Editorial

6 pages, 226 KiB

Open AccessEditorial

Porphyrin-Based Compounds: Synthesis and Application

by Carlos J. P. Monteiro, M. Amparo F. Faustino and Carlos Serpa

Molecules 2023, 28(20), 7108; https://doi.org/10.3390/molecules28207108 - 16 Oct 2023

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Porphyrin-based compounds are an attractive and versatile class of molecules that have attracted significant attention across different scientific disciplines [...] Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

Research

Jump to: Editorial, Review

14 pages, 3309 KiB

Open AccessArticle

8(meso)-Pyridyl-BODIPYs: Effects of 2,6-Substitution with Electron-Withdrawing Nitro, Chloro, and Methoxycarbonyl Groups

by Caroline Ndung’U, Petia Bobadova-Parvanova, Daniel J. LaMaster, Dylan Goliber, Frank R. Fronczek and Maria da Graça H. Vicente

Molecules 2023, 28(12), 4581; https://doi.org/10.3390/molecules28124581 - 06 Jun 2023

Cited by 1 | Viewed by 1081

Abstract

The introduction of electron-withdrawing groups on 8(meso)-pyridyl-BODIPYs tends to increase the fluorescence quantum yields of this type of compound due to the decrease in electronic charge density on the BODIPY core. A new series of 8(meso)-pyridyl-BODIPYs bearing a 2-, [...] Read more.

The introduction of electron-withdrawing groups on 8(meso)-pyridyl-BODIPYs tends to increase the fluorescence quantum yields of this type of compound due to the decrease in electronic charge density on the BODIPY core. A new series of 8(meso)-pyridyl-BODIPYs bearing a 2-, 3-, or 4-pyridyl group was synthesized and functionalized with nitro and chlorine groups at the 2,6-positions. The 2,6-methoxycarbonyl-8-pyridyl-BODIPYs analogs were also synthesized by condensation of 2,4-dimethyl-3-methoxycarbonyl-pyrrole with 2-, 3-, or 4-formylpyridine followed by oxidation and boron complexation. The structures and spectroscopic properties of the new series of 8(meso)-pyridyl-BODIPYs were investigated both experimentally and computationally. The BODIPYs bearing 2,6-methoxycarbonyl groups showed enhanced relative fluorescence quantum yields in polar organic solvents due to their electron-withdrawing effect. However, the introduction of a single nitro group significantly quenched the fluorescence of the BODIPYs and caused hypsochromic shifts in the absorption and emission bands. The introduction of a chloro substituent partially restored the fluorescence of the mono-nitro-BODIPYs and induced significant bathochromic shifts. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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15 pages, 4581 KiB

Open AccessArticle

Syntheses and Electrochemical and EPR Studies of Porphyrins Functionalized with Bulky Aromatic Amine Donors

by Mary-Ambre Carvalho, Khalissa Merahi, Julien Haumesser, Ana Mafalda Vaz Martins Pereira, Nathalie Parizel, Jean Weiss, Maylis Orio, Vincent Maurel, Laurent Ruhlmann, Sylvie Choua and Romain Ruppert

Molecules 2023, 28(11), 4405; https://doi.org/10.3390/molecules28114405 - 29 May 2023

Cited by 1 | Viewed by 1371

Abstract

A series of nickel(II) porphyrins bearing one or two bulky nitrogen donors at the meso positions were prepared by using Ullmann methodology or more classical Buchwald–Hartwig amination reactions to create the new C-N bonds. For several new compounds, single crystals were obtained, and [...] Read more.

