Cobalt salophen complexes for light-driven water oxidation

Asraf, Md. Ali; Younus, Hussein A.; Ezugwu, Chizoba I.; Mehta, Akshay; Verpoort, Francis

doi:10.1039/c5cy02157j

Cited by 28 publications

(11 citation statements)

References 68 publications

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“…Imine donor ligands are rarely utilized in water oxidation catalysts, with the exception of cobalt and manganese Schiff base complexes and several binuclear iridium and ruthenium systems. [80][81][82][83][84] Cyclam ligands with methylated bridging propane moieties produce a less active catalyst (both in terms of TOF and TON), as becomes clear by comparing complexes and 3. The methylation of nitrogen donor atoms also has a negative effect on the activity, as complex 4 is less active than 2, and 5 does not show any activity.…”

Section: Resultsmentioning

confidence: 94%

Nickel is a Different Pickle: Trends in Water Oxidation Catalysis for Molecular Nickel Complexes

Hessels

Masferrer‐Rius

et al. 2020

ChemSusChem

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The development of novel water oxidation catalysts is important in the context of renewable fuels production. Ligand design is one of the key tools to improve the activity and stability of molecular catalysts. The establishment of ligand design rules can facilitate the development of improved molecular catalysts. In this paper it is shown that chemical oxidants can be used to probe oxygen evolution activity for nickel‐based systems, and trends are reported that can improve future ligand design. Interestingly, different ligand effects were observed in comparison to other first‐row transition metal complexes. For example, nickel complexes with secondary amine donors were more active than with tertiary amine donors, which is the opposite for iron complexes. The incorporation of imine donor groups in a cyclam ligand resulted in the fastest and most durable nickel catalyst of our series, achieving oxygen evolution turnover numbers up to 380 and turnover frequencies up to 68 min−1 in a pH 5.0 acetate buffer using Oxone as oxidant. Initial kinetic experiments with this catalyst revealed a first order in chemical oxidant and a half order in catalyst. This implies a rate‐determining oxidation step from a dimeric species that needs to break up to generate the active catalyst. These findings lay the foundation for the rational design of molecular nickel catalysts for water oxidation and highlight that catalyst design rules are not generally applicable for different metals.

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Section: Resultsmentioning

confidence: 94%

Nickel is a Different Pickle: Trends in Water Oxidation Catalysis for Molecular Nickel Complexes

Hessels

Masferrer‐Rius

et al. 2020

ChemSusChem

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“…Additional mononuclear Co-based WOCs that have been proposed to promote light-sensitized H 2 O oxidation through a homogeneous pathway are depicted in Fig. 48 Scheme 9 Proposed mechanism for H 2 O oxidation catalyzed by the fluorinated Co porphyrin 135. and include the [Co II (qpy)(OH 2 ) 2 ] 2+ complex 141 (qpy = 2,2′:6′,2″:6″,2′′′-quaterpyridine), 287 the Co II salophen complex 142 288 and related salophen complexes, 289 and the Co II complex [Co(tpa)Cl] + 143 (tpa = tris(2-pyridylmethyl)amine). 290 Several Co-based complexes with organic ligand frameworks have been shown to act as precatalysts to heterogeneous Co nanoparticles (Fig.…”

Section: Mononuclear Co Catalystsmentioning

confidence: 99%

“…Dalton Transactions and include the [Co II (qpy)(OH 2 ) 2 ] 2+ complex 141 (qpy = 2,2′:6′,2″:6″,2′′′-quaterpyridine), 287 the Co II salophen complex 142 288 and related salophen complexes, 289 and the Co II complex [Co(tpa)Cl] + 143 (tpa = tris(2-pyridylmethyl)amine). 290 Several Co-based complexes with organic ligand frameworks have been shown to act as precatalysts to heterogeneous Co nanoparticles (Fig.…”

Section: Perspectivementioning

confidence: 99%

Water oxidation using earth-abundant transition metal catalysts: opportunities and challenges

2016

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Catalysts for the oxidation of H2O are an integral component of solar energy to fuel conversion technologies. Although catalysts based on scarce and precious metals have been recognized as efficient catalysts for H2O oxidation, catalysts composed of inexpensive and earth-abundant element(s) are essential for realizing economically viable energy conversion technologies. This Perspective summarizes recent advances in the field of designing homogeneous water oxidation catalysts (WOCs) based on Mn, Fe, Co and Cu. It reviews the state of the art catalysts, provides insight into their catalytic mechanisms and discusses future challenges in designing bioinspired catalysts based on earth-abundant metals for the oxidation of H2O.

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“…The presence of both nitrogen and sulphur donor atoms in the backbones of these ligands explains this [9][10]. Schiff bases are advantageous because of their capacity to stabilize metal ions in various oxidation states, their use in a variety of catalytic and industrial applications, and their wide range of biological activities [11][12][13]. The lone pair of electrons of azomethine (-C=N-) group bonding in the structure of stable metal complexes is owing to nitrogen's lone pair of electrons [14].…”

Section: Introductionmentioning

confidence: 99%

Cytotoxicity and Antibacterial Studies of Novel Heterocyclic Pyridinethiophene Derivative and Its Metal Complexes

Kumar

Babu

Karunasree

2022

JASR

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Tranistion metals [Co, Ni, and Cu] complexes of pyridine-thiophene derivative ligand 2-((E)-2-((5-methylthiophen-2-yl) methylene)hydrazinyl)-4-methyl-6-phenylpyridine-3-carbonitrile(MTHPC) have been synthesized and characterized with different spectral investigations viz. UV-Vis, FT-IR, 1H-NMR, and ESR. The ligand and metal complexes were screened for in-vitro cytotoxicity studies against two carcinoma cell lines A549 (Lung carcinoma cells) and HepG2 (Hepatocellular carcinoma cell). The results were found to possess cytotoxic effect. Nickel complex had shown high potent cytotoxic effect for A549 cell lines and Copper complex shown high cytotoxic effect for HepG2 cell lines. The ligand and metal complexes were tested in vitro against Gram -ve bacteria such Pseudomonas desmolyticum, Escherichia coli, and Klebsiella aerogenes, as well as Gram +ve bacteria like Staphylococcus aureus. Copper and Cobalt complex has modest antibacterial action at increasing concentrations, but Nickel complex has significant antibacterial activity.

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Cobalt salophen complexes for light-driven water oxidation

Abstract: Earth-abundant molecular complexes have been found to be excellent catalysts for the light-driven water oxidation reaction.

Cited by 28 publications

References 68 publications

Nickel is a Different Pickle: Trends in Water Oxidation Catalysis for Molecular Nickel Complexes

Nickel is a Different Pickle: Trends in Water Oxidation Catalysis for Molecular Nickel Complexes

Water oxidation using earth-abundant transition metal catalysts: opportunities and challenges

Cytotoxicity and Antibacterial Studies of Novel Heterocyclic Pyridinethiophene Derivative and Its Metal Complexes

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