Two new imidazole-based dicarboxylate ligands, which are 2-(pyridin-4-ylmethyl)-1H-imidazole-4,5-dicarboxylic acid (H3pPyMIDC) and 2-(pyridin-3-ylmethyl)-1H-imidazole-4,5-dicarboxylic acid (H3mPyMIDC), have been designed and successfully synthesized. Both these multidentate ligands are then used to react with different kinds of alkaline earth metal ions under solvothermal conditions, leading to the construction of a series of new coordination polymers (CPs), namely, [Ba(μ5-HpPyMIDC)(H2O)]n (1), [Sr(μ5-HpPyMIDC)(H2O)]n (2), [Ca2(μ4-HpPyMIDC)2(H2O)2]n (3), {[Ca2(μ3-HpPyMIDC)(μ4-HpPyMIDC)(H2O)2]·H2O}n (4), [Ba(μ5-HmPyMIDC)(H2O)]n (5), {[Mg10(μ3-mPyMIDC)3(μ4-mPyMIDC)3(H2O)21]·SO4·12H2O}n (6) and {[Sr(μ2-H2mPyMIDC)2(DMF)2]n·H2O}n (7). Compounds 1 and 2 are isostructural, exhibiting two-dimensional (2D) network structures with a hexagonal honeycomb (6,3) topology if the corresponding metal ions are seen as 3-connected nodes. Compound 3 displays another type of 2D network, which is built by the connection of μ4-HpPyMIDC ligands and Ca(II) centres. Compound 4 is a binodal (3,4)-connected 3D framework with the Schläfli symbol of (6·82)(65·8). The 2D structure of compound 5 is similar to those of compounds 1 and 2, although different kinds of ligands are employed. Compound 6 exhibits an interesting 3D framework with a pcu topology by considering each unusual heptanuclear magnesium cluster as a 6-connected node. In compound 7, connection of μ2-H2mPyMIDC ligands with Sr(II) ions results in the formation of an uncommon 3D chiral framework containing two different types of 1D helical chains. The present results reveal that both these new imidazole-based dicarboxylate ligands containing flexible pyridinylmethyl groups show versatile coordination abilities and are good candidates for fabricating new CPs. Moreover, the thermogravimetric and solid-state luminescence properties of all the compounds have also been studied.

•Co(II) coordination polymers based on a imidazole-tetrazole-bifunctional ligand were obtained.•The structural diversity is induced by inorganic anions and temperatures.•Compound 2 is a 3D framework based on well-defined linear trinuclear SBU.•The magnetic properties of compounds 2–3 were explored.Reactions of Co(II) with 5-(3-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (HIPT) resulted in three Co(II) coordination polymers (CPs), namely, {[Co(IPT)2(H2O)2]·2H2O}n (1), [Co(IPT)2]n (2), and {[Co3(IPT)2(CH3COO)2(OH)2(H2O)2]·2H2O}n (3). Compound 1 that obtained from CoCl2·6H2O at 120 °C is a 2D network based on Co(II) ions and μ2-IPT− ligands. Compound 2 that obtained from CoCl2·6H2O at 170 °C exhibits a 3D framework based on linear trinuclear Co(II) SBUs and features a pcu network topology. Compound 3, which obtained by using Co(Ac)2 as salt, displays a 2D network based on 1D SBUs. The structures of compounds 1–3 are dependent on the temperatures and inorganic anions. The magnetic properties of compounds 2–3 were also explored.Three new Co(II) coordination polymers based on a tetrazolyl-imidazolyl-bifunctional ligand were obtained. Their structural diversity is dependent on the temperatures and inorganic anions. The magnetic properties of selected compounds were explored.Download high-res image (368KB)Download full-size image

