Synthesis, crystal and molecular structure of tetraaquabis(nicotinamide) cobalt(II) phthalate dihydrate

The coordination compound of cobalt(II) with nicotinamide [CoL2(H2O)4][C6H4(COO)2] · 2H2O (I) (where L stands for nicotinamide) was synthesized and characterized by IR spectroscopy, conductometry, and thermogravimetry. The X-ray structure of complex I was determined. Crystals are monoclinic: a = 15.630(2) Å, b = 7.550(2) Å, c = 21.035(4) Å, β = 100.90(5)°, V = 2437.4(4) Å3, Z = 4, space group C2/c. The structural units of complex I are centrosymmetrical cations [CoL2(H2O)4]2+, anions [C6H4(COO)2]2− (lying on axis 2), and molecules of waster of crystallization. Complex cations are packed into layers are alternate with layers containing anions and free H2O molecules. This is a classical case of π-π-staking interactions that lead to the formation of supramolecular layered assemblies.