A series of Zn/Cd coordination polymers constructed from 1,4-naphthalenedicarboxylate and N-donor ligands: Syntheses, structures and luminescence sensing of Cr3+ in aqueous solutions

• π-conjugated semirigid tricarboxylate ligands with naphthalene rings(H3L) were rationally designed.
• Four Zn/Cd coordination polymers based on H3L have been successfully synthesized by solvothermal reaction.
• Compound 3 is a promising luminescent probe for selectively sensing Cr3+ with high sensitivity in aqueous solutions.

A novel series of Zn/Cd coordination polymers based on H3L, namely, [Zn2(HL)2(bipy)2(H2O)6]n (1), [Zn(HL)(phen)]n (2), [Cd3L2(bbi)3]n (3), [Zn3L2(bbi)3]n (4) [(H3L =4-[(1-carboxynaphthalen-2-yl)oxy]phthalic acid, bipy =4,4′-bipyridine, phen =1,10-phenanthroline, bbi =1,1′-(1,4-butanediyl)bis(imidazole] have been successfully synthesized by solvothermal reaction. Compound 1 possesses two diverse 1D chains constructed by different bipy coligands, which were further connected to form a 3D supramolecular architecture by hydrogen bonding interactions. Compound 2 possesses a complicated 1D chain based on secondary building unit (SBU) with binuclear Zn cluster. Compounds 3 and 4 exhibit similar 2D→3D framework, which can be rationalized as (3,4,4)-connected 3D net with a Schläfli symbol of (63.8.102)2(63)2(64.8.10). In particular, compound 3 exhibited a high sensitivity for Cr3+ in aqueous solutions, which suggest that compound 3 is a promising luminescent probe for selectively sensing Cr3+.

A series of novel Zn/Cd coordination polymers have been successfully synthesized by solvothermal reaction. The unique 3D Cd2+ polymer containing bbi as second ligand demonstrates high sensitivity for detection of toxic Cr3+ in aqueous solutions.Figure optionsDownload as PowerPoint slide