Sterically restrictive metal complexes. The synthesis and structural characterization of (1, 2-bis(6-methylpyridin-2-yl)ethane-N,N′)- (malonato)palladium(II) trihydrate. Proton NMR binding studies to cytosine and guanine derivatives

Two different routes for the preparation of the bidentate ligand 1,2-bis(6-methylpyridin-2-yl)ethane (bmpe) have been explored and are described. 1:1 coordination of this ligand with palladium(II) and the isolation of crystals of the complex as the malonate trihydrate has allowed the crystal and molecular structure to be determined. The compound crystallizes in space group P2₁/_n with _a=12.946(1), _b=7.431(1), _c=20.483(2) Å, β=91.941(3)°, Z=4. The structural analysis reveals that the 6-methyl groups of the bidentate bmpe ligand both project over one side of the square-plane, effectively blocking it off. The interaction of the Pd(bmpe)²⁺ complex cation with cytosine and guanine derivatives has been investigated by proton NMR spectroscopy.