Series Of Porphyrins Research Articles

Effects of meso-diarylamino group of porphyrins on optical and electrochemical properties

Introduction of an electron-donating meso-diarylamino group into a porphyrin core affords its broadened and red-shifted absorption and raises the HOMO level of the porphyrin. In this regard, porphyrins with multiple meso-diarylamino groups are expected to show unique optical and electrochemcial properties depending on the number of the meso-diarylamino groups. Herein, we report a series of porphyrins with a different number of the meso-diarylamino groups. They were prepared by the iodine(III)-mediated oxidative amination reaction of the corresponding meso-free porphyrins. With increasing the number of the meso-diarylamino groups, both red shifts and broadening in the absorption and negative shifts in the oxidation potential were observed. Notably, the oxidation potential of the porphyrin with four meso-diarylamino groups is comparable to that of tetrathiafulvalene, which is one of representative electron donors, suggesting the potential utility of multiply meso-aminated porphyrins as hole-transporting materials and as electron donors forming charge-transfer complexes with electron acceptors. We believe that this study sheds light on porphyrins with multiple electron-donating groups as organic functional materials.

A series of porphyrins as interfacial materials for inverted perovskite solar cells

Abstract Interface materials can improve the photovoltaic performance of the hybrid organic-inorganic perovskite solar cells (PSCs). Here, a series of porphyrin derivatives (metalloporphyrins: MTPPS4, M = Zn2+, Cu2+, Co2+, Ni2+; free base porphyrin: TPPS4) were developed to act as interfacial materials in PSCs. The introduction of porphyrin interlayers between PEDOT:PSS and perovskite layer in the inverted PSCs not only made energy level more matching but also improved the quality of the perovskite layer. Compared with the control device without an interlayer, the maximum power conversion efficiencies (PCE) of devices with the interlayers (in the order of ZnTPP4, CuTPP4, CoTPP4, NiTPP4 and TPP4) were increased by 23%, 25%, 21%, 17% and 13%, respectively. The highest PCE of 14.61% was based on the CuTPPS4-modified device. The porphyrins acted as the interlayers to promote carrier transport and reduce charge recombination at the interface, resulting in the increase of open-circuit voltage (VOC), short-circuit current density (JSC) and fill factor (FF).

Synthesis of Porphyrin and Bacteriochlorin Glycoconjugates through CuAAC Reaction Tuning.

Rapid and reproducible access to a series of unique porphyrin and bacteriochlorin glycoconjugates, including meso-glycosylated porphyrins and bacteriochlorins, and beta-glycosylated porphyrins, via copper catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) is reported for the first time. The work presented highlights the system-dependent reaction conditions required for glycosylation to porphyrins and bacteriochlorins based on the unique electronic properties of each ring system. Attenuated reaction conditions were used to synthesize fifteen new glycosylated porphyrin and bacteriochlorin analogs in 74 - 99% yield, and were extended to solid support to produce the first oligo(amidoamine)-based porphyrin glycoconjugate. These compounds hold significant potential as next generation water soluble catalysts and photodynamic therapy/photodynamic inactivation (PDT/PDI) agents.

Excited-State Quenching of Porphyrins by Hydrogen-Bonded Phenol-Pyridine Pair: Evidence of Proton-Coupled Electron Transfer

A series of porphyrins containing methoxy-substituted phenols were treated with different pyridine bases. Besides hydrogen bonding (H-bonding), the pyridine bases have imparted oxidation to the phe...

Electrochemical, Spectroelectrochemical, and Structural Studies of Mono- and Diphosphorylated Zinc Porphyrins and Their Self-Assemblies.

