Synthesis and Characterization of One-Dimensional Zinc(II) Coordination Polymers as Precursors for Preparation of ZnO Nanoparticles via Thermal Decomposition

Two new Zn(II) coordination polymers from the ligand, 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene (bpdh), with different anions; i.e., [Zn(μ-bpdh)(H₂O)₄](ClO₄)₂·2bpdh (1) and [Zn(μ-bpdh)(H₂O)₄](NO₃)₂·2bpdh (2), were synthesized and characterized by IR spectroscopy, elemental analyses and X-ray crystallography. Compounds 1 and 2 are 1D coordination polymers and the zinc atoms are linked by four oxygen atoms from water molecules and two nitrogen atoms of bpdh ligands. There are two uncoordinated bpdh ligands that, along with the perchlorate or nitrate anions, form hydrogen bonds with water molecules. ZnO nanoparticles were obtained by thermolysis of 1–2 in oleic acid at 280 °C in air. The ZnO nanoparticles were characterized by X-ray diffraction and scanning electron microscopy.     

Synthesis,crystal structure and magnetic property of a novel sheet-like polymer [Mn(bpd)(NCS)2(CH3OH)2]n (bpd=1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene)

The novel manganese (II) complex of 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (bpd) [Mn(bpd)(NCS)₂(CH₃OH)₂]_n was synthesized. Its crystal structure was determined, together with the results of variable temperature magnetic susceptibility and IR spectrum. The structure of the complex demonstrates a sheet-like dimensional network by both bpd bridge and hydrogen bond interactions.     

Three unique MOFs constructed by 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and dicarboxylates: From rhombic tetrameric zinc(II) 2D layer to 2D + 2D → 3D polycatenated frameworks

Three metal–organic networks, namely, [Zn₂(Hnip)(4-bpdb)(nip)₂(μ₃-OH)] (1), {[Zn(tbip)(4-bpdb)_1.5]·CH₃OH}_n (2), and {[Ni(1,3-bdc)(4-bpdb)]·2H₂O}_n (3) (4-bpdb = 1.4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, H₂nip = 5-nitroisophthalic acid, H₂tbip = 5-tert-butylisophthalic acid, and 1,3-H₂bdc = 1,3-benzenedicarboxylic acid) are synthesized under hydrothermal conditions. The structure of 1 is built around uncommon rhombic {Zn₄} clusters with double T_d and double O_h Zn(II) geometries, which extend into a 2D network by the rigid deprotonated H₂nip and 4-bpdb bridges. Meanwhile, 2 presents a novel 2D → 3D parallel polycatenated framework assembled from 2D bilayers with cuboids as the fundamental building units. Compound 3 features an interesting 2D → 3D inclined polycatenated network based on 4⁴-sql subunits. Moreover, the thermal stabilities, photoluminescence, and magnetic properties of the compounds are also discussed.     

Synthesis and Characterization of a New Nano Lead(II) Two-dimensional Coordination Polymer by Sonochemical Method: A Precursor to Produce Pure Phase Nano-sized Lead(II) Oxide

A new nano-sized lead(II) coordination polymer, {[Pb₂(μ-3-bpdh)(μ-NO₃)₃(NO₃)]_n (1); (3-bpdh = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene)}, was synthesized by a sonochemical method. The structure of 1, which may be considered coordination polymer of lead(II), consists of metallocyclic chains formed by bridging NO₃ ⁻ and 3-bpdh ligands, thereby making a 2D array of Pb(NO₃)₂ and 3-bpdh. The thermal stability of compound was studied by thermogravimetric and differential thermal analyses. The new nano-structure coordination polymer was characterized by powder X-ray diffraction, elemental analysis and IR spectroscopy. The scanning electron microscopy shows the particle size of the 1 prepared by the sonochemical method is about 95 nm. The PbO nanoparticles were obtained by thermolysis of 1 at 180 °C with oleic acid as a surfactant. The scanning electron microscopy shows that the size of the PbO particles are ~60 nm.     

