Three coordination polymers built from planar tetranuclear clusters and 5-sulfoisophthalic acid

Three coordination polymers built from planar tetranuclear clusters and H₃sip ligands, Pb₂Cl(sip)(bipy) (1), Pb₂Br(sip)(H₂O) (2), and Ni₄(sip)₂(pyz)₂(H₂O)₈(OH)₂·2H₂O (3) (H₃sip?=?5-sulfoisophthalic acid, bipy?=?2,2′-bipyridine, and pyz?=?pyrazine), have been hydrothermally synthesized and characterized by IR, TGA, and single-crystal X-ray diffraction. Compound 1 features a 2-D layer-like structure containing tetranuclear square [Pb₄(SO₃)₂] clusters. Complex 2 has a 3-D open framework architecture constructed from tetranuclear cluster [Pb₄Br₂(SO₃)₂] inorganic building blocks. The tetranuclear units, [Ni₄(OH)₂(COO)₄], in 3 are interlinked through carboxylates and µ₂-pyz ligands to generate a 2-D layer structure. The connecting modes between tetranuclear clusters and organic ligands in the three compounds are discussed in this article. In the solid state at room temperature, yellow photoluminescence in 1 and 2 are observed.     

Exploratory syntheses,structures, and photoluminescent properties of three lead multi-dimensional frameworks

Three structurally diverse Pb^II coordination complexes, [Pb₃O(OH)(4-sphth)]₂(H₂O) (1), [Pb(3,5-Hdhb)]H₂O (2), and [Pb₃(4-nphth)₂(OH)₂] (3) (4-H₃sphth, 4-sulfophthalic acid; 3,5-H₂dhb, 3,5-dihydroxybenzoic acid; 4-H₂nphth, 4-nitrophthalic acid), were synthesized under hydrothermal conditions. X-ray diffraction analyses reveal that 1 is constructed from [Pb₄O₄] cubanes, based on which ladder-shaped structure is built via 4-H₃sphth bridge. This is the first Pb₄O₄-containing polymer. The Pb₂O₂ units in 2 are bridged by two parallel 3,5-HDHB ligands along the a-axis and two other parallel 3,5-HDHB ligands along the b-axis, forming a 3-D framework. For 3, the crystal structure is built up of a layer motif consisting of corner-sharing pyramidal Pb₃O units, which are linked through Pb corners to form a hexagonal unit. Each PbO₆ polyhedron is connected to three polyhedra (Pb₃O) via sharing an edge (two μ ₃-oxygen atoms) and two faces (three μ ₃-oxygen atoms), thus yielding an infinite 2-D Pb–O–Pb (3,6-net) honeycomb layer. The luminescence of 1–3 demonstrates that they may be good candidates for luminescent materials.     

Positional isomeric and N-donor auxiliary chelating ligand effect on engineering crystalline architectures of four lead(II) complexes with diverse fluorescent properties

This work presents an investigation on the positions of the substituent and N-donor auxiliary chelating ligand (bipy/phen) effect on engineering of crystalline architectures of four Pb(II) complexes with a pair of methyl-substituted 3-sulfobenzoic isomers: [Pb(4-msba)(phen)(H₂O)] (1), [Pb(4-msba)(bipy)(H₂O)]·H₂O (2), [Pb(5-msba)(phen)₂]·9H₂O (3), and [Pb₂(5-msba)₂(bipy)₂(H₂O)₂] (4) (4/5-msba?=?4/5-methyl-3-sulfobenzoate, phen?=?1,10-phenanthroline and bipy?=?2,2′-bipyridine). The lead(II) ions exhibit hemidirected geometry in 1–4. The positions of the methyl as well as the auxiliary chelating ligands influence coordination modes of the sulfonates and thus determine the architectures. As the position of methyl in aromatic ring changes from 4 to 5, the structures change from 2-D sheet-like compounds for 1 and 2 to 0-D dimeric species for 3 and 4. A water cluster (H₂O)₁₈ exists in 3, which further assembles into a water tape with a new pattern T4(3)4(3)10(3)A4. Complex 3 loses crystallinity rapidly in the open air and turns into [Pb(5-msba)(phen)₂]·2H₂O (3A). Thermal stabilities and solid state fluorescent properties of 1, 2, 3A, and 4 have been studied.     

