Synthesis and Crystal Structure of the Tris‐bidentate Carbonatobis‐(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 · 6 H₂O in the presence of succinic acid in a CH₃OH–H₂O solution. The compound crystallizes as heptahydrate. The crystal structure (monoclinic, P2₁/c (no. 14), a = 9.897(1), b = 26.384(2), c = 10.582(1) Å, β = 105.87(1)°, Z = 4, R = 0.0505, wR² = 0.1029 for 3166 observed reflections (F ≥ 2σ(F ) 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 Å, d(Ni–O) = 2.051, 2.079 Å. The complex molecules are stacked into 2D corrugated layers parallel to (010) via two types of intermolecular π‐π stacking interactions. One occurs between two quinoline rings of neighboring phen ligands at the distance of 3.63 Å in 010] direction and the other results from 1D π‐π stacking interactions through partially covered phen rings at alternative distances of 3.26 Å and 3.33 Å in 001] direction. The water molecules are sandwiched between 2D layers.