Highly emissive polymorphs of anhydrous cadmium tetracyanoplatinate and their solvated coordination networks.

Two anhydrous polymorphs of cadmium cyanoplatinate Cd[Pt(CN)4] coordination polymers have been synthesized and thermally, spectroscopically, and structurally characterized. α-Cd[Pt(CN)4] and ß-Cd[Pt(CN)4] are densely packed, highly emissive 3-D solids, with quantum yields of 0.85 (λem = 520 nm) and 0.79 (λem = 448 nm) respectively. Their mutual hydrate, Cd(H2O)[Pt(CN)4]·2H2O, forms a complex 3-D coordination polymer with Cd-O-Cd bridges and Pt-Pt interactions. Additionally, exposure of solid α-Cd[Pt(CN)4] and ß-Cd[Pt(CN)4] to several solvent vapours results in the formation of 2-D cyanometallate sheets of the adduct compounds CdL2[Pt(CN)4] (L = DMSO, DMF, and pyridine). Cd(pyridine)2[Pt(CN)4] shows a significantly lower quantum yield (0.32) in comparison to the parent Cd[Pt(CN)4] coordination polymers. Upon heating CdL2[Pt(CN)4] preferentially forms the kinetic product α-Cd[Pt(CN)4].

Coordination-driven assembly of a supramolecular square and oxidation to a tetra-ligand radical species.

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 tetrameric geometry of the supramolecular structure was confirmed via MS, NMR, and electrochemical experiments. While oxidation of the monomeric metalloligand Schiff-base affords a Ni(iii) species, oxidation of the coordination-driven assembly results in ligand radical formation.

Designing anisotropic cyanometallate coordination polymers with unidirectional thermal expansion (TE): 2D zero and 1D colossal positive TE.

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(H2O)2[PtX2(CN)4] (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.

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

The coordination polymers [Cu(H2O)2(µ2-NC)4PtX2] (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)2[PtX2(CN)4] were structurally characterized by PXRD and found to form layers of square grids that align through X···X interactions. The reaction of [Cu(H2O)2(µ2-NC)4PtX2] 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 [Cu(H2O)2(µ2-NC)4PtBr2] results in a greater vapochromic effect in comparison to that in chlorine-containing analogues.