•Compounds based on new 1,4,5,8-naphthalenediimides-based ligand were obtained.•The structural diversity is induced by inorganic anions.•Mixture containing compounds 1–2 can transfer to compound 3 via solvent-mediated process.•Compound 3 is a interpenetrating dia framework based on double-bridged linkers.The coordination of a new 1,4,5,8-naphthalenediimides-based ligand N,N-di-(5-tetrazol)-1,4,5,8-naphthalenetetracarboxydiimide (H2dtNDI) with CdSO4 afforded mixtures containing {[Cd(dtNDI)(DMF)2.5]·DMAc}n (1) and {[Cd2(dtNDI)2(DMAc)2]·DMAc}n (2) as components. Whereas the coordination of H2dtNDI with CdX2 (x = ClO4−, NO3− and I−) afforded pure coordination polymer, namely, {[Cd(dtNDI)(H2O)2.5]·DMAc}n (3). All the compounds contain binuclear M2L2 ring as secondary building block (SBU). Compound 1 is a 1D chain composed of the binuclear SBUs and dimeric Cd(II) MBBs. Compound 2 exhibit a 2D network with (4·82) topology based on a binuclear SBUs. Compound 3 possess a five-fold interpenetrating 3D dia framework with tetrameric Cd(II) MBBs as nodes and binuclear SBUs as linkers. Although the inorganic anions are not appeared in the final frameworks of compounds 1–3, they play an important role in the structural formation during assembly process. In addition, the mixtures composed of compounds 1–2 can transfer to pure compounds 3 via solvent-mediated process.Three Cd(II) coordination polymers based on a new naphthalene diimide ligand were obtained. Their inorganic anion-induced structural diversity and structural transformation were explored.Download high-res image (252KB)Download full-size image

•New extended pyridyl-tetrazolyl-bifunctional ligands were designed.•Compounds 1 and 2 display (3,6)-connected ant topology.•Compound 3 exhibits (3,5)-connected tcj topology.•The topologies of the framework are largely dependent on the angle between two functional groups.Reactions of Cd(II) with three new pyridyl-tetrazole-bifunctional ligands, 3-(4-(1H-tetrazol-5-yl)phenyl)pyridine (HL1), 4-(3-(1H-tetrazol-5-yl)phenyl)pyridine (HL2), and 3-(3-(1H-tetrazol-5-yl)phenyl)pyridine (HL3) resulted in three Cd(II) coordination polymers (CPs), namely, [CdL12]n (1), [CdL22]n (2), and [CdL32(H2O)]n (3). Although the geometry of L1 and L2 is quite different, the coordination modes of Cd(II) ion and ligand, as well as the SBUs in compounds 1 and 2 are quite similar, thus give rise to 3D frameworks with same (3,6)-connected ant topology. Compound 3 is a 3D framework composed of 1D helical chains and features as (3,5)-connected tcj topology. The results showed that the topologies are largely dependent on the coordination angle between two coordination groups. The thermal stabilities and luminescent properties of compounds 1–3 have also been studied.Three Cd(II) coordination polymers based on new extended pyridyl-tetrazolyl-bifunctional ligands were obtained. They exhibit 3D frameworks with ant (compounds 1–2) and tcj (compound 3) topologies. The topologies are dependent on the angle between two functional groups.Download high-res image (286KB)Download full-size image

•Three new CPs based on a bifunctional ligand were constructed.•Compound 1 is a 3D framework composed of 2D coordination layer and helical water chain.•Compound 2 has new pillar-layer 3D structure based on tetranuclear Cd(II) SBUs.Three new coordination polymers, namely, {[Cu2(IPT)(SO4)(OH)(H2O)]·H2O}n (HIPT = 5-(4-(1H-imidazol-1-yl)phenyl)- 1H-tetrazolate, 1), {[Cd2(IPT)(NPA)(OH)]·H2O}n (H2NPA = 5-nitroisophthalic acid, 2), and {[Zn2(IPT)(IDC)(H2O)]·3H2O}n (H3IDC = 1H-imidazole-4,5-dicarboxylic acid, 3), were assembled from a bifunctional organic ligand containing both tetrazole and imidazole groups with/without the aid of carboxylate coligands. Compound 1 possesses 2D structure built by 1D [Cu2(IPT)(SO4)(OH)]n secondary building blocks and IPT− linkers. The 2D networks are linked into 3D supramolecular framework via water chains in helical conformation. Compound 2 displays 3D pillar-layer framework with 2D layers based on tetranuclear Cd(II) SBUs and NPA2 − pillars. Compound 3 exhibits a 3D framework constructed from the interconnection of 1D [Zn-IDC]n chains and binuclear Zn2(IPT)2 rings. The thermal stabilities of porous compound 3 and luminescent properties of compounds 2 and 3 have also been studied in detail. They exhibit intense solid-state fluorescent emissions at room temperature.Three new CPs with interesting structures based on a bifunctional ligand containing both imidazole and tetrazole groups were constructed. Their diverse structures and luminescent properties were studied.

