Structural, Theoretical and Multinuclear NMR Study of a New Polymeric Mercury(II) Complex with an Ambidentate Phosphorus Ylide

The reactions of phosphorus ylides of the type Ph₃P=C(H)C(O)R [R = 2,4-dichlorophenyl (L ¹ ) and 4-isopropylphenyl (L ² )] with HgX₂ [X = Cl (1, 4), Br (2, 5) and I (3, 6)] salts using methanol as a solvent are reported. Single crystal X-ray analysis carried out on L ¹ , 2 and 3 and reveals the presence of a novel polymeric structure for 2 and a centrosymmeteric dimeric structure for 3. The complexes have been studied by elemental analyses, IR, ¹H and ³¹P NMR spectroscopy. On the basis of DFT calculations, the formation of [Hg₂Br₆]^2? anions in 2 has a key role in the formation of the polymeric structure; and, the formation of [Hg₂L₂I₄] molecule thermodynamically is about 25 kcal/mol more favorable than the corresponding [Hg₂L₂Br₄] molecule.     

Theoretical study of the reactive intermediate Si2Me4[(η5-C5H4) Fe(CO)2] 2 2−

In two previous papers (Kinget al., J. Organomet. Chem. 19, 327, 1969; Pannellet al., Organometallics 9, 859, 1990), the synthesis and X-ray structure of the two tetramethyl disilyl complexes [(η⁵-C₅H₅) Fe(CO)₂]₂Si₂Me₄ (I) and Si₂Me₄[(η⁵-C₅H₄) Fe(CO)₂CH₃]₂ (II) were reported. ComplexII is obtained fromI [2]. However, attempts to form other derivatives fromI have generally failed. In the chemical process to getII fromI, an intermediate complex, Si₂Me₄[(η⁵-C₅H₄) Fe(CO)₂] ₂ ^2? (III), is probably formed. This is similar to complexII without the two methyl groups bonded to the Fe atoms. Therefore, a theoretical study that may shed some light on the intermediate structure, stability, and reactivity is justified. We have developed theoretical studies consisting of extended Huckel electronic structure calculations on the simulated intermediate geometry. The results obtained from these calculations suggest that it might be stable enough to form during reactions of complexI. The more reactive sites, which suggest reaction alternatives, are pointed out.     

Two Supramolecular Microporous Metal–Organic Frameworks Templated by Keggin Polyoxometalates

Two new Keggin polyoxometalates (POM)-templated supramolecular metal–organic frameworks (MOF) with micropores, Cu₃(L)₆[H₃(PMo₁₂O₄₀)₂]·6H₂O (1) and Cu₃(L)₆[H₅(SiW₁₂O₄₀)₂]·6H₂O (2) (L?=?1,2-bis(imidazol-1-ylmethyl)ethane), have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and cyclic voltammetry. These two isostructural compounds are constructed by two distinct moieties, a Keggin polyanion and a linear [Cu(L)₂]⁺ subunit. The [Cu(L)₂]⁺ subunits further form a microporous MOF through supramolecular interactions. The Keggin polyanions act as templates inducing the micropores. The electrochemical and electrocatalytic behavior of compounds 1 and 2 bulk-modified carbon paste electrodes (1-, 2-CPE) was studied.     

Positions and Stereochemistry of Methyl Branches in the Novel Sex Pheromone Components Produced by a Lichen Moth, Lyclene dharma dharma

Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produce three sex pheromone components (I–III), for which we assigned the following novel chemical structures; 6-methyl-2-octadecanone (1) for I, 14-methyl-2-octadecanone (2) for II, and 6,14-dimethyl-2-octadecanone (3) for III. In the Iriomote Islands where the insects were collected, a lure including racemic 1 and 2 attracted the male moths without mixing 3. In this study for further confirmation of the plane structures, the positional isomers with a methyl branch at the 4-, 5-, 7-, 13-, or 15-position (4–8, respectively) were synthesized. The GC-MS analyses revealed that natural components I and II were best fitted with those of 1 and 2, respectively, among the methyl-2-octadecanones examined, indicating the usefulness of this analytical instrument and authentic standards for the determination of the positions of methyl branches. In field trapping tests, 4–8 could not substitute for 1 or 2, nor did these compounds inhibit the active binary lure of 1 and 2, indicating that the males strictly recognized the 2-ketones with a methyl branch at the 6- or 14-positions. Next, the absolute configurations of I and II were determined by HPLC with a normal-phased chiral column (Chiralpak AD-H), which could separate the enantiomers of both 1 and 2. The chiral HPLC analysis of a crude pheromone extract indicated that the females exclusively produced (S)-1 and (S)-2. Furthermore, a field evaluation of each enantiomer revealed that (S)-1 and (S)-2 were bioactive but (R)-1 and (R)-2 were not.     

