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The heteroatom-containing porphyrin analogues or core-modified porphyrins that resulted from the replacement of one or two pyrrole rings with other five-membered heterocycles such as furan, thiophene, selenophene, tellurophene, indene, phosphole, and silole are highly promising macrocycles and exhibit quite different physicochemical properties comp...
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Citations
... [195,196] Afterward, intramolecular Ullmann-type coupling of D with the amine group gives rise to the 10-membered cyclic intermediate E, which experiences a reductive elimination to give the title product 200, and the regeneration of the copper(I) catalyst closing the catalytic cycle. [192] In connection with the click chemistry approach for the preparation of 1,2,3-triazoles, it is worth mentioning a coppercatalyzed decarboxylative reaction for the preparation of 1,4disubstituted 5-arylselanyl-1,2,3-triazoles of general formula 204 from propiolic acids (205), diselenides, and benzyl azides (206). [197] This method proved to be reliable, exhibiting high regioselectively, excellent reaction yields, mild conditions, and high substrate acceptability to work under air. ...
... [203] Heteroacenes, in particular, those based on thiophene, have been extensively studied due to their extended conjugation, rigid planarity, and other properties. [205] Consequently, the study of heteroacenes based on selenophene attracted much attention for a number of reasons: a heavy element such as selenium compared to sulfur atom; a large polarizable radius, its narrow optical band gap, strong intermolecular interactions, etc. [206] In addition, benzoselenophene derivatives have captivated the interest of different groups due to their promising physicochemical properties for organic light-emitting diodes and organic conductors. [207,208] A very interesting iron(III)-promoted linear intramolecular cascade cyclization reaction has been Scheme 53. ...
Selenium, originally described as a toxin, turns out to be a crucial trace element for life that appears as selenocysteine and its dimer, selenocystine. From the point of view of drug developments, selenium‐containing drugs are isosteres of sulfur and oxygen with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. In this article, we have focused on the relevant features of the selenium atom, above all, the corresponding synthetic approaches to access a variety of organoselenium molecules along with the proposed reaction mechanisms. The preparation and biological properties of selenosugars, including selenoglycosides, selenonucleosides, selenopeptides, and other selenium‐containing compounds will be treated. We have attempted to condense the most important aspects and interesting examples of the chemistry of selenium into a single article.
... [8] The telluraporphyrinoids are air sensitive and prone to undergo oxidation reactions and thus relatively difficult to handle compared to other chalcogen containing porphyrinoids. [9,10] Although extensive literature available on O, S and Se containing porphyrinoids, [11][12][13][14] the chemistry of Te containing porphyrinoids is remained limited due to inaccessibility of suitable precursors and inherent instability associated with Te containing porphyrinoids. For example, several multiporphyrin arrays containing oxa-and thiaporphyrins have been reported [15][16][17][18] but to the best of our knowledge, there is no report on telluraporphyrinoid containing multiporphyrin arrays. ...
A series of mono‐functionalized aromatic 22π telluradithiasapphyrins containing functional groups such as p‐bromophenyl, p‐iodophenyl, p‐nitrophenyl and p‐trimethylsilylethynyl phenyl groups at one of the meso‐positions were synthesized by condensing appropriately functionalized unsymmetrical bithiophene diol and 16‐telluratripyrrane in CH2Cl2 under acid‐catalyzed conditions. To demonstrate the reactivity of mono‐functionalized telluradithiasapphyrins, we synthesized the first examples of covalently linked diphenyl ethyne bridged four novel 18π porphyrin/metalloporphrin‐22π telluradithiasapphyrin dyads by coupling meso‐ethynyl phenyl porphyrin with telluradithiasapphyrin containing meso‐iodophenyl group under Pd(0) coupling conditions followed by metalation of porphyrin unit by treating free base dyad with appropriate metal salts. The dyads were characterized and studied by mass, 1D & 2D NMR, absorption, cyclic voltammetry, fluorescence and DFT techniques. The DFT analysis showed that the porphyrin/metalloporphyrin and sapphyrin units in dyads orient with each other in different angles and Zn(II) porphyrin‐sapphyrin dyad (Zn‐dyad) showed minimum whereas the free base dyad showed maximum angle of deviation. NMR, absorption, and redox studies indicated that the dyads exhibit the overlapping features of their constituted monomers and maintain their individual characteristic features. The steady‐state fluorescence studies revealed that the fluorescence of the porphyrin/metalloporphyrin unit was significantly quenched due to possible energy/electron transfer from the porphyrin/metalloporphyrin unit to non‐emissive sapphyrin unit in dyads.
