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Zeev Gross - One of the best experts on this subject based on the ideXlab platform.
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phosphorus corrole complexes from property tuning to applications in photocatalysis and triplet triplet annihilation upconversion
Chemical Science, 2019Co-Authors: Atif Mahammed, Jenya Vestfrid, Kepeng Chen, Jianzhang Zhao, Zeev GrossAbstract:Efficient triplet photosensitizers are important for fundamental photochemical studies and applications such as triplet–triplet annihilation upconversion (TTA UC), photoredox catalytic organic reactions and photovoltaics. We now report a series of phosphorus corrole compounds as efficient visible light-harvesting metal-free triplet photosensitizers. While the heavy-atom-free phosphorus Corroles show absorption in the visible spectral region (centered at 573 nm) and have a decent triplet state quantum yield (ΦΔ = 49%), iodo-substitution on the corrole core induces red-shifted absorption (589 nm) and improves intersystem crossing significantly (ΦΔ = 67%). Nanosecond transient absorption spectra confirm triplet state formation upon photoexcitation (τT = 312 μs) and the iodinated derivatives also display near IR phosphorescence in fluid solution at room temperature (λem = 796 nm, τp = 412 μs). Both singlet oxygen (1O2) and superoxide radical anions (O2−˙) may be produced with the phosphorus Corroles, which are competent photocatalysts for the oxidative coupling of benzylamine (the Aza Henry reaction). Very efficient TTA UC was observed with the phosphorus Corroles as triplet photosensitizers and perylene as the triplet acceptor, with upconversion quantum yields of up to ΦUC = 38.9% (a factor of 2 was used in the equation) and a very large anti-Stokes effect of 0.5 eV.
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Fighting Cancer with Corroles
Chemical reviews, 2016Co-Authors: Ruijie D. Teo, Zeev Gross, Jae Youn Hwang, John Termini, Harry B. GrayAbstract:Corroles are exceptionally promising platforms for the development of agents for simultaneous cancer-targeting imaging and therapy. Depending on the element chelated by the corrole, these theranostic agents may be tuned primarily for diagnostic or therapeutic function. Versatile synthetic methodologies allow for the preparation of amphipolar derivatives, which form stable noncovalent conjugates with targeting biomolecules. These conjugates can be engineered for imaging and targeting as well as therapeutic function within one theranostic assembly. In this review, we begin with a brief outline of corrole chemistry that has been uniquely useful in designing corrole-based anticancer agents. Then we turn attention to the early literature regarding corrole anticancer activity, which commenced one year after the first scalable synthesis was reported (1999–2000). In 2001, a major advance was made with the introduction of negatively charged Corroles, as these molecules, being amphipolar, form stable conjugates wit...
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Intriguing Physical and Chemical Properties of Phosphorus Corroles
Inorganic chemistry, 2016Co-Authors: Jenya Vestfrid, Israel Goldberg, Rashmi Kothari, Arseni Kostenko, Boris Tumanskii, Zeev GrossAbstract:The fluorescence intensity of phosphorus Corroles increases upon meso-aryl C–F/C–H and P–OH/P–F substitutions, the latter affects corrole-centered redox processes more than C–H/C–F substitution on the corrole’s skeleton, and the presence of F atoms allows for the first experimental insight into the electronic structures of oxidized Corroles. Experimental and theoretical methodologies reveal that mono- but not bis-chlorosulfonation of the corrole skeleton is under kinetic control. Selective introduction of heavy atoms leads to complexes that are phosphorescent at room temperature.
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Corrole‐Decorated Porphyrin Dendrimer and Its Selective Metallation
European Journal of Organic Chemistry, 2015Co-Authors: Nikolay Semenishyn, Atif Mahammed, Zeev GrossAbstract:Utilization of 4-formylbenzaldehyde in the 2+1 approach for synthesis of Corroles was regulated as to lead to either the one-pot synthesis of meso-meso′-linked dimeric corrole or to a monomeric corrole with a free formyl group. The latter was used as synthon for the preparation of a dendritic porphyrin with four Corroles. The different chelating properties of the similar macrocycles allow for selective insertion of zinc(II) into the central porphyrin and cobalt(III) into the peripheral Corroles.
