Copper(I) Cyanide Networks:  Synthesis, Luminescence Behavior and Thermal Analysis. Part 1. Diimine Ligands

Metal−organic networks of CuCN with diimines (L) = pyrazine (Pyz), 2-aminopyrazine (PyzNH2), quinoxaline (Qox), phenazine (Phz), 4,4‘-bipyridyl (Bpy), pyrimidine (Pym), 2-aminopyrimidine (PymNH2), 2,4-diaminopyrimidine (Pym(NH2)2), 2,4,6-triaminopyrimidine (Pym(NH2)3), quinazoline (Qnz), pyridazine (Pdz), and phthalazine (Ptz) were studied. Open reflux reactions produced complexes (CuCN)2(L) for L = Qox, Phz, Bpy, PymNH2, Pym(NH2)2, Qnz, and Pdz and (CuCN)3(L) complexes for L = Pyz, PyzNH2, Qox, Bpy, Pym(NH2)3, and Pdz. Also produced were (CuCN)3(Pyz)2, (CuCN)(PyzNH2), (CuCN)7(Pym)2, (CuCN)5(Qnz)2 and (CuCN)5(Ptz)2. X-ray structures are presented for (CuCN)2(Pdz), (CuCN)2(PymNH2), and (CuCN)7(Pym)2. Hydrothermal reactions yielded additional X-ray structures of (CuCN)2(PyzNH2), (CuCN)3(Pym(NH2)2), (CuCN)4(Qnz), a second (CuCN)2(Pdz) phase, (CuCN)5(Pdz)2, (CuCN)2(Ptz), and (CuCN)7(Ptz)2. Structural trends, including cuprophilic interactions and cyano-bridged Cu2(CN)2 dimer formation, are discussed. Particularly short Cu···Cu interactions are noted for the novel 4- and 5-coordinate Cu2(CN)2 dimers. Thermal analyses show that most of the complexes decompose with loss of L around 160−180 °C. Luminescence behavior is relatively weak in the products.