Simple, Axial Ligand-Mediated Route to Water-Soluble Iridium Corroles

Thomassen, Ivar Kristian; Rasmussen, Daniel; Einrem, Rune F.; Ghosh, Abhik

doi:10.1021/acsomega.1c02399

Cited by 4 publications

(5 citation statements)

References 38 publications

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“…As noted before for Au phlorins, both complexes exhibit strong NIR absorption in the 700–900 nm region, with λ max at 806 and 770 nm for Ir[DMTPFPhl](py) 2 and Au[DMTPFPhl], respectively (Figure ). These absorption maxima are some 200 nm red-shifted relative to those observed for Ir − and Au − corroles, respectively, indicating a significantly smaller HOMO–LUMO gap in the case of the metallophlorins. The same picture also emerges from cyclic voltammetry measurements, as described below.…”

Section: Resultsmentioning

confidence: 74%

Electronic Structure of Metallophlorins: Lessons from Iridium and Gold Phlorin Derivatives

Larsen,

Adewuyi,

Thomas

et al. 2024

Inorg. Chem.

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Phlorins have long remained underexplored relative to their fully conjugated counterparts, such as porphyrins, hydroporphyrins, and corroles. Herein, we have attempted to bridge that knowledge gap with a scalar-relativistic density functional theory (DFT) study of unsubstituted iridium and gold phlorin derivatives and a multitechnique experimental study of iridium-bispyridine and gold complexes of 5,5-dimethyl-10,15,20-tris(pentafluorophenyl)phlorin. Theory and experiments concur that the phlorin derivatives exhibit substantially smaller HOMO–LUMO gaps, as reflected in a variety of observable properties. Thus, the experimentally studied Ir and Au complexes absorb strongly in the near-infrared (NIR), with absorption maxima at 806 and 770 nm, respectively. The two complexes are also weakly phosphorescent with emission maxima at 950 and 967 nm, respectively. They were also found to photosensitize singlet oxygen formation, with quantum yields of 40 and 28%, respectively. The near-infrared (NIR) absorption and emission are consonants with smaller electrochemical HOMO–LUMO gaps of ∼1.6 V, compared to values of ∼2.1 V, for electronically innocent porphyrins and corroles. Interestingly, both the first oxidation and reduction potentials of the Ir complex are some 600 mV shifted to more negative potentials relative to those of the Au complex, indicating an exceptionally electron-rich macrocycle in the case of the Ir complex.

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Section: Resultsmentioning

confidence: 74%

Electronic Structure of Metallophlorins: Lessons from Iridium and Gold Phlorin Derivatives

Larsen,

Adewuyi,

Thomas

et al. 2024

Inorg. Chem.

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“… 36 , 37 Very recently, the use of water-soluble phosphines has provided convenient access to water-soluble, five-coordinate Ir corroles. 38 …”

Section: Group 9 Metallocorroles (Ir)mentioning

confidence: 99%

“…A large number of six-coordinate 18-electron Ir corrole bis-amine adducts have been synthesized, as well as a smaller number of 16-electron monophosphine adducts (Table ). , Very recently, the use of water-soluble phosphines has provided convenient access to water-soluble, five-coordinate Ir corroles …”

Section: Group 9 Metallocorroles (Ir)mentioning

confidence: 99%

The Story of 5d Metallocorroles: From Metal–Ligand Misfits to New Building Blocks for Cancer Phototherapeutics

et al. 2021

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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 and rich coordination chemistry. The 5d metallocorroles are arguably the icing on that cake. New Zealand chemist Penny Brothers has used the word “misfit” to describe the interactions of boron, a small atom with a predilection for tetrahedral coordination, and porphyrins, classic square-planar ligands. Steve Jobs lionized misfits as those who see things differently and push humanity forward. Both perspectives have inspired us. The 5d metallocorroles are misfits in that they encapsulate a large 5d transition metal ion within the tight cavity of a contracted porphyrin ligand. Given the steric mismatch inherent in their structures, the syntheses of some 5d metallocorroles are understandably capricious, proceeding under highly specific conditions and affording poor yields. Three broad approaches may be distinguished. (a) In the metal–alkyl approach , a free-base corrole is exposed to an alkyllithium and the resulting lithio-corrole is treated with an early transition metal chloride; a variant of the method eschews alkyllithium and deploys a transition metal–alkyl instead, resulting in elimination of the alkyl group as an alkane and insertion of the metal into the corrole. This approach is useful for inserting transition metals from groups 4, 5, and, to some extent, 6, as well as lanthanides and actinides. (b) In our laboratory, we have often deployed a low-valent organometallic approach for the middle transition elements (groups 6, 7, 8, and 9). The reagents are low-valent metal–carbonyl or −olefin complexes, which lose one or more carbon ligands at high temperature, affording coordinatively unsaturated, sticky metal fragments that are trapped by the corrole nitrogens. (c) Finally, a metal acetate approach provides the method of choice for gold and platinum insertion (groups 10 and 11). This Account provides a first-hand perspective of the three approaches, focusing on the last two, which were largely developed in our laboratory. In general, the products were characterized with X-ray crystallography, electrochemistry, and a variety of spectroscopic methods. The physicochemical data, supplemented by relativistic DFT calculations, have provided fascinating insights into periodic trends and relativistic effects. An unexpected feature of many 5d metallocorroles, given their misfit character, is their remarkable stability under thermal, chemical, and photochemical stimulation. Many of them also exhibit long triplet lifetimes on...

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“…Corroles, which were mere curiosities just 25 years ago 1 – 5 , are now a major class of macrocyclic ligands with applications rivaling those of porphyrins 6 , 7 . Besides key photophysical properties 8 – 15 , biomedical applications such as photodynamic therapy (PDT) 16 – 19 require water-soluble and amphiphilic ligands for effective biodelivery 20 – 28 . An attractive approach to effective biodelivery in PDT involves nanodroplets of locally-perfluorinated (fluorous 29 – 35 ) porphyrin analogues dissolved in a fluorocarbon solvent with high oxygen-carrying capacity.…”

Section: Introductionmentioning

confidence: 99%

Phenol- and resorcinol-appended metallocorroles and their derivatization with fluorous tags

Alemayehu

Ghosh

2022

Sci Rep

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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 THF. The M[T(3,5-OH)PC] derivatives also proved moderately soluble in 0.05 M aqueous KOH. Unlike oxidation-prone aminophenyl-substituted corroles, the phenol- and resorcinol-appended metallocorroles could be readily handled in air without special precautions. The phenolic metallocorroles could be readily alkylated with 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoroundecyl iodide (“FtI”) to afford the fluorous-tagged metallocorroles M[TpOFtPC] and M[T(3,5-OFt)PC] in > 90% yields. The simplicity of the synthetic protocols promise a wide range of phenolic and fluorous-tagged porphyrin analogues with potential applications to diverse fields such as sensors, catalysis, and photodynamic therapy, among others.

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Simple, Axial Ligand-Mediated Route to Water-Soluble Iridium Corroles

Cited by 4 publications

References 38 publications

Electronic Structure of Metallophlorins: Lessons from Iridium and Gold Phlorin Derivatives

Electronic Structure of Metallophlorins: Lessons from Iridium and Gold Phlorin Derivatives

The Story of 5d Metallocorroles: From Metal–Ligand Misfits to New Building Blocks for Cancer Phototherapeutics

Phenol- and resorcinol-appended metallocorroles and their derivatization with fluorous tags

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