Pentacyano ferrates

Procedure 4.3 Preparation and Isolation of AA Substituted Pentacyano-ferrate(ll) Complexes, [Fe(CN)5(AA)]n and Infrared Analysis1,2... 

TABLE 4.4 Results Summary for CV Analysis of Substituted Pentacyano ferrate(II) Complexes, [Fe(CN)5(L)]M ... 

Unter Verlust der a-Amino-Gruppe kann 2,6-Diamino-hexansaure durch Dinatrium-nitroso-pentacyano-ferrat(II) bei pH 9,5 oxidativ zu 2-Carboxy-piperidin (39%) cyclisiert werden148. 

There has been a marked resurgence of interest in this area. Recently published kinetic parameters for ligand dissociation from pentacyano-ferrates(II), [Fe(CN)5L] , are shown in Table 8.1, " which also contains earlier kinetic data for a few key complexes for comparison. It may be presumed that these dissociations take place by the limiting D mechanism. 

Redox Reactivity of Coordinated Ligands in Pentacyano(L)Ferrate Complexes Jose A. Olabe... 

REDOX REACTIVITY OF COORDINATED LIGANDS IN PENTACYANO(L)FERRATE COMPLEXES... 

When the above factors are put under control, the possibility of changing the ligand L in the pentacyano(L)ferrate complexes adds a further dimension for studying systematic reactivity changes, brought out by the controlled modification of the redox potentials of the Fe(II)-Fe(III) redox couples. In this way, the rates of electron transfer reactions between a series of [Fen(CN)5L]re complexes toward a common oxidant like [Coin(NH3)5(dmso)]3+ showed a variation in agreement with Marcus predictions for outer-sphere electron transfer processes, as demonstrated by linear plots of the rate constants versus the redox potentials (123). 

The chemistry of redox-active ligands L in the pentacyano(L) ferrate(II) and -(III) complexes is of fundamental concern for disclosing... 

Calzaferri, G., and H. R. Griiniger (1979), Charge-Transfer-Uebergiinge im Pentacyano-benzonitril-ferrat (II), Helv. Chimica Acta 62, 1112-1120. 

Maltz et al. (1971) introduced disodium pentacyano(nitrosyl)ferrate (sodium nitro-prusside, 7.7) as nitrosating reagent. This compound has the advantage that it is effective for nitrosations and diazotizations at pH 9-11. This allows the synthesis of alkyldiazenolates (7.9) without deamination by-products, as well as dediazoniations in neutral or weakly alkaline solutions. 

These reactions evolve to a full completion, i.e., the reverse reactions are neghgible. Consider, for instance, reaction (3) related to the well-studied series of pentacyano(Y)ferrates(III) (Y = H20, or other ligand) (75)... 

Nitrofen Silica gel 60 F254 (Merck) CCI4 ether (3 1) Pentacyano-amino-ferrate 81 82... 

Measurement of the Hg(ll)-diphenylcarbazone derivative (spec A = 562 nm) Measurement of the pyridine-benzidine complex LOD = 0.02 pg Measurement of the pentacyano(N-methylpyrazinium) ferrate (II) complex... 

A) Na4[Fe(CN)5NOS] - Sodium pentacyano nitrosyl sulphido ferrate (III). 

---