A series of nickel(II) porphyrins bearing one or two bulky nitrogen donors at the meso positions were prepared by using Ullmann methodology or more classical Buchwald–Hartwig amination reactions to create the new C-N bonds. For several new compounds, single crystals were obtained, and the X-ray structures were solved. The electrochemical data of these compounds are reported. For a few representative examples, spectroelectrochemical measurements were used to clarify the electron exchange process. In addition, a detailed electron paramagnetic resonance (EPR) study was performed to estimate the extent of delocalization of the generated radical cations. In particular, electron nuclear double resonance spectroscopy (ENDOR) was used to determine the coupling constants. DFT calculations were conducted to corroborate the EPR spectroscopic data. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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10 pages, 2046 KiB

Open AccessArticle

Synthesis and Characterization of New-Type Soluble β-Substituted Zinc Phthalocyanine Derivative of Clofoctol

by Sabrine Dridi, Jamel Eddine Khiari, Gabriele Magna, Manuela Stefanelli, Larisa Lvova, Federica Mandoj, Khaoula Khezami, Mahmut Durmuş, Corrado Di Natale and Roberto Paolesse

Molecules 2023, 28(10), 4102; https://doi.org/10.3390/molecules28104102 - 15 May 2023

Cited by 1 | Viewed by 1346

Abstract

In this work, we have described the synthesis and characterization of novel zinc (II) phthalocyanine bearing four 2-(2,4-dichloro-benzyl)-4-(1,1,3,3-tetramethyl-butyl)-phenoxy substituents on the peripheral positions. The compound was characterized by elemental analysis and different spectroscopic techniques, such as FT-IR, ¹H NMR, MALDI-TOF, and UV-Vis. [...] Read more.

In this work, we have described the synthesis and characterization of novel zinc (II) phthalocyanine bearing four 2-(2,4-dichloro-benzyl)-4-(1,1,3,3-tetramethyl-butyl)-phenoxy substituents on the peripheral positions. The compound was characterized by elemental analysis and different spectroscopic techniques, such as FT-IR, ¹H NMR, MALDI-TOF, and UV-Vis. The Zn (II) phthalocyanine shows excellent solubility in organic solvents such as dichloromethane (DCM), n-hexane, chloroform, tetrahydrofuran (THF), and toluene. Photochemical and electrochemical characterizations of the complex were performed by UV-Vis, fluorescence spectroscopy, and cyclic voltammetry. Its good solubility allows a direct deposition of this compound as film, which has been tested as a solid-state sensing material in gravimetric chemical sensors for gas detection, and the obtained results indicate its potential for qualitative discrimination and quantitative assessment of various volatile organic compounds, among them methanol, n-hexane, triethylamine (TEA), toluene and DCM, in a wide concentration range. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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15 pages, 3898 KiB

Open AccessArticle

Green Aromatic Epoxidation with an Iron Porphyrin Catalyst for One-Pot Functionalization of Renewable Xylene, Quinoline, and Acridine

by Gabriela A. Corrêa, Susana L. H. Rebelo and Baltazar de Castro

Molecules 2023, 28(9), 3940; https://doi.org/10.3390/molecules28093940 - 07 May 2023

Cited by 1 | Viewed by 1257

Abstract

Sustainable functionalization of renewable aromatics is a key step to supply our present needs for specialty chemicals and pursuing the transition to a circular, fossil-free economy. In the present work, three typically stable aromatic compounds, representative of products abundantly obtainable from biomass or [...] Read more.

Sustainable functionalization of renewable aromatics is a key step to supply our present needs for specialty chemicals and pursuing the transition to a circular, fossil-free economy. In the present work, three typically stable aromatic compounds, representative of products abundantly obtainable from biomass or recycling processes, were functionalized in one-pot oxidation reactions at room temperature, using H₂O₂ as a green oxidant and ethanol as a green solvent in the presence of a highly electron withdrawing iron porphyrin catalyst. The results show unusual initial epoxidation of the aromatic ring by the green catalytic system. The epoxides were isolated or evolved through rearrangement, ring opening by nucleophiles, and oxidation. Acridine was oxidized to mono- and di-oxides in the peripheral ring: 1:2-epoxy-1,2-dihydroacridine and anti-1:2,3:4-diepoxy-1,2,3,4-tetrahydroacridine, with TON of 285. o-Xylene was oxidized to 4-hydroxy-3,4-dimethylcyclohexa-2,5-dienone, an attractive building block for synthesis, and 3,4-dimethylphenol as an intermediate, with TON of 237. Quinoline was directly functionalized to 4-quinolone or 3-substituted-4-quinolones (3-ethoxy-4-quinolone or 3-hydroxy-4-quinolone) and corresponding hydroxy-tautomers, with TON of 61. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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19 pages, 1498 KiB

