Lead Coordination Polymer Research Articles

Synthesis and structural characterization of a novel lead coordination polymer: [Pb(L)(1,3-bdc)]·2H2O

Abstract A novel coordination polymer, [Pb(L)(1,3-bdc)]·2H2O (1), (L = 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, 1,3-H2bdc = 1,3-benzenedicarboxylic acid) has been successfully prepared under hydrothermal conditions. The structure of 1 is a 1D chain structure, which further stacks together to form a 3D supramolecular architecture by π–π interactions and C–H⋯π interactions. In addition, the thermogravimetric analysis of 1 has been investigated.

Synthesis, structures and properties of lead coordination polymers based on pyridinedicarboxylate ligand

Two new Pb(II) coordination polymers, namely, [Pb(Hpydc)2]n (1), [Pb(Hpydc)2(H2O)]n·2n(H2O) (2) (H2pydc ​= ​2,5-pyridinedicarboxylic acid) have been prepared by the reaction of PbCl2 with pyridinedicarboxylic acid and fully characterized. Compound 1 contains ‘sql’ topological layers built from one-dimensional (1D) Pb-carboxylate infinite chains, and the layers are further packed into a 3D architecture by strong hydrogen bonds interactions. Compound 2 consists of 1D infinite chains containing Pb-dimers. The 3D supramolecular Pb(II) coordination complex of 2 is created by π – π interactions between the pyridine rings of the Hpydc ligands. In addition, solid-state properties of thermal stability and fluorescence for these crystalline materials are also presented. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanism of the fluorescence emissions are dominantly resulted from the ligand-to-metal charge transfer (LMCT) and partial the intraligand π→π∗ and/or n→π∗ transitions for 1 and 2, which are in good agreement with their fluorescence spectra and crystal structure.

Synthesis and structural characterization of a novel 2D supramolecular lead coordination polymer with phenanthroline derivate and adipic acid

Abstract A new metal-organic coordination polymer, [Pb(L)(adip)0.5] (1) was synthesized under hydrothermal conditions by using 1-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)naphthalen-2-ol (HL) and adipic acid (H2adip). The complex 1 was characterized by diffraction and elemental analyses. In complex 1, the binuclear [Pb2L2] units were formed by the OH-deprotonation bridging neighboring Pb(II) atoms, and the adipate linked the binuclear [Pb2L2] units to form a symmetric one-dimensional chain. The 1D chain was further extended to the 2D supramolecular layer structure through π-π interactions between the L ligands.

Determination of kinetically or thermodynamically stable product between the two lead coordination polymers

To study the effects of ultrasonic irradiation, heating, the molar ratio of initial reactants and reaction time on formation of [Pb2(4,4′-Bipy)I4]n(1) and [Pb(4,4′-Bipy)I2]n (2) coordination polymers, [4,4′-Bipy = 4,4′-Bipyridine], some experiments were designed and eight samples were synthesized under different conditions. The results showed that the [Pb(4,4′-Bipy)I2]n (2) was the only stable product under the designed conditions, and it is the thermodynamically stable product. [Pb2(4,4′-Bipy)I4]n (1) which can be formed only with crystallization technique is kinetically stable product. These samples were characterized by IR spectroscopy, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM).

Synthesis, structures and properties of three lead coordination polymers based on ethylenediaminetetraacetate ligand

Three Pb(II)-edta complexes, [Pb3(edta)(H2O)Cl2]n·(H2O)3n (1), [Pb5(edta)2(H2O)2X2]n·(H2O)2n (X = Cl (2), Br (3)) (H4edta = ethylenediaminetetraacetic acid) have been synthesized by the reaction of PbX2 and H4edta under hydrothermal conditions, and were characterized by elemental analysis, thermal analysis, luminescence, powder X-ray diffraction and single-crystal X-ray diffraction. The results of X-ray crystallographic analysis reveal that these complexes are the first bilayer two-dimensional (2D) Pb-edta coordination polymers with 1D channels. The bilayers of complexes 1, 2 and 3 are linked by [Pb2Cl4], [PbCl2] and [PbBr2] clusters with carboxylate groups respectively. They are 3D supramolecular structures which are resulted from different halogenide anions. The emission spectra of 1–3 are dominated by intense and broad emission bands which are resulted from the [PbX2] clusters. Optical absorption spectra indicate that theses complexes have wide optical band-gaps and can be probably used as wide optical band-gap semiconductor materials.

