Crystal structure of a heterometallic coordination polymer: poly[diaquabis(μ7-benzene-1,3,5-tricarboxylato)dicalcium(II)copper(II)]

Abstract

In the title complex, [Ca2Cu(C9H3O6)2(H2O)2]n, the CaII and CuII cations are bridged by the benzene-1,3,5-tricarboxylate anions (BTC3−) to form the coordination polymer, in which each BTC3− anion bridges two CuII and five CaII cations with a μ7 coordination mode. The CuII cation, located at an inversion centre, is in a nearly square-planar geometry defined by four O atoms from four bridging BTC3− anions, while the CaII cation is in a distorted octahedral geometry defined by five O atoms from bridging BTC3− anions and one water molecule. O—H...O hydrogen bonds between coordinating water molecules and carboxyl groups further stabilize the structure; π–π stacking is also observed between parallel benzene rings, the centroid-to-centroid distance being 3.357 (2) Å.

Keywords

• crystal structure
• heterometallic complex
• copper carboxylates
• calcium carboxylates
• π–π stacking