Two Cu-based cluster coordination polymers constructed from two thioether tripod tricarboxylic acid ligands: Synthesis, crystal structure and fluorescence sensing.

Two new thioether tricarboxylic acid ligands have been designed and used to fabricate Cu-based CPs. Different substituent groups in ligands lead to not only the different valences of copper ions but also different clusters for CPs 1 and 2. CP 1 shows fluorescent sensing toward Fe3+ and Cr 2 O 7 2− ions with good selectivity and low detecting limit. • Two thioether tricarboxylic acid ligands with different substituent groups were designed. • Different substituent groups in ligands lead to monovalent Cu+ and divalent Cu2+ CPs. • Cu(I)- and Cu(II)-CP contains novel hexanuclear [Cu 6 (CO 2) 6 and dinuclear [Cu 2 (CO 2) 4 clusters, respectively. • Cu(I)-CP exhibits fluorescence sensing for Cr 2 O 4 2− and Fe3+ ions. Two new symmetrical tripod thioether tricarboxylic acid ligands, 1,3,5-tris(4-carboxyphenylsulfanylmethyl) benzene and 1,3,5-tris(4-carboxyphenylsulfanylmethyl)-2,4,6-trimethylbenzene (H 3 L and CH 3 -H 3 L) have been designed and synthesized. The reaction of two ligands with Cu2+ ions afforded two Cu-based cluster coordination polymers (CPs), [Cu 3 L] n (1) and {[Cu(CH 3 -HL)DMF]·DMF} n (2). It was interesting to note that the substituent groups on central phenyl rings in ligands caused the bend tripodal and planar geometries as well as different coordinated modes for H 3 L and CH 3 -H 3 L, respectively, leading to different structures of CPs 1 and 2. 1 with monovalent Cu+ ions shows a 3D layer-stacking framework with hexanuclear [Cu 6 (CO 2) 6 clusters, while 2 with divalent Cu2+ ions forms a 1D chain with dinuclear [Cu 2 (CO 2) 4 paddlewheel clusters. 1 shows strong orange fluorescence and exhibits fluorescence sensing for Cr 2 O 4 2− and Fe3+ ions with good selectivity and sensitivity. [ABSTRACT FROM AUTHOR]