Lead(II) coordination frameworks with 3-fluorophthalic acid: hydrothermal synthesis,crystal structure,and luminescence

Hydrothermal reactions of Pb(NO₃)₂ and 3-fluorophthalic acid (H₂Fpht) in the absence or presence of 2,2′-bipyridine (bpy) gave two coordination polymers: Pb₅(Fpht)₄(Fba)₂ (1) and [Pb₂(Fpht)₂(bpy)(H₂O)]·3H₂O (2). The 3-fluorobenzoic acid (HFba) results from an in situ decarboxylation of H₂Fpht. Solid 1 displays a 2-D structure, comprising center-related hexanuclear [Pb₃(COO)₆]₂ units. There are three crystallographically different Pb(II) ions and two different ligands, Fpht and Fba. The Fpht ligands adopt μ_6?:?η⁵η³ and μ_6?:?η³η⁴ unusual bridging coordination modes. A 3-D supramolecular architecture is formed via C–H?F hydrogen bonds. Solid 2 possesses a 1-D chain structure, comprising center-related tetranuclear [Pb₂(COO)₄]₂ units. There are two crystallographically different Pb(II) ions. The Fpht ligands adopt μ_3?:?η²η³ and μ_4?:?η³η³ bridging coordination. The free water molecules form (H₂O)₃ clusters to link the 1-D chain by hydrogen bonds. A 3-D supramolecular assembly is constructed via hydrogen bonds between the free water and the F of Fpht ligands. Fluorescence of the complexes originates from π*–π transitions of the ligands.     

Two lead coordination polymers with nitrilotriacetic acid and oxydiacetic acid: synthesis,characterization, and crystal structure

Two lead coordination compounds [Pb₂(nta)]NO₃ (1) and [Pb(oda)] (2) have been synthesized by slow evaporation or hydrothermal conditions using nitrilotriacetic acid (nta) and 2,2′-oxydiacetic acid (oda) as ligands, respectively. Their structures were determined by single-crystal X-ray diffraction and further characterized by X-ray powder diffraction, infrared absorption spectrum, and thermogravimetric analysis. Compound 1 is a 2-D honeycomb-like layer structure with (6,3) topology. When the bonding limit of Pb–O extends from 2.76 to 2.90 Å, potential weak Pb–O bonds can be found in 1, and the 2-D layer structure can be further linked to generate a 3-D 4-connected supramolecular sra net with the (4².6³.8) Schläfli symbol. Compound 2 contains a 1-D infinite Pb–O chain which is connected through µ₃-, µ₄-, and µ₅-coordination modes of oda to form a new 3-D structure.     

Three different structural lead(II) polymers constructed from newly designed chlorophenyl-imidazole dicarboxylate ligands

A 1-D coordination polymer, {[Pb(o-ClPhH₂IDC)₂]·H₂O}_n (o-ClPhH₃IDC = 2-(2-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid) (1), a 2-D coordination polymer, [Pb₃(p-ClPhIDC)₂(H₂O)]_n (p-ClPhH₃IDC = 2-(4-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid) (2), and a 3-D polymer, [Pb(p-ClPhH₂IDC)₂]_n (3), have been obtained solvothermally and structurally characterized by elemental analyses, IR, and single-crystal X-ray diffraction. Although they were prepared with similar ligands and Pb²⁺, polymers 1–3 show distinct structures. The X-ray powder diffraction and thermal properties of the polymers have been investigated. The influence of the reaction conditions to the final products and coordination of the organic ligands are discussed.     

