Amine/ammine complexes

Similarly, we have also seen already how the copper(II) tetrakis (amine) complex forms in a step manner with four separate stages, rather than in a single step, forming the mono-ammine complex, then the to-ammine, the fra-amminc and finally the /e/ra/d.v-ammine complex. So we start to appreciate that the actual reaction occurring during the burning of octane is more complicated than it first appears to be the ratios in the stoichiometric equation are not useful in determining the reaction mechanism. 

Photoreduction of ammine complexes containing aliphatic amines instead of ammonia does not lead to production of molecular nitrogen instead, a variety of other ligand oxidation products are formed. Moeller and co-workers have studied three such systems in 3M HC1 solution 58 59 rather similar results have been obtained in more dilute acid solutions.55... 

In addition to chelate complexes, the cyclic amine 1,4,7-triazacyclononane will complex to platinum(II) and (IV). The hexacoordinate platinum(IV) complexes are bonded to two molecules of the tridentate ligand, but platinum(II) complexes with the ligand monodentate and bidentate.988 Also the formation of platinum(II) ammine complexes from chloride complexes is a reversible process. The rate constants decrease as the basicity of the leaving amine increases.989... 

As a general rule, the solubility of copper ammine complexes in water and alcohols increases with the rise in coordinating power of the amine concerned the molecular weight of the latter is also involved. The following general... 

The chlorides of the other polyhasic ammine complexes with cobalt described in (II) may easily be prepared in solution by a similar procedure, but only the ethylenedi-amine compound can be directly isolated as a solid. The other chlorides must be made indirectly from the nitrates, bromides, or iodides of the respective series,... 

To a coordination chemist there is little distinction between ammonia and an organic amine. Both have the all important nitrogen donor atom and thus have the potential to behave similarly. Regrettably, structural information for ammine complexes is not included in the Cambridge Crystallographic Data File,2 as simple salts lack the necessary carbon atom. 

Sargeson and his coworkers have developed an area of cobalt(III) coordination chemistry which has enabled the synthesis of complicated multidentate ligands directly around the metal. The basis for all of this chemistry is the high stability of cobalt(III) ammine complexes towards dissociation. Consequently, a coordinated ammonia molecule can be deprotonated with base to produce a coordinated amine anion (or amide anion) which functions as a powerful nucleophile. Such a species can attack carbonyl groups, either in intramolecular or intermolecular processes. Similar reactions can be performed by coordinated primary or secondary amines after deprotonation. The resulting imines coordinated to cobalt(III) show unusually high stability towards hydrolysis, but are reactive towards carbon nucleophiles. While the cobalt(III) ion produces some iminium character, it occupies the normal site of protonation and is attached to the nitrogen atom by a kinetically inert bond, and thus resists hydrolysis. 

An Attempt to Elucidate the Role of the 2Tt, State. We have some preliminary observations which may bear on the role of the 2Ti excited state in the relaxation process. This state can often be found 200 to 1000 cm- above the (2E) state in simple amine and ammine complexes (22). As the symmetry of the complexes decreases, the 2T state splits into two or three... 

In the metal refining of ores, the metal is solubilized in an aqueous solution. The optical control of metal refining requires quick, accurate analysis of the major chemical species present in solution. Raman spectroscopy and resonance Raman are used to identify the amine complexes of Co, Ni, and Cu species, as well as ammonia sulfate and sulfamate, present in these industrial solutions. The Raman spectra of an industrial plant solution from mine tailings are shown in Fig. 7-15. Each solution contains one or more metal species, sulfate, sulfamate, ammonia, ammonium sulfate, and water. From a comparison with model ammine complexes, the vibrations in the spectra are identifiable. Bands were observed at 615, 980 and 1,110 cm-1 and were assigned to the sulfate ion. No bands were observed for free ammonia. A band at 376 cm-1 was assigned to the Ni(NH3)j + specie. A band at 490 cm-1 was assigned to the Co(NH3)g+ specie. 

The procedure described here is based on the observation that amine monohydroxo complexes of cobalt(III), rhodium(IIl), and iridium(III) react directly with carbon dioxide to form the corresponding carbonato complexes,2 3 without effect on the configuration of the amine ligands.4 The amine monoaqua complex is allowed to react with lithium carbonate or carbon dioxide gas at room temperature at pH 8.0 for a few minutes, and the carbonato complex is isolated by adding alcohol. The procedure has been used to prepare salts of the following cations pentaammine(carbonato)-cobalt(III),2 ds-ammine(carbonato)bis(ethylenediamine)cobalt(III),5 trans-... 

Nitrogen Ligands. The affinity of Fem for amines is low. No simple ammine complex exists in aqueous solution addition of aqueous ammonia only precipitates the hydrous oxide. For the reaction... 

Although pyridine and other amine-type ligands form adducts with lanthanide diketonates, few other lanthanide complexes have been made. However, the first homoleptic lanthanide ammine complexes, [Yb(NH3)g] [Cu(S4)2] NH3, [Yb(NH3)s] [Ag(S4)2]-2NH3,and[La(NH3)9] [ 0(84)2],have been synthesised by reactions in aqueous ammonia. ... 

H2O [172] (153 4 H2O) resembles that in the ammine complex, including the detail of intramolecular hydrogen bonding from amine donors to alkoxide acceptors. The structure determination demonstrates that the stronger ethylenediamine ligand is also replaced by the lyxose anions. 

In contrast to the ammine complexes, the dimethylsulfoxide complexes appear to coordinate at the N- 7 of adenine owing to hydrogen bonding between DMSO and the exocyclic amine protons on adenine. 

The ferrous halides combine with gaseous ammonia, forming several ammoniates of which the highest are the hexammoniates that contain the ion, [Fe(NH3)6]2+. Other anhydrous ferrous compounds also absorb ammonia. The ammine complexes are not stable in water, however, except in saturated aqueous ammonia. With chelating amine ligands, many complexes stable in aqueous solution are known. For example, ethylenediamine forms the entire series ... 

Ruthenium(IIl) and Osmium(Hl) Amine and Ammine Complexes. Only a few amine complexes of Os111 are known, but for Ru111 there are several types and some of their reactions have been given in Fig. 26-F-3. Both elements form 2,2 -bipyridine and 1,10-phenanthroline complexes. 

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