Metallo-supramolecular Polymers: Versatile DNA Binding and Their Cytotoxicity

Metallo-supramolecular polymers (RuL1, RuL2, RuL3, FeL3, and FeL4) prepared by complexation of bis(terpyridine) derivatives with Ru²⁺ or Fe²⁺ ions with octahedral coordination structures showed high binding ability to several DNAs (calf thymus DNA, herring sperm DNA, [poly(dA-dT)]₂, and [poly(dG-dC)]₂), which were revealed by UV–Vis absorption titration experiments. The electrostatic interactions between the metal cations of the polymers and phosphate anions of DNA led to formation of conjugate structure. The binding constant observed reached 3.7 × 10⁷ M^?1, which is the highest among values reported for metal complexes to date. Based on a long strand structure of the polymer, groove binding is most possible binding mode. Cell viability experiments showed that RuL3 and FeL3 displayed highly statistical significance (**p<0.01) to human non small cell lung cancer cell lines (NCI-H460).     

Uranyl Coordination Polymers Incorporating η5-Cyclopentadienyliron-Functionalized η6-Phthalate Metalloligands: Syntheses,Structures and Photophysical Properties

The reaction of two η⁵-cyclopentadienyliron(II)-functionalized terephthalate and phthalate metalloligands, namely [(η⁵-C₅H₅)Fe^II(η⁶-1,4-HO₂CC₆H₄CO₂H)][(η⁵-C₅H₅)Fe^II(η⁶-1,4-HO₂CC₆H₄CO₂)][PF₆] and [(η⁵-C₅H₅)Fe^II(η⁶-1,2-HO₂CC₆H₄CO₂H)][(η⁵-C₅H₅)Fe^II(η⁶-1,2-HO₂CC₆H₄CO₂)][PF₆]—hereafter [H₂ CpFeTP][HCpFeTP][PF₆] and [H₂ CpFeP][HCpFeP][PF₆], respectively—with [UO₂(NO₃)₂]·6H₂O under hydrothermal conditions yielded four new coordination polymers; (1) [(UO₂)F(HCpFeTP)(PO₄H₂)]·2H₂O, (2) [(UO₂)₂(CpFeTP)₄]·5H₂O, (3) [(UO₂)₂F₃(H₂O)(CpFeP)], and (4) [H₂ CpFeP][UO₂F₃]. The use of metalloligands has proven to be a viable route towards the incorporation of a secondary metal center into uranyl bearing materials. Depending upon the protonation state, the iron sandwich metalloligands may vary from zwitterionic neutral or monoanionic coordinating species as observed in compounds 1–3, or a positively charged species that hydrogen bonds with anionic [UO₂F₃]^? chains as observed in 4. Further, the hydrolysis of the charge balancing PF₆ ^? anion increases the diversity of UO₂ ²⁺ coordinating species by contributing both F^? and PO₄ ^3? anions (1, 3, 4). The luminescent properties of 1–4 were also studied and revealed the absence of uranyl emission, suggestive of a possible energy transfer from the uranyl cation to the iron(II) metal center.     

Synthesis of a novel triazine flame retardant containing sulfur and its application to cotton fabrics

A novel triazine flame retardant (FR) has been successfully synthesized by the reaction of cyanuric chloride with sodium sulfanilate followed by diethanol amine. Its structure has been fully characterized by IR and ¹H NMR spectroscopy. The effects of reaction solvent, acid-binding agent, reaction temperature, and molar ratio of starting materials on the yield of FR were investigated in detail. Experiments showed that when the molar ratio of intermediate I to diethanol amine is 1 to 1.2 in the presence of sodium carbonate as acid-binding agent in acetone-water at 45 °C, the yield of the obtained FR reaches 81.4%. Thermogravimetry (TG) test indicated that the FR has good thermostability and char-forming ability. In addition, the flame retardancy and thermal behavior of the cotton fabrics treated with FR were studied by limiting oxygen index (LOI), vertical flammability test, and thermogravimetry (TG) to evaluate the flameretardant performance of the target FR. These results demonstrated that the flame retardancy and thermal stability of the cotton fabrics treated with FR were clearly improved.     