Three series of porphyrins containing a Zn(II) central metal ion and zero, one, or two phosphoryl groups at the meso-positions of the macrocycle were characterized as to their electrochemical, spectroscopic, and structural properties in nonaqueous media. The investigated compounds are represented as 5,15-bis(4'-R-phenyl)porphyrinatozinc, 10-(diethoxyphosphoryl)-5,15-bis(4'-R-phenyl)porphyrinatozinc, and 5,15-bis(diethoxyphosphoryl)-10,20-bis(4'-R-phenyl)porphyrinatozinc, where R = OMe, Me, H, or CN. Linear-free energy relationships are observed between the measured redox potentials at room temperature and the electronic nature of the substituents at the 5 and 15 meso-phenyl groups of the macrocycle. The mono- and bis-phosphoryl derivatives with two p-cyanophenyl substituents provide electrochemical evidence for aggregation at low temperature, a greater degree of aggregation being observed in the case of 5,15-bis(diethoxyphosphoryl)-10,20-bis(4'-cyanophenyl)porphyrinatozinc(II). This compound was characterized in further detail by variable-temperature 1H and 31P{1H} NMR spectroscopy in solution combined with single crystal X-ray analysis in the solid state. The data obtained from these measurements indicate that this porphyrin has a dimeric structure in CDCl3 at 223-323 K but forms a 2D polymeric network when it is crystallized from a CHCl3/MeOH mixture.

Spectral, Acid, and Coordination Properties of Dodecasubstituted Porphyrins

The results of investigation of the interrelation between the geometric structure and coordination, acid, and spectral properties of a series of porphyrins with different systems of meso and β substituents are presented. The geometry of polysubstituted porphyrins was optimized at the DFT B3LYP/6-311G level of theory using Gaussian 09. It was shown that the dianionic forms of dodecasubstituted porphyrins hold promise for the development of highly efficient liquid sensors for metal cations.

Role of 2nd sphere H-bonding residues in tuning the kinetics of CO2 reduction to CO by iron porphyrin complexes.

Iron porphyrins are potential catalysts for the electrocatalytic and photocatalytic reduction of CO2. It has been recently established that the reduction of CO2 by an iron porphyrin complex with a hydrogen bonding distal pocket involves at least two intermediates: a Fe(ii)-CO22- and a Fe(ii)-COOH species. A distal hydrogen bonding interaction was found to be key in determining the stability of these intermediates and affecting both the selectivity and rate of CO2 reduction. In this report, a series of iron porphyrins that vary only in the distal H-bonding network are further investigated and these exhibit turnover frequencies (TOFs) ranging from 1.0 s-1 to 103 s-1. The experimental TOFs correlate with the H-bonding ability of the distal superstructure of these iron porphyrin complexes and analysis suggests that H-bonding alone can tune the rate of CO2 reduction by as much as 1000 fold. DFT calculations provide a detailed insight into how the, apparently weak, 2nd sphere interactions lead to efficient CO2 activation for reduction. The ability to tune CO2 reduction rates by changing the H-bonding residue instead of the acid source is a convenient way to tune CO2 reduction electrocatalysis without compromising selectivity by introducing competitive hydrogen evolution reaction or formate generation.

Kinetic and mechanistic aspects of solid state, nanostructured porphyrin diacid photosensitizers in photooxidation of sulfides

The kinetics and mechanism of aerobic photooxidation of sulfides in the presence of a series of electron-rich and electron-deficient porphyrins immobilized on Amberlyst 15 nanoparticles in the form of porphyrin diacids are reported.

Synthesis and Photophysical Properties of a Series of Novel Porphyrin Dendrimers Containing Organoiron Complexes

