NOVEL INCLUSION OF BIS(2-PYRIDYLCARBINOLATO)COPPER(II) BY CYCLODEXTRINS

Formation of the inclusion complexes of bis(2-pyridylcarbinolato)copper(II) with cyclodextrins (CDs) has been studied extensively by electron spin resonance (ESR) and circular dichroism measurements. It has been found that the copper(II) complex forms a 1:1 inclusion complex with alpha-CD but a more stable 2:1 complex with gamma-CD. The stability constants of these inclusion complexes have also been estimated by an ESR method. The 2:1 inclusion complex showed a triplet-state ESR spectrum characteristic of copper(II) dimers. A dimeric structure has been proposed based on computer simulation of the ESR spectrum. This inclusion system may be a new model for multifactorial biological systems for molecular recognition and for mimicking active transport or concentration of substances.