Spectral, structural and theoretical study of novel helical and linear structures of PbI2 and PbBr2 complexes with a triazine ligand

Two coordination polymers of lead(II), 1D-{Pb(DFPT)(μ-Br)2}n (1) and 1D-helical-{Pb(DFPT)(μ-I)2}n (2), with 5,6-di(furan-2-yl)-3-(pyridin-2-yl)-1,2,4-triazine (DFPT) were prepared and identified by elemental analysis, FT-IR, 1H NMR spectroscopy and single-crystal X-ray diffraction. In the 1D-double chain-coordination polymers of 1 and 2, the lead atom has a PbNpyNtz(μ-X)4 (X: Br (1), I (2)) environment with distorted octahedral geometry and hemidirected coordination sphere. The type of the polymeric chain in both complexes is different; 1 has a linear expansion while 2 shows a helix structure with a racemic mixture of the P and M chains. In the crystal network of the complexes, in addition to hydrogen bonds, there are triazine···furyl and furyl···furyl ring π–π stacking interactions. The thermodynamic stability of the compounds, the polymer stability slope for pentameric chains (PSS5) and also the energy variation of the free DFPT ligand for 360° rotation of the pyridine ring were studied by DFT calculations.

Syntheses, Characterization, and Fluorescence Properties of Four Divalent Lead Coordination Polymers based on Zwitterionic Ligands

Four novel divalent lead coordination polymers based on a series of zwitterionic ligands, Pb2Cl4L1 (1), [Pb2Cl4L2]·2H2O (2), Pb2Cl2(CH3COO)2L2 (3), and Pb3Cl4(NO3)2L3 (4) were solvothermally synthesized and successfully characterized. Single crystal structure studies reveal that compound 1 is a chain structure based on the inorganic “PbCl2” chain motif, whereas compounds 2–4 are sheet structures each constructed by inorganic “PbCl2”, “PbCl(CH3COO)”, and “Pb3Cl4” chain motifs. Hydrogen bonding interactions in term of C–H···Cl and C–H···O play a key role to form supramolecular 3D structures of 1–4. Additionally, studies of solid state fluorescence indicate 1–4 emit in the ultraviolet and visible region that can be assigned to the inter‐ligand π*–π and/or π*–n transitions.

Phosphorescence emission and fine structures observed respectively under ambient conditions and at ca. 55 K in a coordination polymer of lead(ii)-thiophenedicarboxylate.

Under solvothermal conditions, a robust Pb2+-based coordination polymer (CP), [Pb(TDC)]n (1), where H2TDC is thiophenedicarboxylic acid, has been achieved. Structural analysis reveals that 1 crystallizes in the monoclinic space group C2/c, where the Pb2+ ions show quadrangular prism coordination geometry. CP 1 represents a 3D coordination network based on a TDC2- ligand as bridges and quadrangular prismatic PbO8 units as nodes, among which the PbO8 units are extended through edge-sharing to form a 2D layer in the bc plane. Interestingly, CP 1 emitted intense and long-lived orange phosphorescence in the solid state at room temperature, with a quantum yield of 6.7% and a phosphorescence lifetime of 1.78 ms. A fine structure is clearly observed in the phosphorescence emission spectra at temperatures below 55 K. The emission mainly arose from the electron transition within the π-type orbitals of the TDC2- ligand. This study gives a fresh impetus to achieve CP-based long-lived phosphorescent materials under ambient conditions.

