Intermediates formed in the reaction of ethylenediaminetetraacetatocobaltate(II) with ferricyanide ion

Discrete Cyanide‐Bridged Mixed‐Valence Co/Fe Complexes: Outer‐Sphere Redox Behaviour

“…The amine protons of the macrocycle are structurally (for any of the two possible conformations, cis or trans) too far away to prevent protonation of any of the equatorial cyanide groups on the iron centre. Furthermore the 13 C NMR spectrum of a sample of trans-[L 15 Co III NCFe II (CN) 5 ] Ϫ in 1.0  HClO 4 ( Figure S2, Supporting Information) agrees with the integrity of the Co III moiety of the complex.…”

“…The new cis-[L 13 Co III NCFe II (CN) 5 ] Ϫ complex behaves as the already known derivatives with macrocycles of different sizes. Given the fact that the outer-sphere redox behaviour of these dinuclear complexes was to be studied under different acidity conditions, and that the [Fe(CN) 6 ] 4Ϫ moiety of the molecule is likely to undergo protonation at low pH, [16] speciation of the dinuclear complexes as a function of pH has been carried out.…”

“…[11,12] From these studies, the formation of a discrete Co III /Fe II species, produced by an inner-sphere redox process starting from the reduced Co II macrocyclic complexes and the corresponding [Fe(CN) 6 ] 3Ϫ ligand, similar to those detected for the classical CoEDTA/Fe(CN) 6 systems has been envisaged. [13] Further studies on these compounds have led us to the full characterisation of a series of molecular mixed-valence Fe II CNCo III complexes with different macrocycles and geometries surrounding the Co III centre.…”

Outer‐Sphere Redox Reactions Leading to the Formation of Discrete CoIII/FeII Pyrazine‐Bridged Mixed‐Valence Compounds

“…[25] Here we present the kinetic and mechanistic study of the reaction of compounds [ [23,24,28] To ascertain the redox-coupled or direct (redox-absent) substitutional nature of the general process being monitored, the reactions with [Co III X(NH 3 ) 5 ] n+ were also monitored in the presence and absence of added ethylenediaminetetraacetic acid (EDTA; [EDTA]/[Co] = 1-2). In the absence of this sequestering agent, an immediate precipitate is formed, as found in other systems, [29][30][31] [6][7][8] For the reactions of complexes with encapsulating macrocycles, [9,10,17,18] the relative stability of the {Co II L} resulting reduced species, as well as the substitution/inner-sphere redox processes that follow the outer-sphere redox reaction ({Co II 4-result in similar outcomes. [9] The nature of the final species formed for the Co III macrocyclic complexes (Scheme 3) was checked by electrochemistry, ion chromatography and 1 H NMR spectrometry experiments.…”

Molecular Approach to Alkali-Metal Encapsulation by a Prussian Blue Analogue FeII/CoIIICube in Aqueous Solution: A Kineticomechanistic Exchange Study

“…The preparation and isolation of the lithium, sodium, and potassium salts of the cube indicated in Chart have been achieved by the self-assembly of {Co III -NC-Fe II } edge units generated from the outer-sphere redox/labile substitution/inner-sphere redox processes known for some time and that we have comprehensively developed. ,, The presence of the {Co III -NC-Fe II -CN-Co III } units can also be achieved from the same processes, but the prevalence of trans isomerism of the iron­(II) hexacyanido unit would not allow the formation of a cubic structure, which requires a fac isomeric assembly . In this respect, the formation of tetranuclear mer -{(Co III -NC) 3 -Fe II } assemblies has also been reported .…”