Tris(β-ketoiminato)ruthenium(III) complexes: Electrochemical and computational chemistry study

Ngake, T.; Potgieter, J.H.; Conradie, Jeanet

doi:10.1016/j.electacta.2019.134635

Cited by 7 publications

(4 citation statements)

References 34 publications

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“…For complexes containing large R substituents, it is expected that the mer isomers are more stable, since they are less affected by steric hindrance caused between bigger R substituents, when compared to their fac isomers. 25 The mer isomers are also expected to be more stable, due to their lower dipole 26,27 (the solvent used for NMR analysis is CDCl 3 ). Experimentally, from the literature, both fac and mer tris (β-diketonato)cobalt(III) isomers were characterized, for example, 20% fac [Co(ba) 3 ] ( 2 ) (based on yield), 28 18% fac [Co(tfaa) 3 ] ( 4 ) (based on NMR measurements), 27,29,30 and both fac and mer [Co(β-diketonato) 3 ] crystal structures are known.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic and DFT study of tris(β-diketonato)cobalt(III) complexes

Twigge

Conradie

Erasmus

2023

Journal of Chemical Research

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Nuclear magnetic resonance measurements confirm that, as expected, the mer isomer of tris(β-diketonato) cobalt(III) complexes is more stable ( mer isomers are more stable because they are less affected by steric hindrance and they have lower dipoles). An excess of the mer isomer or only the mer isomer is experimentally observed. The existence of both fac and mer isomers is predicted by density functional theory calculations. At room temperature, the nuclear magnetic resonance peaks of phenyl-containing mer complexes are broad due to the intermediate rotation of bulky phenyl groups resulting in only the average orientation of the non-equivalent protons in the mer complexes. However, upon heating to 55 °C (thus speeding up the rotation) or cooling to −50 °C (slowing down the rotation), this broad peak is resolved into three sets of carbon peaks appearing in the 13C NMR spectrum, as well as splitting of the 1H NMR peaks for the non-equivalent protons in the mer isomer. In solid-state 13C NMR the aromatic rings do not rotate, resulting in the splitting of all the 13C NMR peaks. Two sets of well-defined peaks are observed for the fluorine-containing compound [Co(CF3COCHCOCPh)3] in both the 13C and 19F NMR spectra, indicating that both the fac and mer isomers are present with a ratio of fac:mer = 0.1:1. The X-ray photoelectron spectroscopy measured binding energy of the Co 2p3/2 photoelectron lines are influenced by the subtle electronic (electron-donating or electron-withdrawing) properties of the R groups on the β-diketonato ligands. Various relationships are established between the binding energy of Co 2p3/2 and several physical and density functional theory–calculated properties, confirming good electronic communication (the measurable electronic effect that a molecular fragment has on the physical properties of another molecular fragment in the molecule) of the substituent groups through the pseudo aromatic system of the β-diketonato backbones to the metal.

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Section: Resultsmentioning

confidence: 99%

Spectroscopic and DFT study of tris(β-diketonato)cobalt(III) complexes

Twigge

Conradie

Erasmus

2023

Journal of Chemical Research

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“…A few other works reported that the aliphatic NH 2 might also react with HCHO; however, there are no clear characterizations to support the reactions. [ 24 ] To confirm the possible reaction of aliphatic NH 2 group with HCHO in water, we carried out a control experiment, in which D‐cysteine with an aliphatic NH 2 was mixed with HCHO, whereas no reaction was observed in 10 h, as confirmed by 1 H NMR [ 25 ] (Figure S3b, Supporting Information). We speculate that, under ambient conditions, aliphatic NH 2 might only adsorb HCHO via physical interactions or hydrogen bonding, while the ONH 2 groups could chemically react with HCHO at the same condition (Figure 2a).…”

Section: Resultsmentioning

confidence: 99%

Zero‐Carbon Emission Chemical Method to Remove Formaldehyde without Catalyst by Highly Porous Polymer Composites at Room Temperature

Wang

Liu

et al. 2022

Macromol. Rapid Commun.

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Herein, the fabrication of reduced graphene oxide (RGO)‐templated polymer composites for chemical removal of gaseous formaldehyde under ambient conditions is presented. The chemical removal of formaldehyde is achieved by a nucleophilic addition reaction between formaldehyde and aminooxy groups on the polymer chain ends to form the oxime bonds with the only byproduct of H2O. RGO is essential since it not only has an ultralarge surface area but also can act as a perfect template for immobilizing pyrene‐terminated and aminooxy‐functionalized polymers via strong π–π stacking interactions, while melamine foam provides a three‐dimensional skeleton for loading RGO/polymer composites to afford a porous 3D structure for efficient formaldehyde removal. Since the oxime bond can be cleaved into aminooxy group in acidic media, the RGO/polymer composite can be regenerated for repeatable usage, which shows an excellent performance of adsorbing 14 mg of formaldehyde by 100 mg of the polymer at ambient condition.

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“…The relative energies of the fac and mer isomers of complexes 1-3 showed that the mer isomer will be found in experiment to be the main isomer (> 99.8 % according to the Boltzmann equation). The mer isomers were less affected by steric hindrance caused by the Ph group [29].…”

Section: Dft Optimized Geometry and Properties Of Moleculesmentioning

confidence: 96%

Cyclic Voltammetric and DFT Analysis of the Reduction of Manganese(III) Complexes with 2‐Hydroxybenzophenones

Adeniyi

Conradie

2020

Electroanalysis

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A comprehensive understanding of the redox behaviour of manganese complexes is significant for its use in different industrial applications, including as redox mediator in dye sensitized solar cells. This study presents the experimental reduction potential of derivatives of manganese(III) complexes coordinated to 2-hydroxybenzophenones, showing that the first observed experimental reduction potential peak is located on the manganese atom, followed by a further ligand-based reduction. A density functional theory study shows that Jahn-Teller distortion has a larger impact on the theoretically determined reduction potential and molecular electrostatic potential at the manganese atom, than the impact of the isomeric forms (fac and mer) on the theoretically predicted reduction potential. Keywords: 2-Hydroxybenzophenone • manganese(III) • reduction • DFT Highlights * First reduction of manganese tris(2-hydroxybenzophenone) complexes is Mn based * Second reduction of manganese tris(2-hydroxybenzophenone) complexes is ligand-based * Influence of Jahn-Teller effect on the theoretically determined reduction potential * Influence fac and mer isomers on the theoretically determined reduction potential * Experimental and theoretical Mn(III/II) reduction of manganese tris(2-hydroxybenzophenone) [a] A

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Tris(β-ketoiminato)ruthenium(III) complexes: Electrochemical and computational chemistry study

Abstract: Research highlights • Ru III/IV , Ru III/II redox couples, as well as ligand based reduction of Rh II complex • Separate Ru III/IV redox couples for fac and mer isomers • DFT calculations provide understanding of the locus of the observed redox couples

Cited by 7 publications

References 34 publications

Spectroscopic and DFT study of tris(β-diketonato)cobalt(III) complexes

Spectroscopic and DFT study of tris(β-diketonato)cobalt(III) complexes

Zero‐Carbon Emission Chemical Method to Remove Formaldehyde without Catalyst by Highly Porous Polymer Composites at Room Temperature

Cyclic Voltammetric and DFT Analysis of the Reduction of Manganese(III) Complexes with 2‐Hydroxybenzophenones

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