedure in which highly reactive oxygen species (ROS) are generated upon excitation of a photosensitizer (PS) when subjected to visible light of an adequate wavelength, resulting in the death of cancer cells. In this work, inspired by the efficacy of tetrapyrrolic macrocycles to act as PS against tumor cells, we report the photophysical characterization and biological assays of isobacteriochlorins and their corresponding chlorins and porphyrins against melanoma cancer cells through a photodynamic process. The non-tumoral L929 fibroblast murine cell line was used as the control. The results show that the choice of adequate tetrapyrrolic macrocycle-based PS can be modulated to improve the performance of PDT.

Perfluorocarbon Nanoemulsions with Fluorous Chlorin-Type Photosensitizers for Antitumor Photodynamic Therapy in Hypoxia

The efficacy of photodynamic therapy (PDT) strictly depends on the availability of molecular oxygen to trigger the light-induced generation of reactive species. Fluorocarbons have an increased ability to dissolve oxygen and are attractive tools for gas delivery. We synthesized three fluorous derivatives of chlorin with peripheral polyfluoroalkyl substituents. These compounds were used as precursors for preparing nanoemulsions with perfluorodecalin as an oxygen depot. Therefore, our formulations contained hydrophobic photosensitizers capable of absorbing monochromatic light in the long wavelength region and the oxygen carrier. These modifications did not alter the photosensitizing characteristics of chlorin such as the generation of singlet oxygen, the major cytocidal species in PDT. Emulsions readily entered HCT116 colon carcinoma cells and accumulated largely in mitochondria. Illumination of cells loaded with emulsions rapidly caused peroxidation of lipids and the loss of the plasma membrane integrity (photonecrosis). Most importantly, in PDT settings, emulsions potently sensitized cells cultured under prolonged (8 weeks) hypoxia as well as cells after oxygen depletion with sodium sulfite (acute hypoxia). The photodamaging potency of emulsions in hypoxia was significantly more pronounced compared to emulsion-free counterparts. Considering a negligible dark cytotoxicity, our materials emerge as efficient and biocompatible instruments for PDT-assisted eradication of hypoxic cells.

Fluorine Atoms on C6H5-Corrole Affect the Interaction with Mpro and PLpro Proteases of SARS-CoV-2: Molecular Docking and 2D-QSAR Approaches

The chymotrypsin-like cysteine protease (3CL^pro, also known as main protease—M^pro) and papain-like protease (PL^pro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been used as the main targets for screening potential synthetic inhibitors for posterior in vitro evaluation of the most promising compounds. In this sense, the present work reports for the first time the evaluation of the interaction between M^pro/PL^pro with a series of 17 porphyrin analogues-corrole (C1), meso-aryl-corrole (C2), and 15 fluorinated-meso-aryl-corrole derivatives (C3–C17) via molecular docking calculations. The impact of fluorine atoms on meso-aryl-corrole structure was also evaluated in terms of binding affinity and physical-chemical properties by two-dimensional quantitative structure–activity relationship (2D-QSAR). The presence of phenyl moieties increased the binding capacity of corrole for both proteases and depending on the position of fluorine atoms might impact positively or negatively the binding capacity. For M^pro the para-fluorine atoms might decrease drastically the binding capacity, while for PL^pro there was a certain increase in the binding affinity of fluorinated-corroles with the increase of fluorine atoms into meso-aryl-corrole structure mainly from tri-fluorinated insertions. The 2D-QSAR models indicated two separated regions of higher and lower affinity for M^pro:C1–C17 based on dual electronic parameters (σ_I and σ_R), as well as one model was obtained with a correlation between the docking score value of M^pro:C2–C17 and the corresponding ¹³C nuclear magnetic resonance (NMR) chemical shifts of the sp² carbon atoms (δ_C-1 and δ_C-2) of C2–C17. Overall, the fluorinated-meso-aryl-corrole derivatives showed favorable in silico parameters as potential synthetic compounds for future in vitro assays on the inhibition of SARS-CoV-2 replication.