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Computational predictions of Corroles as a class of Hsp90 inhibitors
Molecular bioSystems, 2015Co-Authors: Ruijie D. Teo, Zeev Gross, Sijia S. Dong, Harry B. Gray, William A. GoddardAbstract:Corroles have been shown experimentally to cause cell cycle arrest, and there is some evidence that this might be attributed to an inhibitory effect of Corroles on Heat shock protein 90 (Hsp90), which is known to play a vital role in cancer cell proliferation. In this study, we used molecular dynamics to examine the interaction of gallium Corroles with Hsp90, and found that they can bind preferentially to the ATP-binding N-terminal site. We also found that structural variations of the corrole ring can influence the binding energies and affinities of the corrole to Hsp90. We predict that both the bis-carboxylated corrole (4-Ga) and a proposed 3,17-bis-sulfonated corrole (7-Ga) are promising alternatives to Ga(III) 5,10,15-tris(pentafluorophenyl)-2,17-bis(sulfonic acid)-corrole (1-Ga) as anti-cancer agents.
Abhik Ghosh - One of the best experts on this subject based on the ideXlab platform.
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Rhenium-Imido Corroles
Inorganic chemistry, 2020Co-Authors: Abraham B. Alemayehu, Sergey M. Borisov, Simon J. Teat, Abhik GhoshAbstract:MetalloCorroles involving 5d transition metals are currently of interest as near-IR phosphors and as photosensitizers for oxygen sensing and photodynamic therapy. Their syntheses, however, are often bedeviled by capricious and low-yielding protocols. Against this backdrop, we describe rhenium-imido Corroles, a new class of 5d metalloCorroles, synthesized simply and in respectable (∼30%) yields via the interaction of a free-base corrole, Re2(CO)10, K2CO3, and aniline in 1,2,4-trichlorobenzene at ∼190 °C in a sealed vial under strict anaerobic conditions. The generality of the method was shown by the synthesis of six derivatives, including those derived from meso-tris(pentafluorophenyl)corrole, H3[TPFPC], and five different meso-tris(p-X-phenyl)Corroles, H3[TpXPC], where X = CF3, F, H, CH3, OCH3. Single-crystal X-ray structures obtained for two of the complexes, Re[TpFPC](NPh) and Re[TpCF3PC](NPh), revealed relatively unstrained equatorial Re-N distances of ∼2.00 A, a ∼ 0.7-A displacement of the Re from the mean plane of the corrole nitrogens, and an Re-Nimido distance of ∼1.72 A. Details of the corrole skeletal bond distances, diamagnetic 1H NMR spectra, relatively substituent-independent Soret maxima, and electrochemical HOMO-LUMO gaps of ∼2.2 V all indicated an innocent corrole macrocycle. Surprisingly, unlike several other classes of 5d metalloCorroles, the Re-imido complexes proved nonemissive in solution at room temperature and also failed to sensitize singlet oxygen formation, indicating rapid radiationless deactivation of the triplet state, presumably via the rapidly rotating axial phenyl group. By analogy with other metal-oxo and -imido Corroles, we remain hopeful that the Re-imido group will prove amenable to further elaboration and thereby contribute to the development of a somewhat challenging area of coordination chemistry.
