Taro Yamasaki

Stability of the adducts of NiS4 type chelates with N-bases

Abstract The stability constants of the adducts formed between square-planar sulphur-coordinated nickel(II) chelates, such as bis(O,O-dialkyldithiophosphato)nickel(II), bis(dialkylxanthogenato) nickel(II) and bis(diethyldithiophosphinato)nickel(II), and N-bases are obtained from spectrophotometric measurements in benzene solution at 25°C. The effects of sulphur coordinating ligands, N-bases and solvents on the stability of the adducts are discussed and it became evident that the stability of the adducts is mostly affected by the steric hindrance of the ligands and N-bases, as well as by the electron density on the central nickel atom. From NMR and i.r. studies the bond nature in the adducts were deduced.

Adhesion of mercury and glass in aqueous solutions

Abstract Attachment of a mercury droplet to a glass foil in aqueous KF solutions was investigated in the range of 10−3 to 10−1 M concentration at various polarization potentials of mercury. The relation between critical potentials of attachment and solution concentrations below 1.5 × 10−1 M was explained quantitatively by the theory of heterocoagulation of dissimilar particles. Deviations from the theory were found in the concentrations higher than 1.5 × 10−1 M. Critical potentials of detachment were also determined as a function of the concentration. A possible explanation was given for the weakened attachment at high salt concentration by considering the additional repulsion detected when the glass and mercury were close by. Some discussions were also given as the Hamaker constant for dissimilar substances immersed in a liquid medium.