Epoxidation of E-1,4-poly(2-triethylsilyl-1,3-butadiene) and E-1,4-poly-[2,3-bis(trimethylsilyl)-1,3-butadiene] Stereochemical analysis of E-1,4-poly(2,3-epoxy-2-triethylsilyl-1,3-butadiene) and E-1,4-poly-[2,3-bis(trimethylsilyl)-1,3-butadiene] by 13C and 29Si NMR

Summary Reaction of E-1,4-poly(2-triethylsilyl-1,3-butadiene) (I) with m-chloroperbenzoic acid (MCPBA) yields E-1,4-poly(2,3-epoxy-2-triethylsilyl-1,3-butadiene) (II). Similar reaction of E-1,4-poly[2,3-bis(trimethylsilyl)-1,3-butadiene] (III) with MCPBA gives E-1,4-poly[2,3-epoxy-2,3-bis(trimethylsilyl)-1,3-butadiene] (IV). The product polymers have been characterized by ¹H, ¹³C, and ²⁹Si NMR, IR, GPC, TGA and elemental analysis. ¹³C and ²⁹Si NMR permit Stereochemical analysis on the microstructures of II and IV.     

Cobalt(II), Zinc(II) and Cadmium(II)-Squarate Complexes with N-Methylimidazole

Three M(II)-squarate complexes, [Co(sq)(H₂O)(Nmim)₄] (1), [Zn(μ_1,3-sq)(H₂O)₂ (Nmim)₂] _n (2) and [Cd(μ_1,3-sq)(H₂O)₂(Nmim)₂] _n (3) (sq = squarate, Nmim = N-methylimidazole) have been synthesized and characterized by elemental, spectral (IR and UV–Vis.) and thermal analyses. The molecular structures of the complexes have been investigated by single crystal X-ray diffraction technique. The squarate ligand acts as two different coordination modes as a monodentate (in 1) and bis(monodentate) (O ^1– O ³ ) bridging ligand (in 2, 3). The Co(II) atom has a distorted octahedral geometry with the basal plane comprised of three nitrogen atoms of Nmim ligands and a oxygen atom of squarate ligand. The axial position is occupied by a nitrogen atom of Nmim and one aqua ligand. The crystallographic analysis reveals that the crystal structures of 2 and 3 are one-dimensional linear chain polymers along the c and b axis, respectively. The configuration around each metal(II) ions are distorted octahedral geometry with two nitrogen atoms of trans-Nmim, two aqua ligands and two oxygen atoms of squarate-O¹,O³ ligand. These chains are held together by the C–H···π, π···π and hydrogen-bonding interactions, forming three-dimensional network.     

One-Dimensional Cobalt(II) and Zinc(II) Succinato Coordination Polymers with Nicotinamide: Synthesis, Structural, Spectroscopic, Fluorescent and Thermal Properties

Cobalt(II) and zinc(II) succinato (suc) coordination polymers with nicotinamide (nia), {[Co(μ-suc)(H₂O)₂(nia)₂] · 2H₂O} _n (1) and {[Zn(μ-suc)(H₂O)₂(nia)₂] · 2H₂O} _n (2) have been synthesized and characterized by elemental analyses, magnetic moments, IR and TG-DTA. Single-crystal X-ray analyses of 1 and 2 reveal that these complexes are isostructural and crystallize in triclinic space group Complexes 1 and 2 are 1-D coordination polymers, in which the metal(II) ions exhibit an octahedral geometry with two suc, two nia and two aqua ligands. The nia ligand is N-bonded, while the suc ligand bridges the metal centers through the carboxylate groups. The 1D chains are further assembled to form 3D networks by strong N–H···O and OW–H···O hydrogen bonds. IR spectra confirm the coordination modes of both suc and nia ligands, while TG-DTA data are in agreement with the crystal structures. Fluorescent analysis in the solid state shows that all complexes display intraligand (π–π*) emissions of nia.     