A series of 1-D, 2-D and 3-D coordination polymers self-assembled from a flexible dicarboxylate and mixed N-donor ligands: syntheses,structural diversity,and luminescent properties

We have synthesized a series of metal–organic coordination frameworks under solvothermal conditions, formulated as [Cu(L)(phen)](1), [Co₂(L)₂(bib)]·CH₃OH(2), [Co(L)(btmb)_0.5](3), [Zn(L)(bib)]·2H₂O(4), [Cu(L)(bib)]·DMF(5), and [Mn₄(L)₄(bimb)(CH₃OH)](6) based on a flexible multicarboxylic bridging ligand 4,4′-methylenebis(oxy)-dibenzoic acid (H₂L) and flexible N-donor ligands 1,4-bis (1H-imidazol-1-yl)-butane (bib), 1,4-bis(1H-1,2,4-triazol- 1-ylmethyl)benzene (btmb), and 1,4-bis(1H-imidazol-1-ylmethyl)benzene (bimb). The structures of the frameworks have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The crystal structure determinations reveal that 1 has a 1-D Z-shape chain. Compounds 2 and 3 are 2-D twofold parallel interpenetrating 4-connected net with the Schläfli symbol {4⁴·6²}. Compound 4 is a 2-D threefold parallel interpenetrating 4-connected nets with the Schläfli symbol {4⁴·6²}. Compound 5 is 3-D 4-connected net with the Schläfli symbol {6⁵·8}. Compound 6 is characterized by a three-dimensional framework with one-dimensional homogeneous Mn-carboxylate chain. We found that flexible carboxylate ligands have different coordination modes under different synthetic conditions. The flexible skeleton of ligands and the coordination angle between the ligand and the metal ion is described. The luminescence and thermogravimetric properties of these compounds have been investigated.     

Syntheses,crystal structures,and photoluminescent properties of two new Cd(II) coordination polymers based on biphenyl-2,2′,4,4′-tetracarboxylate and dipyridyl-containing ligands

Two new Cd(II) coordination polymers, [Cd₂(btc)(dpe)_1.5(H₂O)]_n (1) and [Cd₂(btc)(bpp)(H₂O)]_n (2), were prepared by the hydrothermal reaction of cadmium nitrate with H₄btc (H₄btc = biphenyl-2,2′,4,4′-tetracarboxylic acid) in the presence of 1,2-di(4-pyridyl)ethylene (dpe) and = 1,2-bis(4-pyridyl)propane (bpp), respectively, structurally characterized by single-crystal X-ray diffraction, and further characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. In 1, btc^4? connect six Cd²⁺ ions, forming a 3-D (3,3,6)-connected [Cd₂(btc)] net, and further connected by 1-D [Cd(dpe)]_n chains to construct the final (4,5,6)-connected (4².5².6⁵.7)(4³.6².7)(4⁵.5³.6⁴.7².8) net. In 2, a 3-D [Cd₂(btc)] net is also constructed from btc^4? connecting six Cd²⁺ ions, giving a 3-D (3,4,7)-connected network. The overall structure of 2 can be regarded as a (4,4,6)-connected (4⁵.6⁴) (4².5.6².8) (4³.5⁴.6⁷.7) framework with bpp linking adjacent Cd ions. Structural comparisons show that the secondary auxiliary N-donors have important effects on the final structure and properties. Photoluminescent properties of 1 and 2 are also discussed.     

Syntheses,structures, and luminescence of two Zn(II) coordination polymers based on 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole and carboxylates

Reactions of Zn(II) salts, 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate (HIPT) and 2-mercaptobenzoic acid or 2-propyl-1H-imidazole-4,5-dicarboxylic acid (H₃PrIDC), result in two mixed-ligand coordination polymers (CPs), [Zn₂(IPT)(DSDB)(OH)]_n (H₂DSDB = 2,2′-disulfanediyldibenzoic acid, 1) and [Zn₂(IPT)(PrIDC)(H₂O)]_n (H₃PrIDC = 2-propyl-1H-imidazole-4,5-dicarboxylic acid, 2). Compound 1 possesses a 2-D structure built by 1-D [Zn(IPT)]_n chains and DSDB^2? connectors, in which the DSDB^2? is generated via in situ reaction from 2-mercaptobenzoic acid. It displays a new intricate 4-nodal {3·4·6·7·8·9}{3·6·7·8·9·10}{3·8·9}{4·6·8} topology. Compound 2 displays a 3-D framework with new 3-connected topology with Schläfli symbol of (4·8·10) (8·12²), in which the 1-D Zn-carboxylate chains were bridged by 3-connected IPT^? ligands. The thermal stabilities and luminescence properties of 1 and 2 have also been studied. The compounds exhibit intense solid-state fluorescent emissions at room temperature.     

