Red Salt

Reaction with nitrous acid can be used to differentiate primary, secondary, and tertiary mononitroparaffins. Primary nitroparaffins give nitrolic acids, which dissolve in alkali to form bright red salts. 

In 1904, Zincke reported that treatment of Al-(2,4-dinitrophenyl)pyridinium chloride (1) with aniline provided a deep red salt that subsequently transformed into A-phenyl pyridinium chloride 5 (Scheme 8.4.2). Because the starting salt 1 was readily available from the nucleophilic aromatic substitution reaction of pyridine with 2,4-dinitrochlorobenzene, the Zincke reaction provided access to a pyridinium salt (5) that would otherwise require the unlikely substitution reaction between pyridine and... 

Werner s coordination theory, 1, 6 Whewellite structure, 6, 849 Wickmanite structure, 6, 849 Wilkinson s catalyst, 6, 239 Wilson s disease, 5, 721 copper, 6,648 removal, 6,769 copper complexes, 2,959 copper metabolism, 6,766 radiopharmaceutical agents, 6,968 Wolfram s red salt, 5,427 Wurzite... 

Such nucleophilic displacements are likely to be addition-elimination reactions, whether or not radical anions are also interposed as intermediates. The addition of methoxide ion to 2-nitrofuran in methanol or dimethyl sulfoxide affords a deep red salt of the anion 69 PMR shows the 5-proton has the greatest upfield shift, the 3- and 4-protons remaining vinylic in type.18 7 The similar additions in the thiophene series are less complete, presumably because oxygen is relatively electronegative and the furan aromaticity relatively low. Additional electronegative substituents increase the rate of addition and a second nitro group makes it necessary to use stopped flow techniques of rate measurement.141 In contrast, one acyl group (benzoyl or carboxy) does not stabilize an addition product and seldom promotes nucleophilic substitution by weaker nucleophiles such as ammonia. Whereas... 

Flash photolysis of the dianion of Roussin s Red Salt, [Fe2S2(NO)4]2, in particular the initial photoinitiated loss of NO (382) and the reverse recombination reaction, en route to the eventual product, the anion of Roussin s Black Salt, [Fe4S3(NO)7] , has been documented (383). A 4-RC6H4S group (R = H, Me, OMe, Cl, or CF3) replaces one of the chloride ligands in [Fe4S4Cl4]2 via a five-coordinated intermediate, with the detailed sequence of steps acid-dependent (384). Loss of chloride is... 

DNICs are spontaneously [128] formed in aqueous media using a simple Fe(II) salt, S-nitrosothiol and thiol, with a ratio of Fe2+/RSH of 1 20. NO is transferred quantitatively from the sulfur atom in the RSNO to the iron. The complete mechanism is yet to be fully determined. A 1 2 ratio results in the formation of an EPR silent yellow dinuclear iron complex ([Fe2(RS)2(NO)4]. At the higherer ratio, the green paramagnetic, mononuclear dinitrosyl predominates. The reaction is very straightforward at pH 7.8, under an inert atmosphere and in water. Under anaerobic conditions the stability of this compound is enhanced, however, in the presence of air and hydrogen peroxide, it readily decomposes to give the dinuclear complex [126] which is similar in structure to the Roussin red salt, as shown in Scheme 5.5. 

The interactions of NO with the iron-sulfur cluster moieties of several enzymes generate iron-sulfur-nitrosyl cluster compounds [156]. However, synthetic nitrosyl clusters such as Roussins black salt (RBS), Roussins red salt (RRS), Roussins red ester (RRE) and [FeNOS]4 (Fig. 5.3) are well known [129, 157] and can be synthesized easily [158-164]. For example, the RBS can be prepared by mixing FeS04 with NaN03 and (NH4)2S in aqueous solution [158]. RRE salts are generally insoluble in water, but recently the water soluble sulfonated derivative, Na2[Fe2(SCH2CH2S03)2(N0)4], has been prepared [165]. 

Fe4S3(NO)7 + S> Fe4S4(NO)7 nitric oxide from Roussin s red salt. 

With concentrated mineral acids azobenzene gives red salts, as may be shown by pouring hydrochloric acid on it. Addition of hydrogen leads to the re-formation of the hydrazo-compound. Oxygen is added on and the azoxy-compound formed by the action of hydrogen peroxide or nitric acid. The synthesis of asymmetrical aromatic azo-compounds from nitroso-compounds and primary amines was discussed above. 

The red salts are the di-alkali salts of the quinonoid phenolcarboxylic acid formulated. This acid is not stable in the free state, but undergoes immediate isomerisation to the colourless lactone. 

Dimethylaminoazobenzene is adsorbed by TiOg as red salt only after ultraviolet irradiation. 

Synonyms AI3-08926 AIDS-19458 l-Amino-4-nitrobenzene 4 Aminonitrobenzene jO-Amino nitrobenzene Azoamine red ZH Azofix Red GG salt Azoic diazo component 37 BRN 0508690 C-02126 CCRIS 1184 C.I. 37035 C.I. azoic diazo component 37 C.I. developer 17 Developer P Devol red GG Diazo fast red GG EINECS 202-810-1 Fast red base GG Fast red base 2J Fast red 2G base Fast red 2G salt Fast red GG base Fast red GG salt Fast red MP base Fast red P base Fast red P salt Fast red salt GG Fast red salt 2J IG base Naphtolean red GG base NCI-C60786 4-Nitraniline jo-Nitraniline Nitrazol 2F extra jo-Nitroaniline para-Nitroaniline 4-Nitrobenzenamine p-Nitrobenzenamine 4-Nitrophenylamine p-Nitrophenylamine PNA RCRA waste number P077 Red 2G base Shinnippon fast red GG base UN 1661. 

Flash photolysis of Roussin s Red Salt, Na2[Fe2S2(NO)4], and of Roussin s Black Salt, NH4[Fe4S3(NO)7], has been described. " Photolysis of [Fe2S2(NO)4] has been reviewed, in... 

Such cyanide complexes are also known for several other metals. All the fer-rocyanide complexes may be considered as the salts of ferrocyanic acid H4Fe(CN)e and ferricyanide complexes are that of ferricyanic acid, H3Fe(CN)e. The iron-cyanide complexes of alkali and alkaline-earth metals are water soluble. These metals form yellow and ruby-red salts with ferro-cyanide and ferricyanide complex anions, respectively. A few of the hexa-cyanoferrate salts have found major commercial applications. Probably, the most important among them is ferric ferrocyanide, FeFe(CN)e, also known as Prussian blue. The names, formulas and the CAS registry numbers of some hexacyanoferrate complexes are given below. Prussian blue and a few other important complexes of this broad class of substances are noted briefly in the following sections ... 

The series is prepared by treating blue potassium chromi-oxalate, [Cr(C204)3]Ks, with aqueous 10 per cent, ethylenediamine until a red salt begins to separate from the dark violet solution. On cooling the mixture the double salt, oxalato-diethylenediamino-ehromium dioxalato-ethylenediamino-chromate, [Cr en2C204][Cr en(C204)2], is obtained in... 

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