Preparation of Zinc(II) Oxide Nanoparticles from a New Nano-Size Coordination Polymer Constructed from a Polypyridyl Amidic Ligand; Spectroscopic, Photoluminescence and Thermal Analysis Studies

A new zinc(II) coordination polymer, {[Zn(bpcdp)₂(DMF)₄](ClO₄)₂·(H₂O)₂}_n (1) bpcdp = 2,6-bis(4-pyridinecarboxamide)pyridine has been synthesized and characterized by IR, ¹HNMR and ¹³CNMR spectroscopy. The single crystal X-ray data of compound 1 shows the zinc(II) atom has been considered as octahedral with ZnN₂O₄ coordination sphere. Two nitrogen atoms of bpcdp ligand and four oxygen atoms of DMF molecules have occupied coordination sphere around zinc(II) atoms. The prepared zinc(II) coordination polymer grows in three-dimensional network by hydrogen bonding and π–π stacking interaction. The nanostructure of compound 1 were obtained by sonochemical process and studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), IR and NMR spectroscopy. Thermal stabilities of single crystalline and nano-size samples of compound 1 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The ZnO nanoparticles were obtained by direct calcination of compound 1 at 400 °C and by thermolysis in oleic acid at 200 °C. The obtained zinc(II) oxide nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).     

Synthesis and crystal structure of a novel zinc(II) coordination polymer with mixed ferrocenyl diketone and bipyridine ligands

A novel zinc(II) coordination polymer [Zn(fca)₂(bpe)]_n·2nH₂O (bpe=1,2-bis(4-pyridyl)ethene, fca=C₅H₅FeC₅H₄C(OH)CHCOCH₃) was obtained by the reaction of Zn(OAc)₂·2H₂O with bpe and 1-ferrocenylbutane-1,3-dione (ferrocenoylacetone, Hfca) in methanol solution. X-ray structural analysis reveals that the compound contains two kinds of ligands: one is the 1,2-bis(4-pyridyl)ethene ligand, directly bridging zinc(II) centers to form a one-dimensional chain [Zn(bpe)]_n, the other is the enolized ferrocenylacetone chelating the central ion. The zinc(II) ion is in an elongated octahedral environment with four oxygen atoms from two distinct enolized ferrocenoylacetone, two nitrogen atoms of the bridging 1,2-bis(4-pyridyl)ethene ligands.     

Hydrothermal Preparation, Crystal Structures, Spectroscopic and Thermal Analyses of Cadmium(II) and Cobalt(II) Coordination Polymers With Pyridine-2,3-dicarboxylic Acid

Two novel 1D coordination polymers, [M(μ-2,3-pydc)(H₂O)₃]_n (M = Cd for 1 and Co for 2) (2,3-pydcH₂ = pyridine-2,3-dicarboxylic acid) have been hydrothermally synthesized. Both complexes were characterized by elemental analysis and by IR and UV–Vis spectroscopy. Their molecular and crystal structures were determined by X-ray crystal structure analysis and their thermal stability by TGA-DTA methods. Compound 1 crystallizes in the orthorhombic Pca2 space group, while compound 2 crystallizes in the triclinic P−1 space group. Polymeric chains of 1 and 2 are composed of M(II) ions bridged by pyridine-2,3-dicarboxylate ions (2,3-pydc) in N,O,O′ fashion. Distorted octahedral coordination geometry around the metal ions is completed by three water molecules. A wide range of hydrogen bonding (of the O–H···O type) is also present in the crystal structures. These interactions lead to formation of a 3D structure for 1 and 2D network for 2.     

Syntheses and Crystal Structures of Zinc(II) and Nickel(II) Coordination Polymers Based on Diphenic Acid and 1,2-Bis(4-pyridyl)ethane Coligands

Two new metal coordination polymers [Zn₂(dpa)₂(bpa)] (1) and [Ni₄(dpa)₄(bpa)₃] (2) [H₂dpa = 2,4′-biphenyldicarboxylic acid and bpa = 1,2-bis(4-pyridyl)ethane] have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complex 1 shows a 2D (4,4) topological net and complex 2 features a 3D network with (4.6²)₂(4².6¹⁰.8³) topology. Fluorescent study of complex 1 shows that it has an emission at 414 nm in the solid state at room temperature.     