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X‑ray Absorption Spectroscopy as a Probe of Ligand Noninnocence in MetalloCorroles: The Case of Copper Corroles
2019Co-Authors: Hyeongtaek Lim, Abhik Ghosh, Kolle E Thomas, Britt Hedman, Keith O. Hodgson, Edward I. SolomonAbstract:The question of ligand noninnocence in Cu Corroles has long been a topic of discussion. Presented herein is a Cu K-edge X-ray absorption spectroscopy (XAS) study, which provides a direct probe of the metal oxidation state, of three Cu Corroles, Cu[TPC], Cu[Br8TPC], and Cu[(CF3)8TPC] (TPC = meso-triphenylcorrole), and the analogous Cu(II) porphyrins, Cu[TPP], Cu[Br8TPP], and Cu[(CF3)8TPP] (TPP = meso-tetraphenylporphyrin). The Cu K rising-edges of the Cu Corroles were found to be about 0–1 eV upshifted relative to the analogous porphyrins, which is substantially lower than the 1–2 eV shifts typically exhibited by authentic Cu(II)/Cu(III) model complex pairs. In an unusual twist, the Cu K pre-edge regions of both the Cu Corroles and the Cu porphyrins exhibit two peaks split by 0.8–1.3 eV. Based on time-dependent density functional theory calculations, the lower- and higher-energy peaks were assigned to a Cu 1s → 3dx2–y2 transition and a Cu 1s → corrole/porphyrin π* transition, respectively. From the Cu(II) porphyrins to the corresponding Cu Corroles, the energy of the Cu 1s → 3dx2–y2 transition peak was found to upshift by 0.6–0.8 eV. This shift is approximately half that observed between Cu(II) to Cu(III) states for well-defined complexes. The Cu K-edge XAS spectra thus show that although the metal sites in the Cu Corroles are more oxidized relative to those in their Cu(II) porphyrin analogues, they are not oxidized to the Cu(III) level, consistent with the notion of a noninnocent corrole. The relative importance of σ-donation versus corrole π-radical character is discussed
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Relativistic Effects on a Metal–Metal Bond: Osmium Corrole Dimers
2019Co-Authors: Abraham B. Alemayehu, Laura J. Mccormick, Hugo Vazquez-lima, Abhik GhoshAbstract:A series of metal–metal bonded osmium corrole dimers, {Os[TpXPC]}2, were synthesized in reasonably good yields (35–46%) via the interaction of the corresponding free-base meso-tris(p-X-phenyl)Corroles (H3[TpXPC], X = CF3, H, CH3, and OCH3), Os3(CO)12, and potassium carbonate in 1,2,4-trichlorobenzene under an inert atmosphere at 180 °C over several hours. The complexes are only the second class of Os Corroles reported to date (the first being OsVIN Corroles) and also the second class of metal–metal bonded metallocorrole dimers (the other being Ru corrole dimers). Comparison of the X-ray structures, redox potentials, and optical spectra of analogous Ru and Os corrole dimers, along with scalar-relativistic DFT calculations, has provided an experimentally calibrated account of relativistic effects in these complexes. Three of the Os corrole dimers (X = CF3, H, and OCH3) were analyzed with single-crystal X-ray diffraction analysis, revealing inversion-related corrole rings with eclipsed Os–N bonds and Os–Os distances of ∼2.24 Å that are ∼0.06 Å longer than the Ru–Ru distances in the analogous Ru corrole dimers. Interestingly, a comparison of scalar-relativistic and nonrelativistic DFT calculations indicates that this difference in metal–metal bond distance does not, in fact, reflect a differential relativistic effect. For a given corrole ligand, the Ru and Os corrole dimers exhibit nearly identical oxidation potentials but dramatically different reduction potentials, with the Os values ∼0.5 V lower relative to Ru, suggesting that whereas oxidation occurs in a ligand-centered manner, reduction is substantially metal-centered, which indeed was confirmed by scalar-relativistic calculations. The calculations further indicate that approximately a third of the ∼0.5 V difference in reduction potentials can be ascribed to relativity. The somewhat muted value of this relativistic effect appears to be related to the finding that reduction of an Os corrole dimer is not exclusively metal-based but that a significant amount of spin density is delocalized over to the corrole ligand; in contrast, reduction of an Ru corrole dimer occurs exclusively on the Ru–Ru linkage. For isoelectronic complexes, the Ru and Os corrole dimers exhibit substantially different UV–vis spectra. A key difference is a strong near-UV feature of the Os series, which in energy terms is blue-shifted by ∼0.55 V relative to the analogous feature of the Ru series. TDDFT calculations suggest that this difference may be related to higher-energy Os(5d)-based LUMOs in the Os case relative to analogous MOs for Ru