Two three-dimensional coordination polymers of lead(II) with iminodiacetate and naphthalene-dicarboxylate anions: Synthesis, characterization and luminescence behavior

Two lead(II) compounds [Pb3(idiac)3(phen)2(H2O)]·2(H2O) (1) and [Pb(ndc)]n (2), where H2idiac=iminodiacetic acid, phen=1,10-phenanthroline and H2ndc=naphthalene-2,6-dicarboxylic acid, have been synthesized and structurally characterized. Single crystal X-ray diffraction analysis showed that compound 1 is a discrete trinuclear complex (of two-fold symmetry) which evolves to a supramolecular 3D network via π–π interactions, while in compound 2 the naphthalene dicarboxylate anion act as a linker to form a three dimensional architecture, where the anion adopts a bis-(bidentate bridging) coordination mode connecting four Pb(II) centers. The photoluminescence property of the two complexes has been studied.

Effect of pH on the construction of lead coordination polymers by the diverse coordination modes of sulfonate functionalized imidazophenanthroline derivative ligand

To determine the influence of reaction conditions on the formation of metal-organic frameworks(MOFs), three PbII-H3sfpip complexes {[Pb(Hsfpip)(H2O)3]·H2O}n (1), {[Pb2(Hsfpip)2(H2O)2]·H2O}n (2), [Pb2(Hsfpip)2(H2O)2]n (3) [H3sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR and single crystal X-ray diffraction. The diverse structures of products show the marked sensitivity of the structural chemistry of the aromatic sulfonate ligand to synthetic conditions. Complex 1 is formed at pH 3.0, and displays a one-dimensional linear chain structure with Hsfpip2− group as a μ2–η2:η1 coordination mode. While at pH 5.0, a two-dimensional double layer structure of 2 is formed, in which Hsfpip2− group shows a μ4–η2:η1:η1:η1 coordination mode. The two-dimensional networks are further connected by hydrogen bonds to result in a three-dimensional supramolecular network. Furthermore a three-dimensional network of 3 is got by increasing pH to 6.5, in which Hsfpip2− group presents the unusual μ5–η2:η1:η1:η1:η1 coordination mode. The structural differences of three complexes give some insights into the effect of pH on the construction of coordination polymers. Additionally, the thermal stabilities and photoluminescence properties of 1–3 were also studied.

On construction of lead coordination polymers derived from N′-(2-hydroxybenzylidene)nicotinohydrazide via covalent and non-covalent interactions

Lead(II) and lead(IV) coordination polymers with N′-(2-hydroxybenzylidene)nicotinohydrazide have been synthesized from lead(II) salts, and subsequently characterized by solid-state UV‒Vis‒IR spectroscopy, thermal analysis, and powder and single-crystal X-ray diffraction techniques. The compounds crystallize in the same space group but differ in the oxidation state of lead, composition, conformation of the organic ligand, its charge, and tautomeric form. The coordination network is propagated by the hydrazone anion in the lead(II) metal-organic framework catena-[(μ2-N-((2-oxidophenyl)methylidene)pyridine-3-carbohydrazonoato-N:N′,O,O′)-lead(II) (1) and by nitrate in a one-dimensional lead(IV) coordination polymer catena-(μ2-nitrato-O,O)-(nitrato-O,O′)-(salicylaldehydeisonicotinoylhydrazonato-N,N′,O)-lead(IV) nitrate (2). The formation of metal-organic framework of 1 is affected by Pb···π interactions.

Assembly and Crystal Structure of a 2D lead(II) Coordination Polymer with 1D Metal–Oxygen Chains

A new lead coordination polymer [Pb2(mip)2] (1) has been synthesized under the intervention of polycarboxylic acid by hydrothermal method (H2mip = 5-methylisophthalic acid). X-ray single-crystal structure determination reveals that the polymer crystallizes in monoclinic C2/c space group: a = 21.118(2) Å, b = 8.0055(7) Å, c = 25.556(3) Å, and β = 111.1730(10)°. The Pb(II) cations are connected by four mip anions to produce a 2D (6,3) double-layered framework. It should be noted that four-membered rings by two Pb atoms with two μ-O atoms of mip groups link each other to form a one-dimensional Pb–O chain through a corner-sharing Pb center.