Open AccessArticle

Comparison of the Performance of Density Functional Methods for the Description of Spin States and Binding Energies of Porphyrins

by Pierpaolo Morgante and Roberto Peverati

Molecules 2023, 28(8), 3487; https://doi.org/10.3390/molecules28083487 - 15 Apr 2023

Cited by 3 | Viewed by 2041

Abstract

This work analyzes the performance of 250 electronic structure theory methods (including 240 density functional approximations) for the description of spin states and the binding properties of iron, manganese, and cobalt porphyrins. The assessment employs the Por21 database of high-level computational data (CASPT2 [...] Read more.

This work analyzes the performance of 250 electronic structure theory methods (including 240 density functional approximations) for the description of spin states and the binding properties of iron, manganese, and cobalt porphyrins. The assessment employs the Por21 database of high-level computational data (CASPT2 reference energies taken from the literature). Results show that current approximations fail to achieve the “chemical accuracy” target of 1.0 kcal/mol by a long margin. The best-performing methods achieve a mean unsigned error (MUE) <15.0 kcal/mol, but the errors are at least twice as large for most methods. Semilocal functionals and global hybrid functionals with a low percentage of exact exchange are found to be the least problematic for spin states and binding energies, in agreement with the general knowledge in transition metal computational chemistry. Approximations with high percentages of exact exchange (including range-separated and double-hybrid functionals) can lead to catastrophic failures. More modern approximations usually perform better than older functionals. An accurate statistical analysis of the results also casts doubts on some of the reference energies calculated using multireference methods. Suggestions and general guidelines for users are provided in the conclusions. These results hopefully stimulate advances for both the wave function and the density functional side of electronic structure calculations. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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10 pages, 2451 KiB

Open AccessArticle

Chiral Porphyrin Assemblies Investigated by a Modified Reflectance Anisotropy Spectroscopy Spectrometer

by Ilaria Tomei, Beatrice Bonanni, Anna Sgarlata, Massimo Fanfoni, Roberto Martini, Ilaria Di Filippo, Gabriele Magna, Manuela Stefanelli, Donato Monti, Roberto Paolesse and Claudio Goletti

Molecules 2023, 28(8), 3471; https://doi.org/10.3390/molecules28083471 - 14 Apr 2023

Cited by 1 | Viewed by 1192

Abstract

Reflectance anisotropy spectroscopy (RAS) has been largely used to investigate organic compounds: Langmuir–Blodgett and Langmuir–Schaeffer layers, the organic molecular beam epitaxy growth in situ and in real time, thin and ultrathin organic films exposed to volatiles, in ultra-high vacuum (UHV), in controlled atmosphere [...] Read more.

Reflectance anisotropy spectroscopy (RAS) has been largely used to investigate organic compounds: Langmuir–Blodgett and Langmuir–Schaeffer layers, the organic molecular beam epitaxy growth in situ and in real time, thin and ultrathin organic films exposed to volatiles, in ultra-high vacuum (UHV), in controlled atmosphere and even in liquid. In all these cases, porphyrins and porphyrin-related compounds have often been used, taking advantage of the peculiar characteristics of RAS with respect to other techniques. The technical modification of a RAS spectrometer (CD-RAS: circular dichroism RAS) allows us to investigate the circular dichroism of samples instead of the normally studied linear dichroism: CD-RAS measures (in transmission mode) the anisotropy of the optical properties of a sample under right and left circularly polarized light. Although commercial spectrometers exist to measure the circular dichroism of substances, the “open structure” of this new spectrometer and its higher flexibility in design makes it possible to couple it with UHV systems or other experimental configurations. The importance of chirality in the development of organic materials (from solutions to the solid state, as thin layers deposited—in liquid or in vacuum—on transparent substrates) could open interesting possibilities to a development in the investigation of the chirality of organic and biological layers. In this manuscript, after the detailed explanation of the CD-RAS technique, some calibration tests with chiral porphyrin assemblies in solution or deposited in solid film are reported to demonstrate the quality of the results, comparing curves obtained with CD-RAS and a commercial spectrometer. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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12 pages, 2970 KiB

