Copper(II) Dihalotetracyanoplatinate(IV) Coordination Polymers and Their Vapochromic Behavior

The coordination polymers [Cu(H2O)(2)(mu(2)-NC)(4)PtX2] (X = Cl, Br) form networks of square grid sheets that align in a staggered manner with one another via weak X center dot center dot center dot 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)(2)[PtX2(CN)(4)] were structurally characterized by PXRD and found to form layers of square grids that align through X center dot center dot center dot X interactions. The reaction of [Cu(H2O)(2)(mu(2)-NC)(4)PtX2] with concentrated aqueous NH3 generated [PtBr(CN)(4)(NH3)](-) and [PtCl(CN)(4)(OH)](2-) 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 [Ca(H2O)(2)(mu(2)-NC)(4)PtBr2] results in a greater vapochromic effect in comparison to that in chlorine -containing analogues.