Summary
Circular dichroism and electronic spectral measurements have established the existence of a covalent hydrate and a pseudobase arising from attack of H2O or HO− at the ligand in tris-(1,10-phenanthroline)nickel(II). In anhydrous solvents and strongly acidic solution, the complex is largely unsolvated. Over a large pH range the dominant species present in aqueous solution is the covalent hydrate while at high pH, this is converted into the pseudo-base. The existence of these species, and the equilibria between them in aqueous solution elegantly explains the pH dependent dissociation and racemization of the parent molecule. It further explains the non-linear variation of these reactions in mixed solvents and indicates that more than one mechanism is responsible over the range of solvents studied here and previously.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
N. R. Davies and F. P. Dwyer,Trans. Farad. Soc., 48, 244 (1952).
F. Basolo, J. C. Hayes and H. M. Neumann,J. Amer. Chem. Soc., 75, 5102 (1953).
R. G. Wilkins and M. J. G. Williams,J. Chem. Soc., 1763 (1957).
N. R. Davies and F. P. Dwyer,Trans. Farad. Soc., 50, 1325 (1954).
T. Fujiwara and Y. Yamamoto, XVII International Conference on Coordination Chem., Abstr., p. 166, Hamburg, September, 1976.
G. K. Schweitzer and J. M. Lee,J. Phys. Chem., 56, 195 (1952).
N. R. Davies and F. P. Dwyer,Trans. Farad. Soc., 49, 180 (1953).
J. A. Broomhead and F. P. Dwyer,Aust. J. Chem., 16, 51 (1963).
R. D. Gillard, L. A. P. Kane-Maguire and P. A. Williams,Transition Met. chem., TMC 76/83
R. D. Gillard,Coord. Chem. Rev., 16, 67 (1974).
F. P. Dwyer and E. C. Gyarfas,Proc. Roy. Soc. New South Wales, 83, 232 (1950).
J. Ferguson, C. J. Hawkins, L. A. P. Kane-Maguire and H. Lip,Inorg. Chem., 8, 771 (1969).
R. D. Gillard, L. A. P. Kane-Maguire and P. A. Williams,Transition Met. Chem., 1, 247 (1976).
R. D. Gillard and J. R. Lyons,J. Chem. Soc. Chem. Comm., 565 (1973).
R. D. Gillard, C. T. Hughes and P. A. Williams,Transition Met. Chem., 1, 51 (1976).
E. Bielli, R. D. Gillard and D. W. James,J. Chem. Soc. Dalton Trans., 1837 (1976).
R. D. Gillard, C. T. Hughes, L. A. P. Kane-Maguire and P. A. Williams,Transition Met. Chem., 1, 226 (1976).
R. D. Gillard, L. A. P. Kane-Maguire and P. A. Williams,J. Chem. Soc. Dalton Trans., in press.
R. D. Gillard and R. E. E. Hill,J. Chem. Soc. Dalton Trans., 1217 (1974).
R. D. Gillard, C. T. Hughes, L. A. P. Kane-Maguire and P. A. Williams, unpublished results.
P. Hemmerich, in W. Pfleiderer and E. C. Taylor, Eds.,Pteridine Chemistry, Pergamon, New York, 1964, p. 143.
P. Ellis, R. G. Wilkins and M. J. G. Williams,J. Chem. Soc., 4456 (1957).
F. Basolo, J. C. Hayes and F. H. Neumann,J. Amer. Chem. Soc., 76, 3807 (1954).
H. Brinzinger, S. Fallab and H. Erlenmeyer,Helv. Chim. Acta, 38, 557 (1955).
E. Bielli, P. M. Gidney, R. D. Gillard and B. T. Heaton,J. Chem. Soc. Dalton Trans., 2133 (1974).
Author information
Authors and Affiliations
Additional information
Part IX,Transition Met. Chem., 2, 12 (1977).
This ready change was pointed out to one of us (R.D.G.) some years ago by Professor B. Bosnich.
Rights and permissions
About this article
Cite this article
Gillard, R.D., Williams, P.A. Equilibria in complexes ofN-heterocyclic molecules, part X. The pH dependent racemization of tris-(1,10-phenanthroline)nickel(II). Transition Met Chem 2, 14–18 (1977). https://doi.org/10.1007/BF01402669
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01402669