Open AccessArticle

Increasing Reaction Rates of Water-Soluble Porphyrins for ⁶⁴Cu Radiopharmaceutical Labeling

by Mateusz Pęgier, Krzysztof Kilian and Krystyna Pyrzynska

Molecules 2023, 28(5), 2350; https://doi.org/10.3390/molecules28052350 - 03 Mar 2023

Cited by 2 | Viewed by 1309

Abstract

Searching for new compounds and synthetic routes for medical applications is a great challenge for modern chemistry. Porphyrins, natural macrocycles able to tightly bind metal ions, can serve as complexing and delivering agents in nuclear medicine diagnostic imaging utilizing radioactive nuclides of copper [...] Read more.

Searching for new compounds and synthetic routes for medical applications is a great challenge for modern chemistry. Porphyrins, natural macrocycles able to tightly bind metal ions, can serve as complexing and delivering agents in nuclear medicine diagnostic imaging utilizing radioactive nuclides of copper with particular emphasis on ⁶⁴Cu. This nuclide can, due to multiple decay modes, serve also as a therapeutic agent. As the complexation reaction of porphyrins suffers from relatively poor kinetics, the aim of this study was to optimize the reaction of copper ions with various water-soluble porphyrins in terms of time and chemical conditions, that would meet pharmaceutical requirements and to develop a method that can be applied for various water-soluble porphyrins. In the first method, reactions were conducted in a presence of a reducing agent (ascorbic acid). Optimal conditions, in which the reaction time was 1 min, comprised borate buffer at pH 9 with a 10-fold excess of ascorbic acid over Cu²⁺. The second approach involved a microwave-assisted synthesis at 140 °C for 1–2 min. The proposed method with ascorbic acid was applied for radiolabeling of porphyrin with ⁶⁴Cu. The complex was then subjected to a purification procedure and the final product was identified using high-performance liquid chromatography with radiometric detection. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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18 pages, 3327 KiB

Open AccessArticle

Sulfonamide Porphyrins as Potent Photosensitizers against Multidrug-Resistant Staphylococcus aureus (MRSA): The Role of Co-Adjuvants

by Sofia N. Sarabando, Cristina J. Dias, Cátia Vieira, Maria Bartolomeu, Maria G. P. M. S. Neves, Adelaide Almeida, Carlos J. P. Monteiro and Maria Amparo F. Faustino

Molecules 2023, 28(5), 2067; https://doi.org/10.3390/molecules28052067 - 22 Feb 2023

Cited by 3 | Viewed by 1524

Abstract

Sulfonamides are a conventional class of antibiotics that are well-suited to combat infections. However, their overuse leads to antimicrobial resistance. Porphyrins and analogs have demonstrated excellent photosensitizing properties and have been used as antimicrobial agents to photoinactivate microorganisms, including multiresistant Staphylococcus aureus (MRSA) [...] Read more.