•A rare coordination mode of terpyridine-based ligand was observed.•Compound 2 is a organozinc compound obtained at acid condition.•Compound 1 undergoes crystal-to-crystal transformation when heated.•The luminescence intensity of compound 1 can be enhanced by the addition of DCP.Reactions of ZnCl2 with 4′-(2,4-disulfophenyl)-2,2′:6′2″-terpyridine (H2DSPT) result to two new compounds with formula, {[Zn(DSPT)(H2O)2]·2H2O}n (1) and {[Zn(DSPT)(H2O)2]·H2O}n (2), respectively. Compound 1 is a binuclear complex, whereas compound 2 is a mononuclear organozinc compound. The coordination compounds can be controllable synthesized by adjust the pH value. The thermal behavior of 1 was explored by TG and VT-PXRD, which indicated that it undergo crystal-to-crystal transformation manner. Both compounds 1 and 2 show weak luminescence in both solid state and water emulsions compared with H2DSPT. The luminescence intensity of compound 1 can strongly enhanced by the addition of diethylchlorophosphonate (DCP), but significant less influenced by dimethylmethylphosphonate (DMMP), diethylcyanophosphonate (DCNP) and other selected organophosphate, which make compound 1 has potential application on nerve-agent detection.Two new compounds based on a terpyridine-based ligand containing sulfo groups were obtained. The crystal-to-crystal transformation and the ability for detecting nerve agent mimics for selected compounds were explored.

We report the design and synthesis of an imine-based two-dimensional covalent organic framework (2D COF) with a novel brick-wall topology by judiciously choosing a tritopic T-shaped building block and a ditopic linear linker. Unlike the main body of COF frameworks reported to-date, which consists of higher-symmetry 2D topologies, the unconventional layered brick-wall topology have only been proposed but never been realized experimentally. The brick-wall structure was characterized by powder X-ray diffraction analysis, FT-IR, solid state 13C NMR spectroscopy, nitrogen, and carbon oxide adsorption–desorption measurements as well as theoretical simulations. Our present work opens the door to the design of novel 2D COFs and will broaden the scope of emerging COF materials.

The reactions of Cd(II) salts and 5-(3-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (3-HIPT) resulted in eight new coordination polymers (CPs), namely, {[Cd(3-IPT)2(H2O)2]·H2O}n (1 and 2), {[Cd(3-IPT)2(H2O)2]·2H2O}n (3), [Cd(3-IPT)(H2O)Cl]n (4), [Cd(3-IPT)Cl]n (5), [Cd(3-HIPT)I2]n (6), [Cd(3-IPT)I]n (7), and [Cd(3-HIPT)2]n (8). Single-crystal X-ray analysis revealed that compound 1 is a 1D beaded chain, whereas compounds 2 and 3 are made of 2D networks. Compounds 1–3 are supramolecular isomers; their synthesis can be controlled under different temperatures and concentrations. The results showed that compounds 1 and 3 are the most thermodynamically and kinetically favored products, respectively. The thermodynamic stability of compound 1 may be attributed to the formation of the smallest M2L2 ring in the compound. Compounds 4–7 were obtained at higher Cl−/I− concentrations. Compound 4 is a 2D net composed of 1D [Cd(3-IPT)]n chains and μ2-Cl and μ2-H2O connectors. Compound 5 is a (3,6)-connected 3D framework with rtl topology. Compound 6 possesses a 1D chain with 3-HIPT ligands on both sides. Compound 7 is a 2D (4·82) net. Compound 8, a 3D pcu framework based on trinuclear linear SBUs, was formed when Cd(CF3CO2)2 was introduced at 170 °C. Based on a temperature-changing cycle, compounds 1 and 3 display crystal-to-amorphous-to-crystal phase transitions accompanying the dehydration–rehydration process, whereas compound 2 only displays crystal-to-amorphous phase transition when the temperature is increased and cannot go back to the crystal phase again. Interestingly, solvent-mediated structural transformations were accomplished among the selected compounds. When compounds 2, 3, 6, 7, or 8 were left in a water and NaCl solution at 170 °C, they were partly/fully transformed into compounds 1 and 5, respectively. When compound 5 was recrystallized in water at 120 and 170 °C, it was partly and fully transformed into compounds 2 and 1, respectively. Such transformations were induced by the temperature or an anion. In addition, the thermal stabilities and luminescence properties of selected compounds have also been studied in detail. The complexes exhibit intense solid-state fluorescence emission at room temperature.

