Porphyrin Derivatives Research Articles

Front Cover: Synthesis, Photophysics, Computational Approaches, and Biomolecule Interactive Studies of Metalloporphyrins Containing Pyrenyl Units: Influence of the Metal Center (Eur. J. Inorg. Chem. 12/2022)

The Front Cover shows the design of meso-tetra-(1-pyrenyl)porphyrin derivatives, which interact with biomolecules. These porphyrins were fully characterized by photophysical and theoretical methods. The presence of metal species in the porphyrin core influences the ground and excited states. Biomolecule interaction experiments show that these porphyrins interact spontaneously in the minor groove of CT-DNA and in subdomain IB in the BSA pocket. The interaction depends on the nature of the metal ion. The cover was designed by Júlio A. F. Arvellos (scientific designer). More information can be found in the Research Article by B. Almeida Iglesias and co-workers.

In Situ Graded Passivation via Porphyrin Derivative with Enhanced Photovoltage and Fill Factor in Perovskite Solar Cells

Perovskite Solar Cells In article number 2100964, Bao Zhang, Mohammad Khaja Nazeeruddin, Yi Zhang, and co-workers developed a type of perovskite solar cells with a graded-passivation of the perovskite layer by using a new D-π-A-like type zinc pyridine porphyrin derivative as a passivation molecular via the antisolvent process. This strategy significantly improved the quality of perovskite films and reduced their defects.

Spectroscopy analysis of the alignment of nanoassemblies of DNA-wrapped carbon nanotubes in stretched gelatin film

We present the polarized Raman studies and light absorption study of nanoassemblies of DNA-wrapped single-walled carbon nanotubes (SWNTs) incorporated into the gelatin film. Nanoassemblies are formed in aqueous suspension with SWNTs:DNA by positively charged 5,10,15,20-tetrakis-(N-methyl-4-pyridyl) porphyrin (TMPyP4). The gelatin film with embedded nanoassemblies was exposed to a mechanical stretching to about 300% tensile strain for making an alignment along a chosen direction. The analysis of the absorption spectra taken along and normal to the stretching direction revealed the strong polarized dependence. The polarized Raman spectra of the stretched gelatin film showed the angular dependence of the integrated intensity of tangential mode of SWNTs that allowed to estimate the alignment degree. It showed that about 60% of the SWNT nanoassemblies are aligned in the range of ± 15° to the direction of the stretching. The addition of the porphyrin derivative does not impede the orientation of the SWNTs:DNA nanohybrids along the stretching direction. The performed studies of embedded SWNTs:DNA:TMPyP4 nanoassemblies in the flexible gelatin film are intended to show the simple method for obtaining the controlled ordered biocompatible nanotube networks functionalized by the porphyrin derivatives inside a polymer matrix.

Regulation of the Assembled Structure of a Flexible Porphyrin Derivative Containing Tetra Isophthalic Acids by Coronene or Different Pyridines.

Based on previous research, a new coassembly formed by a porphyrin derivative (IPETPP), which contains a flexible substituent of m-phthalic acid, is observed with coronene (COR) molecules at a higher concentration. Besides, a fresh IPETPP self-assembly formed at a lower concentration and another new coassembly with COR molecules are obtained. Moreover, the addition of a series of bipyridines alters the diamond arrangement of IPETPP, which enhances the stability of the two-component structures. It is unprecedented that bipyridine derivatives break intermolecular hydrogen bonds containing m-phthalic acid substituents. All the coassemblies are investigated by scanning tunneling microscopy on a highly oriented pyrolytic graphite. Combined with density functional theory, the formation mechanism of the assembled structures is revealed. These results would contribute to understanding the interfacial crystal behaviors and probably provide an efficient pathway to regulate the binary structures.

Effect of meso Positioned Substituents on the Stability and Photodynamic Activity of Lipid-Membrane-Incorporated Porphyrin Derivatives.

In this study we prepared aqueous solutions of lipid-membrane incorporated tetraarylporphyrins and tetrapyridylporphyrin (LMIPors) by the injection method using dimethyl sulfoxide. The porphyrins with proton-donor groups at the meso position afforded stable aqueous solutions of LMIPors. However, although tetrakis(carboxyphenyl)porphyrin was scarcely incorporated in lipid membranes, it was soluble in water. Among these LMIPors, the photodynamic activity of tetrakis(hydroxyphenyl)porphyrin was higher than that of tetrakis(aminophenyl)porphyrin. This was attributed to the self-aggregation of a part of tetrakis(aminophenyl)porphyrin in the liposomes, which induced self-quenching and the consequent decrease of its photodynamic activity.

