Complexes cationic ammonia

In aminations requiring copper, it appears that copper ammonia cations complex with the chloro compound and that this complex addition compound acts as a cyclic catalyst by reacting with ammonia, —OH ion, and the amine. ... 

The LA process may be carried out in the presence of gaseous molecules or near a stream of gas (60) (e.g., oxygen) producing cluster anions such as GdvO( or ammonia producing complex cations such as Cr(NH3)J, where x = 2-15 (61). Metal complexes may also be obtained by LA (e.g., LA of an iron rod produces Fe+), but when the rod is coated with C60 and coronene, ions such as [C60Fe(coronene)]+ are produced (62). 

In the case of cationic complexes with unsaturated macrocycles two molecules of nucleophile, such as ammonia, amines and alkoxides, add to carbon atoms of two inline groups. For example, the reaction of [Ni(Bzo[16]octaeneN4)](C104)2 (Table 106) with sodium methoxide or ethoxide yields the compounds (395),2860 while with secondary amines and diamines complexes of type (396) are obtained.28 1 The reaction of (396) with acetone at room temperature yields complex (397) where the enolate anion of acetone, MeC(0)CH2, replaces the diethylamide group (Scheme 58). 2862 The addition of molecules such as bis(2-hydroxyethyl)methylamine and bis(2-hydroxyethyl) sulfide, HOCH2CH2YCH2CH2OH (Y = NMe, S) results in the formation of derivatives which possess one more coordination site just above the plane of the macrocyclic donors (398).2863... 

The back-extraction (stripping) of palladium is achieved in the hydroxyoxime process by contacting the loaded organic phase with a concentrated solution of hydrochloric acid (about 6 M), thus causing the reversal of reaction (76). Palladium can be recovered from the strip liquor by the addition of ammonia, and the precipitated Pd(NH3)2Cl2 can be calcined to yield pure palladium metal. In the dialkyl sulfide process, however, the extraction reaction (75) is independent of acidity, and is therefore reversed by the use of aqueous ammonia, which forms a stable cationic complex with palladium(II) ... 

In addition, thin solid films obtained by evaporation of metal-ammonia solutions that contain a cation complexing agent (cryptand) have transmission spectra that suggest the existence of expanded metals in these systems (42). 

A number of cationic complexes have been prepared. The physical properties of these complexes are shown in Table 93. The first examples were prepared by allowing ammonia or other nitrogenous bases to react with [RhX(NO)2] complexes (equation 317).1292... 

The ammonia addition complexes of diborane are revealed as true coordination compounds of boron in which hydride ligands are replaced systematically by ammonia molecules. It is worthwhile to note that the analogy is a formal one and has no implications relative to geometry. It simply demonstrates the similar formulas of members of two substitution series. The particular divalent and trivalent cations [HB(NH3)3] and [B(NH3)4]" have not, to the best of my knowledge, been reported as yet, but I confidently predict that both a trivalent and divalent cation of boron will be prepared in the near future. Chelation phenomena, as described in subsequent discussions, may well be helpful in achieving this goal. An earlier, tentative report (19) from my laboratory of the divalent cation [HB(NH3)3]+2 was later shown by us to be in error. More sophisticated methods of synthesis appear to be required. 

Pickard, F.C., Dunn, M.E., Shields, G.C. Comparison of model chemistry and density functional theory thermochemical predictions with experiment for formation of ionic clusters of the ammonium cation complexed with water and ammonia atmospheric implications. J. Phys. Chem. A 2005,109(22), 4905-10. 

The phthalocyanine macrocyclic system, formally derived from four isoindoles, is the basis for many blue dyestuffs. Metal derivatives have a cation complexed at the centre, much as the iron atom in haem. Phthalocyanine can be produced by the reductive cyclisation of 2-cyanobenzamide or, in a route which makes its relationship to isoindole more obvious, by the combination of four molecules of 1,3-diiminoisoindoline with the elimination of ammonia. ... 

Determination of alkali metals, alkaline earth metals, and ammonia is the most often used application of ion chromatography in the range of cation analysis. The key advantage of this method is the ability to determine ammonia in complex samples that contain both inorganic cations and organic amines, as the latter compounds can interfere with the conventional colorimetric or ion selective electrode methods used for ammonia analysis. 

Let s recall that with ammonia, Cu + gives the deep blue cation complex hexam-mine copper(II) (cupritetrammine). In analytical toxicology, Cu° is searched for in the liquid resulting from the sulfonitric mineralization and is identified in it with ammonia. Because of its weak concentration in the mineralization liquid, Cu " " is first displaced by metallic iron, on which it deposits in the form of a red coating of metallic copper. The deposit is purely and simply the result of the following redox reaction ... 

A similar interaction occurs with the very stable complexes of various cations such as Cu ", Ni " or Co ". At high ammonia concentration (pH > 8). [M(NH3)6] complexes dominate in. solution and are adsorbed on various substrates [3). The UV-visible characteristic absorption of the nickel amino complex is not shifted upon adsorption on silica [4]. Adsorption of these complexes does not cause a shift in the intersection point of the proton titration curves (i.e does not cause a shift in the PZC of the oxide [5]). The negatively charged surface of the oxide acts as the counterion of the cation complex (M(NH3)e1 at the most, to the formation of ion pairs ... 

Aqueous ammonia can also behave as a weak base giving hydroxide ions in solution. However, addition of aqueous ammonia to a solution of a cation which normally forms an insoluble hydroxide may not always precipitate the latter, because (a) the ammonia may form a complex ammine with the cation and (b) because the concentration of hydroxide ions available in aqueous ammonia may be insufficient to exceed the solubility product of the cation hydroxide. Effects (a) and (b) may operate simultaneously. The hydroxyl ion concentration of aqueous ammonia can be further reduced by the addition of ammonium chloride hence this mixture can be used to precipitate the hydroxides of, for example, aluminium and chrom-ium(III) but not nickel(II) or cobalt(II). 

The solid readily dissolves chemically in concentrated hydrochloric acid, forming a complex, and in ammonia as the colourless, linear, complex cation [H3N -> Cu <- NHj] (cf AgCl) if air is absent (in the presence of air, this is oxidis to a blue ammino-copper(II) complex). This solution of ammoniacal copper(I) chloride is a good solvent or carbon monoxide, forming an addition compound CuCl. CO. H2O, and as such is used in gas analysis. On passing ethyne through the ammoniacal solution, a red-brown precipitate of hydrated copper(I) dicarbide (explosive when dry) is obtained ... 

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