Bisimidazole-based phosphorescent thiocyanatocadmates. Issue 17 (10th April 2019)

• Record Type: Journal Article
• Authors: Wang, Rong-Yan; Yu, Jie-Hui; Xu, Ji-Qing
• Is Part Of: Dalton transactions. Volume 48:Issue 17(2019)
• Page Start: 5674
• Page End: 5682
• Publication Date: 2019-04-10
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c9dt00852g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Structures of three new bisimidazole-based thiocyanatocadmates (1–3 ) are reported.1 and2 are found to possess phosphorescence properties. Abstract : Simple room-temperature self-assemblies between Cd 2+ salts, SCN − and bisimidazole molecules at pH = 2 created three new organically templated thiocyanatocadmates [H2 (L1)][Cd(SCN)4 ]·H2 O (L1 = 1, 4-bis(1 H -imidazol-1-yl)benzene)1, [H2 (L2)][Cd(SCN)4 ] (L2 = 1, 3-bis(2-methylimidazol-1-yl)propane)2, and [H2 (L3)][Cd2 (SCN)6 ] (L3 = 1, 4-bis(2-methyl-1 H -imidazol-1-yl)butane)3 . X-ray single-crystal diffraction analysis reveals that (i) in1–3, the SCN − groups doubly bridge the Cd 2+ centers to form different thiocyanatocadmates: a linear chain in1 ; a zigzag chain in2 ; and a 2-D layer network (6 3 net) in3 ; and (ii) in1, via Nbase –H⋯NSCN interactions, the L1 molecules extend the thiocyanatocadmate chains into a 2-D supramolecular layer, whereas in2, the zigzag thiocyanatocadmate chains self-assemble into a 3-D supramolecular network via weak S⋯S interactions. Photoluminescence analysis indicates that the three title compounds all emit light: blue light for1 and2 and green light for3 . At low temperatures, the emission positions of the three compounds hardly change, but the emission intensities are largely enhanced. Interestingly, after turning off the UV lamp, 1 and2 still briefly emit light ( ca. 2 s), which means that1 and2 possess phosphorescence properties. Phosphorescence lifetimes at 77 K are 1619 ms for1 and 247 ms for2 .