This article is focused on the design and photophysical properties of a series of novel porphyrin and metalloporphyrin dendrimers containing cationic η6-chloroarene-η5-cyclopentadienyliron(II) complexes functionalized with naphthalene and capped with ferrocene. The incorporation of cationic η6-chloroarene-η5-cyclopentadienyliron moieties into the dendrimer structures enhances solubility, and facilitates nucleophilic aromatic substitution and addition reactions due to the intense electron-withdrawing ability of the iron center. Divergent approaches were employed to yield highly symmetrical branched materials, with interesting and potentially useful properties. The preparation of these dendrimers was achieved via metal-mediated nucleophilic aromatic substitutions and Steglich esterifications. These dendrimers and their precursors were characterized through nuclear magnetic resonance spectroscopy, infrared spectroscopy, and UV–Visible and fluorescence spectroscopy. Substitution on the porphyrin core with various side chains and terminal functional groups and chromophores had little impact on the porphyrin emission properties, allowing for a wide variety of fluorescent macromolecules to be prepared which retain this characteristic emission. Also, the presence or absence of the organopyrene moieties also had little effect on the emission from these compounds. Complexation of a metal cation, such as Zn2+, by these compounds, did however result in a significant blue shift in the observed fluorescence; this interesting result has the potential for applications in the development of fluorescent-based cation sensors.

Synthesis of novel zinc porphyrins and their photocatalytic activity

PurposeThe purpose of this study is to investigate the effect of the spacer length of zinc porphyrin-TiO2 hybrids by photodegradation of methyl orange (MO) in aqueous solution under visible light.Design/methodology/approach5-Mono-[4-hydroxyphenyl]-10,15,20-triphenylporphyrin was synthesized using Alder method. A new series of porphyrins and their corresponding zinc complexes (ZnPp) were obtained from 5-mono-[4-hydroxyphenyl]-10,15,20-triphenylporphyrin via nucleophilic substitution reaction. The ZnPp-TiO2 photocatalysts were prepared by loading ZnPp onto TiO2 and characterized by scanning electron microscope, X-ray diffraction, UV-vis diffuse reflectance spectrum and X-ray photoelectron spectroscopy.FindingsThe results indicated that zinc porphyrins were successfully loaded on the surface of TiO2 microsphere, which is crucial to enhance the activity of the catalytic composite under visible light. All the novel photocatalysts showed much enhanced photoactivity than bare TiO2. Among all the prepared ZnPp-TiO2, 5,10,15-triphenyl-20-[4-(4-naphthoxy)-butoxy]phenyl zinc porphyrin-TiO2 (4b) showed the highest photocatalytic activity for the degradation of MO.Research limitations/implicationsSynthesis of these zinc porphyrins had never been reported previously.Originality/valueFour novel zinc porphyrin-TiO2 photocatalysts which could response to visible light in degradation of MO were synthesized using Alder method. The results show that the photocatalytic activity of 5,10,15-triphenyl-20-[4-(4-naphthoxy)butoxy] phenyl zinc porphyrin- TiO2 is higher than others.

Use of alkylated, amphiphilic zinc porphyrins to disperse individualized SWCNTs

A series of zinc porphyrins, namely ZnPa and ZnPb, which exist predominantly as aggregates, are utilized in a top-down preparation of individualized and stabilized single wall carbon nanotubes (SWCNTs). Sizable interactions in the ground state of the corresponding SWCNT/ZnPa and SWCNT/ZnPb electron donor–acceptor systems lead to charge transfer in the excited state. The product includes the simultaneous reduction of the electron-accepting SWCNTs and the oxidation of the electron-donating ZnPa and ZnPb.