Sulfonamides are a conventional class of antibiotics that are well-suited to combat infections. However, their overuse leads to antimicrobial resistance. Porphyrins and analogs have demonstrated excellent photosensitizing properties and have been used as antimicrobial agents to photoinactivate microorganisms, including multiresistant Staphylococcus aureus (MRSA) strains. It is well recognized that the combination of different therapeutic agents might improve the biological outcome. In this present work, a novel meso-arylporphyrin and its Zn(II) complex functionalized with sulfonamide groups were synthesized and characterized and the antibacterial activity towards MRSA with and without the presence of the adjuvant KI was evaluated. For comparison, the studies were also extended to the corresponding sulfonated porphyrin TPP(SO₃H)₄. Photodynamic studies revealed that all porphyrin derivatives were effective in photoinactivating MRSA (>99.9% of reduction) at a concentration of 5.0 μM upon white light radiation with an irradiance of 25 mW cm⁻² and a total light dose of 15 J cm⁻². The combination of the porphyrin photosensitizers with the co-adjuvant KI during the photodynamic treatment proved to be very promising allowing a significant reduction in the treatment time and photosensitizer concentration by six times and at least five times, respectively. The combined effect observed for TPP(SO₂NHEt)₄ and ZnTPP(SO₂NHEt)₄ with KI seems to be due to the formation of reactive iodine radicals. In the photodynamic studies with TPP(SO₃H)₄ plus KI, the cooperative action was mainly due to the formation of free iodine (I₂). Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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26 pages, 5685 KiB

Open AccessArticle

Synthesis of New Amino-Functionalized Porphyrins:Preliminary Study of Their Organophotocatalytic Activity

by Pol Torres, Marian Guillén, Marc Escribà, Joaquim Crusats and Albert Moyano

Molecules 2023, 28(4), 1997; https://doi.org/10.3390/molecules28041997 - 20 Feb 2023

Cited by 2 | Viewed by 2512

Abstract

The design, synthesis, and initial study of amino-functionalized porphyrins as a new class of bifunctional catalysts for asymmetric organophotocatalysis is described. Two new types of amine–porphyrin hybrids derived from 5,10,15,20-tetraphenylporphyrin (TPPH₂), in which a cyclic secondary amine moiety is covalently linked [...] Read more.

The design, synthesis, and initial study of amino-functionalized porphyrins as a new class of bifunctional catalysts for asymmetric organophotocatalysis is described. Two new types of amine–porphyrin hybrids derived from 5,10,15,20-tetraphenylporphyrin (TPPH₂), in which a cyclic secondary amine moiety is covalently linked either to a β-pyrrolic position (Type A) or to the p-position of one of the meso phenyl groups (Type B), were prepared by condensation, reductive amination, or amidation reactions from the suitable porphyrins (either formyl or methanamine derivatives) with readily available chiral amines. A preliminary study of the possible use of Type A amine–porphyrin hybrids as asymmetric, bifunctional organophotocatalysts was performed using the chiral, imidazolidinone-catalyzed Diels–Alder cycloaddition between cyclopentadiene 28 and trans-cinnamaldehyde 29 as a benchmark reaction. The yield and the stereochemical outcome of this process, obtained under purely organocatalytic conditions, under dual organophocatalysis, and under bifunctional organophotocatalysis, were compared. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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24 pages, 7906 KiB

Open AccessArticle

Interaction of Some Asymmetrical Porphyrins with U937 Cell Membranes–In Vitro and In Silico Studies

by Dragos Paul Mihai, Rica Boscencu, Gina Manda, Andreea Mihaela Burloiu, Georgiana Vasiliu, Ionela Victoria Neagoe, Radu Petre Socoteanu and Dumitru Lupuliasa

Molecules 2023, 28(4), 1640; https://doi.org/10.3390/molecules28041640 - 08 Feb 2023

Cited by 2 | Viewed by 1453

Abstract

The aim of the present study was to assess the effects exerted in vitro by three asymmetrical porphyrins (5-(2-hydroxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl)porphyrin, 5-(2-hydroxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl)porphyrinatozinc(II), and 5-(2-hydroxyphenyl)-10,15,20–tris-(4-acetoxy-3-methoxyphenyl)porphyrinatocopper(II)) on the transmembrane potential and the membrane anisotropy of U937 cell lines, using bis-(1,3-dibutylbarbituric acid)trimethine oxonol (DiBAC4(3)) and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate (TMA-DPH), [...] Read more.