Efficient Decrease in Corrosion of Steel in 0.1 M HCl Medium Realized by a Coating with Thin Layers of MnTa2O6 and Porphyrins Using Suitable Laser-Type Approaches.

The purpose of this research is to meet current technical and ecological challenges by developing novel steel coating systems specifically designed for mechanical equipment used in aggressive acid conditions. Homogeneous sandwich-type layered films on the surface of steel electrodes were realized using a pseudo-binary oxide, MnTa2O6, and two different substituted porphyrin derivatives, namely: 5-(4-carboxy-phenyl)-10,15,20-tris (4-methyl-phenyl)-porphyrin and 5-(4-methyl-benzoate)-10,15,20-tris (4-methyl-phenyl)-porphyrin, which are novel investigated compound pairs. Two suitable laser strategies, pulsed laser deposition (PLD) and matrix-assisted pulsed laser evaporation (MAPLE), were applied in order to prevent porphyrin decomposition and to create smooth layers with low porosity that are extremely adherent to the surface of steel. The electrochemical measurements of corrosion-resistant coating performance revealed that in all cases in which the steel electrodes were protected, a significant value of corrosion inhibition efficiency was found, ranging from 65.6 to 83.7%, depending on the nature of the porphyrin and its position in the sandwich layer. The highest value (83.7%) was obtained for the MAPLE/PLD laser deposition of 5-(4-carboxy-phenyl)-10,15,20-tris (4-methyl-phenyl)-porphyrin/MnTa2O6(h), meaning that the inhibitors adsorbed and blocked the access of the acid to the active sites of the steel electrodes.

Metal Free Porphyrin Photocatalyst Comprising Ionic Liquid with Electron Donor Acceptor Moiety for Visible Light Assisted Oxidative Amination

AbstractMetal leaching and stability of heterogeneous catalysts is the main concern in pharmaceutical, fine chemical industries, enhancing metal contamination of the product. In this protocol, we report design and characterizations of a metal free porphyrin (MFPc) photocatalyst with electron donor acceptor (dicyano) moiety, for oxidative amination of benzyl amine under irradiation of 5 W LED light in a home‐made photoreactor. Contrasted with the poor photocatalytic property of different derivatives of porphyrins, MFPc presents a significant improvement in imine formation (83 %). The influence of various factors including quantity of catalyst, duration, and intensity of light (512 W), for oxidative amination were explored. MFPc with favourable properties like Hammett acidity (1.11), band gap (1.37 eV), explored for the synthesis of pharmaceutically important benzimidazole, from o‐phenylene diamine. Moreover, MFPc displayed good reusability for 6 consecutive runs with negligible decrease in yield of imine at ambient reaction conditions. Additionally, a probable mechanism for imine formation was proposed.

Study on the synthesis, physicochemical, electrochemical properties, molecular structure and antifungal activities of the 4-pyrrolidinopyridine Mg(II) meso-tetratolylporphyrin complex

A novel magnesium(II) metalloporphyrin namely the bis(4-pyrrolidinopyridine)[meso-tetra(p-tolyl)porphyrinato)]magnesium(II) dichloromethane desolate complex with the formula [Mg(TTP)(4-pypo)2]·CH2Cl2 (I) has been synthetized and fully characterized by UV–Vis, fluorescence, IR, 1H NMR spectroscopy and mass spectrometry. The X-ray molecular structure shows that I presents two molecules (1 and 2) [Mg1(TTP)(4-pypo)2] and [Mg2(TTP)(4-pypo)2] in the asymmetric unit while the Hirshfeld surface analysis on this hexacoordinated Mg(II) porphyrin species indicates that the crystal lattice is mainly sustained by C__H…C, C__H…Cg (Cg is the centroid of a phenyl ring) and C__H…Cl intermolecular interactions. The cyclic voltammetry data of I is also reported. The bioactivity of the H2TTP, the [Mg(TTP)] starting material and [Mg(TTP)(4-pypo)2]·CH2Cl2 (I) was evaluated in vitro, by examining their inhibitory effect against three strains of Candida viz. C. albicans, C. glabrata and C. tropicalis with MIC values in the range 2.5 to 10 µg.mL−1. The screening of the susceptibility of M. canis and T. rubrum clinical strains on the three porphyrinic derivatives is also reported.

An Oxidant- and Catalyst-Free Electrooxidative Cross-Coupling Approach to Synthesize meso-Substituted Porphyrin Derivatives.

