• Amphiphilic Rhenium-Oxo Corroles as a New Class of Sensitizers for Photodynamic Therapy 

      Einrem, Rune F.; Alemayehu, Abraham; Borisov, Sergey M.; Ghosh, Abhik; Gederaas, Odrun Arna (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-27)
      A set of rhenium(V)-oxo <i>meso</i>-triarylcorroles bearing ester and carboxylic acid functionalities were synthesized with a view to determining their potential for photodynamic therapy. Toward this end, we measured their near-IR phosphorescence and their ability to sensitize singlet oxygen formation. The two esters studied, Re<sup>V</sup>O 5,10,15-tris(<i>meta</i>-carbomethoxyphenyl)corrole and ...
    • Comparing Isoelectronic, Quadruple-Bonded Metalloporphyrin and Metallocorrole Dimers: Scalar-Relativistic DFT Calculations Predict a > 1-eV Range for Ionization Potential and Electron Affinity 

      Conradie, Jeanet; Vazquez-Lima, Hugo; Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-21)
      A scalar-relativistic DFT study of isoelectronic, quadruple-bonded Group 6 metalloporphyrins (M = Mo, W) and Group 7 metallocorroles (M = Tc, Re) has uncovered dramatic differences in ionization potential (IP) and electron affinity (EA) among the compounds. Thus, both the IPs and EAs of the corrole derivatives are 1 eV or more higher than those of the porphyrin derivatives. These differences ...
    • Electrophilic Activation of Osmium-Nitrido Corroles: The OsN Triple Bond as a π-Acceptor Metallaligand in a Heterobimetallic OsVIN–PtII Complex 

      Reinholdt, Anders; Alemayehu, Abraham; Gagnon, Kevin J.; Bendix, Jesper; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-31)
      Presented herein is a first investigation of the chemical reactivity of osmium-nitrido corroles, which are known for their unusual thermal, chemical, and photochemical stability. Elemental chlorine perchlorinates the β-positions of the triarylcorrole but leaves the OsN unit untouched. The OsN unit is also unaffected by a variety of other electrophilic and nucleophilic reagents. Upon photolysis, ...
    • Influence of Fluorinated Substituents on the Near-Infrared Phosphorescence of 5d Metallocorroles 

      Johannessen, Krister Engedal; Johansen, Martin Amund Langaas; Einrem, Rune Finsås; McCormick McPherson, Laura J.; Alemayehu, Abraham; Borisov, Sergey M.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-12)
      The influence of fluorinated substituents on the luminescent properties of rhenium-oxo, osmium-nitrido, and gold triarylcorroles was studied via a comparison of four ligands: triphenylcorrole (TPC), tris(ptrifluoromethylphenyl)corrole (TpCF<sub>3</sub>PC), tris{3,5-bis(trifluoromethyl)- phenyl}corrole (T3,5-CF<sub>3</sub>PC), and tris(pentafluorophenyl)corrole (TPFPC). For each metal series ...
    • Infrared Spectroelectrochemistry of Iron-Nitrosyl Triarylcorroles. Implications for Ligand Noninnocence 

      Rahman, Md. Hafizur; Ryan, Michael D.; Vazquez-Lima, Hugo; Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-13)
      Recent DFT calculations have suggested that iron nitrosyl triarylcorrole complexes have substantial {FeNO}<sup>7</sup> −corrole<sup>•2−</sup> character. With this formulation, reduction of Fe(C)(NO) complexes, where C = triarylcorrole, should be centered on the corrole macrocycle rather than on the {FeNO}<sup>7</sup> moiety. To verify this proposition, visible and infrared spectroelectrochemical ...
    • Iridium(VII)-Corrole Terminal Carbides Should Exist as Stable Compounds 

      Alemayehu, Abraham; Conradie, Jeanet; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-14)
      Scalar-relativistic DFT calculations with multiple exchangecorrelation functionals and large basis sets foreshadow the existence of stable iridium(VII)−corrole terminal carbide derivatives. For the parent compound Ir[Cor](C), OLYP/STO-TZ2P calculations predict a short Ir− C bond distance of 1.69 Å, a moderately domed macrocycle with no indications of ligand noninnocence, a surprisingly low ...
    • Osmium-nitrido corroles as NIR indicators for oxygen sensors and triplet sensitizers for organic upconversion and singlet oxygen generation 

      Borisov, Sergey M.; Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-26)
      The photophysical properties of nitridoosmium(VI) corroles have been investigated. The complexes exhibit room temperature NIR phosphorescence (l<sub>max</sub> 779–795 nm). Long decay times (110–150 ms in solution and 136–183 ms in polystyrene) are responsible for efficient quenching of the emission by oxygen. All the complexes act as efficient sensitizers of singlet oxygen (quantum yields of ...
    • Phenol- and resorcinol-appended metallocorroles and their derivatization with fluorous tags 

      Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-10)
      Boron tribromide-mediated demethylation of rhenium-oxo and gold meso-tris(4-methoxyphenyl)corrole and meso-tris(3,5-dimethoxyphenylcorrole), M[TpOMePC] and M[T(3,5-OMe)PC] (M = ReO, Au), have yielded the corresponding phenol- and resorcinol-appended metallocorroles, M[TpOHPC] and M[T(3,5-OH)PC], in good yields. The latter compounds proved insoluble in dichloromethane and chloroform but soluble in ...
    • Platinum Corroles 