Fluorescence Properties Change of Lanthanide Coordination Polymers Dispersed in Mesoporous SBA-15 by Energy Transition Process

Four lanthanide coordination polymers, {[Ln(HPDA)(PDA)(H₂O)₂]·4H₂O} _n (Ln?=?Sm (1), Eu (2), Tb (3)) and {[Sm₃(H₂PDA)₂(HPDA)₂(PDA) (OH)₅(H₂O)₃]·2dta·4H₂O} _n (4) (H₂PDA?=?pyridine-2,6-dicarboxylic acid, dta?=?diethyl amine), have been synthesized under hydrothermal conditions and were characterized by elemental analysis, IR spectrometer, and single-crystal X-ray crystallography. In the complexes 1–3, the 1D chains are assembled into 2D layer by hydrogen bonds formed between the carboxyl groups, and were further assembled into 3D framework by hydrogen bonds and π–π stacking interactions. In complex 4, each Sm³⁺ ion connected to the neighboring Sm³⁺ ion through bridging carboxyl oxygen atoms, and then give rise to a new 2D layered open-framework structure. The 3D supramolecular structure of 4 is constructed through hydrogen-bonding and π–π stacking interactions between adjacent metal–organic polymeric coordination chains. Complexes 1–3 were dispersed in mesoporous materials SBA-15 in DMF solution (denoted as ML-SBA-15, ML?=?1, 2, 3), which were characterized by XRD, IR, and fluorescence spectra. Compared to the complexes 1–3, the photoluminescence efficiency of hybrid material was improved by the energy transition between mesoporous materials and the complexes. The complexes encapsulated in mesoporous materials SBA-15 exhibited stronger luminescence intensity and longer fluorescence lifetime.     

Simultaneous Growing of Two New Cd(II) Metal–Organic Frameworks with 2,6-Naphthalendicarboxylic Acid as New Precursors for Cadmium(II) Oxide Nanoparticles: Thermal, Topology and Structural Studies

Crystal structure and thermal stability of two new 3D Cd(II) metal–organic frameworks (MOF) containing 2,6-naphthalenedicarboxylate, [Cd(NDC)(DMF)], 1, and [Cd₃(NDC)₄], 2 (H₂NDC = 2,6-naphthalenedicarboxylic acid; DMF = N,N-dimethylformamide) have been studied. These two MOFs grow simultaneously within the same solution to give multiple crystals that are due to the general lability of Cd(II) complexes. Structure 1 shows a 3D neutral metal–organic framework with PtS topology and crystallizes in the triclinic system, space group P-1 (No. 2), whilst 2 crystallizes in the orthorhombic system, space group Fdd2 (No. 43) with body-centered cubic bcu-(4²⁴.6⁴) topology. The elongated nature of NDC results in large cavities in both compounds; however, the pores are filled by coordinated DMF molecules in 1. The thermal stability of 1 and 2 were studied by thermogravimetry and show stability to 400 °C for 1 and continuous weight loss for 2. CdO nanoparticles were prepared by direct calcination of 1 and 2 at 600 °C. The CdO nanoparticles were characterized by X-ray powder diffraction and its morphology were studied by scanning electron microscopy. The results show that the CdO is pure and has a uniform morphology.     

Syntheses and Structural Analytical Studies of Two Co(II) Complexes Based on 1,4-Di(benzimidazole-1-yl)benzene

Two new Co(II) complexes of 1,4-di(benzimidazole-1-yl)benzene ligand (L) with the formulas [(CoLCl₂)(CHCl₃)(DMF)]_∞ (1) and [CoL(NO₃)₂]_∞ (2) have been synthesized by anion-directed self-assembly. Both complexes have been characterized by elemental analyses, IR, and X-ray single crystal diffraction. Complexes 1 and 2 exhibit 1D chain structures. In 1, Co(II) ions possess a distorted tetrahedral coordination environment composed of N₂Cl₂ donors from two L ligands and two chloride ions, while the Co(II) ions in 2 reveal a distorted octahedral structure defined by the N₂O₄ donors from two L ligands and two nitrate anions. These results illustrate that the anions play an important role in the self-assembly of metal–organic materials.     

