Novel phosphonium salt for paste electrode to study the redox properties of insoluble compounds

Influence of the Substituent's Size in the Phosphinate Group on the Conformational Possibilities of Ferrocenylbisphosphinic Acids in the Design of Coordination Polymers and Metal-Organic Frameworks

This paper illustrates how the size and type of substituent R in the phosphinate group of ferrocenyl bisphosphinic acids can affect conformational possibilities and coordination packing. It also demonstrates that H-phosphinate plays a key role in variational mobility, while Me- or Ph- substituents of the phosphinate group can only lead to 0D complexes or 1D coordination polymer. Overall, this paper provides valuable insights into the design and construction of coordination polymers based on ferrocene-contained linkers. It sheds light on how different reaction conditions and substituents can affect conformational possibilities and coordination packing, which could have significant implications for developing new polymers with unique properties.

Ferrocene-based P-chiral amidophosphinate: stereoselective synthesis and X-ray structural study

Racemic and enantiopure ferrocene-based P-chiral amidophosphinates have been simply and stereoselectively synthesized by ortho-lithiation of rac- or (R)-Ugi's amine and further reaction with amidochlorophenylphosphinate Cl-P(O)(Ph)NEt₂. This is the first example of an asymmetric reaction of ortho-lithiated Ugi's amine with tetracoordinated phosphorus(V) chlorides. The structures of rac- and (R)-Ugi's amine ferrocenyl(phenyl)phosphinic acid N,N-diethylamide have been extensively studied experimentally (NMR, X-ray analysis, electrochemistry). The CV first peak refers to the oxidation of the amine fragment, which is clearly seen when (R)-Ugi's amine ferrocenyl(phenyl)phosphinic acid N,N-diethylamide reacts with anhydrous acid. The addition of two equivalents of CF₃COOH leads to the protonation of nitrogen atoms, and a classical reversible wave of oxidation of Fe(II) to Fe(III) is observed.

Conductive Mediators in Oxidation Based on Ferrocene Functionalized Phosphonium Ionic Liquids

Herein, the synthesis of ferrocene-containing salts is presented. Acylation of ferrocene (Fc) according to the Friedel-Crafts method led to ω-bromoacyl ferrocenes. The ω-bromoacyl ferrocenes were subsequently introduced to quaternization reaction with tri-tert-butyl phosphine, which resulted in phosphonium salts. Obtained phosphonium salts were characterized by physical methods. The electrochemical properties of phosphonium salts were studied by cyclic voltammetry (CV). It was found that the replacement of n-butyl fragments at the phosphorus atom by tert-butyl leads to a more anodic potential shift. In contrast to isolobal structures Fc-C(O)(CH₂)_nP⁺(n-Bu)₃X^- and Fc-(CH₂)_n+1P⁺(n-Bu)₃X^-, the CV curves of Fc-C(O)(CH₂)_nP⁺(t-Bu)₃X^- and Fc-(CH₂)_n+1P⁺(t-Bu)₃X^- did not show a large discrepancy between forward and reverse currents. The transformation of the C=O groups to CH₂ fragments had a significant effect on the electrochemical properties of ferrocene salts, the oxidation potential of which is close to that of pure ferrocene.

Magnesium and Nickel Complexes with Bis(p-iminoquinone) Redox-Active Ligand

Abstract

Poorly soluble in the most part of organic solvents dimeric complexes $${\text{M}}{{{\text{g}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF (I) and $${\text{N}}{{{\text{i}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF (II) (L is 4,4'-(1,4-phenylenebis(azanylylidene))bis(3,6-di-tert-butyl-2-hydroxycyclohexa-2,5-dien-1-one dianion)) are synthesized by the reactions of magnesium and nickel acetates with the ditopic redox-active ligand of the hydroxy-para-iminoquinone type in a DMF solution. The molecular and crystal structures of the synthesized compounds are determined by X-ray diffraction analysis (CIF files CCDC nos. 2045665 (I) and 2045666 (II·3DMF)). The thermal stability is studied by thermogravimetry. The redox-active character of the organic bridging ligand in the dimeric complexes $${\text{M}}{{{\text{g}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF and $${\text{N}}{{{\text{i}}}_{{\text{2}}}}{\text{L}}_{2}^{2}$$·4DMF is confirmed by the data of solid-phase electrochemistry.

Ferrocene-Containing Sterically Hindered Phosphonium Salts

The synthesis and physical properties of the series of the ferrocenyl-containing sterically hindered phosphonium salts based on di(tert-butyl)ferrocenylphosphine is reported. Analysis of voltamogramms of the obtained compounds revealed some correlations between their structures and electrochemical properties. The elongation of the alkyl chain at the P atom as well as replacement of the Br⁻ anion by [BF₄]⁻ shifts the ferrocene/ferrocenium transition of the resulting salts into the positive region. DFT results shows that in the former case, the Br⁻ anion destabilizes the corresponding ion pair, making its oxidation easier due to increased highest occupied molecular orbital (HOMO) energy. Increased HOMO energy for ion pairs with the Br⁻ ion compared to BF₄⁻ are caused by contribution of bromide atomic orbitals to the HOMO. The observed correlations can be used for fine-tuning the properties of the salts making them attractive for applications in multicomponent batteries and capacitors.