A binuclear CuII/CaII thiocyanate complex with a Schiff base ligand derived from o-vanillin and ammonia

Abstract

The new heterometallic complex, aqua-1κO-bis(μ2-2-iminomethyl-6-methoxyphenolato-1κ2 O 1,O 6:2κ2 O 1,N)bis(thiocyanato-1κN)calcium(II)copper(II), [CaCu(C8H8NO2)2(NCS)2(H2O)], has been synthesized using a one-pot reaction of copper powder, calcium oxide, o-vanillin and ammonium thiocyanate in methanol under ambient conditions. The Schiff base ligand (C8H9NO2) is generated in situ from the condensation of o-vanillin and ammonia, which is released from the initial NH4SCN. The title compound consists of a discrete binuclear molecule with a {Cu(μ-O)2Ca} core, in which the Cu...Ca distance is 3.4275 (6) Å. The coordination geometries of the four-coordinate copper atom in the [CuN2O2] chromophore and the seven-coordinate calcium atom in the [CaO5N2] chromophore can be described as distorted square planar and pentagonal bipyramidal, respectively. In the crystal, O—H...S hydrogen bonds between the coordinating water molecules and thiocyanate groups form a supramolecular chain with a zigzag-shaped calcium skeleton.