The Surprisingly Positive Effect of Zinc-Phthalocyanines With High Photodynamic Therapy Efficacy of Melanoma Cancer

Phthalocyanine (Pc) dyes are photoactive molecules that can absorb and emit light in the visible spectrum, especially in the red region of the spectrum, with great potential for biological scopes. For this target, it is important to guarantee a high Pc solubility, and the use of suitable pyridinium units on their structure can be a good strategy to use effective photosensitizers (PSs) for photodynamic therapy (PDT) against cancer cells. Zn(II) phthalocyanines (ZnPcs) conjugated with thiopyridinium units (1–3) were evaluated as PS drugs against B16F10 melanoma cells, and their photophysical, photochemical, and in vitro photobiological properties were determined. The photodynamic efficiency of the tetra- and octa-cationic ZnPcs 1–3 was studied and compared at 1, 2, 5, 10, and 20 µM. The different number of charge units, and the presence/absence of a-F atoms on the Pc structure, contributes for their PDT efficacy. The 3-(4′,5′-dimethylthiazol-2′-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays on B16F10 melanoma cells show a moderate to high capacity to be photoinactivated by ZnPcs 1–3 (ZnPc 1 > ZnPc 2 > ZnPc 3). The best PDT conditions were found at a Pc concentration of 20 μM, under red light (λ = 660 ± 20 nm) at an irradiance of 4.5 mW/cm² for 667 s (light dose of 3 J/cm²). In these conditions, it is noteworthy that the cationic ZnPc 1 shows a promising photoinactivation ratio, reaching the detection limit of the MTT method. Moreover, these results are comparable to the better ones in the literature.

Corroles at work: a small macrocycle for great applications

Corrole chemistry has witnessed an impressive boost in studies in the last 20 years, thanks to the possibility of preparing corrole derivatives by simple synthetic procedures. The investigation of a large number of corroles has highlighted some peculiar characteristics of these macrocycles, having features different from those of the parent porphyrins. With this progress in the elucidation of corrole properties, attention has been focused on the potential for the exploitation of corrole derivatives in different important application fields. In some areas, the potential of corroles has been studied in certain detail, for example, the use of corrole metal complexes as electrocatalysts for energy conversion. In some other areas, the field is still in its infancy, such as in the exploitation of corroles in solar cells. Herein, we report an overview of the different applications of corroles, focusing on the studies reported in the last five years.

Photophysicochemical, sonochemical, and biological properties of novel hexadeca-substituted phthalocyanines bearing fluorinated groups

This study presents the preparation of a novel tetra-substituted phthalonitrile (1), namely, 3,6-bis(hexyloxy)-4,5-bis(4-(trifluoromethoxy)phenoxy)phthalonitrile (1) and its metal-free (2)/metal {M = Zn (3), Cu (4), Co (5), Lu(CH₃COO) (6), Lu (7)} phthalocyanines. A series of various spectroscopic methods (UV-vis, FT-IR, mass, and ¹H NMR spectroscopy) were performed for the characterization of the newly synthesized compounds. The potential of compounds 2, 3, and 6 as photosensitizing materials for photodynamic and sonophotodynamic therapies was evaluated by photophysical, photochemical, and sonochemical methods. The highest singlet quantum yields were obtained for the zinc phthalocyanine derivative 3 by performing photochemical and sonochemical methods. In addition, several biological activities of the new compounds 1-7 were investigated. The newly synthesized phthalocyanines exhibited excellent DPPH scavenging activity and also DNA nuclease activity. The antimicrobial activity of the new compounds was evaluated by the disc diffusion assay. Effective microbial cell viability inhibition was observed with phthalocyanine macromolecules. The photodynamic antimicrobial therapy of the phthalocyanines showed 100% bacterial inhibition when compared to the control. They also exhibited significant biofilm inhibition activity against S. aureus and P. aeruginosa. These results indicate that new phthalocyanines are promising photodynamic antimicrobial therapies for the treatment of infectious diseases.