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Stable Platinum(IV) Corroles: Synthesis, Molecular Structure, and Room-Temperature Near-IR Phosphorescence
2018Co-Authors: Abraham B. Alemayehu, Kevin J Gagnon, Laura J. Mccormick, Sergey M. Borisov, Abhik GhoshAbstract:A series of stable Pt(IV) corrole complexes with the general formula PtIV[TpXPC](m/p-C6H4CN)(py), where TpXPC3– is the trianion of a tris(p-X-phenyl)corrole and X = CF3, H, and CH3, has been synthesized, affording key physicochemical data on a rare and elusive class of metalloCorroles. Single-crystal X-ray structures of two of the complexes revealed very short equatorial Pt–N distances of 1.94–1.97 Å, an axial Pt–C distance of ∼2.03 Å, and an axial Pt–N distance of ∼2.22 Å. The complexes exhibit Soret maxima at ∼430 nm, which are essentially independent of the meso-aryl para substituents, and strong Q bands with the most intense peak at 595–599 nm. The substituent-independent Soret maxima are consistent with an innocent PtIV–corrole3– description for the complexes. The low reduction potentials (−1.45 ± 0.08 V vs saturated calomel reference electrode) also support a highly stable Pt(IV) ground state as opposed to a noninnocent corrole•2– description. The reductions, however, are irreversible, which suggests that they involve concomitant cleavage of the Pt–aryl bond. Unlike Pt(IV) porphyrins, two of the complexes, PtIV[TpXPC](m-C6H4CN)(py) (X = CF3 and CH3), were found to exhibit room-temperature near-IR phosphorescence with emission maxima at 813 and 826 nm, respectively. The quantum yield of ∼0.3% is comparable to those observed for six-coordinate Ir(III) Corroles
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Halterman Corroles and Their Use as a Probe of the Conformational Dynamics of the Inherently Chiral Copper Corrole Chromophore
Inorganic Chemistry, 2018Co-Authors: Kolle E Thomas, Laura J. Mccormick, Hugo Vazquez-lima, Daniel Carrie, Gerard Simonneaux, Abhik GhoshAbstract:Halterman Corroles have been synthesized for the first time from pyrrole and Halterman's aldehyde via Gryko's "water-methanol method". These were derivatized to the corresponding copper complexes and subsequently to the β-octabromo complexes. Electronic circular dichroism spectra were recorded for the enantiopure copper complexes, affording the first such measurements for the inherently chiral Cu corrole chromophore. Interestingly, for a given configuration of the Halterman substituents, X-ray crystallographic studies revealed both P and M conformations of the Cu-corrole core, proving that the substituents, even in conjunction with β-octabromination, are unable to lock the Cu-corrole core into a given chirality. The overall body of evidence strongly indicates a dynamic equilibrium between the P and M conformations. Such an interconversion, which presumably proceeds via saddling inversion, provides a rationale for our failure so far to resolve sterically hindered Cu Corroles into their constituent enantiomers by means of chiral HPLC.
Harry B. Gray - One of the best experts on this subject based on the ideXlab platform.
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Fighting Cancer with Corroles
Chemical reviews, 2016Co-Authors: Ruijie D. Teo, Zeev Gross, Jae Youn Hwang, John Termini, Harry B. GrayAbstract:Corroles are exceptionally promising platforms for the development of agents for simultaneous cancer-targeting imaging and therapy. Depending on the element chelated by the corrole, these theranostic agents may be tuned primarily for diagnostic or therapeutic function. Versatile synthetic methodologies allow for the preparation of amphipolar derivatives, which form stable noncovalent conjugates with targeting biomolecules. These conjugates can be engineered for imaging and targeting as well as therapeutic function within one theranostic assembly. In this review, we begin with a brief outline of corrole chemistry that has been uniquely useful in designing corrole-based anticancer agents. Then we turn attention to the early literature regarding corrole anticancer activity, which commenced one year after the first scalable synthesis was reported (1999–2000). In 2001, a major advance was made with the introduction of negatively charged Corroles, as these molecules, being amphipolar, form stable conjugates wit...
