Solvation of inorganic complexes: transfer chemical potentials for mono- and bi-nuclear cobalt(III) complexes to methanol + water mixtures

Abstract

Solubilities in MeOH-H 2 O mixtures at 298.2 K are reported for a number of salts of mono-and bi-nuclear cobalt(III) complexes. From these solubilities and published single ion transfer chemical potentials, on the TPTB (Ph 4 P + ¼ BPh À 4 ) assumption, transfer chemical potentials have been derived for these mono-and bi-nuclear cobalt(III) complexes. The results and trends are discussed in relation to those for other complexes and ions in these binary aqueous solvent mixtures.

Solubilities and Transfer Chemical Potentials for Cobalt(III) Complexes in t-butanol– i-propanol–, and ethanol–water Mixtures

“…Whereas there is a great deal of information available for, e.g., alkali metal and halide ions, there is considerably less information on metal complexes. We recently reported solubilities and transfer chemical potentials for a number of mono-and bi-nuclear cobalt(III) complexes to aqueous MeOH [3]. We now extend that investigation to other alcohol co-solvents, specifically EtOH, i-PrOH, and, especially, t-BuOH.…”

“…Tables 2 and 3 in the Discussion section below also include some solubilities, obtained in order to derive transfer chemical potentials for the [Co(en) 3 ] 3+ cation and the S 2 O 2À 6 (dithionate) anion, in solvent mixtures containing up to 90 vol% t-BuOH for the former, and in several alcohol-water mixtures for the latter.…”

“…Table 2 develops a series of TATB-based transfer chemical potentials beyond our normally studied t-BuOH content, leading to the establishment of a )=1/2 d m l°(Ph 4 AsBPh 4 ). 4 Co(l-OH)(l-NH 2 )Co(NH 3 anion in a range of t-BuOH-, i-PrOH-, and EtOH-H 2 O mixtures, values required for the derivation of transfer chemical potentials of the complex cations isolated as dithionates. The pattern of values obtained for the dithionate anion as a function of the nature and amount of co-solvent is as expected.…”

“…The majority of the Co(III) complexes used in this investigation were the same as those used in our recent MeOH-H 2 O study; the preparative methods used were detailed and referenced in our report on that study [3]. [(H 3 N) 3 Co(l-OH) 2 (l-CO 3 )Co(NH 3 ) 3 ](ClO 4 ) 3 was prepared by the published method [4], then converted into the dithionate salt by metathetical reaction with potassium dithionate.…”

“…[(H 3 N) 3 Co(l-OH) 2 (l-CO 3 )Co(NH 3 ) 3 ](ClO 4 ) 3 was prepared by the published method [4], then converted into the dithionate salt by metathetical reaction with potassium dithionate. The experimental methods and instruments used were the same as those used in our previous study [3].…”