Cobalt complex compounds ethylenediamine

The examples of metal-chiral structures are mainly cationic mixed-ligand cobalt(III) complexes of ethylenediamine and its monodimethylphosphine analogue [Co(H2NCH2CH2NH2)3(H2NCH2CH2PMe3)3 J3+. Their synthesis, separation to enantiomers, and establishment of absolute configuration have been carried out for these compounds [276]. The binuclear cobalt(III) complexes 924 possess similar optical properties [277] ... 

It was her thesis work with Alfred Werner34 that was to enter her in the annals of the history of chemistry. Among the compounds she made was cis-bis(ethylenediamine)dinitro-cobalt(III) bromide. This was the very first synthesis of a chiral octahedral cobalt complex, though at the time the significance of her synthesis was overlooked.31(a) Werner was so impressed with her work that, for her last year, he took her on as his personal assistant, the first women to be chosen for this prestigious post.35 More important for the impoverished Humphrey, she at last had some income in very expensive Switzerland. 

Another case involving cobalt complexes was studied by Work (19), who prepared, among others, a compound containing three different bidentate amines—ethylenediamine, trimethylene-diamine, and neopentanediamine, [Co(en)(tn)(dan)]CI3, by following and extending a synthesis first described by Werner (20) ... 

The very different basicities of water and of ammonia lead to different reactivity patterns for iSNlcb base hydrolyses of cobalt(iii) compounds. The latest contribution in this area has been a study of base hydrolysis of a series of complexes [Co(NH3)6(RNHa)] + in liquid ethylenediamine. The basicity or solvating power of the solvent determines the form of the rate law for substitutions at copper(ii)-Schiff base complexes. The term corresponding to solvolysis is, of course, only significant for solvents with an affinity for copper(ii). ... 

In the complex [Co(NH3)6]Cl3, the cation is [Co(NH3)6]3+, and it is named first. The coordinated ammonia molecules are named as ammine, with the number of them being indicated by the prefix hexa. Therefore, the name for the compound is hexaamminecobalt(III) chloride. There are no spaces in the name of the cation. [Co(NH3)5C1]C12 has five NH3 molecules and one CN coordinated to Co3+. Following the rules just listed leads to the name pentaamminechlorocobalt(III) chloride. Potassium hexacyanoferrate(III) is K3[Fe(CN)6j. Reinecke s salt, NH4[Cr(NCS)4(NH3)2], would be named as ammonium diamminetetrathiocyanatochro mate (III). In Magnus s green salt, [Pt(NH3)4][PtCl4], both cation and anion are complexes. The name of the complex is tetraammineplatinum(II) tetrachloroplatinate(II). The compound [Co(en)3](N03)3 is named as tris(ethylenediamine)cobalt(III) nitrate. 

The importance of metal coordination compounds in biological systems has led to the study of polydentate Schilf base complexes of cobalt(II), nickel(II), and copper(II) (204, 205). Dimers have been observed in the spectra of complexes of both tri- and tetradentate ligands [e.g., salicylaldehydeand A,A-bis(salicylidene)ethylenediamine]. The parent ions form the base peaks, and the spectra are characterized... 

Chloropentaamminecobalt(III) chloride forms red-violet rhomb-shaped crystals which decompose on heating above 150° with the stepwise loss of ammonia. The solubility of the salt in water at 25° is 0.4 g./lOO ml. The compound readily aquates in hot water, forming the aquopentaammine chloride. Chloropentaamminecobalt(III) chloride reacts with hot aqueous ethylenediamine or dZ-propylenediamine to form tris (ethylenediamine) cobalt (III) chloride or the corresponding propylenediamine compound, with liberation of ammonia. Concentrated sulfuric acid at room temperature produces a complex hydrogen sulfate of the chloro-pentaamminecobalt(III) ion. Aqueous mercury(II) chloride forms a characteristic precipitate of a double salt, [Co(NH3)6Cl]Cl2-3HgCl2, suitable for microchemical identification. Complete physical and chemical data may be found in Gmelin s handbook. ... 

The first successful resolution of coordination compounds was reported by Werner in 1911 and involved two series of complexes, the cw-chloroammine-bis(ethylenediamine)cobalt(III) series (with V. L. King) and the m-bromo-amminebis(ethylenediamine)cobalt(III) series (with E. Scholze). Of the two, the bromoammine series is easier to resolve because of the greater difference in solubility between the diastereoisomers that are formed with the resolving agent, silver ( + )-octahedral configuration first postulated by Werner for cobalt(III) in 1893. 

The as-bromoamminebis(ethylenediamine)cobalt(III) bromide crystallizes in purple platelets. The compound has been resolved/ and the kinetics of the reactions of hydroxide ion with the d- and Z-isomers in water have been determined. The red-orange crystals of as-aquoammine-bis(ethylenediamine)cobalt(III) bromide are compact and almost cubic, in contrast to the orange needle-plates of the trans isomer. The crystals of water exchange of the aquoammine complexes have been studied. ... 

Octahedral compounds have been used in many of the earlier illustrations in this chapter and others. Other octahedral complexes include tris(ethylenediamine) cobalt(III),... 

When diethylmalonate or cyanoacetate have been used instead of bis-ethylenediamine cobalt(III) pyruvate, the cobalt(III) oxoaza-and oxosarcophaginates were isolated by analogy with the previous scheme [133], The semiclathrochelate [Co(azasen)]Cl3 and [Co(sen)]Brs complexes, respectively, were used as initial compounds. 

Copper complexes (152) of o-hydroxy-o -(p-aminoethylamino)diarylazo compounds have been prepared ° by the reaction of the corresponding o-chloro-o -hydroxydiarylazo compounds and ethylenediamine in the presence of copper(II) ions (c/. Section 58.2.3. l(iii)(c)). Dyestuffs of this type have been evaluated on nylon but are reported to have very poor fastness properties. Copper complexes such as (153) have been preparedby similar methods. Other, related tetradentate diarylazo compounds, e.g. (154), (155) and (156), are obtained by the reaction of a suitable diazonium salt with the appropriate diarylamine. Chromium(III) and cobalt(III) complexes of dyes of this type, in which the coordination sphere of the metal is completed by a colourless bidentate ligand such as ethylenediamine, salicylic acid or 8-hydroxyquinoline, are reported to have dyeing properties on wool similar to those of the comparably charged 2 1 complexes derived from tri-... 

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