New organically templated thiocyanatocadmates and chlorocuprate(ii): synthesis and structural characterization?

Dalton Transactions Pub Date: 2015-05-13 DOI: 10.1039/C5DT01355K

Abstract

With various organic base molecules as the countercations, five new thiocyanatocadmates [H2(tmen)][Cd(SCN)4] (tmen = N,N,N′,N′-tetramethylethylenediamine) 1, [H2(tmba)][Cd2(SCN)6] (tmba = N,N,N′,N′-tetramethyl-1,4-butanediamine) 2, [H2(teen)][Cd2(SCN)6] (teen = N,N,N′,N′-tetra-ethylethylenediamine) 3, [H(amp)][Cd(SCN)2(CH3COO)] (amp = 2-amino-6-methylpyridine) 4 and [H(abp)]4[Cd(SCN)4]SO4·H2O (abp = 2-amino-6-bromopyridine) 5, and one new chlorocuprate(II) [H2(cha)][CuCl4] (cha = 1,4-cyclohexanediamine) 6 were obtained from a series of simple room-temperature self-assemblies at pH = 2 or 6.5. X-ray single-crystal diffraction analysis reveals that (i) templated by [(CH3)2NH(CH2)2NH(CH3)2]2+ (H2(tmen)2+), the anion [Cd(SCN)4]2? in 1 shows a 1-D linear single-chain structure, whereas templated by [(CH3)2NH(CH2)4NH(CH3)2]2+ (H2(tmba)2+), the anion [Cd2(SCN)6]2? in 2 shows a 1-D linear double-chain structure. The number of C atoms between the two N atoms in the templating agent controls the width of the anionic chain through the Namino–H?NSCN interactions; (ii) templated by [(C2H5)2NH(CH2)2NH(C2H5)2]2+ (H2(teen)2+), the anion [Cd2(SCN)6]2? in 3 exhibits a 3-D open-framework structure, which is based on zigzag anionic chains. A direct change of the substituent group from –CH3 to –C2H5 alters indirectly the shape of the anionic chain from a linear shape to a zigzag shape; (iii) 4 shows a 3-D supramolecular network structure, which is built up from the 1-D zigzag anionic structures by the H(amp)+ molecules via N–H?O interactions. The formation of the zigzag chain derives from the chelation of the CH3COO? groups to the Cd2+ centers; (iv) 5 is indeed a double salt of [H(abp)]2[Cd(SCN)4] and [H(abp)]2SO4. SO42? and H(abp)+ form a supramolecular aggregation. Surrounded by the aggregations, the anion [Cd(SCN)4]2? only shows a dinuclear structure; and (v) templated by H2(cha)2+, the anion [CuCl4]2? in 6 displays a 2-D perovskite layer structure. The photoluminescence analysis indicates that upon excitation (λex = 335 nm for 4, λex = 395 nm for 5), 4 and 5 emit light (λem = 365 nm for 4, λem = 470 nm for 5), which can be seen clearly under the UV lamp.

Graphical abstract: New organically templated thiocyanatocadmates and chlorocuprate(ii): synthesis and structural characterization
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