Photophysicochemical and Biological Properties of New Phthalocyanines Bearing 4-(trifluoromethoxy)phenoxy and 2-(4-methylthiazol-5-yl)ethoxy Groups on Peripheral Positions

As thiazoles and fluorinated groups are well known as active species of hybrid pharmaceutical agents, this study aimed to evaluate the synergic effect of these groups on the biological features of phthalocyanines for the first time in the hope of discovering efficient pharmaceutical agents. Therefore, a new phthalonitrile derivative namely 4-(2-(4-methylthiazol-5-yl)ethoxy)-5-(4-(trifluoromethoxy)phenoxy)phthalonitrile (1) and its metal-free (2)/metal phthalocyanines (3-5) were prepared and characterized using various spectroscopic techniques. Solubility of new phthalocyanines (2-5) was examined in a series of polar and nonpolar solvents. Additionally, sono/photochemical methods were applied to examine the photophysical and sono/photochemical properties of new zinc phthalocyanine to measure its potential as a probable material for sono/photodynamic therapies. The antioxidant activities of compounds (1-5) were evaluated using the DPPH scavenging activity method and the highest radical scavenging activity was obtained 92.13% (200 mg L^-1 ) for manganese phthalocyanine. All the phthalocyanines demonstrated high DNA nuclease activity, as well. The antimicrobial activities of compounds (1-5) were investigated using disk diffusion and microdilution methods. The phthalocyanines exhibited effective microbial cell inhibition activity against Escherichia coli (E. coli). Antimicrobial photodynamic therapy activity was investigated against E. coli by LED irradiation. Compounds (2-5) acted as photosynthesizers. Also, they displayed significant biofilm inhibition activity against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa).

Crystal structure of (3E,5E)-1-(4-cyanobenzenesulfonyl)-3,5-bis(3-fluorobenzylidene)piperidin-4-one-dichloromethane (1/1), C27H20Cl2F2N2O3S

C27H20Cl2F2N2O3S, triclinic, P 1 ‾ $P‾{1}$ (no. 2), a = 8.7887(4) Å, b = 11.2517(6) Å, c = 13.7609(7) Å, α = 74.962(4)°, β = 81.084(4)°, γ = 71.259(4)°, V = 1240.68(11) Å3, Z = 2, R gt (F) = 0.0582, wR ref (F 2) = 0.1543, T = 100.0(1) K.

Crystal structure of (3E,5E)-3,5-bis(4-fluorobenzylidene)-1-((4-trifluoromethyl)benzenesulfonyl)piperidin-4-one, C26H18F5NO3S

C26H18F5NO3S, triclinic, P 1 ‾ $P‾{1}$ (no. 2), a = 7.8831(4) Å, b = 11.9591(7) Å, c = 13.3258(7) Å, α = 69.072(5)°, β = 88.556(4)°, γ = 73.730(5)°, V = 1122.48(11) Å3, Z = 2, R gt (F) = 0.0507, wR ref (F 2) = 0.1216, T = 100.0(1) K.

Applications of Fluorous Porphyrinoids: An Update†

Porphyrins and related macrocycles have been studied broadly for their applications in medicine and materials because of their tunable physicochemical, optoelectronic and magnetic properties. In this review article, we focused on the applications of fluorinated porphyrinoids and their supramolecular systems and summarized the reports published on these chromophores in the past 5-6 years. The commercially available fluorinated porphyrinoids: meso-perfluorophenylporphyrin (TPPF₂₀ ) perfluorophthalocyanine (PcF₁₆ ) and meso-perfluorophenylcorrole (CorF₁₅ ) have increased photo and oxidative stability due to the presence of fluoro groups. Because of their tunable properties and robustness toward oxidative damage these porphyrinoid-based chromophores continue to gain attention of researchers developing advanced functional materials for applications such as sensors, photonic devices, component for solar cells, biomedical imaging, theranostics and catalysts.

Probing the Interactions of Porphyrins with Macromolecules Using NMR Spectroscopy Techniques