Synthesis and Characterization of ZnS and ZnO Nanoparticles via Thermal Decomposition of Two New Synthesized One-Dimensional Coordination Polymers at Two Different Temperatures

Two new Zn(II) coordination polymers from ligand 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene (bpdh) with different anions, [Zn(μ-bpdh)₂(NCS)₂]_n (1) and [Zn(μ-bpdh)₂(N₃)₂]_n (2) were synthesized and characterized by IR spectroscopy, elemental analyses and X-ray crystallography. The structures of the 1 and 2 may be considered coordination polymers of zinc(II) consisting of metallocyclic chains formed by bridging bpdh ligands, making a one-dimensional array of Zn^II and bpdh in a 1:2 stoichiometry. Different morphologies of ZnS and ZnO nano-particles were obtained by thermolyses of compounds 1–2 in oleic acid at different temperatures under air atmosphere, respectively. The ZnS and ZnO nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).     

Syntheses and structures of two- and one-dimensional organic–inorganic hybrid compounds assembled from PbI2 and 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene

The reaction of the elongated Schiff base 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene and PbI₂ in DMF gave rise to two- and one-dimensional organic–inorganic hybrid compounds [PbI₂(C₁₂H₁₀N₄)]_2n·0.5n(C₁₂H₁₀N₄) (1) and [PbI₂(C₁₂H₁₀N₄)]_n (2), respectively, at different M/L ratios 2:1 and 1:1,and their structures were determined by single-crystal X-ray crystallography. Compound 1 exhibits 2D-layered structure formed from PbI₂ chains bridged by the Schiff base with the free ligand regularly lying between two layers, while compound 2 possesses a 1D-zig-zag chain where lead atom is in the rarely observed four-coordinate holodirected configuration. 2 is the first example of PbI₂-based polymer with terminal coordinated iodine atoms.     

Structural diversity and solution behavior of low-valent iridium complexes bearing 1,4-diazabutadiene ligands

Three types of 1,4-diazabutadiene stabilized low-valent iridium complexes, namely [IrCl(cod)(MesDAB)] (1), [IrCl(coe)(MesDAB)] (2) and [IrCl(MesDAB)₂] (3), have been prepared from 1,4-bis(2,4,6-trimethylphenyl)-1,4-diaza-1,3-butadiene (MesDAB) and [IrCl(cod)]₂ or [IrCl(coe)₂]₂, respectively. The complexes have been investigated by NMR spectroscopy and X-ray diffraction experiments. While tetra-coordinated 2 and penta-coordinated 3 maintain their solid state structure in solution, penta-coordinated 1 shows fluxional behavior. The crystal structures determined indicate strong π-backbonding towards the MesDAB ligand in all cases.     

Controllable Assembly of Two Zn(II) Polymers via Varying Auxiliary Ligand: From 4-Connected cds Net to 4-Connected sql Tetragonal Plane Net

Two new Zn(II) coordination polymers, namely [Zn(H₂ODPT)(bpe)(H₂O)] _n (1) and [Zn(H₂ODPT)(bpp)] _n (2) (H₄ODPT = 4,4′-oxydiphthalic acid, bpe = 1,2-bis(4-pyridyl)-ethane, bpp = 1,3-bis(4-pyridyl)-propane) were successfully synthesized via varying auxiliary ligands. Single crystal X-ray analysis reveals that 1 features a three-dimensional extended framework, which can be simplified into a 4-connected cds topological network; and, 2 features a two-dimensional layered framework, which can be simplified into a 4-connected sql tetragonal plane net. In addition, the luminescent and thermal stabilities properties were also investigated.     

Hydrothermal Synthesis, Characterization of Mn(II) and Cd(II) Coordination Polymers Assembled from Semi-Rigid Oxo-Bridged Carboxylate and N-Donor Ligands

Two new metal–organic coordination polymers containing Mn(II) and Cd(II) with oxo-bridged and N-donor ligands, [Mn(oba)(2,2′-bipy)] _n (1) and {[Cd(oba)(bib)]·H₂O} _n (2) [2,3′-H₂oba = 2-(3-carboxyphenoxy)benzoic acid, 2,2′-bipy = 2,2′-bipyridine, and bib = 4,4′-bis(2-methylimidazole-1-ylmethyl)biphenyl], have been prepared and characterized by elemental analysis, Fourier infrared spectroscopy, and X-ray diffraction. Complex 1 has a 3D supramolecular network constructed from 1D zigzag chain via π–π stacking interactions. Complex 2 features 1D ladder-like chain which consists of 1D helical arrays and bib pillars. Moreover, photoluminescence properties of the bib ligand and the Cd(II) complex were investigated.     

