Solubility of d-elements salts in organic and aqueous-organic solvents: I. Copper, cobalt, and cadmium sulfates

Solubility of d-element salts in organic and aqueous–organic solvents: II. Effect of halocomplex formation on solubility of cobalt bromide and chloride and nickel chloride

“…Equilibrium was reached by (1) the isothermal saturation method or (2) the supersaturation removal method. The specified systems containing a precipitate (1) or heated up to the complete dissolution of it (2) were placed in an air thermostat where they were held at 25.0±0.1°C for a day with permanent stirring. If there was no precipitate, the addition of the salt was continued up to formation of a visible solid phase amount, and then the solution with the precipitate was held in the same conditions within a week for final reaching equilibrium.…”

“…The formation of several coordination compounds (rather stable halocomplexes in solution and various solid crystal solvates) makes the behavior of aqueousorganic solutions of such salts more diverse than that of the systems containing sulfates of d-elements, where ionic association is the dominating process [1]. The study of solubility in the systems copper(II) halideaqueous-organic solvent [3] has shown that the formation of halocomplexes along with resolvation leads to the fact that the stability of formed halocomplexes [4,5], but not dielectric permittivity of a solvent, becomes the major factor defining the solubility.…”

“…In absence of complexation with anions (in the systems with cobalt, cadmium and copper sulfates in organic and mixed aqueous-organic solvents) ionic association is the dominating process in concentrated solutions and, as a consequence, solubility is determined mainly by the solvent dielectric permittivity [1]. This paper presents results of studying systems consisting of cobalt and nickel halides in aqueous-organic mixtures with various content of non-aqueous oxygendonor solvents: dimethyl sulfoxide (DMSO), dimethyl acetamide (DMA), and dimethyl formamide (DMF).…”

Co(iii) 2-ethylhexanoate, a hydrophobic and highly soluble Co(iii) precursor for thin coatings for water electrolysis

“…The entire spectrum of readily available Co(III) compounds is insoluble in extremely apolar media such as alkanes. [1][2][3][4][5] Inorganic Co(III) salts are soluble in water and polar solvents only, 1,2 while Co(III) carboxylates and several metal-organic complexes, such as the frequently used Co(III) acetylacetonate, are soluble in many common organic solvents but are only moderately soluble or insoluble in strongly apolar solvents. [3][4][5] This is due to the particularly hard character of the Co 3+ center, i.e.…”

“…the high positive charge concentrated in a small ionic radius. 1,2 The lack of such a Co(III) precursor showing high affinity for markedly apolar environments hinders the development of easy and direct synthetic protocols for Co(III)-based metal-organic frameworks (MOFs), 6,7 hydrophobic nanoparticles, 8 and solvogels, [9][10][11] which frequently require anhydrous, non-reactive, apolar conditions. A precursor soluble in highly apolar (hence highly volatile) solvents is also one of the most desirable features to prepare Co(III)-based coatings in environmental conditions via chemical solution deposition (CSD) processes.…”