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Computational predictions of Corroles as a class of Hsp90 inhibitors
Molecular bioSystems, 2015Co-Authors: Ruijie D. Teo, Zeev Gross, Sijia S. Dong, Harry B. Gray, William A. GoddardAbstract:Corroles have been shown experimentally to cause cell cycle arrest, and there is some evidence that this might be attributed to an inhibitory effect of Corroles on Heat shock protein 90 (Hsp90), which is known to play a vital role in cancer cell proliferation. In this study, we used molecular dynamics to examine the interaction of gallium Corroles with Hsp90, and found that they can bind preferentially to the ATP-binding N-terminal site. We also found that structural variations of the corrole ring can influence the binding energies and affinities of the corrole to Hsp90. We predict that both the bis-carboxylated corrole (4-Ga) and a proposed 3,17-bis-sulfonated corrole (7-Ga) are promising alternatives to Ga(III) 5,10,15-tris(pentafluorophenyl)-2,17-bis(sulfonic acid)-corrole (1-Ga) as anti-cancer agents.
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near ir phosphorescence of iridium iii Corroles at ambient temperature
Journal of the American Chemical Society, 2010Co-Authors: Joshua H. Palmer, Zeev Gross, Jay R. Winkler, Alec C Durrell, Harry B. GrayAbstract:The photophysical properties of Ir(III) Corroles differ from those of phosphorescent porphyrin complexes, cyclometalated and polyimine Ir(III) compounds, and other luminescent metalloCorroles. Ir(III) corrole phosphorescence is observed at ambient temperature at wavelengths much longer (>800 nm) than those of most Ir(III) phosphors. The solvatochromic behavior of Ir(III)-corrole Soret and Q absorption bands suggests that the lowest singlet excited states (S2 and S1) are substantially more polar than the ground state.
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how do Corroles stabilize high valent metals
Comments on Inorganic Chemistry, 2006Co-Authors: Zeev Gross, Harry B. GrayAbstract:Trianionic Corroles are readily oxidized, yet they are able to stabilize metals in high oxidation states. In an attempt to solve this apparent puzzle, we have estimated both metal d and corrole π orbital energies by analysis of well established experimental data. Although the corrole π orbitals are at higher energies than those of closely related porphyrins, the d orbital energies are even higher, owing to greatly enhanced σ bonding dictated by the relatively rigid macrocyclic trianionic—ligand framework. Understanding the relative importance of corrole π and σ effects sheds new light on metallocorrole stability and reactivity that in turn will further advance this hot area of chemistry.
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Specific Delivery of Corroles to Cells via Noncovalent Conjugates with Viral Proteins
Pharmaceutical Research, 2006Co-Authors: Hasmik Agadjanian, Atif Mahammed, Harry B. Gray, Jeremy J. Weaver, Altan Rentsendorj, Sam Bass, Jihee Kim, Ivan J. Dmochowski, Ruth Margalit, Zeev GrossAbstract:Purpose Corroles are amphiphilic macrocycles that can bind and transport metal ions, and thus may be toxic to cells. We predicted that anionic Corroles would poorly enter cells due to the negatively charged cell membrane, but could be ideal tumor-targeted drugs if appropriate carriers enabled delivery into tumor cells. In this work, we test the hypothesis that recombinant cell penetrating proteins of the adenovirus (Ad) capsid form noncovalent conjugates with Corroles to facilitate target-specific delivery and cell death. Methods Corroles mixed with recombinant proteins were tested for conjugate assembly, cell penetration, stability, targeted binding, and cell killing in vitro . Results Sulfonated Corroles entered cells only with carrier proteins, and formed stable complexes with recombinant Ad capsid proteins. ErbB receptor-targeted conjugates were cytotoxic to ErbB2-positive but not ErbB2-negative breast cancer cells, whereas molar equivalents of free corrole had no effect on these cells. Conclusions Sulfonated Corroles are cytotoxic to ErbB2-positive breast cancer cells when delivered by a targeted cell penetrating protein. The relatively low dose required to accomplish this compared to untargeted compounds suggests that Corroles may lend themselves to targeted therapy. Importantly, the amphiphilicity of Corroles enables a unique approach to bioconjugate formation whereby the carrier and drug form a stable complex by noncovalent assembly.
