Kinetics of the reduction of Mn2+ at the dropping mercury electrode in non-aqueous media

Gaur, J.N.; Goswami, N.K.

doi:10.1016/0013-4686(67)80064-1

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…Finally, further extending these calculations to additional species, the computed reduction of Ni I (IB)X to Ni 0 (IB)X or Ni 0 (IB) is calculated to occur at exceedingly negative formal potentials (∼−3 to −4 V). These calculated potentials for Ni 0 formation are significantly more negative than the reduction potentials of typical reductants used in cross-coupling reactions (e.g., ∼−1.11 V vs Fc +/0 in DMA for tetrakis(dimethylamino)ethylene (TDAE) or ∼−1.94 V vs Fc +/0 in DMF for Mn 0 ). , Similarly, the disproportionation of Ni I (IB)X to Ni II (IB)X 2 and Ni 0 (IB) is thermodynamically highly unfavorable, with a Δ G (CPCM) of ∼+57 kcal mol –1 for both X = Cl and Br. Thus, Ni 0 is unlikely to be a catalytically relevant redox state.…”

Section: Computational Resultsmentioning

confidence: 99%

“…Reactions involving electron transfers were corrected by adding the energy of Mn 0/2+ redox couple or TDAE 0/+ , which were used as the external reducing agents in refs and . Note that we have adopted values of E ° = −1.94 V vs Fc +/0 for Mn 2+/0 obtained from the experiments in refs and and E ° = −1.34 V vs Fc +/0 for TDAE +/0 from computations in this article.…”

Section: Discussionmentioning

confidence: 99%

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Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling

et al. 2023

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Ni II (IB) dihalide [IB = (3aR,3a′R,8aS,8a′S)-2,2′-(cyclopropane-1,1-diyl)bis(3a,8a-dihydro-8H-indeno[1,2-d]-oxazole)] complexes are representative of a growing class of first-row transition-metal catalysts for the enantioselective reductive cross-coupling of C(sp 2 ) and C(sp 3 ) electrophiles. Recent mechanistic studies highlight the complexity of these ground-state cross-couplings but also illuminate new reactivity pathways stemming from one-electron redox and their significant sensitivities to reaction conditions. For the first time, a diverse array of spectroscopic methods coupled to electrochemistry have been applied to Ni II -based precatalysts to evaluate specific ligand field effects governing key Ni-based redox potentials. We also experimentally demonstrate DMA solvent coordination to catalytically relevant Ni complexes. Coordination is shown to favorably influence key redox-based reaction steps and prevent other deleterious Ni-based equilibria. Combined with electronic structure calculations, we further provide a direct correlation between reaction intermediate frontier molecular orbital energies and cross-coupling yields. Considerations developed herein demonstrate the use of synergic spectroscopic and electrochemical methods to provide concepts for catalyst ligand design and rationalization of reaction condition optimization.

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Section: Computational Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling

et al. 2023

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“…In some cases, as seen from Table 1 the value of K f decreases and irreversibility increases in acetonitrile in comparison to water. Since the value of dielectric constant of solvent is very low and again viscosity also decreases regularly, the shifts of E 1/2 to more positive values and the change of i d can be best explained on the basis of salvation and viscosity [15][16][17].…”

Section: Resultsmentioning

confidence: 99%

Study of Complex Formation Constants for Some Cations With O-Phenylenediamine in Binary Systems Using Square Wave Polarography Technique

Nezhadali¹,

Hanieh²

2010

ENG

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The formation of metal cation complexes between o-phenylenediamine with metal ions, Ni2+, Cu2+, Zn2+, Pb2+ and Cr3+ were studied in the dimethylformamide/water(DMF/H2O), acetonitrile/water(AN/H2O) and ethanol/water(EtOH/H2O) binary systems using square wave polarography (SWP) technique. The stoichiometry and stability of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the ligand concentration. In the most cases, the formation constants of complexes decreased with increasing amounts of H2O, DMF and EtOH in AN/H2O, DMF/H2O and EtOH/H2O binary systems, respectively. The stoichiometry of the complexes was found 1:1. The results obtained show that there is an inverse relationship between the formation constant of the complexes and the donor number of the solvents based on the Gatmann donocity scale. Also, the stability constants show a high sensitivity to the composition of the mixed solvent systems. In most of the systems investigated, Cr3+ cation forms a more stable complex with o-phenylenediamine than other four cations and the order of selectivity of this ligand for cations in pure water is:Cr3+>>Cu2+>Ni2+>Zn2+>Pb2+