Sonochemical synthesis and structural characterization of a nano-structure Pb(II) benzentricarboxylate coordination polymer: new precursor to pure phase nanoparticles of Pb(II) oxide

Microcrystals of a new Pb(II) coordination polymer, [Pb₂(1,3,5-HBTC)₂(H₂O)₄] · H₂O (1) (1,3,5-H₃BTC = 1,3,5-benzentricarboxylic acid), was synthesized by a sonochemical method. The structure was characterized by scanning electron microscopy, X-ray powder diffraction, elemental analyses, and IR spectroscopy. Thermal stability was studied by thermal gravimetric and differential thermal analyses. After the calcination of nanosized 1 at 400°C, pure phase nanosized Pb(II) oxide has been produced.     

In Situ: 2-D Inorganic Layer Lead-MOF Built from [(<Emphasis Type="Italic">μ</Emphasis><Subscript>4</Subscript>-O)Pb<Subscript>4</Subscript>] Core

In situ lead-MOF derived from 2-Methyl-3-acetylnaphtho[2,3-b]furan-4,9-dione (MAFD), [Pb₇O₂(OH)₂(1,2-BDC)₄(H₂O)] 1, 1,2-BDC = C₆H₄(COOH)₂, phthalic acid, has been synthesized and characterized by elemental analysis, IR, TG-DTA, powder X-ray diffraction (XRD) and single crystal X-ray diffraction. Compound 1 possesses 2-D inorganic layer structure built from rare tetranuclear unit [(μ ₄-O)Pb₄]. In 1, both crystallographic distinct Pb(1) and Pb(4) ions adopt six-coordination geometry, and the other two crystallographic distinct Pb(2) and Pb(3) ions display eight-coordination geometry under the condition of Pb–O bond length extended to 3.10 Å. A 3-D supramolecular network is also formed by hydrogen bonds (C–H···O). Result of photoluminescence measurement indicates an emission band at 385 nm (λ _excitation = 209 nm).     

Crystal structure and magnetic properties of Co(II) coordination polymer with CsCl-like topology

One Co(II) coordination polymer with 4-hydroxypyridine-2,6-dicarboxylic acid (H₃L)-[Co_1.5L(H₂O)₄]_n (1) has been fabricated under hydrothermal condition through reaction of Co(OH)₂ and H₃L with mole ratio of 1?:?1. Single-crystal X-ray diffraction analysis reveals that 1 crystallizes in triclinic space group Pī with a 1-D stair-like structure and rich hydrogen bonding interactions expand the 1-D structure to a CsCl-like 8-connected topology. Magnetic properties of 1 have been studied showing antiferromagnetic exchange interaction between Co(II) ions.     

Three 1-D molybdenum(V) phosphates with copper/nickel coordination cations

Three 1-D reduced molybdenum(V) phosphates, [Ni(OH)₂][Na₂(H₂O)₃]₂{Ni[(MoO₂)₆(OH)₃(HPO₄)₃(PO₄)]₂}?·?2C₆H₁₄N₂?·?2H₃O?·?5H₂O (1), [Ni(H₂O)₂][K(H₂O)₅]₂{Ni[(MoO₂)₆(OH)₃(HPO₄)₃(PO₄)]₂}?·?2C₆H₁₄N₂?·?2H₃O?·?4H₂O (2), and [Cu(H₂O)₂][Na(H₂O)₅]₂{Cu[(MoO₂)₆(OH)₃(HPO₄)₃(PO₄)]₂}?·?2C₆H₁₄N₂?·?2H₃O?·?4H₂O (3), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The crystallographic analysis reveals that 1 is based on {Ni[Mo₆O₁₂(OH)₃(HPO₄)₃(PO₄)]₂} clusters connected through {[Ni(OH)₂][Na₂(H₂O)₃]₂} pentanuclear mixed-metal cluster units to yield unusual 1-D chains along the c-axis, which further form 3-D supramolecular networks via hydrogen-bonding. Compounds 2 and 3 are heterogeneous isostructural compounds. Both are built from M[Mo₆P₄]₂ (M?=?Ni or Cu) blocks as the structural motif combined with [MO₄(H₂O)₂] (M?=?Ni or Cu) octahedra to form 1-D chains, where M[Mo₆P₄]₂ (M?=?Ni or Cu) is bonded by [M′(H₂O)₅] (M′?=?K or Na). Furthermore, bulk carbon paste electrode modified with 1 (1-CPE) displays good electrocatalytic activity toward reduction of nitrite or bromate.     