Nine new coordination compounds, namely, {[Zn(HDSPTP)2(H2O)4]·6H2O}n (H2DSPTP = 4′-(2,4-disulfophenyl)-4,2′:6′,4′′-terpyridine, (1), [Cd(DSPTP)(H2O)2]n (2), {[Ag(HDSPTP)]·30H2O}n (3), {[Ag(HDSPTP)(H2O)]·3H2O}n (4), [Ag2(DSPTP)]n (5), {[Ag4(DSPTP)2(H2O)3]·2H2O}n (6), [Pb(DSPTP)(H2O)2]n (7), {[Pb(DSPTP)(H2O)3]·3H2O}n (8), and [PbK(DSPTP)(NO3)(H2O)2]·H2O}n (9), were synthesized by introducing a ligand with both terpyridyl and sulfo groups as organic linkers. The reaction of H2DSPTP with Zn(II) salts only resulted in a mononuclear complex (compound 1), in which most donor groups appear uncoordinated, whereas the reaction with Cd(II) salts under similar conditions resulted in a three-dimensional (3D) twofold interpenetrated dia framework (compound 2). The reactions of H2DSPTP with AgCF3CO2 or AgNO3 resulted in compounds 3–6 with different structures: a porous supramolecular framework via interlaced packing of one-dimensional (1D) coordination chains (compound 3), a two-dimensional (6,3) network based on coordination bonds and Ag⋯O interactions (compound 4), a 3D framework based on 1D [Ag2(2-SO3−)2]n secondary building blocks (compound 5), and a twofold interpenetrated framework with a binodal (4,6)-connected fsh topology based on planar tetranuclear SBUs as nodes (compound 6). The reactions of H2DSPTP with Pb(NO3)2 resulted in the following three compounds: a 3D twofold interpenetrated dia framework (complex 7), a twofold interpenetrated (6,3) network (compound 8), and a 3D complicated framework based on tetranuclear SBUs, double-bridge DSPTP2− ligands, and [K(H2O)]+ species (compound 9). The structural diversity is mainly attributed to the rich coordination behaviors of the HDSPTP−/DSPTP2− ligands and the metal center and can be controllably synthesized by altering the metal to ligand ratio, added alkali, and the pH value for the Ag(I) and Pb(II) compounds. Compound 2 exhibits a high thermal stability above 500 °C, undergoes a crystalline–amorphous–crystalline phase transition as temperature is increased from 25 °C to 500 °C, and shows an amorphous–crystalline phase transition when rehydrated. Moreover, the luminescence properties of all the compounds were also investigated.

