Crystal and molecular structure of bis[diaaqua(1H-cyclopenta(2,1-b : 3,4-b')(dipyridine-2,5-dione))nickel(II)] dihydrate

The title compound [Ni(CPDD)(H2O)(2)](2) (H2O)(2), {Ni-2(C44H28N8O12)] (H2O )(2) }, where CPDD = 1H-cyclopenta(2,1-b:3,4-b')(dipyridine -2,5-dione) has been prepared and its crystal structure determined by single crystal X-ray diffraction at room temperature. The complex crystallizes in the triclinic space group PI with two molecules in the asymmetric unit. The cell dimensi ons are a=10.452(1), b=14.098(1) & c=16.023 Angstrom; alpha =110.13(1), bet a= 100.63(1) & gamma = 100.85(1)degrees. The two independent molecules in t he asymmertic unit are related by pseudo two fold symmetry. In both the mol ecules the coordination environment around the Ni(II) may be best described as a distorted octahedral. Due to some delocalization. of charge towards o ne of the oxygens(O1a) from the O2a atom some degree of bond localization h as been observed. The individual diones of both the molecules are almost ri ght angles at the metal atom. Along the y-axis inversion related molecules are forming pseudo-dimers through hydrogen bonding.