Photoinduced Energy and Electron Transfer in Bacterichlorins

Bacteriochlorins are characterized by intense near-infrared absorption bands (700-800 nm), which are of interest for diverse applications such as photodynamic therapy (PDT) of diseased tissues or dyes in solar cells. Although naturally-occurring bacteriochlorin derivatives are labile and this limits their applications, we synthesized photostable bacteriochlorins that can endure many cycles of photoinduced energy and electron transfer reactions without photodecomposition. The factors contributing to this photostability are discussed. In particular, it is shown that bacteriochlorins are prone to oxidation but this can be prevented by introducing electron-withdrawing substituents in the phenyl groups of tetraphenylbacteriochlorins. The oxidation potentials of tetraphenylbacteriochlorins increase when such substituents are present, and it is shown that in a series of structurally-related bacteriochlorins, chlorins and porphyrins, the photodecompositing quantum yields decrease as the oxidation potentials increase. The control of the oxidation potential is also relevant to determine the propensity of these photosensitizers to undergo energy or electron transfer to molecular oxygen. Efficient energy transfer (Type II process) and electron transfer (Type I process) to molecular oxygen, with the consequent formation of reactive oxygen species, is critical to the success of PDT of solid tumors. We tuned the properties of tetraphenylbacteriochlorins to optimize a photosensitizer for PDT of cancer. The optimized photosensitizer, named redaporfin, proved very effective in the treatment of tumors implanted in animal models and is now in clinical trials for advanced head and neck cancer References Pucelik, R. Paczyński, G. Dubin, M. M. Pereira, L. G. Arnaut, J. M. Dąbrowski, Plos ONE, 12 (2017) e0185984Pucelik, L. G. Arnaut, G. Stochel, J. M. Dąbrowski, ACS Appl. Mater. Interfaces, 8 (2016) 22039-22055Tão, J. R. S. Campos, L. C. Gomes-da-Silva, F. A. Schaberle, J. M. Dabrowski, L. G. Arnaut, ChemBioChem, 17 (2016) 836-842.M. Dabrowski, L. G. Arnaut, Photochem. Photobiol. Sc., 14 (2015) 1765-1780.B. Rocha, L. C. Gomes-da-Silva, J. M. Dabrowski, L. G. Arnaut, Eur. J. Cancer, 51 (2015) 1822-1830.Saavedra, L. B. Rocha, J. M. Dąbrowski, L. G. Arnaut, ChemMedChem, 9 (2014) 390-398.G. Arnaut, M. M. Pereira, J. M. Dabrowski,* E. F. F. Silva, F. A. Schaberle, A. R. Abreu, L. B. Rocha, M. M. Barsan, K. Urbanska, G. Stochel, C. M. A. Brett, Chem. Eur. J., 20 (2014) 5346-5357.

Porphyrin decorated Bi2O2CO3 nanocomposites with efficient difunctional properties of photocatalysis and optical nonlinearity

Considerable attention has been paid to design multifunctional hybrid materials for developing novel optoelectronic systems. Here, a series of novel porphyrin decorated Bi2O2CO3 nanocomposites (BOC/TPP) loaded with different porphyrin contents was prepared by a facile solvothermal technique to maximize the photocatalysis and optical nonlinearity. The photoresponsive range of the BOC/TPP nanocomposites can be extended from UV to visible light, and the band gap can be continuously tuned. The wide absorption of the as-prepared nanocomposites in the visible light region makes them suitable for photocatalytic and nonlinear transmission studies. The associated photocatalysis and optical nonlinearity for the BOC/TPP nanocomposites are shown to be dependent on the contents of porphyrin. Compared to BOC, TPP and other prepared nanocomposites with different TPP loadings, the BOC/0.03TPP nanocomposite with 3 wt% TPP exhibits the highest photocatalytic performance and nonlinear optical absorption effect, due to the efficient interfacial charge transfer and the strong interfacial electronic interactions between TPP and BOC. These findings provide an ideal scientific platform to guide the rational design of difunctional nanomaterials with desired optoelectronic performances.

Polymer nanoparticles loaded with FeCl-tetraphenylporphyrin for binary catalytic therapy of neoplasms

In order to study the possibility of using a metal complex of the porphyrin series, FeIIICl-tetraphenylporphyrin (FeClTPP), and its polymeric form as antitumor agents for binary catalytic therapy, the technology of preparation of polymer particles containing FeClTPP was developed for the first time. The experimental data obtained allow one to conclude that the developed form using a copolymer of lactic and glycolic acids (ratio of monomer units 50: 50), ultrasonic homogenization, D-mannitol (as a cryoprotectant), the active agent to polymer ratio 1: 10, and the organic to aqueous phase ratio 1: 10 and 1: 20, respectively, has the optimal physicochemical parameters. It was found that the free substance of FeClTPP and polymer particles with FeClTPP are active against MCF-7 (human breast adenocarcinoma), HeLa (human cervical carcinoma), and MG-63 (human osteosarcoma) cell lines. The polymer particles containing FeClTFP exhibit the highest cytotoxic effect against MCF-7 lines as compared to the free substance. The results of the study indicate that both the substance of tetraphenylporphyrin and its resulting polymeric form are promising for the treatment of tumor diseases in binary catalytic therapy.

