Anodic oxidation of manganous ion in liquid ammonia

Brown, O.R.; Clarke, Steven

doi:10.1016/s0022-0728(76)80264-1

Cited by 5 publications

(1 citation statement)

References 7 publications

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“…The electrode kinetic data in conjunction with structural and magnetic results (vide supra) indicate that Mn(II) → Mn(III) → Mn(IV) oxidation of Mn(pzb) 2 n + complexes proceeds through a low-spin Mn(III) rather than high-spin Mn(III) oxidation state (Scheme 1). Thus, each Mn(III)/Mn(II) electrode reaction is accompanied by a change in metal atom spin state: Mn(III)/Mn(II) electron-transfer reactions frequently are slow . Although underlying causes are not well established in most instances, the structural and magnetic information reported here confirms that spin crossover occurs and is a distinguishing feature in the kinetics of Mn(pzb) 2 +/0 versus Mn(pzb) 2 2+/+ electrode reactions.…”

Section: Resultsmentioning

confidence: 57%

Synthesis, Structure, and Properties of Low-Spin Manganese(III)−Poly(pyrazolyl)borate Complexes

et al. 2007

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The manganese(III)-bis[poly(pyrazolyl)borate] complexes, Mn(pzb)2SbF6, where pzb- = tetrakis(pyrazolyl)borate (pzTp) (1), hydrotris(pyrazolyl)borate (Tp) (2), or hydrotris(3,5-dimethylpyrazolyl)borate (Tp*) (3), have been synthesized by oxidation of the corresponding Mn(pzb)2 compounds with NOSbF6. The Mn(III) complexes are low-spin in solution and the solid state (microeff = 2.9-3.8 microB). X-ray crystallography confirms their uncommon low-spin character. The close conformity of mean Mn-N distances of 1.974(4), 1.984(5), and 1.996(4) A in 1, 2, and 3, respectively, indicates absence of the characteristic Jahn-Teller distortion of a high-spin d4 center. N-Mn-N bite angles of slightly less than 90 degrees within the facially coordinated pzb- ligands produce a small trigonal distortion and effective D3d symmetry in 1 and 2. These angles increase to 90.0(4)degrees in 3, yielding an almost perfectly octahedral disposition of N donors in Mn(Tp*)2+. Examination of structural data from 23 metal-bis(pzb) complexes reveals systematic changes within the metal-(pyrazolyl)borate framework as the ligand is changed from pzTp to Tp to Tp*. These deformations consist of significant increases in M-N-N, N-B-N, and N-N-B angles and a minimal increase in Mn-N distance as a consequence of the steric demands of the 3-methyl groups. Less effective overlap of pyrazole lone pairs with metal atom orbitals resulting from the M-N-N angular displacement is suggested to contribute to the lower ligand field strength of Tp* complexes. Mn(pzb)2+ complexes undergo electrochemical reduction and oxidation in CH3CN. The electrochemical rate constant (ks,h) for reduction of t2g4 Mn(pzb)2+ to t2g3eg2 Mn(pzb)2 (a coupled electron-transfer and spin-crossover reaction) is 1-2 orders of magnitude smaller than that for oxidation of t2g4 Mn(pzb)2+ to t2g3 Mn(pzb)22+. ks,h values decrease as Tp* > pzTp > Tp for the Mn(pzb)2+/0 electrode reactions, which contrasts with the behavior of the comparable Fe(pzb)2+/0 and Co(pzb)2+/0 couples.

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Section: Resultsmentioning

confidence: 57%

Synthesis, Structure, and Properties of Low-Spin Manganese(III)−Poly(pyrazolyl)borate Complexes

et al. 2007

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Manganese

Schultz

Duncan

Rigsby

2006

Encyclopedia of Electrochemistry

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The sections in this article are Introduction Mononuclear Complexes with Acyclic and Other Common Ligands Redox Potentials Coupled Chemical and Electrochemical Reactions Electron‐transfer Kinetics Mononuclear Complexes with Porphyrins, Schiff Bases, Phthalocyanine, and Related Macrocyclic Ligands Introduction Studies in Nonaqueous Media Studies in Aqueous Media Electrocatalytic Studies Binuclear and Polynuclear Complexes Introduction Studies in Nonaqueous Media Studies in Aqueous Media Biological Systems Introduction Manganese Catalase Manganese Peroxidase Manganese Superoxide Dismutase Oxygen‐evolving Center in Photosystem II

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Korrosion durch Reaktion in nichtwäßrigen Medien

Heitz¹,

Heusler²

2001

Korrosion Und Korrosionsschutz

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Anodic oxidation of manganous ion in liquid ammonia

Cited by 5 publications

References 7 publications

Synthesis, Structure, and Properties of Low-Spin Manganese(III)−Poly(pyrazolyl)borate Complexes

Synthesis, Structure, and Properties of Low-Spin Manganese(III)−Poly(pyrazolyl)borate Complexes

Manganese

Korrosion durch Reaktion in nichtwäßrigen Medien

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