The synthesis of porphyrin and chlorin derivatives has attracted significant attention due to their numerous applications. Herein, we report an environment friendly oxidant- and catalyst-free electrooxidative cross-coupling approach for multiple coupling reactions to synthesize meso C-N, C-O, and C-S substituted porphyrin and chlorin derivatives. For C-N cross-coupling reactions, diaminated porphyrins were obtained as the main products, while using 4-bromo-2,6-dimethyl aniline resulted in monoaminated product. Similarly, electrochemical catalysis of porphyrins with phenol and thiophene produced meso-disubstituted porphyrins in moderate yields under a smaller current. Chlorins were also applicable, and 20-substituted products were efficiently produced regioselectively. To the best of our knowledge, this work represents the first example of electrooxidative C-X cross-coupling of porphyrins and chlorins.

Synthesis, Characterization, and Hydrogen Evolution Activity of Metallo-meso-(4-fluoro-2,6-dimethylphenyl)porphyrin Derivatives.

Zn(II), Cu(II), and Ni(II) 5,10,15,20-tetrakis(4-fluoro-2,6-dimethylphenyl)porphyrins (TFPs) have been synthesized and characterized. The electronic spectroscopy and cyclic voltammetry of these compounds, along with the free-base macrocycle (2H-TFP), have been determined; 2H-TFP was also structurally characterized by X-ray crystallography. The Cu(II)TFP exhibits catalytic activity for the hydrogen evolution reaction (HER). The analysis of linear sweep voltammograms shows that the HER reaction of Cu(II)TFP with benzoic acid is first-order in proton concentration with an average apparent rate constant for HER catalysis of kapp = 5.79 ± 0.47 × 103 M–1 s–1.

Facile construction of luminescent silicone elastomers from the compatibilization of porphyrins via the Piers-Rubinsztajn reaction

In this work, in order to improve the low solubility and expand the applications of porphyrins in polysiloxanes, a series of designed siloxane-modified porphyrin derivatives was fabricated based on the Piers-Rubinsztajn reaction. The solubility of the porphyrin derivatives in polysiloxanes could be controlled by adjusting the siloxane chain length. Furthermore, the silicone-modified porphyrin derivatives were doped into a silicone elastomer prepolymer to obtain luminescent elastomers, which also showed good transparency and interfacial stability. In addition, the thermal stability and mechanical properties were well preserved compared with the original elastomer. Finally, based on the above-mentioned properties, an organosilicon elastomer doped with porphyrin showed good processability and plasticity, and could be fabricated into various complex three-dimensional models.

Capillary Gas Chromatographic Separation Performances of a Tetraphenyl Porphyrin Stationary Phase

Tetraphenyl porphyrin (TPP) has enormous potential for use as gas chromatography stationary phases because it has a distinctive extended π–π conjugated coplanar structure and a range of interesting properties such as a good solubility in dichloromethane, high melting point, and good thermal stability. In this work, a TPP column was successfully prepared using a static method. The column was nonpolar and had a high efficiency. The chromatographic selectivity of the TPP column was assessed. The TPP column showed superiority retention and higher resolution for alicyclic, aromatic molecules through ring matching and π-π stacking interaction comparable to HP-5MS column. The unique mechanisms through which the TPP column retained polychlorinated biphenyls allowed the peak pair of 2,2ʹ,5-trichlorobiphenyl and 4,4ʹ-dichlorobiphenyl to be resolved better on the TPP column than the HP-5MS column. The TPP column was thermally stable even at 260°C for 2 h and gave results of a high degree of precision (run-to-run and column-to-column) with relative standard deviations <0.05% and <4.96%, respectively. The results indicated that porphyrin derivatives will be useful gas chromatography stationary phases.

Synthesis and study of fluorine-functionalized ZnTPPs

Five fluorinated zinc tetraphenyl porphyrins derivatives, fluorinated either on all ortho positions of the meso phenyl rings (Zn(II)-5,10,15,20-tetrakis(2,6-difluorophenyl)porphyrin) or in [Formula: see text]-positions with two, four, six or eight fluorine groups (2,3-difluoro-5,10,15,20-tetraphenylporphyrin, 7, 8,17,18-tetrafluoro-5,10,15,20-tetraphenylporphyrin, 7,8,12,13,17,18-hexafluoro-5,10,15,20-tetraphenyl- porphyrin and 2,3,7,8,12,13,17,18-octafluoro-5,10,15,20-tetraphenylporphyrin, respectively), were studied to probe the effect of fluorine in on-surface synthesis approaches. Additionally, bulkier substituents have been used in 7,8,17,18-tetrabromo-5,10,15,20-tetraphenylporphyrin and 7,8,17,18-tetramethyl-5,10,15,20-tetraphenylporphyrin, for a direct comparison with the corresponding fluorinated compounds. Reported are the synthesis and electronic structure characterization of the compounds, using UV-vis absorption and fluorescence spectroscopies as well as electronic structure calculations of the ground state molecular properties. Steric and electronic effects of fluorination are explored. For all molecules studied, substitution with fluorine maintains a planar tetrapyrrole macrocycle and shifts in the absorption spectra were consistent with calculated changes in the HOMOs and LUMOs energies of the molecules. In contrast, the bromo and methyl-substituted derivatives exhibit chemical instability and spectral shifts, compared to parent compound ZnTPP, consistent with structural distortions and accounted for calculations. The site-specific effects of fluorination on the electronic structure are discussed in detail.