Porphyrinic compounds are widespread in nature and play key roles in biological processes such as oxygen transport in blood, enzymatic redox reactions or photosynthesis. In addition, both naturally derived as well as synthetic porphyrinic compounds are extensively explored for biomedical and technical applications such as photodynamic therapy (PDT) or photovoltaic systems, respectively. Their unique electronic structures and photophysical properties make this class of compounds so interesting for the multiple functions encountered. It is therefore not surprising that optical methods are typically the prevalent analytical tool applied in characterization and processes involving porphyrinic compounds. However, a wealth of complementary information can be obtained from NMR spectroscopic techniques. Based on the advantage of providing structural and dynamic information with atomic resolution simultaneously, NMR spectroscopy is a powerful method for studying molecular interactions between porphyrinic compounds and macromolecules. Such interactions are of special interest in medical applications of porphyrinic photosensitizers that are mostly combined with macromolecular carrier systems. The macromolecular surrounding typically stabilizes the encapsulated drug and may also modify its physical properties. Moreover, the interaction with macromolecular physiological components needs to be explored to understand and control mechanisms of action and therapeutic efficacy. This review focuses on such non-covalent interactions of porphyrinic drugs with synthetic polymers as well as with biomolecules such as phospholipids or proteins. A brief introduction into various NMR spectroscopic techniques is given including chemical shift perturbation methods, NOE enhancement spectroscopy, relaxation time measurements and diffusion-ordered spectroscopy. How these NMR tools are used to address porphyrin-macromolecule interactions with respect to their function in biomedical applications is the central point of the current review.

Electronic, molecular, and solid-state structural effects of strong electron withdrawing and donating groups in functionalized fluorophthalonitriles

Perfluoro phthalonitrile substituted separately with perfluoroalkyl (EWG) and NH2, NHMe, and NMe2 (EDG) groups generate a series of aromatic C-H bonds-free nitriles that can now lose electrons, whose HOMO–LUMO gap is narrowed by EDG beyond the level induced by EWG, and whose dipole moments double. Molecular parameters vary linearly with Hammett’s free-energy constants, their electronic underpinning being uncovered by DFT calculations. The phthalonitriles’ assembling in solid-state structures is determined by forces that transition from van der Waals, in the case of EWG, to H-bonding and/or [Formula: see text]-stacking interactions in the case of EDG, as revealed by their single-crystal X-ray structures.

Synthesis and evaluation of novel fluorinated hematoporphyrin ether derivatives for photodynamic therapy

A photosensitizer with high phototoxicity, suitable amphipathy and low dark toxicity could play a pivotal role in photodynamic therapy (PDT). In this study, a facile and versatile approach was adopted to synthesize a series of novel fluorinated hematoporphyrin ether derivatives (I1-I5 and II1-II4), and the photodynamic activities of these compounds were studied. Compared to hematoporphyrin monomethyl ether (HMME), all PSs showed preferable photodynamic activity against A549 lung tumor cells. The longest visible absorption wavelength of these compounds was approximately 622 nm. Among them, II3 revealed the highest singlet oxygen yield (0.0957 min-1), the strongest phototoxicity (IC50 = 1.24 μM), the lowest dark toxicity in vitro, and exhibited excellent anti-tumor effects in vivo. So compound II3 could act as new drug candidate for photodynamic therapy.

Synthesis, characterization, and cellular investigations of porphyrin- and chlorin-indomethacin conjugates for photodynamic therapy of cancer

Indomethacin is a potent non-steroidal anti-inflammatory drug (NSAID) with a strong selective inhibitor activity towards cyclooxygenase-2 (COX-2), an enzyme that is highly overexpressed in various tumour cells, being involved in tumourigenesis. Concomitantly, porphyrins have gained much attention as promising photosensitizers (PSs) for the non-invasive photodynamic therapy (PDT) of cancer. Herein, we report the design, and determine the singlet oxygen generation capacity and in vitro cellular toxicity of porphyrin- and chlorin-indomethacin conjugates (P2-Ind and C2-Ind). Both the conjugates were obtained in high yields and were characterized by 1H, 19F and 13C NMR as well as by high resolution mass spectrometry. The singlet oxygen generation properties were assessed by the 1,3-diphenylisobenzofuran singlet oxygen trap method, which showed that C2 and C2-Ind are the best singlet oxygen photosensitizers. In addition, it was found that the presence of indomethacin did not influence the singlet oxygen generation of porphyrin or chlorin. Cytotoxicity studies of the conjugate in human HEp2 cells revealed that the porphyrin- and chlorin-indomethacin conjugates have similar dark cytotoxicities, while chlorin C2 was shown to be the most phototoxic. Despite having lower cellular uptake than C2-Ind after 24 hours, chlorin C2 had a broad localization in HEp2 cells while the chlorin-indomethacin conjugate C2-Ind could be detected in the form of small aggregates. DFT calculations were performed to shed light on the reaction energy involved in the formation of the indomethacin conjugates and to compare the relative stability of selected isomers in solution. Moreover, the calculated energy of their first excited triplet state structures confirmed their use as suitable photosensitizers to generate singlet oxygen for PDT.

