Inorganic complexes aqueous solutions

Liposomes formed in complex aqueous solutions may include some of the solution compnents. Water soluble surface-inactive substances (inorganic electrolytes) may become passively incorporated into inner volume... 

This chapter reviews the literature up to approximately January 1984. Previous comprehensive reviews of the chemistry of zirconium and hafnium are available, and annual surveys of the inorganic and coordination chemistry of these elements have been published since 1981 The present treatment emphasizes the chemistry of discrete, isolable complexes, although some attention has been given to the extremely complex aqueous solution chemistry of Zr and Hf. In general, zirconium forms slightly more stable complexes in solution than does hafnium stability constants may be found in standard compilations.In cases where the structural chemistry of discrete complexes is closely related to that of chain, layer or extended three-dimensional structures, the discussion of the discrete complexes has been set in the broader context the section on fluorometallate complexes is a case in point. Organometallic compounds of zirconium and hafnium have been excluded almost entirely. 

In the case of inorganic solutes we are concerned largely with samples in aqueous solution so that it is necessary to produce substances, such as neutral metal chelates and ion-association complexes, which are capable of extraction into organic solvents. For organic solutes, however, the extraction system may sometimes involve two immiscible organic solvents rather than the aqueous-organic type of extraction. 

The solvation of inorganic substances and complex formation in non-aqueous solutions. A. M. Golub, Russ. Chem. Rev. (Engl. Transl.), 1976,45, 479-500 (358). 

It is very common for inorganic chemists to neglect or ignore the presence of solvent molecules coordinated to a metal centre. In some cases, this is just carelessness, or laziness, as in the description of an aqueous solution of cobalt(ii) nitrate as containing Co ions. Except in very concentrated solutions, the actual solution species is [Co(H20)6] . In other cases, it is not always certain exactly what ligands remain coordinated to the metal ion in solution, or how many solvent molecules become coordinated. Solutions of iron(iii) chloride in water contain a mixture of complex ions containing a variety of chloride, water, hydroxide and oxide ligands. 

Generally, cement-forming liquids are aqueous solutions of inorganic or organic adds. These adds include phosphoric add, multifunctional carboxylic adds, phenolic bodies and certain metal halides and sulphates (Table 2.1). There are also non-aqueous cement-forming liqtiids which are multidentate acids with the ability to form complexes. 

The inorganic elements in aqueous solution reactions, both acid-base complex formation, precipitation and oxidation/reduction, frequently come rapidly to equilibrium when no more reactions are possible. The implication is that in the environment and in organisms many of their properties cannot change unless circumstances change, for example the introduction of new components. 

Few inorganic ligands form stable complexes with the beryllium ion in aqueous solution. This is a reflection of the fact that on the one hand Be2+ shows a strong preference for oxygen donor ligands such as water and the hydroxide ion, and on the other hand reacts with the more basic ligands such as ammonia to give the insoluble hydroxide. Reported equilibrium constants are in Table V. 

Inorganic ligands in aqueous solutions, and in particular in natural freshwaters, include, in addition to H2O and OH, the major ions carbonate and bicarbonate, chloride, sulfate and also phosphate [29], The distribution of metal ions between these ligands depends on pH and on the relative concentrations of the ligands. The pH is a master variable with regard to the occurrence of hydrolysed species and to the formation of carbonate and bicarbonate complexes. 

Extractions of aqueous solutions of racemic amino-acid ester salts with solutions of / -6/s(dinaphthyl)-22-crown-6 [284] in chloroform revealed the dependence of the enantiomeric distribution constant on the structure of the amino acid ester (Table 64). In order to limit the concentrations of complex in the aqueous phase, inorganic salts were added. In the case of tyrosine, serine and alanine no extraction of salt was observed obviously these salts form very hydrophilic complexes. The highest degree of chiral recognition was found with [284] and p-hydroxyphenylglycine methyl ester hexafluorophosphate [A(AG°)... 

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