... In this regard, when taking their azaporphyrinic equivalents as a reference, heteroporphyrins exhibit remarkable bathochromic shifts in the Soret and Q bands. In this case, the magnitude of this effect is dependent on the number and size of heteroatoms incorporated into the porphyrin core [110]. Thus, this redshift is larger for di-heteroatom-substituted porphyrins than for those monosubstituted, while for a given number of substitutions, the bathochromic shift becomes more significant as the size of the heteroatom increases. ...
... In a similar way, novel affinities of the metal center for axial ligands may also be found when studying metallated heteroporphyrins. Nevertheless, while these molecules have been widely explored from a synthetic point of view [110], their utilization in photocatalysis is still lacking [113]. Several factors may lie behind the limited scope of heteroporphyrins in energy-related research. ...
... Several factors may lie behind the limited scope of heteroporphyrins in energy-related research. In this respect, poor quantum yields and low singlet excited-state lifetimes have usually been reported for these compounds [110]. As known, these attributes are detrimental to photocatalytic performance in terms of electron-hole recombination. ...
Over the years, porphyrins have arisen as exceptional photosensitizers given their ability to act as chlorophyll-mimicking dyes, thus, transferring energy from the light-collecting areas to the reaction centers, as it happens in natural photosynthesis. For this reason, porphyrin-sensitized TiO2-based nanocomposites have been widely exploited in the field of photovoltaics and photocatalysis in order to overcome the well-known limitations of these semiconductors. However, even though both areas of application share some common working principles, the development of solar cells has led the way in what is referred to the continuous improvement of these architectures, particularly regarding the molecular design of these photosynthetic pigments. Yet, those innovations have not been efficiently translated to the field of dye-sensitized photocatalysis. This review aims at filling this gap by performing an in-depth exploration of the most recent advances in the understanding of the role played by the different structural motifs of porphyrins as sensitizers in light-driven TiO2-mediated catalysis. With this goal in mind, the chemical transformations, as well as the reaction conditions under which these dyes must operate, are taken in consideration. The conclusions drawn from this comprehensive analysis offer valuable hints for the implementation of novel porphyrin–TiO2 composites, which may pave the way toward the fabrication of more efficient photocatalysts.
... There are different ways to modify the pyrrole containing porphyrinoid macrocycles such as replacing one or more pyrrole rings with other five or six membered heterocycles namely furan, thiophene, selenophene, tellurophene, pyridine and carbocycles such as cyclopentadiene, benzene, naphthalene, azulene and so on. [1][2][3][4][5][6][7][8] The core-modification of porphyrinoid macrocycle significantly alters the π-conjugation which reflects in changes in reactivity, electronic and coordination properties. [9][10] Several types of core-modified porphyrinoids have been synthesized, explored their physico-chemical and coordination properties and exploited their use for wide range of applications. ...
Condensation of dibenzofuran based tripyrrane with dipyrroethene diol under acid catalyzed porphyrin forming conditions resulted in the formation of dibenzofuran embedded calix pentaphyrins with two meso‐sp³ carbons instead of expected fully conjugated dibenzofuran (DBF) embedded pentaphyrins. Three examples of DBF embedded calix pentaphyrins have been synthesized by adopting the [3+2] condensation methodology and characterized by various spectroscopic and theoretical methods. The NMR studies that include COSY, NOESY, HMBC and HSQC clearly confirmed the molecular structures of DBF embedded bis‐(calix)‐pentaphyrins. The optimized structures showed that the DBF embedded bis‐(calix)‐pentaphyrin macrocycles adopted figure eight conformation due to presence of two sp³ carbon atoms (C1 and C22) at meso positions which obstructed the conjugation throughout the macrocycle. The absorption spectra of macrocycles showed non‐aromatic features with a sharp strong band at 480 nm and a broad band in the region of 600–800 nm which were significantly red shifted with distinct colour change in protonated derivatives of DBF embedded bis‐(calix)‐pentaphyrins.
... Porphyrin represents one of the most widely studied of all known macrocyclic ring systems [21,22]. Porphyrins are a class of macromolecular heterocyclic compounds formed by the interconnection of the α-carbon atoms of four pyrrole-like subunits through a methine bridge [23,24]. ...