Biophysical Characterization and Anticancer Activities of Photosensitive Phytoanthraquinones Represented by Hypericin and Its Model Compounds

Photosensitive compounds found in herbs have been reported in recent years as having a variety of interesting medicinal and biological activities. In this review, we focus on photosensitizers such as hypericin and its model compounds emodin, quinizarin, and danthron, which have antiviral, antifungal, antineoplastic, and antitumor effects. They can be utilized as potential agents in photodynamic therapy, especially in photodynamic therapy (PDT) for cancer. We aimed to give a comprehensive summary of the physical and chemical properties of these interesting molecules, emphasizing their mechanism of action in relation to their different interactions with biomacromolecules, specifically with DNA.

Synthesis and Structure of meso-Substituted Dibenzihomoporphyrins

Bench-stable meso-substituted di(p/m-benzi)homoporphyrins were synthesized through acid-catalyzed condensation of dipyrrole derivatives with aryl aldehydes. The insertion of a 1,1,2,2-tetraphenylethene (TPE) or but-2-ene-2,3-diyldibenzene unit in the porphyrin framework results in the formation of dibenzihomoporphyrins, merging the features of hydrocarbons and porphyrins. Single crystal X-ray analyses established the non-planar structure of these molecules, with the phenylene rings out of the mean plane, as defined by the dipyrromethene moiety and the two meso-carbon atoms. Spectroscopic and structural investigations show that the macrocycles exhibit characteristics of both TPE or but-2-ene-2,3-diyldibenzene and dipyrromethene units indicating the non-aromatic characteristics of the compounds synthesized. Additionally, the dibenzihomoporphyrins were found to generate singlet oxygen, potentially allowing their use as photosensitizers.

Porphyrin Derivative Nanoformulations for Therapy and Antiparasitic Agents

Porphyrins and analogous macrocycles exhibit interesting photochemical, catalytic, and luminescence properties demonstrating high potential in the treatment of several diseases. Among them can be highlighted the possibility of application in photodynamic therapy and antimicrobial/antiparasitic PDT, for example, of malaria parasite. However, the low efficiency generally associated with their low solubility in water and bioavailability have precluded biomedical applications. Nanotechnology can provide efficient strategies to enhance bioavailability and incorporate targeted delivery properties to conventional pharmaceuticals, enhancing the effectiveness and reducing the toxicity, thus improving the adhesion to the treatment. In this way, those limitations can be overcome by using two main strategies: (1) Incorporation of hydrophilic substituents into the macrocycle ring while controlling the interaction with biological systems and (2) by including them in nanocarriers and delivery nanosystems. This review will focus on antiparasitic drugs based on porphyrin derivatives developed according to these two strategies, considering their vast and increasing applications befitting the multiple roles of these compounds in nature.

Nature of fluorine interactions in ‘wheel and axle’ topology based hexa-coordinated Sn(iv)-porphyrins: an experimental and theoretical analysis

The experimental and theoretical investigations on Sn(iv)-tetrapyridylporphyrins demonstrate that ‘Gulliver effect’ has to be taken into consideration in explaining the genesis of F-based intermolecular interactions.

Lipophilicity of Bacteriochlorin-Based Photosensitizers as a Determinant for PDT Optimization through the Modulation of the Inflammatory Mediators

