Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/930150
- Synthesis and metal(II) ion complexation of pyridine-2, 6-diamides incorporating amino alcohols
Lawrance, Geoffrey A.
- The University of Newcastle. Faculty of Science & Information Technology, School of Environmental and Life Sciences
- Reaction of 2,6-bis(methoxycarbonyl)pyridine with two equivalents of a β-amino alcohol yields pyridine-2,6-diamides C₆H₃N(CONH–CR₁R₂–CHR₃–OH)₂ [(1) R₁ = R₂ = R₃ = H; (2) R₁ = R₂ = H, R₃ = CH₃; (3) R₁ = CH₃, R2 = R₃ = H; (4) R₁ = C₂H₅, R₂ = R₃ = H; (5) R₁ = C₆H₅CH₂, R₂ = R₃ = H; (6) R₁ = O₂NC₆H₄CH(OH), R₂ = R₃ = H; (7) R₁ = R₂ = CH₃, R₃=H] incorporating the amino alcohols, several of which are chiral, whereas the free diamide ligands show no capacity toward deprotonation up to pH > 12. In the presence of metal(II) ions they undergo concomitant deprotonation and complexation to form [M(L-2H)] compounds. Formation constants have been determined for Cu(II), Ni(II), and Zn(II) complexes of the suite of ligands. Determined values for the two observed steps of log β ML-2H and log β ML-3H (where additional alcohol or coordinated water deprotonation occurs) are approximately −10 and −20, respectively. As pKa values of the diamide cannot be determined independently, absolute log KML-2H values for the di-deprotonated complexes cannot be definitively assigned, although estimates are made using predicted pKa values for the diamide. The circular dichroism spectra of optically active complexes were determined and are discussed.
- Journal of Coordination Chemistry Vol. 63, Issue 14-16, p. 2400-2418
- Publisher Link
- Taylor & Francis
circular dichroism spectroscopy
- Resource Type
- journal article