Bis(O,O'-diisopropyl dithiophosphato-S,S')(1,10-phenanthroline-N,N')metal(II) complexes with cadmium(II) and iron(II).

The two title compounds, [M(C6H14O2PS2)2(C12H8N2)], where M = CdII and FeII, are isomorphous. Each compound has a crystallographic twofold axis of symmetry through the metal atom and the 1,10-phenanthroline molecule. The central metal atom is coordinated to four S atoms from the two dithiophosphate groups and two N atoms from the 1,10-phenanthroline ligand. The environment of the metal atom is a distorted octahedron.

Direct-method-aided phasing of MAD data.

The direct methods of breaking the phase ambiguity intrinsic in one-wavelength anomalous scattering (OAS) data and MAD phasing are powerful methods in their own rights. In a different context, in addition to their success in phasing OAS data, direct methods can also be useful in the treatment of MAD data. The idea has been tested with the MAD data at 2.5 A resolution from the protein human adenosine kinase [Mathews et al. (1998), Biochemistry, 37, 15607--15620]. The results showed that the incorporation of direct methods in MAD phasing led to a significant improvement of phases over those obtained from the conventional MAD phasing method alone, as indicated by improved map correlation coefficients (with the existing model), reduced phase errors by 4.5 degrees and improved map connectivity.