: Photodynamic therapy (PDT) augments the host antitumor immune response, but the role of the PDT effect on the tumor microenvironment in dependence on the type of photosensitizer and/or therapeutic protocols has not been clearly elucidated. We employed three bacteriochlorins (F2BOH, F2BMet and Cl2BHep) of different polarity that absorb near-infrared light (NIR) and generated a large amount of reactive oxygen species (ROS) to compare the PDT efficacy after various drug-to-light intervals: 15 min. (V-PDT), 3h (E-PDT) and 72h (C-PDT). We also performed the analysis of the molecular mechanisms of PDT crucial for the generation of the long-lasting antitumor immune response. PDT-induced damage affected the integrity of the host tissue and developed acute (protocol-dependent) local inflammation, which in turn led to the infiltration of neutrophils and macrophages. In order to further confirm this hypothesis, a number of proteins in the plasma of PDT-treated mice were identified. Among a wide range of cytokines (IL-6, IL-10, IL-13, IL-15, TNF-α, GM-CSF), chemokines (KC, MCP-1, MIP1α, MIP1β, MIP2) and growth factors (VEGF) released after PDT, an important role was assigned to IL-6. PDT protocols optimized for studied bacteriochlorins led to a significant increase in the survival rate of BALB/c mice bearing CT26 tumors, but each photosensitizer (PS) was more or less potent, depending on the applied DLI (15 min, 3 h or 72 h). Hydrophilic (F2BOH) and amphiphilic (F2BMet) PSs were equally effective in V-PDT (>80 cure rate). F2BMet was the most efficient in E-PDT (DLI = 3h), leading to a cure of 65 % of the animals. Finally, the most powerful PS in the C-PDT (DLI = 72 h) regimen turned out to be the most hydrophobic compound (Cl2BHep), allowing 100 % of treated animals to be cured at a light dose of only 45 J/cm2.

Efficient Photocatalytic Removal of Methylene Blue Using a Metalloporphyrin-Poly(vinylidene fluoride) Hybrid Membrane in a Flow-Through Reactor

A novel combination of a poly(vinylidene fluoride) (PVDF) membrane with pore size 0.2 μm and a photosensitizer 5,10,15,20-tetrakis (pentafluorophenyl)-21H,23H-porphine palladium(II) (PdTFPP) makes a promising hybrid material for the generation of singlet oxygen (¹O₂) and, thus, water treatment applications. The fabricated photocatalytic membrane exhibits permeability of 4280 ± 250 L·m^-2·h^-1·bar^-1 and stable photocatalytic degradation performance over a 90 h period, when illuminated with green light (528 ± 20 nm) and operated in a dead-end, single-pass configuration. Methylene blue (MB) degradation of 83% was achieved for MB concentration of 1 mg·L^-1 under the flow rate of 0.1 × 10^-3 L·min^-1 (flux of 30 L·m^-2·h^-1), light intensity of 21 mW·cm^-2, and PdTFPP loading of 25 μmol·g^-1. Due to an enhanced mass transfer, the reaction rate of MB removal (with apparent rate constant of k_app = 6.52 min^-1) results in an efficient photodegradation of MB inside the PdTFPP-PVDF membrane. The influence of experimental parameters such as catalyst loading, flow rate, light intensity, and solute concentration on MB removal was investigated. This research enables the application of photocatalytic PdTFPP-PVDF membranes as a potential technology for water decontamination under visible-light illumination.

Facile synthesis of fluorinated nanophotosensitizers with self-supplied oxygen for efficient photodynamic therapy

Tumor hypoxia severely reduces the efficiency of photodynamic therapy (PDT) through the insufficient supply of oxygen. In this work, we reported on a design of fluorinated nanophotosensitizers (NPSs) prepared by a facile reprecipitation-encapsulation method, with the aim of addressing the issue of hypoxia. The fluorinated NPSs consisted of a hybrid particle core of perfluorosiloxane-polystyrene, doped with a fluorinated photosensitizer, and a biocompatible poly-l-lysine shell. Compared with non-fluorinated counterpart NPSs that are similarly prepared except for the replacement of perfluorosiloxane with alkoxysilane, the fluorinated NPSs saturated with O₂ exhibit approximately 3.5 fold higher singlet oxygen production yield and higher in vitro PDT efficiency due to the O₂-carrying capability of intra-particle 'F-C' bonds.

Photoproperties, PVP formulation and 19F NMR of a Zn phthalocyanine with 24 magnetically pseudo-equivalent fluorine atoms

In an attempt to investigate its potential as a PDT [Formula: see text]F MRI molecular theranostic, a Zn phthalocyanine with 24 pseudo-equivalent fluorine atoms was designed and prepared. Compared to its H analogues, the fluorinated derivative has a much higher generation of singlet oxygen. [Formula: see text]F NMR signals in CDCl3 showed that all the fluorine atoms are magnetically pseudo-equivalent with only two close fluorine signals. Formulation in PVP (polyvinylpyrrolidone), a FDA-approved additive, enabled water-solubilization of the phthalocyanines but no satisfying [Formula: see text]F NMR signal could be obtained, probably due to self-quenching caused by aggregation.