•Two Ln(III) coordination polymers based on H3PyIDC were successfully synthesized.•Compound 1 displays 3D frameworks with new (3,4)-connected topology.•Compound 2 exhibits a rare (3,4)-connected dmc topology.Two new lanthanide (III) coordination polymers, namely, {[Eu3(μ3-HPyIDC)4]·Cl}n, (1) and {[Tb2(μ3-HPyIDC)2(μ2-Ox) (H2O)2]·4H2O}n (2) (H3PyIDC = 2-(3-Pyridyl)-1H-4, 5-imidazoledicarboxylic acid; Ox = oxalate), were successfully synthesized under hydro(solvo)thermal conditions and structurally characterized. Compound 1 displays a 3D framework with new (3,4)-connected {4.8.10}4{4.84.12}2{42.84} topology built by 3-connected μ3-HPyIDC− nodes and 4-connected metal ions. Compound 2 exhibits a rare (3,4)-connected dmc topology, in which μ3-HPyIDC− anions are 3-connected nodes and metal ions are 4-connected nodes. Moreover, the thermal stabilities and luminescence of compounds 1–2 were also investigated.Two novel three-dimensional Ln(III) coordination frameworks with (3,4)-connected topologies based on H3PyIDC with/without ox auxiliary ligands were successfully obtained.

Three coordination polymers based on different organic ligands, namely [Cu(bbn)2Cl]n (bbn = 4-(1H-benzimidazol-1-yl)benzonitrile, 1), [Zn(tpb)2]n (Htpb = 1-(4-(2H-tetrazol-5-yl)phenyl)-1H-benzimidazole, 2), and [Cd(bba)2(H2O)]n (Hbba = 4-(1H-benzimidazol-1-yl)benzoic acid, 3), were constructed from the same precursor, bbn. The bbn precursor remains unchanged in complex 1 but undergoes in situ reactions to give complexes 2 and 3 under different experimental conditions. Complex 1 is a 1D chain based on [CuCl]n chains and bbn ligands. Complex 2 has a 1D chain composed of [Zn2(tpb)2] subunits and tpb linkers. Complex 3 displays a twofold interpenetrating framework with dia topology. The results showed that the generation of different organic ligands from the same precursor via in situ reactions is a simple method for obtaining coordination polymer with diverse structures. The thermal stabilities and luminescent properties of selected compounds have been studied.

Reactions of Ln(III) salts with 4′-(2,4-disulfophenyl)-2,2′:6′2′′-terpyridine (H2DSPT) result in five types of coordination polymers, namely, {[Gd(DSPT)(OH)(H2O)2]·4H2O}n (type I, 1), {[Ln(DSPT)(ox)0.5]·H2O}n (type II, Ln = Nd (2), Eu (3), Tb (4), Er (5), Yb (6), Lu (7), ox = oxalate), {[Ln(DSPT)(ox)0.5(H2O)]·4H2O}n (type III, Ln = Yb (8), Lu (9)), {[Ln(DSPT)(pBDC)0.5·(H2O)2]·5H2O}n (type IV, Ln = Yb (10), Lu (11), H2pBDC = 1,4-benzenedicarboxylic acid), and {[Ln(DSPT)(pBDC)0.5·(H2O)2]·5H2O}n (type V, Ln = Dy (12), Er (13)). Type I is a 1D chain built from binuclear Ln2(DSPT)2 building blocks and OH− linkers. Type II is a 2D layer with (4,5)-connected topology constructed by binuclear Ln2(DSPT)2 building blocks and ox− anions. Type III is also a 2D network based on Ln(III), DSPT2−, and ox−, but with (3,4)-connected topology. The ox− anion is generated in situ from carboxylic acid precursor in type II and type III structures. The formation of Lu(III) complexes of type II or type III can be tuned by the addition of different carboxylic precursors. Type IV posseses a 2D layered structure based on the [Ln(DSPT)]n chain connected by pBDC2−. Type V exhibits a 3D framework formed by binuclear [Ln2(SO3)2(COO)2] secondary building blocks and DSPT2− and pBDC2− linkers, resulting in a uninodal 8-connected sqc4 topology. The Nd- and Yb-centered complexes show strong NIR luminescence, whereas the Tb- and Eu-centered complexes exhibit strong luminescence in the visible region at room temperature in both solid state and water emulsions. Their luminescence intensity can be strongly quenched by the addition of diethylchlorophosphonate (DCP), but significantly less influenced by dimethylmethylphosphonate (DMMP), diethylcyanophosphonate (DCNP) and other selected organophosphate, which make this material have a potential application in nerve-agent detection.

