New Thiocyanatocadmate and Halo-thiocyanatocadmates Modified by Imidazole or Triazole Derivatives: Synthesis, Structural Characterization, and Photoluminescence Property.

At pH 2, the simple room-temperature self-assemblies between Cd2+ salts, SCN− and organic bases created one new thiocyanatocadmate as [H2(L1)][Cd2(SCN)6] (L1 = 1,4-bis(2-methyl-1<italic>H</italic>-imidazol-1-ylmethyl)benzene) <bold>1</bold>, and two new halo-thiocyanatocadmates as [H2(L2)][CdI2(SCN)2]·H2O (L2 = 3,5-bis (4-pyridyl)-1,2,4-triazole) <bold>2</bold>, and [CdCl(SCN)(L3)] (L3 = 3-pyrazinyl-1,2,4-triazole) <bold>3</bold>. X-ray single-crystal diffraction analysis reveals that (a) in <bold>1</bold>, with H2(L1)2+ as the countercation, the SCN− groups tri-bridge the Cd2+ centers into a 1-D chained thiocyanatocadmate; (b) <bold>2</bold> is only a mononuclear iodo-thiocyanatocadmate, and H2(L2)2+ acts as the countercation. But via the π···π and Npyridyl-H···NSCN interactions, H2(L2)2+ and CdI2(SCN)22− aggregate together to form a 1-D supramolecular tube. Amongst the tubes, a chained water cluster with a zig-zag shape is observed; (c) <bold>3</bold> is an organically extended chloro-thiocyanatocadmate. Note that the report on this type of material is rather rare. It possesses a 3-D network structure with a <bold>dia</bold> topology, in which a castellated CdCl+ single chain is observed. L3 and Cl− act as a mixed bridge, whereas SCN− just serves as a terminal ligand in <bold>3</bold>. The photoluminescence analysis indicates that the title compounds <bold>1</bold>-<bold>3</bold> all emit light (green light for <bold>1</bold>, blue light for <bold>2</bold> and <bold>3</bold>), which should be attributed to the ligand-centered electronic excitations. [ABSTRACT FROM AUTHOR]