The design and synthesis of a supramolecular square was achieved by coordination-driven assembly of redox-active nickel(ii) salen linkers and (ethylenediamine)palladium(ii) nodes.

The coordination polymers [Cu(HO)(μ-NC)PtX] (X = Cl, Br) form networks of square grid sheets that align in a staggered manner with one another via weak X···X interactions. Upon stepwise dehydration, the layers fuse, forming a 3-D network of distorted cubes. The materials were tested for visible vapochromic, Raman, and IR response to dimethyl sulfoxide, N,N-dimethylformamide, and pyridine. Analyte-bound coordination polymers of the form Cu(analyte)[PtX(CN)] were structurally characterized by PXRD and found to form layers of square grids that align through X···X interactions. The reaction of [Cu(HO)(μ-NC)PtX] with concentrated aqueous NH generated [PtBr(CN)(NH)] and [PtCl(CN)(OH)] anions that were incorporated into 1-D chain structures. UV-visible reflectance data show that a combination of shifting d-d transitions and the visible Br-Pt LMCT absorption band in [Cu(HO)(μ-NC)PtBr] results in a greater vapochromic effect in comparison to that in chlorine-containing analogues.

Oxidative addition of halogens to tetracyanoplatinate results in the formation of a Pt(iv)-building block that, combined with Cu(ii), forms coordination polymers Cu(HO)[PtX(CN)] (X = Br, Cl). These materials exhibit directional anisotropic thermal expansion: nearly zero expansion within the cyanometallate sheets and positive thermal expansion in the third dimension.