M. Dale Alexander

Accumulation of elemental gold on the alga Chlorella vulgaris

Abstract The accumulation of Au(0) by lyophilized preparations of the alga Chlorella vulgaris has been investigated. Gold is bound to the algae upon suspending dried algal cells in solutions containing hydrogen tetrachloroaurate (III). Relative amounts of ionic and atomic algal-bound gold were determined by thiourea extraction. It was found that the amount of algal-bound atomic gold produced from ionic gold increased with time. The effect of algal-bound gold concentration on the rate and extent of gold reduction was observed. It is suggested that at least three different classes of sites are available for gold binding and reduction. The effect of Au(0) accumulation on the binding ability of gold-bound algae was also investigated, and an apparent enhancement of gold binding ability is reported.

Binuclear chloropentaaminecobalt(III) complexes

Abstract A series of binuclear cobalt(III) complexes of the formulation where n is 2, 3, 4 and 6, and X is Cl or Br have been prepared and characterized. The kinetics of the mercury(II) induced equation of these complexes has been studied and the results correlated with the accepted mechanism for this type of reaction.

EPR of Spin‐52 Mn(II) Complexes with Very Large Ligand‐Field Splittings

An unusual manganese complex has been constructed in which the Mn(II) is in a spin‐52 state with large ligand‐field splitting. The angular dependence of the EPR spectrum indicates significant mixing of |M〉 states (i.e., those differing in electronic quantization along the z axis) by terms such as 12(− 3 sinθ cosθ)b20 × [(S+′ + S−′)Sz′ + Sz(S+′ + S−′(] and B(S+I− + S−I+). This mixing causes an unusual angular dependence of EPR transitions that occur near magnetic fields where two levels cross. When water is removed from the crystal, the Mn(II) ligand‐field splitting becomes greater such that only one EPR transition is observed for most orientations of the crystal in the magnetic field. Magnetic susceptibility measurements indicate that the Mn(II) is still in a spin‐52 state. This is the only Mn(II) complex known by us in which the Mn(II) has a single‐line EPR spectrum while in a spin‐52 state. The g factor of the dehydrated complexes is larger than the free‐spin value indicating strong covalent coupling of...

Simple Method for Isolating the Isomers of Mixed R-Propylenediamine Ethylenediamine Cobalt(III) Complexes

Abstract A new and convenient method of separating the isomers of [Co(en)x-(R-pn)3-x]Cl3 is described.