Antimicrobial and antioxidant properties of novel octa-substituted phthalocyanines bearing (trifluoromethoxy) phenoxy groups on peripheral positions

This study presents a novel phthalonitrile derivative (2) bearing (trifluoromethoxy)phenoxy groups in 4,5 positions. Cyclotetramerization of (2) in [Formula: see text],[Formula: see text]-dimethylaminoethanol (DMAE) gave a series of peripherally octa-substituted metallophthalocyanines (3-Zn, 3-Co and 3-Cu). The newly synthesized phthalocyanines have been characterized by a combination of various spectroscopic techniques. Effects of solvent nature on aggregation behavior of 3-Zn were studied using different solvents such as acetone, CHCl3 and dichloromethane (DCM). In addition, the aggregation behavior of the phthalocyanine complex 3-Zn was examined in DCM at different concentrations ranging from 4 × 10[Formula: see text]–14 × 10[Formula: see text] M. Antimicrobial activities of synthesized compounds were tested by using the thin layer chromotography (TLC)-direct bioautography and disk diffusion methods. In both assays, the molecules showed activity on the tested Gram (+) bacteria. Antioxidant activities of the molecules, on the other hand, were determined by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and a reducing power assay. The highest activity was obtained with 3-ZnPc for both methods.

Synthesis of non-peripherally tetra-substituted copper(ii) phthalocyanines: characterization, optical and surface properties, fabrication and photo-electrical properties of a photosensitive diode

This study describes the synthesis and characterization of a non-peripherally tetra-substituted copper(ii) phthalocyanine bearing 4-(trifluoromethoxy)phenol groups.

Structural and Electronic Effects Due to Fluorine Atoms on Dibenzotetraaza-Annulenes Complexes

The preparation and characterization of Ni(II) (1F) and Cu(II) (2F) complexes of the ligand 15,16,17,18,19,20,21,22-octafluoro-dibenzotetraaza[14]annulene (L_F) are here reported. These compounds have been characterized by elemental analysis, mass and UV-vis spectroscopies, single-crystal X-ray diffraction, and computational studies. The effects due to the presence of fluorine atoms have been highlighted by comparison with the analogous complexes of the ligand L_H (Ni: 1H; Cu: 2H), which bears hydrogen atoms at the benzenoid rings instead of fluorine. 1F and 2F are isostructural, with the metal ions bound to the four nitrogen atoms in a square-planar geometry and where the planar molecules are arranged in a herringbone motif in the crystal lattice. Remarkable differences in the intermolecular interactions between 1F and 2F and the corresponding H-complexes are shown by Hirshfeld surface calculations. Moreover, the effects of fluorination on the electronic structures have been investigated by density functional theory (DFT) and time-dependent DFT calculations. The compounds with L_F and L_H ligands present corresponding molecular orbitals (MOs) with similar shapes. Furthermore, while the presence of F-atoms lowers the energy of the MOs in comparison with those of the L_H complexes, it does not remarkably affect the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) and HOMO-LUMO + 1 gaps, in agreement with the UV-vis results.

New synthetic pathway leading to oxospirochlorins

In this work we propose a completely new approach for the synthesis of spirochlorin derivatives based on the use of an imino-keto intermediate formed in situ from 2-amino-5,10,15,20-tetraphenylporphyrins and inverse electron demand Diels-Alder (iEDDA) cycloaddition with 3,6-di-2-pyridyl-1,2,4,5-tetrazine. The mechanism of reaction was analyzed employing theoretical methods by comparing the difference in energy of Frontier Molecular Orbitals (FMO) for appropriate reagents. Ground-state molecular electrostatic (ESP) potential maps were employed as additional tools allowing explanation of the reactivity of substrates. The new class of spirochlorin compounds was fully characterized by means of mass spectrometry, IR, liquid and solid state NMR and X-ray crystallography. Correlation between molecular structure and optical properties for the obtained title compounds is discussed.

