sym-polymethylferricinium hexafluorophosphates

Nesmeyanov, A. N.; Materikova, R.B.; Lyatifov, I.R.; Kurbanov, T. Kh.; Kochetkova, N. S.

doi:10.1016/s0022-328x(00)91129-x

Cited by 22 publications

(9 citation statements)

References 8 publications

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“…The preparations of [1]X (X = PF 6 , [19] BF 4 [20] )a nd [3]X (X = PF 6 , [21] BF 4 [7] )c an be found in the literature. The preparations of [1]X (X = PF 6 , [19] BF 4 [20] )a nd [3]X (X = PF 6 , [21] BF 4 [7] )c an be found in the literature.…”

Section: Methodsmentioning

confidence: 99%

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Crystal Structures and Phase Sequences of Metallocenium Salts with Fluorinated Anions: Effects of Molecular Size and Symmetry on Phase Transitions to Ionic Plastic Crystals

Mochida

Funasako

Ishida

et al. 2016

Chemistry A European J

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Sandwich compounds often exhibit various phase transitions, including those to plastic phases. To elucidate the general features of the phase transitions in metallocenium salts, the thermal properties and crystal structures of [Fe(C Me ) ]X ([1]X), [Co(C Me ) ]X ([2]X), and [Fe(C Me H) ]X ([3]X) have been investigated, where the counter anions (X) are Tf N (=(CF SO ) N ), OTf (=CF SO ), PF , and BF . The Tf N salts commonly undergo phase transitions from an ordered phase at low temperatures to an anion-disordered phase, followed by a plastic phase and finally melt at high temperatures. All these salts exhibit a phase transition to a plastic phase, and the transition temperature generally decreases with decreasing cation size and increasing anion size. The crystal structures of these salts comprise an alternating arrangement of cations and anions. About half of these salts exhibit phase transitions at low temperatures, which are mostly correlated with the order-disorder of the anion.

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Section: Methodsmentioning

confidence: 99%

“…[Co(C 5 Me 5 ) 2 ]PF 6 ([ 2 ]PF 6 ) was purchased from Sigma–Aldrich and was used after recrystallization from acetonitrile. The preparations of [ 1 ]X (X=PF 6 , BF 4 ) and [ 3 ]X (X=PF 6 , BF 4 ) can be found in the literature. The general procedure for the preparation of other salts is as follows.…”

Section: Methodsmentioning

confidence: 99%

Crystal Structures and Phase Sequences of Metallocenium Salts with Fluorinated Anions: Effects of Molecular Size and Symmetry on Phase Transitions to Ionic Plastic Crystals

Mochida

Funasako

Ishida

et al. 2016

Chemistry A European J

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“…The BNAH and PNAH were synthesized according to literature methods . The dideuterated compounds BNAD and PNAD were prepared from the corresponding monodeuterated compounds by three cycles of oxidations with p -chloranil in dimethylformamide and reduction with dithionite in deuterium oxide. , The ferrocenium hexafluorophosphate (Fc + PF 6 – ) was synthesized according to published procedures. , …”

Section: Methodsmentioning

confidence: 99%

New Insight into the Mechanism of NADH Model Oxidation by Metal Ions in Nonalkaline Media

2018

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For a long time, it has been controversial that the three-step (e-H-e) or two-step (e-H) mechanism was used for the oxidation of nicotinamide adenine dinucleotide coenzyme (NADH) and its models by metal ions in nonalkaline media. The latter mechanism has been accepted by the majority of researchers. In this work, 1-benzyl-1,4-dihydronicotinamide (BNAH) and 1-phenyl-l,4-dihydronicotinamide are used as NADH models and ferrocenium (Fc) metal ion as an electron acceptor. The kinetics for oxidation of the NADH models by Fc in pure acetonitrile was monitored by using UV-vis absorption and a quadratic relationship between k and the concentrations of NADH models was found for the first time. The rate expression of the reactions developed according to the three-step mechanism is quite consistent with the quadratic curves. The rate constants, thermodynamic driving forces, and kinetic isotope effects of each elementary step for the reactions were estimated. All results supported the three-step mechanism. The intrinsic kinetic barriers of the proton transfer from BNAH to BNAH and the hydrogen-atom transfer from BNAH to BNAH were estimated by using Zhu equation; the results showed that the former is 11.8 kcal/mol and the latter is larger than 24.3 kcal/mol. It is the large intrinsic kinetic barrier of the hydrogen-atom transfer that makes the reactions choose the three-step rather than two-step mechanism. Further investigation of the factors affecting the intrinsic kinetic barrier of chemical reactions indicated that the large intrinsic kinetic barrier of the hydrogen-atom transfer originated from the repulsion of positive charges between BNAH and BNAH. The greatest contribution of this work is the discovery of the quadratic dependence of k on the concentrations of the NADH models, which is inconsistent with the conventional viewpoint of the "two-step mechanism" on the oxidation of NADH and its models by metal ions in the nonalkaline media.

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“…The reactants containing the redox couple of sym. Ме 8 Fc +/0 were synthesized by methods indicated in the works [12,13]. For NMR research, methylferrocenes were twice sublimated, and hexafluorophosphate salts were twice recrystallized from acetone solution.…”

Section: Experimental Partmentioning

confidence: 99%

Research Into Kinetics of Electron Exchange Reactions in the System Sym. Octamethylferrocene/Sym. Octamethylferricinium Hexafluorophosphate

Ibrahimova¹,

Jafarov²,

Taghiyev³

et al. 2019

Chemical Problems

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The constant of electron exchange rate (k ex .) in the system of sym. octamethylferrocene/sym. octamethylferricinium hexafluorophosphate [(СН 3) 4 С 5 Н] 2 Fe/(СН 3) 4 С 5 Н] 2 Fe + PF 6  ] (hereinafter are denoted as Ме 8 Fс +/0) was determined by method of 1 H NMR line broadening. The appearance of eight methyl groups in each reagent of the redox-system of Ме 8 Fс +/0 increases the constant of exchange rate approximately 4.8 times, in comparison with the unsubstituted ferrocene-ferricinium system [(С 5 Н 5) 2 Fe/(С 5 Н 5) 2 Fe + PF 6  ] (Fс +/0). The increase of exchange rate in series of Fс +/0 Ме 6 Fc +/0 Ме 8 Fс +/0 Ме 10 Fс +/0 , though it corresponds to the electron donor property of the methyl group, is interpreted by us as the result of reduction of reorganization energy of solvent molecule (acetone) by increasing the reagent volumes of the redox couples of Ме n Fс +/0 (n = 6, 8, 10).

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sym-polymethylferricinium hexafluorophosphates

Cited by 22 publications

References 8 publications

Crystal Structures and Phase Sequences of Metallocenium Salts with Fluorinated Anions: Effects of Molecular Size and Symmetry on Phase Transitions to Ionic Plastic Crystals

Crystal Structures and Phase Sequences of Metallocenium Salts with Fluorinated Anions: Effects of Molecular Size and Symmetry on Phase Transitions to Ionic Plastic Crystals

New Insight into the Mechanism of NADH Model Oxidation by Metal Ions in Nonalkaline Media

Research Into Kinetics of Electron Exchange Reactions in the System Sym. Octamethylferrocene/Sym. Octamethylferricinium Hexafluorophosphate

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