Synthesis and crystal structure of the tris-bidentate carbonato-bis-(1,10-phenanthroline-N,N′)nickel(II) [Ni(C12H8N2)2(CO3)]

The tris-bidentate complex [Ni(C12H8N2)(2)(CO3)] was synthesized by the reaction of Na2CO3, 1,10-phenanthroline (phen=C12H8N2) and NiSO4 . 6H(2)O in the presence of succinic acid in a CH3OH-H2O solution. The compound crystallizes as heptahydrate. The crystal structure (monoclinic, P2(1)/c (no. 14), a = 9.897(1), b = 26.384(2), c = 10.582(1) Angstrom, beta = 105.87(1)degrees Z = 4, R = 0.0505, wR(2) = 0.1029 for 3166 observed reflections (F-o(2) greater than or equal to 2 sigma(F-o(2)) out of 6100 unique reflections) consists of hydrogen bonded water molecules and [Ni(phen)(2)(CO3)] complex molecules. The Ni atoms are sixfold octahedrally coordinated by the four N atoms of two bidentate chelating phen ligands and by two O atoms of the bidentate chelating carbonate group with d(Ni-N) = 2.092-2.100 Angstrom, d(Ni-O) = 2.051, 2.079 Angstrom. The complex molecules are stacked into 2D corrugated layers parallel to (010) via two types of intermolecular pi-pi stacking interactions. One occurs between two quinoline rings of neighboring phen ligands at the distance of 3.63 Angstrom in [010] direction and the other results from 1D pi-pi stacking interactions through partially covered phen rings at alternative distances of 3.26 Angstrom and 3.33 Angstrom in [001] direction. The water molecules are sandwiched between 2D layers.