Urothermal Synthesis of a Photoluminescent Coordination Polymer with Rutile Topology

A new coordination polymer [Cd₃(btc)₂(e-urea)₄]^.(e-urea)₂ (1; btc = 1,3,5-benzenetricarboxylate; e-urea = ethyleneurea) has been urothermally synthesized using ethyleneurea hemihydrate as the solvent and exhibits (3,6)-connected rutile (rtl) topology. The structure of 1 consists of trinuclear Cd units and the btc linkers. Species 1 features a non-interpenetrating three-dimensional open framework with channels filled by the e-urea additives and guest molecules. The thermogravimetric behavior and photoluminescent property of 1 were studied.     

Synthesis, Crystal Structures and Properties of Two Metal–Organic Frameworks Constructed from Pyridine Dicarboxylate and Flexible Bis(imidazole) Ligand

Two novel interesting metal–organic frameworks, [Zn(PDA)(bbi)] _n (1) and [Cd₂(PDA)₂(bbi)₂(H₂O)₂·10H₂O] _n (2) [H₂PDA = pyridine-2,6-dicarboxylic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)] have been isolated under hydrothermal conditions and structurally characterized. X-ray single crystal structure analysis reveals that complex 1 crystallize in monoclinic P2₁/c space group, while complex 2 crystallize in triclinic P-1 space group. The PDA^2? anions act in two different coordination modes: terminal chelating for 1 and chelating and bis-monoatomic bridging for 2. Polymeric chains of 1 and 2 are composed of Zn(II) and Cd(II) ions bridged by bbi ligands. The fluorescent properties of 1 and 2 were also investigated.     

Unique microstructure analysis of ethylene-propylene copolymer synthesized using catalytic system based on α-diimine nickel complexes: a comparative study by 13C NMR technique

The microstructure of rubber-like ethylene-propylene copolymer (MN4) produced by a mixed nickel-based system (MN) containing catalysts of dibromo[N,N′-bis(2,6-diisopropylphenyl)-2,3-butanediimine]nickel(II) n1 and dibromo[N,N′-(phenanthrene-9,10-diylidene)bis(2,6-diisopropylaniline)]nickel(II) n2 was determined by ¹³C NMR technique. Sequences distribution of ethylene (E), propylene (P), EP, inverted propylene and uninterrupted methylene and also methylene number-average sequence lengths for the copolymer (MN4) were estimated. The results obtained from the MN4 EP copolymer were compared with reported copolymers which had been synthesized using constrained geometry catalyst (CGC) and vanadium-based Ziegler-Natta catalyst. The results demonstrated that the MN4 EP copolymer had fewer alternating comonomer sequences than ethylene-propylene elastomers obtained by CGC and vanadium-based (V) catalysts. A large number of the inversion structures (66 %) and high mole percent of sequences containing a long branch (3.2 mol%) were also observed in unique microstructure of the copolymer (MN4).     

Crystal Structures and Luminescent Properties of Two Lanthanide(III) Complexes Featuring Double-Stranded Helical Chains of Based on 2-Sulfoterephthalate

Hydrothermal reaction of Eu³⁺ and Dy³⁺ salts with monosodium 2-sulfoterephthalate (NaH₂stp) gives two 2D lanthanide coordination polymers, [Ln(stp)(H₂O)₂] _n (Ln = Eu (1) and Dy (2)). Single-crystal X-ray diffraction of the complexes reveal that both 1 and 2 crystallize in the triclinic crystal system of Pī space group. For 1, each Eu³⁺ ion lies in a 9-coordinated slightly distorted tri-capped triangle pyramidal configuration. The stp ligands adopt a μ ₄-type link to the metal ions to form a 2D layer-like structure, of which there exist the left- and right-handed double-stranded helical chains. For 2, each Dy³⁺ ion is in a 8-coordinated distorted bi-capped triangle pyramidal geometry. The double-stranded helical chains in 2 differ from those in 1. The thermal stabilities of the two compounds are studied by TGA. The solid state photoluminescence of 1 and 2 are reported. The fluorescent decay curves of the ligand and compounds indicate that 1 has the lifetime of 286.7 μs, τ ₁ = 0.51 ns and τ ₂ = 3.07 ns for the ligand, and for 2, τ ₁ = 0.53 ns and τ ₂ = 2.71 ns.     