Atif Mahammed - One of the best experts on this subject based on the ideXlab platform.
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phosphorus corrole complexes from property tuning to applications in photocatalysis and triplet triplet annihilation upconversion
Chemical Science, 2019Co-Authors: Atif Mahammed, Jenya Vestfrid, Kepeng Chen, Jianzhang Zhao, Zeev GrossAbstract:Efficient triplet photosensitizers are important for fundamental photochemical studies and applications such as triplet–triplet annihilation upconversion (TTA UC), photoredox catalytic organic reactions and photovoltaics. We now report a series of phosphorus corrole compounds as efficient visible light-harvesting metal-free triplet photosensitizers. While the heavy-atom-free phosphorus Corroles show absorption in the visible spectral region (centered at 573 nm) and have a decent triplet state quantum yield (ΦΔ = 49%), iodo-substitution on the corrole core induces red-shifted absorption (589 nm) and improves intersystem crossing significantly (ΦΔ = 67%). Nanosecond transient absorption spectra confirm triplet state formation upon photoexcitation (τT = 312 μs) and the iodinated derivatives also display near IR phosphorescence in fluid solution at room temperature (λem = 796 nm, τp = 412 μs). Both singlet oxygen (1O2) and superoxide radical anions (O2−˙) may be produced with the phosphorus Corroles, which are competent photocatalysts for the oxidative coupling of benzylamine (the Aza Henry reaction). Very efficient TTA UC was observed with the phosphorus Corroles as triplet photosensitizers and perylene as the triplet acceptor, with upconversion quantum yields of up to ΦUC = 38.9% (a factor of 2 was used in the equation) and a very large anti-Stokes effect of 0.5 eV.
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Corrole‐Decorated Porphyrin Dendrimer and Its Selective Metallation
European Journal of Organic Chemistry, 2015Co-Authors: Nikolay Semenishyn, Atif Mahammed, Zeev GrossAbstract:Utilization of 4-formylbenzaldehyde in the 2+1 approach for synthesis of Corroles was regulated as to lead to either the one-pot synthesis of meso-meso′-linked dimeric corrole or to a monomeric corrole with a free formyl group. The latter was used as synthon for the preparation of a dendritic porphyrin with four Corroles. The different chelating properties of the similar macrocycles allow for selective insertion of zinc(II) into the central porphyrin and cobalt(III) into the peripheral Corroles.
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Specific Delivery of Corroles to Cells via Noncovalent Conjugates with Viral Proteins
Pharmaceutical Research, 2006Co-Authors: Hasmik Agadjanian, Atif Mahammed, Harry B. Gray, Jeremy J. Weaver, Altan Rentsendorj, Sam Bass, Jihee Kim, Ivan J. Dmochowski, Ruth Margalit, Zeev GrossAbstract:Purpose Corroles are amphiphilic macrocycles that can bind and transport metal ions, and thus may be toxic to cells. We predicted that anionic Corroles would poorly enter cells due to the negatively charged cell membrane, but could be ideal tumor-targeted drugs if appropriate carriers enabled delivery into tumor cells. In this work, we test the hypothesis that recombinant cell penetrating proteins of the adenovirus (Ad) capsid form noncovalent conjugates with Corroles to facilitate target-specific delivery and cell death. Methods Corroles mixed with recombinant proteins were tested for conjugate assembly, cell penetration, stability, targeted binding, and cell killing in vitro . Results Sulfonated Corroles entered cells only with carrier proteins, and formed stable complexes with recombinant Ad capsid proteins. ErbB receptor-targeted conjugates were cytotoxic to ErbB2-positive but not ErbB2-negative breast cancer cells, whereas molar equivalents of free corrole had no effect on these cells. Conclusions Sulfonated Corroles are cytotoxic to ErbB2-positive breast cancer cells when delivered by a targeted cell penetrating protein. The relatively low dose required to accomplish this compared to untargeted compounds suggests that Corroles may lend themselves to targeted therapy. Importantly, the amphiphilicity of Corroles enables a unique approach to bioconjugate formation whereby the carrier and drug form a stable complex by noncovalent assembly.