The aim of the present study was to assess the effects exerted in vitro by three asymmetrical porphyrins (5-(2-hydroxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl)porphyrin, 5-(2-hydroxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl)porphyrinatozinc(II), and 5-(2-hydroxyphenyl)-10,15,20–tris-(4-acetoxy-3-methoxyphenyl)porphyrinatocopper(II)) on the transmembrane potential and the membrane anisotropy of U937 cell lines, using bis-(1,3-dibutylbarbituric acid)trimethine oxonol (DiBAC4(3)) and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate (TMA-DPH), respectively, as fluorescent probes for fluorescence spectrophotometry. The results indicate the hyperpolarizing effect of porphyrins in the concentration range of 0.5, 5, and 50 μM on the membrane of human U937 monocytic cells. Moreover, the tested porphyrins were shown to increase membrane anisotropy. Altogether, the results evidence the interaction of asymmetrical porphyrins with the membrane of U937 cells, with potential consequences on cellular homeostasis. Molecular docking simulations, and Molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) free energy of binding calculations, supported the hypothesis that the investigated porphyrinic compounds could potentially bind to membrane proteins, with a critical role in regulating the transmembrane potential. Thus, both the free base porphyrins and the metalloporphyrins could bind to the SERCA2b (sarco/endoplasmic reticulum ATPase isoform 2b) calcium pump, while the metal complexes may specifically interact and modulate calcium-dependent (large conductance calcium-activated potassium channel, Slo1/KCa1.1), and ATP-sensitive (K_ATP), potassium channels. Further studies are required to investigate these interactions and their impact on cellular homeostasis and functionality. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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20 pages, 7926 KiB

Open AccessArticle

Effects of Substituents on the Photophysical/Photobiological Properties of Mono-Substituted Corroles

by Vitória Barbosa de Souza, Vinícius N. da Rocha, Paulo Cesar Piquini, Otávio Augusto Chaves and Bernardo A. Iglesias

Molecules 2023, 28(3), 1385; https://doi.org/10.3390/molecules28031385 - 01 Feb 2023

Cited by 2 | Viewed by 1380

Abstract

The trans-A₂B-corrole series was prepared starting with 5-(pentafluorophenyl)dipyrromethene, which was then reacted with respective aryl-substituted aldehyde by Gryko synthesis. It was further characterized by HRMS and electrochemical methods. In addition, we investigated experimental photophysical properties (absorption, emission by steady-state and [...] Read more.

The trans-A₂B-corrole series was prepared starting with 5-(pentafluorophenyl)dipyrromethene, which was then reacted with respective aryl-substituted aldehyde by Gryko synthesis. It was further characterized by HRMS and electrochemical methods. In addition, we investigated experimental photophysical properties (absorption, emission by steady-state and time-resolved fluorescence) in several solvents and TDDFT calculations, aggregation, photostability and reactive oxygen species generation (ROS), which are relevant when selecting photosensitizers used in photodynamic therapy and many other photo-applications. In addition, we also evaluated the biomolecule-binding properties with CT-DNA and HSA by spectroscopy, viscometry and molecular docking calculations assays. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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12 pages, 942 KiB

Open AccessArticle

Selective Determination of Glutathione Using a Highly Emissive Fluorescent Probe Based on a Pyrrolidine-Fused Chlorin

by Francisco G. Moscoso, Carla Queirós, Paula González, Tânia Lopes-Costa, Ana M. G. Silva and Jose M. Pedrosa

Molecules 2023, 28(2), 568; https://doi.org/10.3390/molecules28020568 - 05 Jan 2023

Cited by 1 | Viewed by 1321

Abstract

We report the use of a carboxylated pyrrolidine-fused chlorin (TCPC) as a fluorescent probe for the determination of glutathione (GSH) in 7.4 pH phosphate buffer. TCPC is a very stable, highly emissive molecule that has been easily obtained from meso-tetrakis(4-methoxycarbonylphenyl) porphyrin (TCPP) through [...] Read more.

