Abstract
The preparation and crystal structure of mercury(II) and nickel(II) complexes of 2-hydrazino-4-hydroxy-6-methylpyrimidine (LH) are described. The crystal of the mercury(II) complex, [HgCl4](LHH)2·2H2O is triclinic with a=7.481(2), b=19.535(6), c=7.482(2)Å, α=94.77(3)°, β=106.28(5)°, γ=85.24(3)°, V=1043.8(6)Å3, Dx=2.102g·cm-3, Z=2, and space group P1^-. The atomic parameters were refined to a final R value of 0.044 for 3115 reflections. In the mercury(II) complex, one [HgCl4]2- group which completes a regular tetrahedral coordination and two LHH+ molecules which take a keto form (>C(4)=O), constitute a double salt type structure, in which both units are bound together hydrogen bonds. It is notable that two different modes of stackings along the a and c axis are found between pyrimidine rings in the crystal. The crystal of the nickel(II) complex, [Ni(LH)2(H2O)2]Cl2·2H2O is triclinic with a=8.911(2), b=9.197(2), c=6.791(1)Å, α=93.41(3)°, β=102.31(3)°, γ=114.32(4)°, V=490.1(3)Å3, Dx=1.633g·cm-3. Z=1, and space group P1^-. The atomic parameters were refined to a final R value of 0.049 for 1310 reflections. The nickel(II) ion completes an octahedral coordination with two ring nitrogen N(3) and two hydrozino Namino nitrogen atmos of the two neighboring ligand molecules and two water molecules. The chloride ion is not bonded to nickel(II) ion but is hydrogen bonded to N(1)-H of the pyrimidine base. The length of C(4)-O(9), 1.249, in the LH residue suggests the keto form. Therefore, in the same preparation method with excess protons, the mercury(II) complex forms a double salt type structure, [HgCl4](LHH)2·2H2O, whereas the nickel(II) complex forms a chelate type structure, [Ni(LH)2(H2O)2]Cl2·2H2O.
