Ferricinium salts

The anti-cancer properties of ferrocene-containing molecules first gained attention in the 1970s [12-14] and this field greatly benefited from the discovery of the anti-proliferative properties of simple ferricinium salts on Ehrlich ascite tumours in... 

C. U. Pittman, Jr., J. C. Lai, D. P. Vanderpool, Polymers of Ferrocenylmethyl Acrylate and Ferrocenylmethyl Methacrylate and Their Ferricinium Salts, in Polymer Characterization Interdisciplinary Approaches, C. D. Craver, Ed., pp. 97-124, Plenum Press, New York, 1971. 

It had already been observed that ferricinium salts such as (7r-CsH5)2FeBr give only very small quadrupole splittings [32, 33]. Although it was suspected... 

The spectra of the dicarbollide carborane derivatives (Me4,N)Fe(C2B9Hi 1)2 and CpFe(C2B9Hii)2 are very similar to those of ferricinium salts [41], and confirm the similarity of the bonding in the dicarbollide to that of ferrocene. 

Isotopic. Iron-55 is an electron-capture isotope with a half-life of 2.94 years. Iron-59 is a mixed /3-7 emitter the main radiations of which areO.27 M.e.v. 8 (46%), 0.46M.e.v. /8 (54%), 1.10 M.e.v. 7 (57%), and 1.29 M.e.v. 7 (43%). The half-life of Fe is 45.1 days. The radioactive samples are most readily assayed with a standard thin-mica-window Geiger counter which will detect mainly the Fe /3-particles. Decomposition of ferrocene and ferricinium salts in a boiling mixture of four parts by volume of concentrated nitric acid and one part of 75% perchloric acid and the subsequent electrodeposition of iron on copper disks gives samples which exhibit excellent counting reproducibility. 

Ferricinium perchlorate, nitrate, and chloride are readily soluble in water and alcohols, somewhat soluble in hydrocarbons, but insoluble in ether-type solvents. The ferricinium ion is blue, and it may be precipitated from solution as the triiodide, tungstosilicate, picrate, reineckate, etc. Ferricinium salts may be reduced to ferrocene by tin(II) chloride. 

A good way to reduce O2 dependence is to incorporate into the enzyme layer a species that substitutes for O2 in Reaction 17-5. A substance that transports electrons between the analyte (glucose, in this case) and the electrode is called a mediator. Ferricinium salts serve this purpose nicely ... 

Catalytic amounts of a ferricinium salt or of anodic current induce the chelation of [Fe(C5R5)(CO)2(Tl -dtc)] with liberation of CO in THF. The cross ET is endergonic but the E° of the oxidation could not be obtained because the partial reversibility of the oxidation was unobservable even after scanning at 5000 V / The electrocatalytic system is thus driven by the chemical propagation step (fast chelation). The coulombic efficiency of the ferricinium catalyzed chelation was found to be low but, interestingly, depends on the nature of the ferricinium counter anion (Table I). Unchanged starting material is found after the reaction when the optimum chelation yield is obtained (Table II) ... 

Ferricinium salts also are most conveniently prepared by oxidation of ferrocene. Ferric chloride or ceric sulfate will effect this oxidation, as will oxygen passing through acid containing a trace of ferric or cupric ion. In organic media, the oxidation of ferrocene to ferricinium cation may be accomplished by Br2 in CCI4 (86), by quinone in benzene (87), or by concentrated sulfuric acid (S5). 

The reduction of tetrazolium salts by NADH is greatly accelerated by electron transfer agents (ETAs) such as phenazine methosulfate (PMS 233) or its derivatives.451-454 Other classes of ETAs such as quinones.455,456 ferricinium,457 phenothiazine,458 the viologens,459 acridiniums,460 and phe-nazinium or quinoxalinium salts461 as well as the enzyme diaphorase462 have been used. 

Thus, oxidation of the readily prepared [Fe S4(SR)4] complexes with the sterically hindered thlolates 2,3,5,6-tetra-methylthiophenolate and 2,A,6-triisopropylthiolphenolate by ferricinium ion proceeds with smooth formation of the corresponding monoanlon (37), Isolated as the crystalline Bu N salt for SR = 2,A,6-i-Pr3CgH2S its structure is shown in Figure 8a. 

Oxidation of the borazole complexes [(/75-C3H3B(Me)NR)2Co] (R=Me, f-Bu, SiMe3) by iodine leads to [( 5-C3H3B(Me)NR)2Co] ( = 3-5). The hexafluorophosphate salts are obtained by oxidation using ferricinium hexafluorophosphate (83JOM(256)225, 86JOM(305)1). 

Solubility products as concentration quotients, are preliminary unpubli ed observations by B. Alexander, E. C. Ko and A. J. Parker unless stated otherwise. Ferrocene is a polar molecule, not a salt, this value is log (solubility) in mole litre i. Ferrocene is denoted by F, Ferricinium cation by F+in the mathematical expressions. Seetext. < Luehis,Iwamoto and Kleinberg (1966). /Pavlopoulis and Strehlow (1964). v Comparable results are in reference e. Comparable results are in reference /. 

The Lewis acid B(C6p5)3 see Lewis Acids Base, as well as the trityl salt [Ph3C][B(C6F5)4], can abstract a methyl group from Cp2ZrMe2 and related zirconocenes to form [Cp2ZrMe] +. A single-electron oxidation of dialkylzirconocenes with a ferricinium or a silver salt induces the formation of a cationic zirconocene (equation 17). ... 

Various redox compounds that fulfil catalyst characteristics have been investigated in systems with recycling of NAD by electrocatalytic methods. Quinones, formed either by oxidation of carbon surfaces [143, 145] or adsorbed to the electrode surface [146, 147], phenazines [148, 149], phenoxazine derivatives such as Meldola Blue [182], 9-naphthoyl-Nile Blue [151, 152] and l,2-benzophenoxazine-7-one [153], and also the organic conducting salt N-methyl phenazinium tetracyanoquinodimethanide (TTF TCNQ") [154, 155], ferricinium ions [156, 157] and hexacyanoferrat(IIl) ions [158, 159] can act as catalysts for the electrochemical oxidation of NADH. It is assumed that in corresponding electron-transfer reactions a charge-transfer complex between the immobilized mediator and NADH is formed. The intermediate reduced redox mediator will be reoxidized electrochemically. Most systems mentioned, however, suffer from poor electrode stabilities. 

If a solid salt is required, the anode solution is poured into a five-fold excess of petroleum ether, which is cooled in a Dry-Ice bath. The precipitated ferricinium perchlorate may then be removed by centrifugation and dried. 

FeM.5 (C6H6)2a04 Ferricinium-(Fe ) perchlorate, 7 203 analogous salts, 7 205 [Fe(CBH6N)4]Cl2 Tetrapyridine-iron(II) chloride, 1 184 FeCl2 Iron (II) chloride, 6 172 1-hydrate, 6 181 2-hydrate, 6 179... 

Electrosynthesis of the polythiopene was realized on an indium-tin-oxide (ITO) electrode (glass blade covered with an indium-doped tin-oxide film). Before conducting the experiment, each electrode was cleaned by ultrasonication for 10 min in different solvents (acetone, dichloromethane, ether). Electrochemical experiments were performed in a three-compartment cell. The working electrode was the ITO electrode, the counter electrode was a Pt wke, and the reference electrode was an aqueous-saturated calomel electrode (E°/SCE = E°/NHE — 0.2412 V) with a salt bridge containing the supporting electrode. The SCE electrode was checked against the ferrocene/ferricinium couple (E = -1-0.405 V/SCE) before and after each experiment. 

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