Metal Ion and Metal‐to‐Ligand Ratio Regulated Construction of Cu(II) and Co(II) Coordination Polymers as Efficient Catalysts for Ring‐Opening Polymerization of L‐Lactide

Three new coordination polymers (CPs), {[Cu(NDC)(Fbtx)(H 2 O)] ⋅ 1.5H 2 O} n ( 1 ), {[Co(NDC)(Fbtx)(H 2 O) 2 ] ⋅ 0.5Fbtx} n ( 2 ), and [Co 2 (NDC) 2 (Fbtx)] n ( 3 ), were synthesized by employing acid‐base mixed ligands of rigid 1,4‐naphthalenedicarboxylic acid (H 2 NDC) and flexible bis(1,2,4‐triazole‐1‐ylmethyl)‐2,3,5,6‐tetrafluorobenzene (Fbtx) under both hydrothermal and microwave‐assisted reaction conditions. Single‐crystal structure analysis establishted that both compounds 1 and 2 exhibit two‐dimensional (2D) layered structures, while compound 3 features a three‐dimensional (3D) complicated framework. The geometries of metal ions vary from square pyramidal (in 1 and 3 ) to distorted octahedral (in 2 ). Topological strudy showed that compounds 1 and 2 have exposed common 4‐connected 4 4 ‐ sql net, while compound 3 has made a novel 4,5‐connected net with point symbol of (4 3 ⋅ 6 2 ⋅ 7)(4 3 ⋅ 6 4 ⋅ 7 2 ⋅ 8). The catalytic performance of the three complexes for the solvent‐free ring‐opening polymerization of L ‐lactide has been investigated. The results indicated that compound 3 with coordinatively unsaturated cobalt(II) sites showed good activity and the molecular weight of the polymer obtained was high. Moreover, the complex 3 catalyst could be recycled up to five times with the retention of both catalytic activity and crystal structure.