A polyfluoroalkyl substituted phthalocyanine based supramolecular light switch for photothermal and photodynamic antibacterial activity against Escherichia coli

A polyfluoroalkyl phthalocyanine based supramolecular light switch was assembled and it exhibited synergic photothermal and photodynamic antibacterial activity upon irradiation with light.

Theoretical study on the interaction of CO2 and H2O molecules with metal doped-fluorinated phthalocyanines

This investigation reports the molecular properties of metal (M = Mg, Sc, Cu, Zn) doped-fluorinated phthalocyanines (M-FPcs) and their ability to separate and capture CO₂ in the presence of H₂O using DFT studies.

Structural, spectroscopic and electrochemical investigations on fluorinated meso-tetraaryl porphyrins

Two series of meso-phenyl fluorinated porphyrins and their metal complexes, 5,10,15,20-tetrakis(2[Formula: see text],4[Formula: see text],6[Formula: see text]-trifluorophenyl)porphyrin, MT(2[Formula: see text],4[Formula: see text],6[Formula: see text]-TFP)Ps (2a–2d) and 5,10,15,20-tetrakis[3[Formula: see text],5[Formula: see text]-bis(trifluoromethylphenyl)]porphyrin, MT(3[Formula: see text],5[Formula: see text]-BTFMP)Ps (3a–3d); where M [Formula: see text] 2H; Ni(II); Cu(II) and Zn(II) have been synthesized and characterized using various spectroscopic techniques including UV-visible, fluorescence and [Formula: see text]H NMR and mass spectrometry. Electronic absorption spectra of porphyrins show the typical Soret (B) and visible (Q) bands. Free ligands and zinc(II) derivatives display two well-defined emission bands around 600–660 nm and 650–720 nm upon exciting the Soret band. Porphyrins, 1d, 2a, 2b, 2c, 3a and 3d were structurally characterized by single crystal XRD analysis, and various intermolecular interactions present in them were quantified on the basis of Hirshfeld surfaces and 2D fingerprint plots. Electrochemical studies were performed and the HOMO–LUMO energy gap is high for all the porphyrins compared to MTPPs.

A Cost-Efficient Method for Unsymmetrical Meso-Aryl Porphyrin Synthesis Using NaY Zeolite as an Inorganic Acid Catalyst

Herein we report the synthesis of unsymmetrical meso-aryl substituted porphyrins, using NaY zeolite as an inorganic acid catalyst. A comparative study between this method and the several synthetic strategies available in the literature was carried out. Our method presented a better, more cost-efficient rationale and displayed a significantly lower environmental impact. Furthermore, it was possible to verify the scalability of the process as well as the reutilization of the inorganic catalyst NaY (up to 6 times) without significant yield decrease. In addition, this method was applied to the synthesis of several other unsymmetrical porphyrins, from a low melting point porphyrin to mono-carboxylated halogenated unsymmetrical porphyrins, in yields higher than those found in the literature. Additionally, for the first time, two acetamide functionalized halogenated porphyrins were prepared in high yields. This methodology opens the way to the preparation of high yielding functionalized porphyrins, which can be easily immobilized for a variety of applications, either in catalysis or in biomedicine.

Structure and dynamics processes in free-base chlorins controlled by chemical modifications of macroring and aryl groups in meso-positions

The synthesis, detailed structural characterization and analysis of molecular motion for unsymmetrical pyrrolidine-fused chlorins employing NMR, UV spectroscopy and DFT theoretical calculations are presented.

Synthesis under high hydrostatic pressure — a new method to prepare 5,10,15,20-tetrakis[4-(substituted amino)-2,3,5,6-tetrafluorophenyl]porphyrins

5,10,15,20-Tetrakis(pentafluorophenyl)porphyrin reacts with primary alkylamines and heterocyclic amines, at 50°C and under high pressure (450 MPa), to produce the [Formula: see text]-substituted tetraamino derivatives in high yields. Under similar conditions, the reaction with the bulky dibutylamine and dipentylamine affords the corresponding mono-substituted dialkylaminoporphyrins in 10% yield. This new protocol arises as a considerable improvement of the methods already known, which usually require high temperatures and are not effective when using secondary amines having long alkyl groups.