Electrochemistry and Spectroelectrochemistry of Cobalt Porphyrins with π-Extending and/or Highly Electron-Withdrawing Pyrrole Substituents. In Situ Electrogeneration of σ-Bonded Complexes.

A series of cobalt porphyrins with π-extending or highly electron-withdrawing β-pyrrole substituents were investigated as to their electrochemistry, spectroscopic properties, and reactivity after electroreduction or electroxidation in nonaqueous media. Each porphyrin, represented as PorCo (where Por = TPP(NO2)Y2 or TPP(NO2)Y6 and Y = phenyl, phenylethynyl, Br, or CN) was shown to undergo multiple redox reactions involving the conjugated π-ring system or central metal ion which could exist in a Co(III), Co(II), or Co(I) oxidation state under the application of an applied oxidizing or reducing potential. Thermodynamic half-wave potentials for the stepwise conversion between each oxidation state of [PorCo]n (where n ranged from +3 to -3) were measured by cyclic voltammetry and analyzed as a function of the compound structure and properties of the electrochemical solvent. UV-visible spectra were obtained for each oxidized or reduced porphyrin in up to six different oxidation states ranging from [PorCo]3- to [PorCo]3+ and analyzed as a function of the compound structure and utilized electrochemical solvent. Chemically or electrochemically generated Co(I) porphyrins are known to be highly reactive in solutions containing alkyl or aryl halides, and this property was utilized to in situ generate a new series of methyl carbon-bonded cobalt(III) porphyrins with the same π-extending or highly electron-withdrawing substituents as the initial Co(II) derivatives. The electrosynthesized carbon-bonded Co(III) porphyrins were then characterized as to their own electrochemical and spectroscopic properties after the addition of one, two, or three electrons in nonaqueous media.

Tetraindole Derivatives of Porphyrins as Building Blocks in the Synthesis of Monodisperse Polyphenols

A new strategy for the synthesis of monodisperse polyphenols chemically bound to a rigid thermally stable molecular platform has been suggested. The platform has been prepared by the Suzuki–Miyaura reaction of a tetraboryl porphyrin derivative and 3-(4′-bromophenyl)-4,6-dimethoxyindole. Subsequent reactions of complete demethylation of obtained tetraindole and partial blocking of the corresponding phenolic hydroxyls by acid-labile protective groups have led to the formation of a final modified polyphenol compound of the porphyrin series. On the basis of the this polyphenol, a positive photoresist for lithography with exposure radiation at a wavelength of 13.5 nm has been developed; the photoresist affords the fabrication of topological structures with 16-nm resolution.

Design of zinc porphyrin‐perylene diimide donor‐bridge‐acceptor chromophores for large second‐order nonlinear optical response: A theoretical exploration