Chirality plays a key role in many fields of natural sciences as well as life sciences. Chiral materials are widely developed and used for electrochemical chiral recognition. In recent years, carbon quantum dots (CQDs) have been widely used as a novel carbon nanomaterial due to their excellent charge transfer properties, good biocompatibility, and low cost. The special structure of π-conjugated porphyrin attracts attention. Supramolecular self-assembly shows a way to construct chiral materials by self-assembling simple molecules into chiral composites. Herein, we demonstrate the self-assembly of achiral porphyrins induced by chiral carbon quantum dots assembled from L- and or D-tryptophan (L- and or D-Trp) with carbon quantum dots, resulting in 5,10,15,20-tetrakis (4-carboxyPheyl) (TCPP) self-assembled structure. The electrochemical chiral recognition of chiral self-assembled materials was studied using Phenylalanine (Phe) enantiomer as a chiral analyte. Electrochemical chiral recognition results showed that the chiral self-assembled materials induced by chiral templates have a good ability to discriminate Phe enantiomers. Therefore, this research provides a new idea for the synthesis of chiral composites and further expands applications to electrochemical chiral recognition.
Graphical Abstract
... Despite all other applications, separation ability of these systems for proton isotope is not documented. Here, mono substituted Porphyrinoids, reported in literature [63] are studied computationally to compare their separation properties for proton isotopes with porphyrin, having 4 pyrrole in structure. The energy curve for protium ion isotopes are computed by density-functional theory to calculate better selectivity. ...
Porphyrin based 2D materials with single atom thickness and uniform pore size have not been explored for the separation of proton isotopes. We computationally designed the porphyrin and its derivatives with the doping of oxygen, sulphur and selenium atoms and computed the kinetic energy barrier for H⁺, D⁺, and T⁺ permeation through porphyrin and core modified porphyrins by using M05-2X along with 6-31G (d,p). Zero-point energy is calculated at transition state for protium ion and its relevant isotopes permeation through porphyrin derivatives. Tunneling ratio of proton isotopes through these 2D structures is calculated by using zero-point energy (ZPE) difference of protium ion to its isotopes. Core modification of porphyrin provides better tunneling ratio for proton isotopes. Among these, mono selenium heteroporphyrin provides the most suitable results. Our study provides the molecular level insight of permeation pathway for proton isotopes through these 2D materials.
... Among the porphyrin derivatives, numerous researches on meso-tetraarylporphyrins (Chatterjee et al., 2017) have been carried out. However, only very few studies were reported about meso-diarylporphyrins, namely 5,15-diarylporphyrins. ...
Purpose
Esophageal cancer is the most common gastrointestinal tumor and is difficult to be eradicated with conventional treatment. Porphyrin-based photosensitizers (PSs) mediated photodynamic therapy (PDT) could kill tumor cells with less damage to normal cells. As the most widely used porphyrin-based photosensitizer in clinics, Photofrin II has excellent anti-tumor effect. However, it has some disadvantages such as weak absorption at near infrared region, the complexity of components and prolonged skin photosensitivity. Here series novel 5,15-diaryl-10,20-dihalogeno porphyrin derivatives were afforded and evaluated to develop more effective and safer photosensitizers for tumor therapy.
Methods
The photophysical properties and singlet oxygen generation rates of 5,15-diaryl-10,20-dihalogeno porphyrins (I1-6, II1-4) were tested. The cytotoxicity of I1-6 and II1-4 were measured by MTT assay. The pathway of cell death was studied by flow cytometry. In vivo photodynamic efficacy of I3 and II2-4 in Eca-109 tumor-bearing BABL/c nude mice were measured and histopathological analysis were examined.
Results
5,15-Diaryl-10,20-dihalogeno porphyrins I1-6 and II1-4 were synthesized. The longest absorption wavelength of these halogenated porphyrins (λmax = 660 nm) displayed a red shift around 30 nm compared to the unhalogenated porphyrins PS1 (λmax = 630 nm). The singlet oxygen generation rates of I1-6 and II1-4 were significantly higher than PS1 and HMME. All PSs mediated PDT showed obvious cytotoxic effect against Eca-109 cells compared to HMME in vitro and in vivo. Among these PSs, II4 exhibited appropriate absorption in the phototherapeutic window, higher ¹O2 generation rate (k = 0.0061 s⁻¹), the strongest phototoxicity (IC50 = 0.4 μM), lower dark toxicity, high generation of intracellular ROS in Eca-109 cells and excellent photodynamic anti-tumor efficacy in vivo. Besides, cell necrosis was induced by compound II4 mediated PDT.
Conclusion
All new compounds have obvious photodynamic anti-esophageal cancer effects. Among them, the photosensitizer II4 showed excellent efficacy in vitro and in vivo, which has the potential to become a photodynamic anti-tumor drug.
... [8] The introduction of other donor atoms such as O, S, C, Te, P etc in place of N in porphyrinoid core results in new varieties of coordination complexes where metals can be stabilized in unusual oxidation states or they can form organometallic complexes with unusual geometries. [9] Since norroles are new isomers of corroles, we recently attempted to prepare meso-triaryl 22-oxanorroles 5 via oxidation of oxabilanes which were key precursors for the synthesis of 22-oxanorroles [10] 5. The oxabilanes were prepared by [3 + 1] condensation of readily available (1H-pyrrol-3-yl)(ptolyl)methanol and 16-oxatripyrrane under mild acid catalyzed conditions. ...