Three PbII coordination polymers based on 2-(pyridin-2-yl)-1H-imidazole-4,5-dicarboxylic acid: Syntheses, crystal structures, and fluorescent properties

Abstract Three lead coordination polymers, [PbCl(C10H6N3O4)(H2O)·H2O]n (1), [Pb(C10H6N3O4)2(H2O)]n (2) and [Pb3(C10H5N3O4)3]n (3) (C10H7N3O4=2-(pyridin-2-yl)-1H-imidazole-4,5-dicarboxylic acid), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. In 1, Cl anions connected neighboring wave-like 2D layers, which are constructed with left- and right-handed helical chains, into a 3D network structure with a (63)(65·8) topology. In 2, Pb cations are linked into a 3D 66 network with left- and right-handed helixes by μ2-bridging C10H6N3O4− ligands. In 3, C10H5N3O42− ligands link Pb6O12 clusters into a 3D (412·63) network. Their fluorescent properties were also investigated.

Synthesis and Structural Characterization of a New 1-D Lead(II) Coordination Polymer: A New Precursor for Preparation Pb3I2O2 Nano Particles Via Thermal Decomposition

A new lead (II) coordination polymer [Pb2(8-HQuin)2(μ-I)2] n (1) was prepared from reaction of ligand 8-hydroxyquinolin (8-HQuin) with lead(II) acetate and potassium iodide. The compound was characterized by elemental analysis, IR spectroscopy and structurally determined by X-ray single crystal diffraction. The structure of compound 1 may be considered coordination polymer of lead (II) that Pb(II) ions are bridged by iodide ions forming double chains and making one dimensional array of Pb(II) and 8-HQuin, respectively. Pure phase Lead(II) Oxide Iodide Pb3I2O2 nano particles were obtained by calcination of compound 1 at 400 °C under air atmosphere which were characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). Coordination polymers are good precursors to synthesis of nano oxides. SEM image of Pb3I2O2 nanoparticles produced by calcination of [Pb2(8-HQuin)2(μ-I)2] n .

New Flower-Shaped Lead(II) Coordination Polymer at the Nano Scale: Synthesis, Structural Characterization and DFT Calculations of [Pb(o-phen)(N3)2] n Containing the Pb-(μ1,1-N3)(μ1,3-N3) Motif

A new nano-flower lead(II) azido coordination polymer from the ligand, orthophenanthroline (o-phen), [Pb(o-phen)(μ1,1-N3)(μ1,3-N3)] n (1), was synthesized by a sonochemical method. Compound 1 was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), elemental analyses and IR spectroscopy. Single crystalline material was obtained using a heat gradient applied to a solution of the reagents. The structure of 1 is a coordination polymer of lead(II) containing the Pb-(μ1,1-N3)(μ1,3-N3) motif, formed of one-dimensional chains. The structure of the 1 was optimized by density functional theory. Structural parameters and IR spectra for 1 are consistent with the crystal structure. Pure phase PbO nanoparticles were obtained by thermolysis of 1 with oleic acid as a surfactant at 180 and 200 °C an air. PbO nanoparticles were characterized by XRD and SEM.

Two new metal-organic coordination polymers of lead with O-, N-donor ligands: Synthesis, characterization, luminescence and thermal behavior

The synthesis of two new lead(II) coordination polymers, [Pb2(picOH)4]·H2O (1) and [Pb3(Sip)2(H2O)2]·H2O (2) has been reported, where HpicOH=3-hydroxypicolinic acid and NaH2Sip=5-sulfoisophthalic acid monosodium salt. Both the complexes were structurally characterized by X-ray single crystal diffraction analysis. Complex 1, where the 3-hydroxypicolinate ligand is used for the first time in conjunction with Pb(II), revealed to be a 1D polymeric array. Complex 2 showed a 3D structure with 5-sulfoisophthalate ligand adopting two novel binding modes of high denticity (η6μ6 and η7μ7). The photoluminescence and thermal properties of the two complexes have been studied.