AbstractThe electronic structures and second‐order nonlinear optical (NLO) properties of a series of zinc porphyrin (ZnP)‐perylene diimide (PDI) donor‐bridge‐acceptor (D‐π‐A) molecules have been investigated using density functional theory (DFT) and time‐dependent DFT (TDDFT). The results show that these compounds possess excellent second‐order NLO properties and large static first hyperpolarizabilities (β0) values on the order of 103 – 104 esu−30. A DFT benchmark calculation of β0 value was first performed, confirming the optimally tuned range‐separated functionals (LC‐BLYP* and ωB97X*) can produce similar magnitudes for β0 as Møller–Plesset second‐order perturbation (MP2) calculations. The magnitudes of β0 values were studied as a function of different types of bridges: oligo‐p‐phenylenevinylene (OPV), carbon‐bridged oligo‐p‐phenylenevinylene (COPV), oligo‐thienylenevinylene (OTV), carbon‐bridged oligo‐thienylenevinylene (COTV), and also the length of π‐bridges. The calculated β0 values were found to be inversely related to the bond length alternation (BLA) values of various π‐bridges. Next, we found that the static β0 value of designed ZnP‐COTV1‐PDI molecule can be significantly enhanced by finely tuning the dihedral angles between the π‐bridge and ZnP donor or PDI acceptor. The calculated β0 value is also sensitive to the substitution positions of PDI, that is, ortho‐(α‐), bay‐(β‐), nitrogen‐(N‐). A two‐level model was proven to be useful for the qualitative description of the β0 values and further the substantial oscillator strength and the difference in transition dipole moments between the ground and excited state mainly contribute to the large β0 values. The presented work will be beneficial for potential applications of the ZnP‐PDI‐based chromophores in the optoelectronic devices and high‐performance NLO materials.

Chromatographic isolation of vanadyl porphyrins from heavy oil resins

A broad fraction of petroleum vanadyl porphyrins of high spectral purity was isolated from heavy oil resins with high vanadium content using a two-step chromatographic method. At the first step, the primary concentrate of vanadyl porphyrins was separated from the resins on the silica gel column. At the second step, it was further purified by the gradient elution through the column packed with sulfo-cationite. According to UV—VIS spectroscopy, this technique allows one to isolate up to 70% of vanadyl porphyrins with the spectral purity corresponding to the best results of other purification methods providing only narrow fractions of vanadyl porphyrins of comparable purity. Deoxophylloerythroetioporphyrin (DPEP) and etioporphyrin (Etio) series of vanadyl porphyrins with the carbon number range of C28—C42 and DPEP/ Etio ratio equal to 1.18 were identified by MALDI-TOF mass-spectrometry.

A comparative study on the catalytic performance of heme and non‐heme catalysts: Metal porphyrins versus metal Schiff bases

Catalytic activity and oxidative stability of a series of iron and manganese porphyrins with 2‐chlorophenyl, phenyl and 4‐methoxyphenyl at the meso positions and metallosalens (Mn‐ and Fe‐salens) including N,N′‐bis(salicylidene)ethylenediamine, N,N′‐bis(5‐ chlorosalicylidene)ethylenediamine and N,N′‐bis(2,4‐dihydroxysalicylidene)ethylenediamine for the oxidation of olefins with tetra‐n‐butylammonium periodate (TBAP) and tetra‐n‐butyl‐ammonium Oxone (TBAO) have been investigated and compared. Although the metalloporphyrins showed an increased catalytic activity relative to the Schiff base complexes, the former provided no significant catalytic advantage over the latter. Also, a comparable or slightly higher oxidative stability was observed for the Schiff base complexes under the reaction conditions. Furthermore, in spite of large difference between the oxidizing ability of TBAO and TBAP, similar patterns were observed for the order of catalytic activity and oxidative stability of the used heme and non‐heme catalysts. The introduction of a methyl group at the ɑ position of styrene led to an increase in its reactivity, indicating the dominance of electronic effects over the steric ones in these catalytic systems.

Antimony Complexes for Electrocatalysis: Activity of a Main-Group Element in Proton Reduction.

Main-group complexes are shown to be viable electrocatalysts for the H2 -evolution reaction (HER) from acid. A series of antimony porphyrins with varying axial ligands were synthesized for electrocatalysis applications. The proton-reduction catalytic properties of TPSb(OH)2 (TP=5,10,15,20-tetra(p-tolyl)porphyrin) with two axial hydroxy ligands were studied in detail, demonstrating catalytic H2 production. Experiments, in conjunction with quantum chemistry calculations, show that the catalytic cycle is driven via the redox activity of both the porphyrin ligand and the Sb center. This study brings insight into main group catalysis and the role of redox-active ligands during catalysis.