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Specific delivery of Corroles to cells via noncovalent conjugates with viral proteins.
Pharmaceutical research, 2006Co-Authors: Hasmik Agadjanian, Atif Mahammed, Harry B. Gray, Jeremy J. Weaver, Altan Rentsendorj, Sam Bass, Jihee Kim, Ivan J. Dmochowski, Ruth Margalit, Zeev GrossAbstract:Corroles are amphiphilic macrocycles that can bind and transport metal ions, and thus may be toxic to cells. We predicted that anionic Corroles would poorly enter cells due to the negatively charged cell membrane, but could be ideal tumor-targeted drugs if appropriate carriers enabled delivery into tumor cells. In this work, we test the hypothesis that recombinant cell penetrating proteins of the adenovirus (Ad) capsid form noncovalent conjugates with Corroles to facilitate target-specific delivery and cell death. Corroles mixed with recombinant proteins were tested for conjugate assembly, cell penetration, stability, targeted binding, and cell killing in vitro. Sulfonated Corroles entered cells only with carrier proteins, and formed stable complexes with recombinant Ad capsid proteins. ErbB receptor-targeted conjugates were cytotoxic to ErbB2-positive but not ErbB2-negative breast cancer cells, whereas molar equivalents of free corrole had no effect on these cells. Sulfonated Corroles are cytotoxic to ErbB2-positive breast cancer cells when delivered by a targeted cell penetrating protein. The relatively low dose required to accomplish this compared to untargeted compounds suggests that Corroles may lend themselves to targeted therapy. Importantly, the amphiphilicity of Corroles enables a unique approach to bioconjugate formation whereby the carrier and drug form a stable complex by noncovalent assembly.
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Corrole-sensitized TiO2 solar cells
Journal of Porphyrins and Phthalocyanines, 2006Co-Authors: Don Walker, Atif Mahammed, Harry B. Gray, Shlomit Chappel, Bruce S. Brunschwig, Jay R. Winkler, Arie Zaban, Zeev GrossAbstract:We are investigating the properties of corrole-sensitized TiO2 solar cells. The TiO2-adsorbed free base and GaIII Corroles display cell efficiencies under AM 1.5 illumination that are about half that of a standard N3-sensitized cell (N3 = cis-bis(4,4'-dicarboxy-2,2'-bipyridine)dithiocyanato ruthenium(II)), while that of the SnIV-based cell is much lower. The properties of the corrole-TiO2 solar cells, along with results obtained with electrodes of lower conduction band energies clearly reveal that the reducing power of the singlet excited states of the free base and GaIII corrole, but not of the SnIV derivative, is sufficiently high for efficient injection into the TiO2 conduction band.
Israel Goldberg - One of the best experts on this subject based on the ideXlab platform.
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Intriguing Physical and Chemical Properties of Phosphorus Corroles
Inorganic chemistry, 2016Co-Authors: Jenya Vestfrid, Israel Goldberg, Rashmi Kothari, Arseni Kostenko, Boris Tumanskii, Zeev GrossAbstract:The fluorescence intensity of phosphorus Corroles increases upon meso-aryl C–F/C–H and P–OH/P–F substitutions, the latter affects corrole-centered redox processes more than C–H/C–F substitution on the corrole’s skeleton, and the presence of F atoms allows for the first experimental insight into the electronic structures of oxidized Corroles. Experimental and theoretical methodologies reveal that mono- but not bis-chlorosulfonation of the corrole skeleton is under kinetic control. Selective introduction of heavy atoms leads to complexes that are phosphorescent at room temperature.
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Intriguing Chemistry of Molybdenum Corroles
Inorganic chemistry, 2013Co-Authors: Izana Nigel-etinger, Israel Goldberg, Zeev GrossAbstract:The development of new methodologies for gaining access to low-valent molybdenum complexes led to spectroscopic identification of mononuclear (oxo)molybdenum(IV) Corroles, as well as the full characterization of a binuclear molybdenum(IV) corrole that is bridged through axial O atoms by a Mg(THF)4 moiety.