Synthesis, Crystal Structures and Fluorescence Properties of Two One-Dimensional Cadmium(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two one-dimensional Cd(II) coordination polymers constructed by ribbon-like molecules, {[Cd(L₁)₂(NO₃)]·NO₃} _n (1) (L₁ = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)benzene) and [Cd(L₂)₂(NO₃)₂] _n (2) (L₂ = 1,3-bis(benzimidazol-1-yl)benzene) have been obtained through assembly of the two structurally similar flexible bis(benzimidazole)-based ligands and cadmium nitrate tetrahydrate. The cadmium(II) centers display different coordination environments with trigonal-bipyramidal geometry in 1, and a octahedral geometry in 2. Weak C–H···O interactions in 1 result in a two-dimensional supramolecular layer; two π–π interactions are present in 2 forming a three-dimensional supramolecular network structure. The solid state fluorescence properties of 1 and 2 were investigated.     

Synthesis and Characterization of ZnO Nano-rods via Thermal Decomposition of Zinc(II) Coordination Polymers and Their Photocatalytic Properties

Two Zinc(II) coordination polymers [Zn(NO₂)₂(3-bapp)]_n·nH₂O (1) and [Zn(NO₂)₂(4-bapp)]_n·nH₂O (2) have been synthesized by using zinc acetate, sodium nitrite, {3-bapp: 2,6-bis (3-amidopyridyl) pyridine} and {4-bapp: 2,6-bis (4-amidopyridyl) pyridine} as precursor. Pure phase ZnO nano-rods were obtained by thermolyses of compound 1 and 2 in 600 °C for 3 h under air atmosphere. The ZnO nano-rods were characterized by X-ray diffraction and scanning electron microscopy. The average crystallite size of ZnO nano-rods (1), (2) were determined 30 and 40 nm respectively. The particle size of hexagonal nano-rods of (1) and (2) are in the range of 20–70 and 30–80 nm respectively. The photo-catalytic performance of degradation of Congo red solution was increased when the particles size were decreased.     

Synthesis,Crystal Structure and Luminescence Property of a New (6,3)-Connected Zn(II) Coordination Polymer

The 2D coordination polymer, [Zn(dpa)(bpp)] _n (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, bpp = 1,3-di(4-pyridyl)propane) was prepared by hydrothermal synthesis in the presence of NaOH and characterized by single-crystal X-ray diffraction, FTIR spectra, element analysis and thermal analysis. The crystal structure determination reveals that the carboxylate groups of 2,4′-biphenyldicarboxylic acid are acting as bridging ligands and adopt two coordination modes; bis-monodentate and bidentate chelating. The network consists of a 2D (6,3)-connected architecture. At room temperature the solid-state luminescence spectrum of [Zn(dpa)(bpp)] _n shows a blue emission at about 354 nm upon excitation at 333 nm.     

Sonochemical Syntheses of Nano-Scale Mixed-Ligand Lead(II) Coordination Polymers; Different Nano-Structures with Different Anions

Nano-structures of three new Pb(II) coordination polymers, [Pb(3-pyc)(N₃)(H₂O)] _n (1), [Pb(3-pyc)I] _n (2), and [Pb(3-pyc)Br] _n (3), {3-Hpyc =3-pyridinecarboxylic acid}, were synthesized by a sonochemical method. The new nano-structures were characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. Compound 1 and 2 were structurally characterized by single-crystal X-ray diffraction and consists of two and three-dimensional coordination polymers, respectively. The thermal stability of compounds 1–3 were studied by thermal gravimetric and differential thermal analyses and compared. This study demonstrates the sonochemical may be suitable method for the preparation of nanoscale coordination polymers and dependent on their packing they may produce different and interesting morphologies.