Nanoplatform Self-Assembly from Small Molecules of Porphyrin Derivatives for NIR-II Fluorescence Imaging Guided Photothermal-Immunotherapy.

Combinatorial photothermal and immunotherapy have demonstrated great potential to remove primary tumors, suppress metastases, and prevent tumor recurrence. However, this strategy still confronts patients with many limitations, such as complex components, sophisticated construction, and inadequate therapeutic efficacy. In this work, small molecules of porphyrin derivatives (PPor) which can self-assemble into monodispersed nanoparticles without supplement of any other ingredients or surfactants are developed. The formed PPor nanoparticles (PPor NPs) exhibit highly photothermal conversion efficiency of 70% and NIR-II luminous abilities originate from the strong intramolecular charge transfer (ICT) effect of D-A structure under 808nm laser irradiation, thus achieving NIR-II fluorescence imaging guided photothermal therapy (PTT) against primary tumors with a high cure rate. More importantly, tumor-associated antigens (TAAs), together with damage-associated molecular patterns (DAMPs) released from PTT-treated cancer cells, are proved to elicit immune responses to some degree. After combination with programmed cell death-1 (PD-1) antibodies, a robust systematic antitumor immunity is generated to restrain both primary and abscopal tumors growth, prolong survival, and prevent pulmonary metastasis on an aggressive 4T1 murine breast tumor model. Thus, this study provides a promising therapeutic paradigm with porphyrin derivatives nano-assembly as phototheranostic agents for the treatment of aggressive tumors with high efficiency.

Activatable Persistent Luminescence from Porphyrin Derivatives and Supramolecular Probes with Imaging‐Modality Transformable Characteristics for Improved Biological Applications**

AbstractPersistent luminescence without excitation light and tissue autofluorescence interference holds great promise for biological applications, but is limited by available materials with long‐wavelength emission and excellent clinical potential. Here, we report that porphyrin derivatives can emit near‐infrared persistent luminescence over 60 min after cessation of excitation light or on interaction with peroxynitrite. A plausible mechanism of the successive oxidation of vinylene bonds was demonstrated. A supramolecular probe with a β‐sheet structure was constructed to enhance the tumor targeting ability and the photoacoustic and persistent luminescence signals. Such probes featuring light‐triggered function transformation from photoacoustic imaging to persistent luminescence imaging permit advanced image‐guided cancer surgery. Furthermore, peroxynitrite‐activated persistent luminescence of the supramolecular probe also enables rapid and precise screening of immunogenic cell death drugs.

Activatable Persistent Luminescence from Porphyrin Derivatives and Supramolecular Probes with Imaging‐Modality Transformable Characteristics for Improved Biological Applications**

AbstractPersistent luminescence without excitation light and tissue autofluorescence interference holds great promise for biological applications, but is limited by available materials with long‐wavelength emission and excellent clinical potential. Here, we report that porphyrin derivatives can emit near‐infrared persistent luminescence over 60 min after cessation of excitation light or on interaction with peroxynitrite. A plausible mechanism of the successive oxidation of vinylene bonds was demonstrated. A supramolecular probe with a β‐sheet structure was constructed to enhance the tumor targeting ability and the photoacoustic and persistent luminescence signals. Such probes featuring light‐triggered function transformation from photoacoustic imaging to persistent luminescence imaging permit advanced image‐guided cancer surgery. Furthermore, peroxynitrite‐activated persistent luminescence of the supramolecular probe also enables rapid and precise screening of immunogenic cell death drugs.

Structural and nanomechanical assessment of photosensitization induced membrane disruption

Photosensitization is a treatment modality that made into the first-line treatment as well. The basis of the treatment is that a dye molecule (usually a porphyrin derivative) is irradiated by light at the site of disease, which leads to the formation of reactive oxygen species (ROS). The limited lifetime of the generated ROS confines the bulk of the harmful alterations of cell components in the region where the photosensitizer is accumulated inside the cells. Most photosensitizers are preferably located in lipid membranes.