Five new coordination polymers, [Mg(DSPT)(H2O)2]·2H2O (H2DSPT = 4′-(2,4-disulfophenyl)-2,2′:6′2′′-terpyridine) (1), {[Ca(DSPT)(H2O)2]·1.5H2O}n (2), {[Pb(DSPT)(H2O)]·2H2O}n (3), {[Pb(DSPT)]·0.5H2O}n (4), and {[Pb3(DSPT)3(H2O)]·8H2O}n (5), were prepared under hydrothermal conditions. They are all complexes containing similar M2L2 binuclear metal–terpyridine building units. Complex 1 is a discrete binuclear molecule that extends to 2D layers via O–H⋯O hydrogen bonds between coordinated water and a sulfo group on H2DSPT. Complexes 2 and 3 are 1D coordination chains based on [M2(DSPT)2] ring subunits but are connected by different M–O bonds, and the 1D chains are also further connected by O–H⋯O hydrogen bonds between coordinated water and a sulfo group on H2DSPT to a 2D layer. Complex 4 exhibits a 2D coordination network also based on the [M2(DSPT)2] ring subunits. Complex 5 is a by-product of the synthesis of complex 4 that displays a 1D coordination chain structure containing the same [M2(DSPT)2] ring subunits. Interestingly, the 2D layers described above show identical skeletons when the bond types between [M2(DSPT)2] ring subunits are neglected. The 2D layers in complexes 1–3 can be derived from replacing selected coordination bonds in complex 4 with hydrogen bonds, and such structural diversity is largely dependent on the number of coordinated water molecules around the metal center. Thermogravimetric analyses of 1–4 showed that they were stable at temperatures higher than 500 °C. The luminescent properties of complexes 1–4 were also investigated.

•Three new mixed-ligand Zn(II) coordination polymers were constructed.•Compound 1 is a 3D (3,4)-connected framework with InS topology.•Compound 2 has 2D bilayer structure with new 4-nodal (3,4)-connected topology.Reactions of Zn(II) salts, presynthesized 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (HIPT) and various carboxylate ligands result to three new coordination polymers (CPs), namely, [Zn2[(IPT)2(ox)]}n (H2ox = oxalic acid, 1), [Zn2(IPT)2(mNBDC)]n (H2mNBDC = 5-nitroisophthalic acid, 2), and [Zn2(IPT)(CA)(H2O)]n (H3CA = citric acid, 3). Compound 1 can be seen as constructed from 2D [Zn(IPT)]n layers with (6,3) topology and pillared by ox2 −. It is a 3D (3,4)-connected framework with InS topology. Compound 2 has 2D bilayer structure based on 2D [Zn(IPT)]n single layer and mNBDC2 − linkers. Compound 3 is a 3D pillar-layer framework built by Zn–CA bilayers and IPT− pillars. The results showed that the coordination modes, configurations of IPT−, and the structure of carboxylate co-ligands have great influence on the structures of the final network. The choice of carboxylate can decide the result of CPs in Zn–IPT chains/net subunits plus carboxyl linkers or Zn–carboxylate chains/net subunits plus IPT− linkers. The thermal stabilities and luminescent properties of selected compounds have also been studied.Three new Zn(II) CPs with 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (HIPT) and various carboxylate ligands were constructed. They display diverse structures and luminescent properties.