We report the use of a carboxylated pyrrolidine-fused chlorin (TCPC) as a fluorescent probe for the determination of glutathione (GSH) in 7.4 pH phosphate buffer. TCPC is a very stable, highly emissive molecule that has been easily obtained from meso-tetrakis(4-methoxycarbonylphenyl) porphyrin (TCPP) through a 1,3-dipolar cycloaddition approach. First, we describe the coordination of TCPC with Hg(II) ions and the corresponding spectral changes, mainly characterized by a strong quenching of the chlorin emission band. Then, the TCPC-Hg²⁺ complex exhibits a significant fluorescence turn-on in the presence of low concentrations of the target analyte GSH. The efficacy of the sensing molecule was tested by using different TCPC:Hg²⁺ concentration ratios (1:2, 1:5 and 1:10) that gave rise to sigmoidal response curves in all cases with modulating detection limits, being the lowest 40 nM. The experiments were carried out under physiological conditions and the selectivity of the system was demonstrated against a number of potential interferents, including cysteine. Furthermore, the TCPC macrocycle did not showed a significant fluorescent quenching in the presence of other metal ions. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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20 pages, 4304 KiB

Open AccessArticle

Panchromatic Absorbers Tethered for Bioconjugation or Surface Attachment

by Rui Liu, Jie Rong, Zhiyuan Wu, Masahiko Taniguchi, David F. Bocian, Dewey Holten and Jonathan S. Lindsey

Molecules 2022, 27(19), 6501; https://doi.org/10.3390/molecules27196501 - 01 Oct 2022

Cited by 1 | Viewed by 1495

Abstract

The syntheses of two triads are reported. Each triad is composed of two perylene-monoimides linked to a porphyrin via an ethyne unit, which bridges the perylene 9-position and a porphyrin 5- or 15-position. Each triad also contains a single tether composed of an [...] Read more.

The syntheses of two triads are reported. Each triad is composed of two perylene-monoimides linked to a porphyrin via an ethyne unit, which bridges the perylene 9-position and a porphyrin 5- or 15-position. Each triad also contains a single tether composed of an alkynoic acid or an isophthalate unit. Each triad provides panchromatic absorption (350–700 nm) with fluorescence emission in the near-infrared region (733 or 743 nm; fluorescence quantum yield ~0.2). The syntheses rely on the preparation of trans-AB-porphyrins bearing one site for tether attachment (A), an aryl group (B), and two open meso-positions. The AB-porphyrins were prepared by the condensation of a 1,9-diformyldipyrromethane and a dipyrromethane. The installation of the two perylene-monoimide groups was achieved upon the 5,15-dibromination of the porphyrin and the subsequent copper-free Sonogashira coupling, which was accomplished before or after the attachment of the tether. The syntheses provide relatively straightforward access to a panchromatic absorber for use in bioconjugation or surface-attachment processes. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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14 pages, 2315 KiB

Open AccessArticle

Photodynamic Inactivation of Microorganisms Using Semisynthetic Chlorophyll a Derivatives as Photosensitizers

by Marciana Pierina Uliana, Andréia da Cruz Rodrigues, Bruno Andrade Ono, Sebastião Pratavieira, Kleber Thiago de Oliveira and Cristina Kurachi

Molecules 2022, 27(18), 5769; https://doi.org/10.3390/molecules27185769 - 06 Sep 2022

Cited by 7 | Viewed by 1489

Abstract

In this study, we describe the semisynthesis of cost-effective photosensitizers (PSs) derived from chlorophyll a containing different substituents and using previously described methods from the literature. We compared their structures when used in photodynamic inactivation (PDI) against Staphylococcus aureus, Escherichia coli, [...] Read more.

