Effect of second-sphere coordination 11. Selectivity in adduct formation of polypyridineruthenium(II) complexes with crown ethers

Adduct formation of polypyridineruthenium(II) complexes involving a different type of protic ligand was investigated for a series of crown ethers with different ring size. Changes in redox potential and in absorption spectra of the complex were measured on addition of crown ether to the complex solution. The magnitude of the change in both properties is dependent on the ring size of crown ethers. Chemical shifts of protic ligand of the complexes were measured at various concentrations of crown ethers. The stability constants of crown ether adduct were determined from the dependences of the chemical shift on crown ether concentration. It is found from their stability constants that the individual complex shows the different selectivity in adduct formation with crown ethers.