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oxygen atom transfer reactions from isolated oxo manganese v Corroles to sulfides
Journal of the American Chemical Society, 2010Co-Authors: Anil Kumar, Israel Goldberg, Mark Botoshansky, Yekaterina Buchman, Zeev GrossAbstract:A series of five free-base Corroles were metalated and brominated to form 10 manganese(III) Corroles. Two of the free-base Corroles and six manganese(III) Corroles were analyzed by X-ray crystallography, including one complex that may be considered a transition-state analogue of oxygen atom transfer (OAT) from (oxo)manganese(V) to thioansisole. Oxidation by ozone allowed for isolation of the 10 corresponding (oxo)manganese(V) Corroles, whose characterization by (1)H and (19)F NMR spectroscopy and electrochemistry revealed a low-spin and triply bound manganese-oxygen moiety. Mechanistic insight was obtained by investigating their reactivity regarding stoichiometric OAT to a series of p-thioanisoles, revealing a magnitude difference on the order of 5 between the β-pyrrole brominated (oxo)manganese(V) Corroles relative to the nonbrominated analogues. The main conclusion is that the (oxo)manganese(V) Corroles are legitimate OAT agents under conditions where proposed oxidant-coordinated reaction intermediates are irrelevant. Large negative Hammett ρ constants are obtained for the more reactive (oxo)manganese(V) Corroles, consistent with expectation for such electrophilic species. The least reactive complexes display very little selectivity to the electron-richness of the sulfides, as well as a non-first-order dependence on the concentration of (oxo)manganese(V) corrole. This suggests that disproportionation of the original (oxo)manganese(V) corrole to (oxo)manganese(IV) and (oxo)manganese(VI) Corroles, followed by substrate oxidation by the latter complex, gains importance when the direct OAT process becomes progressively less favorable.
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synthesis and full characterization of molybdenum and antimony Corroles and utilization of the latter complexes as very efficient catalysts for highly selective aerobic oxygenation reactions
Inorganic Chemistry, 2006Co-Authors: Inna Luobeznova, Israel Goldberg, Marina Raizman, Zeev GrossAbstract:Two molybdenum and three antimony Corroles were isolated and characterized by NMR, EPR, and electrochemistry. The very negative reduction potentials of the (oxo)molybdenum(V) Corroles are clearly related to their inactivity as oxygen transfer reagents and the unsuccessful attempts to isolate lower-valent molybdenum Corroles. X-ray crystallography of the (oxo)molybdenum(V) corrole 1a and the trans-difluoroantimony(V) corrole 2c, the first of their kind, revealed that their molecular structures represent extreme cases of such complexes: a highly domed corrole with very large out-of-plane metal displacement for 1a (0.73 A) and a very flat corrole with the metal ion in its center for 2c. All three antimony Corroles displayed high activity and selectivity as catalysts for the photoinduced oxidation of thioanisole by molecular oxygen, with superior results obtained in alcoholic solvents with 2c as catalyst. Allylic and tertiary benzylic CH bonds were also oxidized under those conditions, with absolute selectiv...
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Iron(III) and Iron(IV) Corroles: Synthesis, Spectroscopy, Structures, and No Indications for Corrole Radicals
Inorganic chemistry, 2002Co-Authors: Liliya Simkhovich, Israel Goldberg, Zeev GrossAbstract:A delicate control of reaction conditions allows the isolation of several distinctively different iron complexes of tris(pentafluorophenyl)- and tris(2,6-dichlorophenyl)corrole. As long as coordinating ligands are present, the iron(III) complexes are stable in solution. Otherwise they are aerobically oxidized to either mononuclear chloroiron(IV) or dinuclear (μ-oxo)iron(IV) complexes, in acidic and basic solutions, respectively (the latter holds only for tris(pentafluorophenyl)corrole). When treated with NaNO2, the mononuclear chloroiron(IV) Corroles are efficiently converted into diamagnetic iron nitrosyl complexes. The low- and intermediate-spin iron(III), iron nitrosyl, and chloroiron(IV) Corroles were fully characterized by a combination of spectroscopic methods and X-ray crystallography. There was no indication for an open-shell corrole in any of the complexes.
