A binuclear Cu II /Ca II thio-cyanate complex with a Schiff base ligand derived from o -vanillin and ammonia.

The new heterometallic complex, aqua-1κ O -bis-(μ ₂ -2-imino-methyl-6-meth-oxy-phenolato-1κ ² O ¹ , O ⁶ :2κ ² O ¹ , N )bis-(thio-cyanato-1κ N )calcium(II)copper(II), [CaCu(C ₈ H ₈ NO ₂ ) ₂ (NCS) ₂ (H ₂ O)], has been synthesized using a one-pot reaction of copper powder, calcium oxide, o -vanillin and ammonium thio-cyanate in methanol under ambient conditions. The Schiff base ligand (C ₈ H ₉ NO ₂ ) is generated in situ from the condensation of o -vanillin and ammonia, which is released from the initial NH ₄ SCN. The title compound consists of a discrete binuclear mol-ecule with a {Cu(μ-O) ₂ Ca} core, in which the Cu⋯Ca distance is 3.4275 (6) Å. The coordination geometries of the four-coordinate copper atom in the [CuN ₂ O ₂ ] chromophore and the seven-coordinate calcium atom in the [CaO ₅ N ₂ ] chromophore can be described as distorted square planar and penta-gonal bipyramidal, respectively. In the crystal, O-H⋯S hydrogen bonds between the coordinating water mol-ecules and thio-cyanate groups form a supra-molecular chain with a zigzag-shaped calcium skeleton.
(© Plyuta et al. 2020.)