Substituent and Temperature Effect on the Assemblies of Three Lead(II) Coordination Polymers based on Asymmetrical Biphenyl Tritopic Ligands

Three Pb‐based metal‐organic frameworks, [Pb₆(L1)₄] · H₂O ( 1 ), [Pb₂(L2)₂(H₂O)] · H₂O ( 2 ), and [Pb(L2)(H₂O)] · H₂O ( 3 ) were constructed based on two asymmetrical tritopic ligands, 3‐(2′,5′‐dicarboxylphenyl)benzoic acid (H₃L1) and 3‐(2′,5′‐dicarboxylphenyl)pyridine acid (H₂L2), under hydrothermal conditions. The substituents on the two ligands and the induced temperature had effects on the resulting structures. All of the complexes were structurally characterized by X‐ray diffraction analyses and further identified by infrared spectra, elemental analyses, powder X‐ray diffraction, and thermogravimetric analyses. Complexes 1 and 3 are 3D frameworks, which construct from 1D inorganic Pb–O–Pb rod‐shaped secondary building units (SBUs) and H₃L1/H₂L2 ligands as pillars. Complex 2 is a 3D framework based on discrete tetranuclear Pb₄(COO)₈ clusters SBUs and H₂L2 ligands. The effects of both the substituent groups on the aromatic rings and the reaction temperature are discussed in details. The fluorescence properties and thermal stabilities of complexes 1 – 3 were also measured.     

Two new metal-organic frameworks possessing binodal high-connected topologies based on Cd4-clusters and organic ligands

Two new compounds, [Cd₂(bptc)(bpimb)(H₂O)]?·?2H₂O (1) and [Cd₂(bptc)(bpib)]?·?4H₂O (2) (where H₄bptc?=?biphenyl-3,3′,4,4′-tetracarboxylic acid, bpimb?=?1,3-bis((2-(pyridin-2-yl)-1H-imidazol-1-yl)methyl)benzene, bpib?=?1,4-bis(2-(pyridin-2-yl)-1H-imidazol-1-yl)butane), were synthesized by reactions of the corresponding metal salts with H₄bptc and N-containing auxiliary ligands and their structures have been determined by single-crystal X-ray diffraction. Compound 1 is built by Cd₄-clusters which further construct a 3-D (3,8)-connected framework with tfz-d notation; 2, also built by Cd₄-clusters, is a 3-D (4,8)-connected framework with (3²?·?4²?·?5²)(3⁴?·?4⁸?·?5¹²?·?6⁴) topology. In addition, the elemental analyses, infrared spectra, fluorescence, and thermogravimetric analyses for 1 and 2 are discussed.     

Synthesis and crystal structures of two lead(II) complexes of 4,4,4-trifluoro-1-naphthyl-1,3-butanedione ligand,subtle interplay of weak intermolecular interactions

[Pb₂(tfnb)₄ (µ-CH₃OH)] _n (1) and [Pb₂(dmp)₂(tfnb)₄] (2) (tfnb and dmp are the abbreviations for 4,4,4-trifluoro-1-naphthyl-1,3-butanedionate and 2,9-dimethyl-1,10-phenanthroline) have been synthesized and characterized by elemental analysis, IR, ¹H NMR spectroscopy, and thermal analysis. The single-crystal structure of 1 shows that the complex forms two 1-D polymeric networks containing four types of Pb²⁺ with coordination numbers seven for Pb(1) and Pb(3), five for Pb(2), and six for Pb(4). The single-crystal structure of 2 shows that the complex forms a dinuclear complex with eight-coordinate Pb(II). The supramolecular features in this complex are guided by lone-pair activity and the control of weak directional intermolecular interactions and aromatic π–π stacking interactions.     