Seeding Chiral Ensembles of Prolinated Porphyrin Derivatives on Glass Surface: Simple and Rapid Access to Chiral Porphyrin Films.

An easy and fast method to achieve chiral porphyrin films on glass is herein reported. The on-surface formation of organized supramolecular architectures with distinctive and remarkable chiroptical features strictly depends on the macrocycles used, the solvent chosen for the casting deposition, and most importantly, on the roughness of the glass slide. Dynamic light scattering studies performed on 10−4–10−6 M porphyrin solutions revealed the presence of small porphyrin aggregates, whose size and number increase depending on the initial concentration. Once transferred on surface, these protoaggregates act as nucleation seeds for the following, self-assembling into larger structures upon solvent evaporation, with a process driven by a fine balance between intermolecular and molecule–substrate interactions. The described method represents a straightforward way to fabricate porphyrin-based chiral surfaces onto a transparent and economic substrate in few minutes. The results obtained can be particularly promising for the development of sensors based on stereoselective optical active films, targeting the detection of chiral analytes of practical relevance, such as the so-called emerging pollutants released in the environment from agrochemical, food, and pharmaceutical manufacturing.

Photophysical characterization and in vitro anti-leishmanial effect of 5,10,15,20-tetrakis(4-fluorophenyl) porphyrin and the metal (Zn(II), Sn(IV), Mn(III) and V(IV)) derivatives.

In this report 5 compounds were synthesized and structural and their photophysical characterization was performed (ΦΔ and Φf). Furthermore, in this in vitro study, their biological activity against Leishmania panamensis was evaluated. The photophysical behavior of these compounds was measured and high ΦΔ and low Φf was observed. Besides, DFT quantum calculations on the electronic structures were performed. Finally, the biological activity was determined by means of the compounds capacity to inhibit the viability of parasites using the MTT assay. The inclusion of the metal ions substantially modified the photophysical and biological properties in comparison with the free metal porphyrin (1). In fact, Zn2+ porphyrin derivative (2) showed a marked decrease of Φf and increase of ΦΔ. In this sense, using TDDFT approaches, a luminescent process for Sn4+ derivative (3) was described, where emissive states involve the ML-LCT transition. So, this led to a decrease in the singlet oxygen production (0.82-0.67). Biological results showed that all compounds inhibit the viability of L. panamensis with high efficiency; the decrease in the viability was greater as the concentration of exposure increased. Finally, under light irradiation the IC50 of L. panamensis against the Zn(II)-porphyrin (2) and V(IV)-porphyrin (5) was lower than the IC50 of the Glucantime control (IC50 = 2.2 and 6.95μM Vs IC50 = 12.7μM, respectively). We showed that the use of porphyrin and metalloporphyrin-type photosensitizers with exceptional photophysical properties can be successful in photodynamic therapy (PDT) against L. panamensis, being the diamagnetic ion Zn2+ a candidate for the preparation of metalloporphyrins with high singlet oxygen production.

Evaluation of the effect of a cell penetrating peptide (TAT) towards tailoring the targeting efficacy and tumor uptake of porphyrin.

Cell penetrating peptides (CPPs) are known to possess a unique capacity to penetrate biological membranes and translocate various molecules into the cells. Therefore, porphyrin-CPP conjugates could be envisaged to boost the intracellular delivery of porphyrins thereby providing an improved tool for the development of agents for multi-modal applications for cancer management. Working in this direction, an unsymmetrically substituted porphyrin derivative was conjugated with a transactivating transcriptional activator peptide (TAT) and various in vitro andin vivostudies were carried out in order to study the effect of adding a CPP to the porphyrin derivative. MTT assay revealed the preferential light dependent toxicity of the porphyrin derivative which was further enhanced upon peptide conjugation. Fluorescence and flow cytometry studies revealed the relatively higher cellular internalization of the porphyrin-TAT conjugate in comparison with the porphyrin derivative. The elevated light dependent cell toxicity of the porphyrin-TAT conjugate along with its capability of generating cytotoxic singlet oxygen indicated the advantages of using the porphyrin-TAT conjugate for PDT applications. Also, porphyrin and the porphyrin-peptide conjugate were radiolabelled with 68Ga to investigate their possible potential as PET agents. In vivo biodistribution studies revealed a higher tumor uptake for the 68Ga-porphyrin-TAT conjugate (6.32 ± 1.24% IA per g) than for 68Ga-porphyrin (2.45 ± 0.88% IA per g) at 60 min post-administration. However, the observation of a higher non-target retention of the radiolabelled agents during in vivo studies might pose a limitation on their possible application in PET imaging.