Two new crystal structures of two-dimensional lead(II) coordination polymers with flexible alicyclic carboxylate ligands

ABSTRACT

Two new coordination polymers with flexible alicyclic carboxylate ligands, generally formulated as [Pb(chda)]_n (1, H₂chda = 1,1′-cyclohexanediacetic acid) and [Pb(tmg)]_n (2, H₂tmg = 3,3′-tetramethyleneglutate), have been successfully synthesized through the liquid–liquid diffusion method. They represent the first main group of metal–organic hybrid compounds assembled from H₂chda and H₂tmg. Compound 1 crystallized in the non-centrosymmetric space group Pca2₁, whereas 2 adopts the centrosymmetric P2(1)/c space group. Their structure features one-dimensional infinite chains extended into two-dimensional layer framework. Interestingly, the lead atoms exhibit hemi- as well as holo-directed coordination geometry with coordination number seven in both compounds.

KEYWORDS:

• Lead(II) coordination polymers
• flexible ligands
• two-dimensional structure
• hemi- and holo-directed coordination geometry

Funding

This work is supported by the National Natural Science Foundation of China (No. 21441008, 21301002, 51303002), Natural Science Foundation of Anhui Province (No. 1508085QB40), Natural Science Foundation for Colleges and Universities in Anhui Province (No. KJ2013A045), and State Key Laboratory of Structural Chemistry (No. 20140006).