1-D and 2-D coordination polymers of lead(II) thiocyanate with substituted 2,2′-bipyridine ligand

Two lead(II)-thiocyanato coordination polymers with 5,5′-dimethyl-2,2′-bipyridine (5,5′-dm-2,2′-bpy) and 4,4′-dimethoxy-2,2′-bipyridine (4,4′-dmo-2,2′-bpy) as chelating ligands were synthesized and characterized by elemental analysis, IR and 1H-NMR spectroscopy, thermal behavior, and X-ray crystallography. These complexes have formulas [Pb(5,5′-dm-2,2′-bpy)(NCS)2] n (1) and [Pb(4,4′-dmo-2,2′-bpy)(NCS)2] n (2). The coordination numbers of PbII in 1 and 2 are four, PbN4, with “stereo-chemically active” electron pairs and hemidirected coordination spheres. Considering Pb···S as weak bonds, 1 and 2 are 1- and 2-D coordination polymers, respectively. The supramolecular features in these complexes are guided/controlled by weak directional intermolecular interactions.

Sonochemical Synthesis of two New Nano-structured Lead(II) and Mercury(II) Coordination Polymers

Two new nano-sized lead(II) and mercury(II) coordination polymers, [Pb(2-bpdh)(NO3)2(H2O)]n(1); (2-bpdh = 2,5-bis(2-pyridyl)-3,4-diaza2,4-hexadiene)} and [Hg(4-bpdb)(SCN)2]n (2); (4-bpdb= 1,4-bis(4pyridyl)-3,4-diaza-1,3-butadiene) were synthesized by a sonochemical method. The structure of 1 may be considered coordination polymer of lead(II) and Single crystal X–ray analysis of compound 2reveals that consists of one-dimensional zigzag chains formed by bridging SCN and 4-bpdb ligand. The new nano-structures of coordination polymers were characterized by scanning electron microscopy, powder X-ray diffraction, elemental analyses and IR spectroscopy. The size of the samples was about 70 nm and 60 nm for compound 1 and 2, respectively.

Synthesis of a New Lead(II) Coordination Polymers with N-donor Ligand as Precursor for Preparation of PbO Nano-structure; Spectroscopic, Thermal, Fluorescence and Structural Studies

A new coordination polymer of lead(II) nitrate complexes with bridging trans-1,2-bis(4-pyridyl)ethene (bpe) ligand, [Pb(µ-NO3)2(bpe)(MeOH)]n (1), has been synthesized and characterized by elemental analysis, FT-IR, 1H, 13C-NMR, thermal analysis and single crystal X-ray diffraction. In compound 1, lead(II) ions are bridged by nitrate ligands forming linear chains, which are also further coordinated by neutral bpe and methanol ligands into a two-dimensional polymeric chain. This polymeric precursor has been used to prepare PbO nano-particles using two different method. The prepared lead(II) oxide nano-structure was characterized by scanning electron microscopy and X-ray powder diffraction.

Synthesis and structural characterization of new two-dimensional lead(II) coordination polymer: New precursor for preparation of pure phase lead(II) oxide nanoparticles via thermal decomposition

The new lead(II) nitrate coordination polymer from ligand 2,7-bis(2-pyridyl)-3,6-diaza-2,6-octadiene (2-bpdhe), [Pb(NO3)2(2-bpdhe)]n (1) was synthesized. The compound 1 was characterized by IR spectroscopy, elemental analyses and X-ray crystallography. The structure of 1 may be considered coordination polymer of lead(II) consisting of metallocyclic chains formed by bridging 2-bpdhe ligands, making two-dimensional array of Pb(NO3)2 and 2-bpdhe, respectively. Pure phase PbO nano-particles were obtained by thermolyses of compound 1 in oleic acid as surfactant at 180 and 200°C under air atmosphere. The PbO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).