•Three new Ln(III) coordination polymers based on H3PyIDC were constructed.•Compound 3 features a uninodal 10-connected 3D topology.•The structural diversity is dependent on the coordination modes of the H3PyIDC.Three new lanthanide (III) coordination polymers based on 2-(pyridine-3-yl)-1H-4, 5-imidazoledicarboxylic acid (H3PyIDC) with or without oxalate (Ox) coligand, namely, {[Sm(μ3-HPyIDC)(H2O)3]·Cl·H2O}n (1), {[Tb(μ1-H2PyIDC)(μ2-Ox)(H2O)3]·H2O}n (2), and {[Sm(μ4-HPyIDC)(μ2-Ox)0.5(H2O)]·- 2H2O}n (3), have been successfully synthesized. Compound 1 has a two-dimensional (2D) network structure with (4,4) topology based on binuclear [Sm2(COO)2] as secondary building units (SBUs). Compound 2 possesses a 1D lanthanide-oxalate zigzag chain with μ1-H2PyIDC− ligands hanging on both sides. Compound 3 features an unprecedented uninodal 10-connected 3D open framework with (312·424·58·6) topology based on binuclear [Sm2O2] SUBs. The results revealed that the structural diversity is mainly attributed to the different coordination modes of the H3PyIDC ligand as well as the introduction of Ox2 − auxiliary ligand. Moreover, the thermal stabilities and luminescence properties of the selected complexes were also investigated.Three new lanthanide (III) coordination polymers based on 2-(pyridine-3-yl)-1H-4, 5-imidazoledicarboxylic acid with or without oxalate coligand were constructed and studied.

•Two main group coordination polymers based on H3TFMIDC are firstly constructed.•Compound 1 is an achiral CP based on irregular helical chains.•Compound 2 exhibits a chiral framework based on 1D helical chains.Two new coordination polymers, {[Pb(μ2-H2TFMIDC)2-(μ2-H2O)]·H2O}n (H3TFMIDC = 2-(trifluoromethyl)-4,5-imidazole dicarboxylic acid, 1) and [Ba(μ2-H2TFMIDC)(μ4-H2TFMIDC)(H2O)]n (2), were constructed under hydrothermal/solvothermal conditions. Compound 1 is an achiral 3D framework based on irregular helical chains and displays a 6-connected pcu network topology. Compound 2 exhibits a 3D chiral framework based on homochiral 1D helical chains with a (4,8)-connected network topology. The luminescence properties of compounds 1–2 were also investigated.Two 3D main group coordination polymers displaying helical structures based on 2-(trifluoromethyl)-4,5-imidazole dicarboxylic acid were constructed.

•Two main group coordination polymers based on H4hmIDC are constructed.•The layer in 1 containing two types of inorganic anions.•Compound 2 exhibits a rare 5-connected noy topology.•Compound 2 exhibits luminescent emission with large red-shift of 79 nm.Two new main group coordination polymers, [Ba3(μ5-H2hmIDC)(μ5-H3hmIDC)(μ4-NO3)2(μ3-Cl)]n (1) and [Pb(μ5-HhmIDC)]n (2), were obtained under hydrothermal conditions. Compound 1 exhibits a 3-dimensional pillar-layer framework, the Cl− and NO3− anions link Ba(II) ions to generate a interesting two-dimensional layer containing two types of inorganic anions, which is further pillared by the H4hmIDC linkers, giving the final three-dimensional pillared-layer networks. Compound 2 is a 3D framework based on 1D secondary building blocks and exhibits a 5-connected noy topology. The thermogravimetric analyses and luminescence properties of compounds 1–2 were also investigated.Two 3D main group coordination polymers based on 2-(hydroxymethyl)-1H-imidazole-4,5-dicarboxylic acid were constructed. They are 3D pillar-layer and 5-connected framework, respectively. The Pb(II) compound display luminescent emission with large red-shift of 79 nm.

Four new 4d–4f heterometallic coordination polymers, namely, {[LnAg(DSPT)(mBDC)(H2O)2]·H2O}n [Ln = Sm, (1); Ln = Er, (2); H2DSPT = 4′-(2,4-disulfophenyl)-2,2′:6′2″-terpyridine); H2mBDC = 1,3-benzenedicarboxylic acid], {[CeAg(DPST)(mBDC)(H2O)2]·H2O}n (3), and {[TbAg3(DPST)2(INC)2(H2O)]}n [HINC = isonicotinic acid, (4)], have been successfully synthesized under hydrothermal conditions and structurally characterized. The four components, including Ln(III) ions, Ag(I) ions, and the two organic ligands, are successfully incorporated into a single framework. They are all heterometallic complexes based on two kinds of molecular building blocks (MBBs), the Ag2(DSPT)2 ring (MBB I) and Ln2(COO)2 dimeric unit (MBB II). Complexes 1 and 2 are isostructural and exhibit a 2D network constructed by MBBs I and II, and further linked by Ag···π interactions to a 3D supramolecular framework. Complexes 3 and 4 are 3D frameworks with sqc-21 and sqc-495 topologies by considering MBB I and II as nodes and coordination bonds/Ag···O interactions as linkers. Complexes 1–4 represent rare examples of 4d–4f coordination polymers containing two kinds of organic ligands. Moreover, thermal gravimetric analysis and luminescence properties studies of selected complexes were also investigated.

