Formation of cobalt(II), nickel(II) and copper(II) chloro complexes in alcohols and the Irving-Williams order of stabilities

Abstract

Co n chloro complexes were studied in MeOH at 25 ~ and at constant ionic strength of 1 tool dm 3. Formation of three complexes is postulated for which the overall stability constants are calculated: log/~1=1.2, log/~2 = 1.7 and log fi3 = 1.4. The electronic spectra and the formation curves of the identified species are presented for the first time in this medium. The results are compared with those obtained in other alcohols and increasing stability with increasing molecular weight of the solvents is established. Further comparative study showed that the maximum stability of the chloro complexes is found with the Cu n ion as the central atom. This confirms the IrvingWilliams order of stabilities for the first transition metal complexes in this alcoholic medium and the result is explained in terms of the second ionization potential of the elements.

Furannic Thiosemicarbazone Complexes of Co(II), Ni(II), and Cu(II) in Ethanol Solutions and of Co(II) in the Solid State

“…However, with other metals the same ligands form very weak complexes. This is expected, however, as it was shown earlier that the Irving-Williams Order of Stabilities is equally valid in such systems; 17 hence, the stability of the complexes is highest with copper as compared to other metals.…”

“…This result is in accord with the Irving-William Order of Stabilities and we reported earlier such behaviour in similar systems. 17 The complexes formed with the ligand 3FTSC have the highest stability when compared with the other three ligands. This can be explained by the position of the thiosemicarbazone part on the furanic cycle.…”

Novel polydentate phosphonic acids: Protonation and stability constants of complexes with Fe(III) and Cu(II) in aqueous medium

“…This change is due to the ability of Cu(II) to coordinate in a square planar geometry in the cases of symmetrical ligands like L1 and L3. Finally, these stability constants follow the Irving-Williams series [39,40], with higher stability for Cu(II) complexes than for iron complexes.…”

Stability of Binary and Ternary Copper(II) Complexes with 1,10-Phenanthroline, 2,2'-Bipyridyl and Some .ALPHA.-Amino Acids in Aqueous Medium

“…The purity of chemicals was checked and the exact concentrations of the solutions were determined by the Gran method with standard HCI. 37) Phen (99.5%) was purchased from Merck. Bpy (98%) and Gly (99%) were purchased from Fluka.…”