      Alemayehu, Abraham; Vazquez-Lima, Hugo; Beavers, Christine M.; Gagnon, Kevin J.; Bendix, Jesper; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-09)
      Platinum has been inserted into corroles for the first time and three oxidized PtIV(corrole2)ArAr0 complexes have been structurally characterized. The Soret maxima of these complexes exhibit an unusually strong dependence on the meso-aryl substituents on the corrole, indicating aryl - corrole2 charge transfer character in these transitions.
    • Platinum corroles 

      Alemayehu, Abraham; Lima, Hugo Vazquez; Beavers, Christine M.; Gagnon, Kevin J.; Bendix, Jesper; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-09)
      Platinum has been inserted into corroles for the first time and three oxidized Pt<sup>IV</sup>(corrole<sup>2-</sup>)ArAr0 complexes have been structurally characterized. The Soret maxima of these complexes exhibit an unusually strong dependence on the meso-aryl substituents on the corrole, indicating aryl - corrole<sup>2-</sup> charge transfer character in these transitions.
    • Relativistic Effects on a Metal-Metal Bond: Osmium Corrole Dimers 

      Alemayehu, Abraham; McCormick, Laura J; Vazquez Lima, Hugo; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-07)
      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 ...
    • Rhenium Biscorrole Sandwich Compounds: XAS Evidence for a New Coordination Motif 

      Alemayehu, Abraham; Abernathy, Macon Jedediah; Conradie, Jeanet; Sarangi, Ritimukta; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-23)
      The interaction of three free-base meso-tris(p-X-phenyl)corroles H3[TpXPC] (X = H, CH3, OCH3) with Re2(CO)10 at 235 °C in the presence of K2CO3 in o-dichlorobenzene has led to putative rhenium biscorrole sandwich compounds with the formula ReH[TpXPC]2. Density functional theory calculations and Re L3-edge extended X-ray absorption fine structure measurements suggest a seven-coordinate metal center, ...
    • Rhenium Corrole Dimers: Electrochemical Insights into the Nature of the Metal–Metal Quadruple Bond 

      Alemayehu, Abraham; Mccormick-Mcpherson, Laura J; Conradie, Jeanet; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-17)
      The interaction of free-base triarylcorroles with Re<sub>2</sub>(CO)<sub>10</sub> in 1,2- dichlorobenzene in the presence of 2,6-lutidine at 180 °C under strict anerobic conditions afforded approximately 10% yields of rhenium corrole dimers. The compounds exhibited diamagnetic <sup>1</sup> H NMR spectra consistent with a metal−metal quadruple bond with a σ<sup>2</sup> π<sup>4</sup> δ<sup>2</sup> ...
    • Rhenium-Imido Corroles 

      Alemayehu, Abraham; Teat, Simon J.; Borisov, Sergey M.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-10)
      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 ...
    • Stable Platinum(IV) Corroles: Synthesis, Molecular Structure, and Room-Temperature Near-IR Phosphorescence 

      Alemayehu, Abraham; McCormick, Laura J; Gagnon, Kevin J.; Borisov, Sergey M.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-17)
      A series of stable Pt(IV) corrole complexes with the general formula Pt<sup>IV</sup>[TpXPC](<i>m/p</i>-C<sub>6</sub>H<sub>4</sub>CN)(py), where TpXPC<sup>3–</sup> is the trianion of a tris(<i>p</i>-X-phenyl)corrole and X = CF<sub>3</sub>, H, and CH<sub>3</sub>, has been synthesized, affording key physicochemical data on a rare and elusive class of metallocorroles. Single-crystal X-ray structures of ...
    • Stepwise Deoxygenation of Nitrite as a Route to Two Families of Ruthenium Corroles: Group 8 Periodic Trends and Relativistic Effects 

      Alemayehu, Abraham; Vazquez Lima, Hugo; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-19)
      Given the many applications of ruthenium porphyrins, the rarity of ruthenium corroles and the underdeveloped state of their chemistry are clearly indicative of an area ripe for significant breakthroughs. The tendency of ruthenium corroles to form unreactive metal–metal-bonded dimers has been recognized as a key impediment in this area. Herein, by exposing free-base meso-tris(p-X-phenyl)corroles, ...
    • The Story of 5d Metallocorroles: From Metal–Ligand Misfits to New Building Blocks for Cancer Phototherapeutics 

      Alemayehu, Abraham; Thomas, Kolle E.; Einrem, Rune Finsås; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-23)
      CONSPECTUS: Porphyrin chemistry is Shakespearean: over a century of study has not withered the field’s apparently infinite variety. Heme proteins continually astonish us with novel molecular mechanisms, while new porphyrin analogues bowl us over with unprecedented optical, electronic, and metal-binding properties. Within the latter domain, corroles occupy a special place, exhibiting a unique ...
    • Unexpected Molecular Structure of a Putative Rhenium-Dioxo-Benzocarbaporphyrin Complex. Implications for the Highest Transition Metal Valence in a Porphyrin-Type Ligand Environment 

      Alemayehu, Abraham; Vazquez-Lima, Hugo; Teat, Simon J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-18)
      A combination of quantum chemical calculations and synthetic studies was used to address the possibility of very high (>6) valence states of transition metals in porphyrin‐type complexes. With corrole as a supporting ligand, DFT calculations ruled out Re(VII) and Ir(VII) dioxo complexes as stable species. Attempted rhenium insertion into benzocarbaporphyrin (BCP) ligands on the other hand led to two ...