A series of new three-dimensional (3D) d–f heterometallic coordination polymers, namely, [LnM(μ5-PyIDC)(μ2-INIC)(μ3-INIC)]·xH2O [Ln = Sm, M = Co, x = 3 (1); Ln = Sm, M = Ni, x = 1 (2); Ln = Eu, M = Co, x = 3 (3); Ln = Eu, M = Cd, x = 3 (4); Ln = Eu, M = Zn, x = 3 (5); Ln = Gd, M = Co, x = 3 (6); Ln = Gd, M = Cd, x = 3 (7); Ln = Tb, M = Co, x = 3 (8); Ln = Tb, M = Cd, x = 2 (9); Ln = Tb, M = Zn, x = 3 (10); H3PyIDC = 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylic acid; HINIC = isonicotinic acid], have been successfully synthesized under hydrothermal conditions and structurally characterized. All the complexes are isostructural and exhibit novel 3D pillar-layered coordination frameworks constructed by the linkages of 2D heterometallic layers and INIC– pillars. Topological analysis indicates that those complexes possess a rare uninodal 10-connected bct topology based on planar hexanuclear heterometallic [Ln2M4(PyIDC)2] second building units. To the best of our knowledge, complexes 1–10 represent examples of 3D lanthanide–transition heterometal–organic coordination polymers with highly connected bct networks. Moreover, the luminescence properties of complexes 3–5 and 7–10 and the magnetic properties of 6–8 were also investigated.

Four novel three-dimensional (3D) barium–organic coordination polymers formulated as [Ba(μ5-H2hmIDC)(μ2-H2O)]n (1), [Ba(μ3-H3hmIDC)2(μ1-H2O)]n (2), [Ba(μ5-H2hmIDC)(μ2-O2)0.5]n (3), and [Ba(μ3-H3hmIDC)(μ4-H3hmIDC)]n (4) were synthesized under the solvothermal conditions of 2-(hydroxymethyl)-1H-imidazole-4,5-dicarboxylic acid (H4hmIDC) with BaCl2·2H2O using a combination of water or dimethyl formamide (DMF) with various alcohol solvents (methanol, ethanol, n-propanol, isopropanol, and n-butanol). Complex 1 is a 3D framework based on two-dimensional secondary building units (SBUs) and μ5-H2hmIDC2– pillars. This complex contains a unique alb network topology with the Schläfli symbol (45·6)2(410·614·84). Complex 2 is a (3,10)-connected framework with binuclear [Ba2(COO)2] SBUs as 10-connected nodes and two types of μ3-H2hmIDC2– ligands as 3-connected nodes. Complex 3 is a 3D framework formed with one-dimensional (1D) SBUs and μ5-H2hmIDC linkers, wherein the unprecedented oxygen molecules are coordinated using a linear-μ-η1:η1-peroxo fashion, showing (5,6)-connected network topology with the Schläfli symbol (46·53·6)(46·54·65). Complex 4 is a 3D framework based on 1D SBUs with μ3-H3hmIDC and μ4-H3hmIDC as linkers. This complex exhibits a trinodal (3,4,7)-connected 3D framework with the Schläfli symbol (42·6)(43·63)(48·611·82). The results revealed that the alcohol solvent plays a subtle yet essential role in the crystallization and construction of Ba(II)-organic coordination frameworks with diverse 3D structures, although these alcohol molecules do not appear in the frameworks.