Dications of L-histidine and L-ornithine in layers of copper(II) and cobalt(II) dipicolinato anions

摘要

Cobalt(II) and copper(II) dipicolinato complexes having L-histidine and L-ornithine dications are synthesized in water and are characterized by various spectroscopic techniques. X-ray studies reveal that the L-histidine dications are strongly hydrogen bonded and intercalated in the layered structures of dipicolinato complex anions with repeated unit in 1:1 ratio. Whereas L-ornithine dications form hydrogen bonded repeated units of cations and anions in 2:2 ratio. The cations are held in the layered structures formed by the association of the amino acid cations and metal dipicolinato anions supported by water through strong hydrogen-bond interactions. The complexes thus formed are optically active and exhibit specific rotation in the range of +4 to +12°.