In this study, we describe the semisynthesis of cost-effective photosensitizers (PSs) derived from chlorophyll a containing different substituents and using previously described methods from the literature. We compared their structures when used in photodynamic inactivation (PDI) against Staphylococcus aureus, Escherichia coli, and Candida albicans under different conditions. The PSs containing carboxylic acids and butyl groups were highly effective against S. aureus and C. albicans following our PDI protocol. Overall, our results indicate that these nature-inspired PSs are a promising alternative to selectively inactivate microorganisms using PDI. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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14 pages, 3246 KiB

Open AccessArticle

Biophysical Characterization of the Interaction between a Transport Human Plasma Protein and the 5,10,15,20-Tetra(pyridine-4-yl)porphyrin

by Otávio Augusto Chaves, Bernardo A. Iglesias and Carlos Serpa

Molecules 2022, 27(16), 5341; https://doi.org/10.3390/molecules27165341 - 22 Aug 2022

Cited by 9 | Viewed by 1454

Abstract

The interaction between human serum albumin (HSA) and the non-charged synthetic photosensitizer 5,10,15,20-tetra(pyridine-4-yl)porphyrin (4-TPyP) was evaluated by in vitro assays under physiological conditions using spectroscopic techniques (UV-vis, circular dichroism, steady-state, time-resolved, synchronous, and 3D-fluorescence) combined with in silico calculations by molecular docking. The [...] Read more.

The interaction between human serum albumin (HSA) and the non-charged synthetic photosensitizer 5,10,15,20-tetra(pyridine-4-yl)porphyrin (4-TPyP) was evaluated by in vitro assays under physiological conditions using spectroscopic techniques (UV-vis, circular dichroism, steady-state, time-resolved, synchronous, and 3D-fluorescence) combined with in silico calculations by molecular docking. The UV-vis and steady-state fluorescence parameters indicated a ground-state association between HSA and 4-TPyP and the absence of any dynamic fluorescence quenching was confirmed by the same average fluorescence lifetime for HSA without (4.76 ± 0.11 ns) and with 4-TPyP (4.79 ± 0.14 ns). Therefore, the Stern–Volmer quenching (K_SV) constant reflects the binding affinity, indicating a moderate interaction (10⁴ M⁻¹) being spontaneous (ΔG°= -25.0 kJ/mol at 296 K), enthalpically (ΔH° = -9.31 ± 1.34 kJ/mol), and entropically (ΔS° = 52.9 ± 4.4 J/molK) driven. Binding causes only a very weak perturbation on the secondary structure of albumin. There is just one main binding site in HSA for 4-TPyP (n ≈ 1.0), probably into the subdomain IIA (site I), where the Trp-214 residue can be found. The microenvironment around this fluorophore seems not to be perturbed even with 4-TPyP interacting via hydrogen bonding and van der Waals forces with the amino acid residues in the subdomain IIA. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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34 pages, 17765 KiB

Open AccessReview

Porphyrin Macrocycles: General Properties and Theranostic Potential

by Rica Boscencu, Natalia Radulea, Gina Manda, Isabel Ferreira Machado, Radu Petre Socoteanu, Dumitru Lupuliasa, Andreea Mihaela Burloiu, Dragos Paul Mihai and Luis Filipe Vieira Ferreira

Molecules 2023, 28(3), 1149; https://doi.org/10.3390/molecules28031149 - 23 Jan 2023

Cited by 7 | Viewed by 3136

Abstract

Despite specialists’ efforts to find the best solutions for cancer diagnosis and therapy, this pathology remains the biggest health threat in the world. Global statistics concerning deaths associated with cancer are alarming; therefore, it is necessary to intensify interdisciplinary research in order to [...] Read more.

Despite specialists’ efforts to find the best solutions for cancer diagnosis and therapy, this pathology remains the biggest health threat in the world. Global statistics concerning deaths associated with cancer are alarming; therefore, it is necessary to intensify interdisciplinary research in order to identify efficient strategies for cancer diagnosis and therapy, by using new molecules with optimal therapeutic potential and minimal adverse effects. This review focuses on studies of porphyrin macrocycles with regard to their structural and spectral profiles relevant to their applicability in efficient cancer diagnosis and therapy. Furthermore, we present a critical overview of the main commercial formulations, followed by short descriptions of some strategies approached in the development of third-generation photosensitizers. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application)

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