Isomorphous and isostructural lanthanide coordination polymers based on 2-(4-chlorobenzoyl)benzoic acid: Synthesis, structure, characterization, and luminescent properties

• Isomorphous and isostructural coordination polymers of [Ln(cbba)3H2O]∞ have been synthesized under hydrothermal conditions.
• I–III are assembled into 3D networks based on Ln2O2(OCO)2 through C–H⋯π and C–H⋯Cl interactions between the 1D chains.
• The double-stranded helix entangled by one left- and one right-handed helical chain in coaxial manner.
• I–III display similar characteristic emission bands in the near-infrared regions.

Self-assembly of a flexible ligand Hcbba (2-(4-chlorobenzoyl)benzoic acid) and lanthanide salts yield a series of three-dimensional (3D) coordination polymers under hydrothermal conditions, namely, [Ln(cbba)3H2O]∞ (Ln = La(I), Pr(II), and Nd(III)). Their structures were determined by single-crystal X-ray diffraction analyses and characterized by elemental analyses and infrared spectroscopy, which verified that they are isomorphous and isostructural. Findings indicate that the subunit of cavate cages (Ln2O2(OCO)2) are observed in I–III, which are connected into a one-dimensional (1D) chain through cbba− anions in μ2-η1:η1 fashion and further assembled into 3D architecture via C–H⋯π and C–H⋯Cl interactions between the neighboring parallel 1D chains. I–III feature that the double-stranded helix entangled by one left- and one right-handed helical chain coaxially along c axis in each 1D infinite chain. Luminescent properties reveal that II and III may be potential ion-selective luminescent probes for Hg2+ and Ag+, respectively.

A series of isomorphous and isostructural coordination polymers [Ln(cbba)3H2O]∞ (Ln = La, Pr, and Nd) have been synthesized under hydrothermal conditions. I–III are assembled into 3D networks based on the subunit of cavate 10-membered cages (Ln2O2(OCO)2) through C–H⋯π and C–H⋯Cl interactions between the parallel 1D chains. The double-stranded helix entangled by one left-handed and one right-handed helical chain in coaxial manner is observed in 1D infinite chain.Figure optionsDownload as PowerPoint slide