Metal and Ligand Effects on the Construction of Divalent Coordination Polymers Based on bis-Pyridyl-bis-amide and Polycarboxylate Ligands

Ten coordination polymers constructed from divalent metal salts, polycarboxylic acids, and bis-pyridyl-bis-amide ligands with different donor atom positions and flexibility are reported. They were structurally characterized by single-crystal X-ray diffraction. The ten coordination polymers are as follows: (1) {[Ni(L¹)(3,5-PDA)(H₂O)₃]·2H₂O}_n (L¹ = N,N'-di(3-pyridyl)suberoamide, 3,5-H₂PDA = 3,5-pyridinedicarboxylic acid); (2) {[Ni₂(L¹)₂(1,3,5-HBTC)₂(H₂O)₄]·H₂O}_n (1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid); (3) {[Ni(L²)(5-tert-IPA)(H₂O)₂]·2H₂O}_n (L² = N,N'-di(3-pyridyl)adipoamide, 5-tert-H₂IPA = 5-tert-butylisophthalic acid); (4) [Ni(L³)_1.5(5-tert-IPA)]_n (L³ = N,N'-di(4-pyridyl)adipoamide); (5) [Co(L¹)(1,3,5-HBTC)(H₂O)]_n; (6) {[Co₃(L¹)₃(1,3,5-BTC)₂(H₂O)₂]·6H₂O}_n; (7) [Cu(L⁴)(AIPA)]_n (L⁴ = N,N'-bis(3-pyridinyl)terephthalamide, H₂AIPA = 5-acetamido isophthalic acid); (8) {[Cu(L²)_0.5(AIPA)]·MeOH}_n; (9) {[Zn(L⁴)(AIPA)]·2H₂O}_n; and (10) {[Zn(L²)(AIPA)]·2H₂O}_n. Complex 1 forms a 1D chain and 2 is a two-fold interpenetrated 2D layer with the sql topology, while 3 is a 2D layer with the hcp topology and 4 shows a self-catenated 3D framework with the rare (4²·6⁷·8)-hxg-d-5-C2/c topology. Different Co/1,3,5-H₃BTC ratios were used to prepare 5 and 6, affording a 2D layer with the sql topology and a 2D layer with the (4·8⁵)₂(4)₂(8³)₂(8) topology that can be further simplified to an hcp topology. While complex 7 is a 2D layer with the (4²·6⁷·8)(4²·6)-3,5L2 topology and 8 is a 2-fold interpenetrated 3D framework with the pcu topology, complexes 9 and 10 are self-catenated 3D frameworks with the (4²⁴·6⁴)-8T2 and the (4⁴·6¹⁰·8)-mab topologies, respectively. The effects of the identity of the metal center, the ligand isomerism, and the flexibility of the spacer ligands on the structural diversity of these divalent coordination polymers are discussed. The luminescent properties of 9 and 10 and their photocatalytic effects on the degradation of dyes are also investigated.