The first examples of meso-triaryl 22-oxabenzonorroles were synthesized in 18-21% yields by oxidation of appropriate meso-triaryl oxabenzobilane. The key precursors, the meso-triaryl oxabenzobilanes were synthesized readily by treating 16-oxatripyrrane with (1H-indol-3-yl)(p-tolyl)methanol under acid catalyzed conditions. The meso-triaryl 22-oxabenzonorroles were obtained in free base form by following our simple straight-forward synthetic strategy. The X-ray structure obtained for meso-tritolyl 22-oxabenzonorroles revealed that the indole ring was deviated by an angle of 41.27o from the mean plane. The NMR studies supported the presence of diatropic ring current effect as inner NH and CH protons were observed in the upfield region. The absorption spectra of 22-oxabenzonorroles exhibited one strong Soret band and four weak Q-bands. The electrochemical studies revealed that the macrocycles are electron rich and undergo easier oxidations. The DFT and TD-DFT studies were in agreement with the experimental observations and NICS and HOMA values supports the aromatic nature of meso-triaryl oxabenzonorroles.
... Replacement of a pyrrole ring by thiophene or furan results in monosubstituted heteroporphyrins containing a single proton in the macrocycle core or none if the molecule is doubly substituted. Therefore, their acid-base and coordination properties differ substantially from those of the porphyrins themselves [6][7][8][9][10][11]. In general, the spectral and luminescent properties of heteroporphyrins resemble those of porphyrins because they are isoelectronic (26 π-electrons each) [6][7][8]. ...
... Therefore, their acid-base and coordination properties differ substantially from those of the porphyrins themselves [6][7][8][9][10][11]. In general, the spectral and luminescent properties of heteroporphyrins resemble those of porphyrins because they are isoelectronic (26 π-electrons each) [6][7][8]. Also, addition of heavy heteroatoms to the macrocycle affects the photophysical characteristics of heteroporphyrins formed under the infl uence of signifi cantly increased spin-orbit coupling [8,[12][13][14]. ...
... In general, the spectral and luminescent properties of heteroporphyrins resemble those of porphyrins because they are isoelectronic (26 π-electrons each) [6][7][8]. Also, addition of heavy heteroatoms to the macrocycle affects the photophysical characteristics of heteroporphyrins formed under the infl uence of signifi cantly increased spin-orbit coupling [8,[12][13][14]. ...
The spectral and luminescent properties of hydrophilic 21-thia-5,10,15,20-tetra(4-sulfonatophenyl)porphyrin and 5,10,15,20-tetra(4-sulfonatophenyl)porphyrin in solutions at 293 K were compared. Peculiarities of halochromic effects due to the replacement of a pyrrole by a thiophene ring in the macrocycle were revealed for the first time. Multicenter interactions on the periphery and in the core of the macrocycle led to modulation of spin–orbit couplings, which became apparent in changes of the fluorescence quenching efficiency. Fluorescence of the doubly protonated heteroporphyrins was shown to be quenched as compared to the free bases whereas fluorescence enhancement was observed for the doubly protonated forms.
... 13 Others have referred to a select group among them as heteroporphyrins (or their expanded analogues) 15 or as core-modified porphyrins. 16,17 Irrespective of their naming, the group of PMPs is inherently different from heterocycle-appended porphyrins (that are not subject of this Review). 18,19 A number of general reviews on the syntheses and properties of PMPs are available. ...
... 134,183−186 The groups of Chandrashekar and (later independently) Ravikanth explored a large number of so-called core-modified expanded porphyrins, the PMP-analogues of the expanded porphyrins, and their coordination chemistry. 15,16,25,31,187,188 Other key events that enabled the field of total synthesis of PMPs were the [3 + 1]-type synthetic methodologies 66,189 (and later [2 + 2] methods) that were perfected by the group of Lash for their application in the preparation of a structurally wide variety of (mostly carbaporphyrin-type) PMPs. 9,10,27,100,180 More generally, an early book on expanded porphyrins by Sessler 190 certainly inspired the field, as did the scientific success and general resonance that his work on the Texas-sized texaphyrin-class of PMPs generated. ...
... The increase in the number of heteroatoms induces nonplanarity, further eroding the metal binding properties of the oligoheteroporphyrins. 16 Nonetheless, many metal complexes of the heteroporphyrins are known and have been reviewed. 16,30 We will discuss only a few representative examples. ...
