Structure and spectroscopic characterization of free base and metal complexes of 5,5-dimethyl-10,15-bis(pentafluorophenyl)isocorrole

Costa, Roshinee; Geier, G. Richard; Ziegler, Christopher J.

doi:10.1039/c1dt10112a

Cited by 25 publications

(24 citation statements)

References 23 publications

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“…X-ray analysis data indicate that both the 5-isocorrole and two 10-isocoroles are (nearly) planar. [15] One needs to take into account that the 5-isororrole core is similar in size to that in corrole: the N-N distances are 2.58, 2.63, 2.65 and 3.00 Å versus 2.90, 2.78, 2,64 and 2.67 Å with hydrogen bonds or 2.91, 2.62, 2.61 and 2.71 Å without (in 5,10,15-tris-pentafluorophenylcorrole). Therefore, the suggestion can be made that the repulsive interactions of the three protons are the main source of intrinsic strain imposed to the corrole macrocycle.…”

Section: Character Of the Macrocycle Conformation And Search For A Prmentioning

confidence: 99%

Molecular Structure and Conformation of Free Base Corroles

Kruk¹,

Klenitsky²,

Maes³

2019

MHC

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Corroles represent a unique family of tetrapyrrolic chromophores with distinct structural, chemical and photophysical properties, which render them promising materials for numerous applications. The lack of one of the meso-carbon atoms ultimately leads to nonplanar macrocycle distortions. The aim of this review is to summarize the peculiarities of the molecular conformations of free base corroles and provide a unified approach for their analysis.

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Section: Character Of the Macrocycle Conformation And Search For A Prmentioning

confidence: 99%

Molecular Structure and Conformation of Free Base Corroles

Kruk¹,

Klenitsky²,

Maes³

2019

MHC

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“…[18][19][20]24,48 Recent work has been aimed at development of nonaromatic tetrapyrrole scaffolds (e.g. phlorins, [49][50][51][52][53][54][55][56] biladienes, [57][58][59][60] and isocorroles [61][62][63][64][65][66][67] ) that include an sp 3 -hybridized meso-carbon and which support unique photophysical and multielectron redox properties. These nontraditional tetrapyrroles provide alternate platforms to consider for ORR and other small molecule activation processes and may offer distinct reactivity profiles and catalytic activities.…”

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confidence: 99%

An Easily Prepared Monomeric Cobalt(II) Tetrapyrrole Complex that Efficiently Promotes the 4e–/4H+ Peractivation of O2 to Water

Cai

Tran

Qiu

et al. 2021

Preprint

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The selective 4e–/4H+ reduction of dioxygen to water is an important reaction that takes place at the cathode of fuel cells. Monomeric aromatic tetrapyrroles (such as porphyrins, phthalocyanines, and corroles) coordinated to Co(II) have been considered as oxygen reduction catalysts due to their low cost and relative ease of synthesis. How- ever, these systems have been repeatedly shown to be selective for O2 reduction by the less desired 2e –/2H+ pathway to yield hydrogen peroxide. Herein, we report the initial synthesis and study of a Co(II) tetrapyrrole complex based upon a non-aromatic isocorrole scaffold that is competent for 4e–/4H+ ORR. This Co(II) 10,10-dimethyl isocorrole (Co[10- DMIC]) is obtained in a just four simple steps and excellent yield from a known dipyrromethane synthon. Evaluation of the steady state spectroscopic and redox properties of Co[10-DMIC] against those of Co(II) porphyrin ([Co(TPFPP)]) and corrole ([Co(TPFPC)(PPh3)]) homologs demonstrated that the light harvesting and electrochemical properties of the isocorrole are distinct from those displayed by more traditional aromatic tetrapyrroles. Further, investigation of the ORR activity of Co[10-DMIC] using a combination of electrochemical and chemical reduction studies revealed that this simple, unadorned monomeric Co(II) tetrapyrrole is ~85% selective for the 4e–/4H+ reduction of O2 to H2O over the more kinetically facile 2e–/2H+ process that delivers H2O2. By contrast, the same ORR evaluations conducted for the Co(II) porphyrin and corrole homologs demonstrated that these traditional aromatic systems catalyze the 2e–/2H+ conversion of O2 to H2O2 with near complete selectivity. Despite being a simple, easily prepared, monomeric tetrapyrrole platform, Co[10-DMIC] supports an ORR catalysis that has historically only been achieved using elaborate porphyrinoid-based architectures that incorporate pendant proton-transfer groups, ditopic molecular clefts, or which impose cofacially ori- ented O2 binding sites. Accordingly, Co[10-DMIC] represents the first simple, unadorned, monomeric metalloisocorrole complex that can be easily prepared and which shows a privileged performance for the 4e–/4H+ peractivation of O2 to water as compared to other simple Co(II) tetrapyrroles.

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“…Nevertheless, a string of papers over the last decade have highlighted their potential importance. 4,5,6,7 They are relatively stable and practical to work with. They are also increasingly accessible, albeit in rather variable yields, via simple derivatization of corroles.…”

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confidence: 99%