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Three 3D Ln(III)–Zn(II) 3d-4f heterometallic coordination polymers (HCPs) constructed from the coligands 3-amino-1H-1,2,4-triazole and oxalate, {[Ln2Zn19(atz)18(ox)9(Cl)8]·17H2O}n(Ln = Eu 1, Gd 2, Tb 3, Hatz = 3-amino-1H-1,2,4-triazole, ox = oxalic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis and X-ray diffraction. X-ray diffraction analysis reveals that these complexes are isostructural and feature 3D pillar-layered coordination frameworks constructed by the linkages of 2D layers and 1D zigzag chains, possessing a 5-nodal net topology with Schlafli symbol of {32;52;62}3{33;44;57;65;72}6{33;45;55;6;7}6{36;415;56;6}2{53}4. In addition, the magnetic property of 2 and the luminescence properties of 1 and 3 were also investigated.

A series of Ln(III)-Ag(I) 4d–4f heterometallic coordination polymers [LnAg(oba)2(H2O)]n (Ln = Dy 1, Ho 2, Er 3) have been synthesized under hydrothermal reactions of 4,4′-oxybis(benzoicacid) (H2oba) with Ln(NO3)3 · 6H2O and AgNO3 at 180 °C. All complexes are isostructural with 3D networks expanded from 1D zigzag chains and 2D layers. In addition, the luminescent property of compound 1 was investigated in the solid-state at room temperature.

Two different types of novel lanthanide coordination polymers constructed from 5-nitroisophthalic acid, and picolinic acid as auxiliary ligand, namely, {[Ln 2 (nip) 2 (pic) 2 (H 2 O)]} n (type I, Ln = Pr 1 , Nd 2 , Sm 3 , Eu 4 , and H 2 nip = 5-nitroisophthalic acid, Hpic = picolinic acid), and {[Ln 4 (nip) 5 (pic) 2 (H 2 O) 2 ]·2H 2 O} n (type II, Ln = Tb 5 , Dy 6 , Ho 7 , Er 8 ), have been hydrothermally synthesized and characterized by IR, elemental analysis, thermogravimetric analysis (TGA), single-crystal X-ray diffraction analyses and powder X-ray diffraction (PXRD). Complexes 1 – 4 (type I) are isostructural and the infinite 1D Sm-carboxylate chains are bridged by pia ligands to form 2D sheets, such sheets are further united together to generate a 3D supramolecular structure. Complexes 5 – 8 (type II) are isostructural and the infinite 1D Tb–carboxylate chains are bridged by pia ligands to form 2D sheets, such sheets are further united together to generate a 3D supramolecular structure. Furthermore, the luminescence properties of compounds 4 and 5 have also been studied.

Three novel compounds, {[Ln(Hbidc)(ox)0.5(H2O)]·H2O}n [Ln = Pr (1), Sm (2), Eu (3)] were synthesized by hydrothermal reaction of 1H-benzimidazole-5, 6-dicarboxylic acid (H3bidc) and oxalate (ox) with Ln(NO3)3·6H2O in the presence of NaOH solution at 180 °C, and were structurally characterized by elemental analysis, FT-IR, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction analysis reveal that all the compounds are isomorphous, displaying 3D networks with 9-connected topology based on the linkages of 2D layers and 1D zigzag chains. In addition, complex 3 exhibits strong luminescent property in the solid state at room temperature.

Two 2D zinc(II) layered coordination polymer compounds [Zn2(atz)2(na)2]n (1), and [Zn(atz)(ina)]n (2) (Hatz = 3-amino-1H-1, 2, 4-triazole, na = nicotinic acid, ina = isonicotinic acid) were synthesized and structurally characterized by elemental analysis, FT-IR, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. The interconnection of a coplanar six-membered hexagonal ring and a 16-membered non-planar chair-like ring results in a 2D sheet with (4, 82) topological network. Hydrogen bonds connect the neighboring planes into 3D supramolecular architectures. Furthermore, both complexes exhibit strong luminescent properties in the solid state at room temperature.

To explore the influence of different carboxylate ligands on the structures of metal–organic frameworks (MOFs), five novel Zn(II) coordination polymer compounds, namely, {[Zn(atz)(bia)]}n (1), {[Zn3(atz)3(tpa)3/2]}n (2), {[Zn2(atz)2(pda)]}n (3), {[Zn4(atz)2(btc)]·4H2O}n (4) and {[Zn2(atz)2(btec)]·H2O}n (5) have been successfully obtained by introducing various secondary auxiliary ligands in Zn(II)–L systems, characterized by elemental analysis, FT-IR, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction (Hatz = 3-amino-1,2,4-triazolate, Hbia = benzoic acid, H2tpa = 1,4-terephthalic acid, H2pda = 1,4-benzenediacetic acid, H3btc = 1,3,5-benzenetricarboxylate, H4btec = 1,2,4,5-benzenetetracarboxylic). Compound 1 features a 2D layer with (4.82) topology, which is further stabilized by hydrogen bonds between the uncoordinated amino groups and uncoordinated oxygen atoms from bia ligands. Compound 2 exhibits a 3D 3,4-connected framework with {4.82.103}{4.82} topology, constructed from Zn(II) ions and μ3-atz ligand. Compound 3 displays a 3D 3,4-connected network with {4.6.8}{4.62.83} topology. Compound 4 possesses a 3D 9-nodal network with a point symbol of {4.8.9}2{4.82}{4.83.9.10}{5.8.9}4{5.82}. Compound 5 shows a 3D 3,4,4-connected framework with {4.82}4{42.83.10}2{84.102} topology. The diverse structures of these five complexes demonstrate that the skeleton of carboxylate ligands have a significant impact on the construction of MOFs. Moreover, the luminescence properties of complexes 1–5 were investigated in the solid state.