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Anion‐directed assemblies of europium(III) coordination polymers based on 1 H ‐benzimidazole‐5,6‐dicarboxylate: structures and luminescence properties
Author(s) -
Zheng Wenxu,
Wu Kechen
Publication year - 2020
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/s2053229620000637
Subject(s) - europium , chromaticity , luminescence , chemistry , ligand (biochemistry) , excited state , crystallography , hydrogen bond , benzimidazole , ion , stereochemistry , molecule , materials science , physics , organic chemistry , biochemistry , receptor , optoelectronics , nuclear physics , optics
Two europium(III) coordination polymers (CPs), namely, poly[[diaquabis(μ 4 ‐1 H ‐benzimidazole‐5,6‐dicarboxylato‐κ 6 N 3 : O 5 , O 5′ : O 5 , O 6 : O 6′ )(μ 2 ‐oxalato‐κ 4 O 1 , O 2 : O 1′ , O 2′ )dieuropium(III)] dihydrate], {[Eu 2 (C 9 H 4 N 2 O 4 ) 2 (C 2 O 4 )(H 2 O) 2 ]·2H 2 O} n ( 1 ), and poly[(μ 3 ‐1 H ‐benzimidazol‐3‐ium‐5,6‐dicarboxylato‐κ 5 O 5 : O 5′ , O 6 : O 6 , O 6′ )(μ 3 ‐sulfato‐κ 3 O : O ′: O ′′)europium(III)], [Eu(C 9 H 5 N 2 O 4 )(SO 4 )] n ( 2 ), have been synthesized via the hydrothermal method and structurally characterized. CP 1 shows a three‐dimensional network, in which the oxalate ligand acts as a pillar, while CP 2 has a two‐dimensional network based on a europium(III)–sulfate skeleton, further extended into a three‐dimensional framework by hydrogen‐bonding interactions. The structural diversity in the two compounds can be attributed to the different acidification abilities and geometries of the anionic ligands. The luminescence properties of 1 display the characteristic europium red emission with CIE chromaticity coordinates (2/3, 0.34). Interestingly, CP 2 shows the characteristic red emission with CIE chromaticity coordinates (0.60, 0.34) when excited at 280 nm and a near‐white emission with CIE chromaticity coordinates (0.38, 0.29) when excited at 340 nm.