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“…Together, these calculations and the ligand field spectroscopy both indicate for the first time that the RAMO energy is an excellent descriptor of the redox properties of these metal-based cross-coupling catalysts, and DFT calculations provide a useful approach for analyzing ligand contributions to potentials.Finally, further extending these calculations to additional species, the computed reduction of Ni I (IB)X to Ni 0 (IB)X or Ni 0 (IB) is calculated to occur at exceedingly negative formal potentials (~-3 V to -4 V). These calculated potentials for Ni 0 formation are significantly more negative than the reduction potentials of typical reductants used in cross-coupling reactions (e.g., ~-1.11 V vs.Fc +/0 in DMA for tetrakis(dimethylamino)ethylene (TDAE) or ~-1.94 V vs Fc +/0 in DMF for Mn 0 ) 46,47. Similarly, the disproportionation of Ni I (IB)X to Ni II (IB)X2 and Ni 0 (IB) is thermodynamically highly unfavorable, with a ΔG(CPCM) of ~+57 kcal mol -1 for both X = Cl and Br.…”

mentioning

confidence: 89%

Electronic structures of nickel(II)-bis(indanyloxazoline)-dihalide catalysts: Understanding ligand field contributions that promote C(sp2)–C(sp3) cross-coupling

McNicholas

Tong

Bím

et al. 2023

Preprint

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NiII(IB) dihalide [IB = (3aR,3a'R,8aS,8a'S)-2,2'-(cyclopropane-1,1-diyl)bis(3a,8a-dihydro-8H-indeno[1,2-d]-oxazole)] complexes are representative of a growing class of first-row transition metal catalysts for the enantioselective reductive cross-coupling of C(sp2) and C(sp3) electrophiles. Recent mechanistic studies highlight the complexity of these ground state cross-couplings, but also illuminate new reactivity pathways stemming from one-electron redox and their significant sensitivities to reaction conditions. For the first time, a diverse array of spectroscopic methods coupled to electrochemistry has been applied to NiII-based pre-catalysts to evaluate specific ligand field effects governing key Ni-based redox potentials. We also experimentally demonstrate DMA solvent coordination to catalytically-relevant Ni complexes. Coordination is shown to favorably influence key redox-based reaction steps and prevent other deleterious Ni-based equilibria. Combined with electronic structure calculations, we further provide a direct correlation between reaction intermediate frontier molecular orbital energies and cross-coupling yields. Considerations developed herein demonstrate the use of synergic spectroscopic and electrochemical methods to provide concepts for catalyst ligand design and rationalization of reaction condition optimization.

show abstract

Kinetics of the reduction of Mn2+ at the dropping mercury electrode in non-aqueous media

Cited by 11 publications

References 8 publications

Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling

Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling

Study of Complex Formation Constants for Some Cations With O-Phenylenediamine in Binary Systems Using Square Wave Polarography Technique

Electronic structures of nickel(II)-bis(indanyloxazoline)-dihalide catalysts: Understanding ligand field contributions that promote C(sp2)–C(sp3) cross-coupling

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Kinetics of the reduction of Mn2+ at the dropping mercury electrode in non-aqueous media

Cited by 11 publications

References 8 publications

Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp2)–C(sp3) Cross-Coupling

Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp2)–C(sp3) Cross-Coupling

Study of Complex Formation Constants for Some Cations With O-Phenylenediamine in Binary Systems Using Square Wave Polarography Technique

Electronic structures of nickel(II)-bis(indanyloxazoline)-dihalide catalysts: Understanding ligand field contributions that promote C(sp2)–C(sp3) cross-coupling

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Product

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Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling

Electronic Structures of Nickel(II)-Bis(indanyloxazoline)-dihalide Catalysts: Understanding Ligand Field Contributions That Promote C(sp²)–C(sp³) Cross-Coupling