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A new Cd II coordination polymer with a self‐penetrating architecture induced by the molecular conformation of a rigid bithiophene ligand
Author(s) -
Ji Ning-Ning,
Shi Zhi-Qiang,
Hu Hai-Liang
Publication year - 2018
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618001006
Subject(s) - ligand (biochemistry) , crystallography , octahedron , chemistry , pentagonal bipyramidal molecular geometry , molecule , benzoic acid , crystal structure , coordination polymer , single crystal , deprotonation , stereochemistry , organic chemistry , ion , biochemistry , receptor
The design and synthesis of coordination polymers with a self‐penetrating architecture has attracted much interest not only due to their interesting structures but also due to their potential applications. 5,5′‐Bis(pyridin‐4‐yl)‐2,2′‐bithiophene (bpbp), as a conjugated bithiophene ligand, can exhibit trans and cis conformations and this can lead to the construction of a self‐penetrating architecture. In addition, the semi‐rigid ancillary ligand 4,4′‐oxybis(benzoic acid) (H 2 oba) can adopt different coordination modes, resulting in coordination polymers with high‐dimensional skeletons. A new Cd II coordination polymer based on mixed ligands, namely poly[diaquapentakis[μ‐5,5′‐bis(pyridin‐4‐yl)‐2,2′‐bithiophene‐κ 2 N : N ′]bis(nitrato‐κ 2 O , O ′)tetrakis(μ 3 ‐4,4′‐oxydibenzoato)‐κ 10 O : O , O ′: O ′′, O ′′′;κ 6 O : O ′: O ′′‐pentacadmium(II)], [Cd 5 (C 14 H 14 O 5 ) 4 (NO 3 ) 2 (C 18 H 12 N 2 S 2 ) 5 (H 2 O) 2 ] n , (I), has been synthesized under solvothermal conditions and characterized by single‐crystal X‐ray diffraction, IR spectroscopy and elemental analysis. Single‐crystal X‐ray diffraction indicates that there are three crystallographically independent Cd II cations, three bpbp ligands, two deprotonated oba 2− ligands, one nitrate ligand and one coordinated water molecule in the asymmetric unit. One Cd II centre is seven‐coordinated, exhibiting a distorted {CdN 2 O 5 } pentagonal bipyramidal geometry, while the other two Cd centres are both six‐coordinated, showing slightly distorted {CdN 2 O 4 } octahedral geometries. The most interesting feature is the co‐existence of trans and cis conformations in a single net, allowing structural interpenetration via self‐threading and yet the expected self‐penetrating structure was obtained. Topological analysis shows that the whole three‐dimensional framework can be classified as a 3‐nodal (4,6,6)‐c net with Schläfli symbol {6 13 .8 2 } 2 {6 6 }, which is a new topology. Furthermore, the luminescence properties of (I) were examined in the solid state at room temperature.