Structures and luminescent properties of four compounds based on binuclear metal-terpyridine building blocks

Four new coordination polymers, [Cd(3-TPTP)Cl]₂ (3-HTPTP = 4′-(3-tetrazolylphenyl)2,2′:6′2′′-terpyridine, 1), {[Cd(3-TPTP)(pBDC)_0.5]?4H₂O}_n (pH₂BDC = 1,4-benzenedicarboxylic acid, 2), {[Mn(3-TPTP)(mBDC)_0.5]?5H₂O}_n (mH₂BDC = 1,3-benzenedicarboxylic acid, 3), and [Pb(3-TPTP)(H₂O)₂]?OH (4), were obtained. Compounds 1–3 are composed of binuclear [M₂(3-TPTP)₂] ring as building unit. In 1, the binuclear rings pack into a 3-D supramolecular framework via various hydrogen bonds. In 2 and 3, the binuclear rings are connected by mBDC^2? and pBDC^2?, respectively, resulting in two types of 1-D chains. In 4, the mononuclear [Pb(3-TPTP)] units are connected by Pb?N weak interactions, giving a chiral 1-D coordination chain, which is further connected by O–H?N interaction to form a chiral 3-D supramolecular framework. The phase purity of 1–4 and luminescence properties of 1, 2, and 4 were also investigated.     

Synthesis,characterization, and properties of copper and manganese complexes with 5-(benzimidazol-1-ylmethyl)isophthalate

Four new complexes, [Cu(L)] (1), [Cu₂(L)(dpe)_0.5]?·?2.5H₂O (2), [Mn(L)] (3), and [Mn(L)(pybim)] (4) [H₂L?=?5-(benzimidazol-1-ylmethyl)isophthalic acid, dpe?=?1,2-di(pyridin-4-yl)ethylene, pybim?=?2-(pyridin-2-yl)-1H-benzimidazole], have been synthesized under hydrothermal conditions and characterized by single-crystal and powder X-ray diffractions, FT-IR, and elemental analysis. The crystal structural analyses reveal that 1 and 4 are uninodal 3-connected 2-fold interpenetrated 2-D networks with (6³) topology, 2 shows an infinite 1-D double-stranded chain structure, and 3 exhibits a uninodal 4-connected 2-D network with (4⁴?·?6²) topology. The factors influencing the structures of the coordination polymers are discussed. In addition, the thermal stabilities of 1–4, second-order non-linear optical effect of 1, and preliminary magnetic property of 3 have also been investigated.     

U(VI) and Zn(II) coordination complexes with 5-[N-acetato(4-pyridyl)]tetrazolate anions

A U(VI) mononuclear coordination complex [UO₂(a4-ptz)₂·(H₂O)₃] (1) and a Zn(II) 1-D coordination polymer [Zn(a4-ptz)₂·(H₂O)₂]·2H₂O (2) have been synthesized with 5-[N-acetato(4-pyridyl)]tetrazolate (a4-ptz) as ligand. Complex 1 has a slightly distorted pentagonal bipyramid around each U center. Complex 2 is octahedral with four a4-ptz and two water ligands. Each Zn center is linked by carboxylate-O(1) and tetrazolate-N(2) of a4-ptz forming a 1-D polymeric chain. Complexes 1 and 2 are self-assembled to form 3-D supramolecular structures through hydrogen bonds. The luminescence properties of 1 and 2 were investigated at room temperature in the solid state. The results suggest that 1 and 2 may be useful as photoactive materials.     

Syntheses,structures, and optical properties of two cadmium complexes with chelidamic acid

[Cd₂(C₇H₃NO₅)₂ · 4(H₂O)] _n · 3nH₂O · 0.5n(CH₃OH) (1) and [Cd₃(C₇H₂NO₅)₂ · 10(H₂O)] · 2H₂O ·0.5CH₃OH (2) were synthesized and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that both Cds are seven-coordinate with pentagonal bipyramid geometries. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Complex 2 is a discrete structure, then independent [Cd₃(C₇H₂NO₅)₂ · 10(H₂O)] are linked by hydrogen bonds into a 3-D network. The optical properties of 1 and 2 were investigated with fluorescent spectra; both exhibit strong green luminescence probably originating from π–π* transition of the ligand.