Syntheses,Crystal Structures and Physical Properties of Four Zinc/Cadmium Coordination Polymers Based on 4-Nitrophthalic Acid and N-donor Auxiliary Ligands

Four new d¹⁰ metal coordination polymers, [Zn(4-NPA)(2,2-bipy)] _n (1), [Zn(4-NPA)(1,3-bimb)·H₂O] _n (2), [Cd(4-NPA)(2,2-bipy)] _n (3) and [Cd(4-NPA)(1,3-bimb)·H₂O] _n (4) (4-NPAH₂ = 4-nitrophthalic acid, 2,2-bipy = 2,2-bipyridine, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl)-benzene), have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, and X-ray single crystal diffractions. Compounds 1?3 possess different one-dimensional (1D) chain structures. Compound 4 shows a two-dimensional (2D) layered structure. Moreover, the luminescent and thermal stabilities properties of compounds 1–4 were investigated in the solid state.     

Preparation of a Novel Class of Cationic Gemini Imidazolium Surfactants Containing Amide Groups as the Spacer: Their Surface Properties and Antimicrobial Activity

A class of novel cationic Gemini imidazolium surfactants containing amide groups as the spacer were synthesized from ethylenediamine and 1-bromoalkane(C₈, C₁₀, C₁₂, C₁₄, C₁₆) by N-alkylation to get N,N′-dialkyl ethylenediamine (1a–e), 1a–e was further reacted with chloroacetyl chloride by N-acylation to get N,N′-(ethane-1,2-diyl)bis(2-chloro-N-alkylacetamide) (2a–e), which was further reacted respectively with 1-methyl imidazole by quaternized to form the surfactant molecule, N,N′-((ethane-1,2-diyl)bis(alkyl-azanediyl)bis(2-oxoethane-2,1-diyl)) bis(1-methyl-1H-imidazol-3-ium) dichloride. The structures of intermediates (1a–e) and (2a–e) were characterized by IR and ¹H NMR. The structures of the surfactants (3a–e) were characterized by IR, ¹H-NMR and ¹³C-NMR and element analysis. The critical micelle concentrations (CMC) of 3a–e were determined by the conductivity method at 25 °C. The CMC values decreased with increasing the length of the hydrophobic chain. The surfactants (3a–e) showed good foaming stability, emulsion ability and wetting ability. The surfactants (3a–e) also have good antimicrobial activity against Staphylococcus aureus, Escherichia coli and Bacillus subtilis.     

Synthesis, Analysis, and Field Activity of Sordidin, a Male-Produced Aggregation Pheromone of the Banana Weevil, Cosmopolites sordidus

An efficient synthesis of the diastereoisomers of sordidin (1), a male-produced aggregation pheromone of Cosmopolites sordidus, has been developed from commercially available 4-methylpent-4-en-2-ol (2). Preparation of exo-β-sordidin (1a) and endo-β-sordidin (1b) is via the anti epoxide, 4d, which is derived via iodocarbonation of 2. The endo-α-sordidin (1c) and exo-α-sordidin (1d) are prepared from the corresponding syn epoxide, which is available via stereo-controlled epoxidation of the triisopropylsilyloxy derivative, 3b. Silyloxy derivatives of the epoxides, 4, efficiently alkylate the anions of N-cyclohexyldiethylketimine (6a) and 3-pentanone N,N-dimethylhydrazone (6b). Acidic work-up of these alkylation reactions promotes cyclization to give 1. Gram quantities of 1a?1d, 1a + 1b and 1c + 1d have been prepared by this route. In field tests in a banana plantation in Costa Rica, compounds 1a?1d significantly increased capture rates of standard pseudostem traps. Comparable numbers of adults were attracted to pseudostem traps baited with the major naturally occurring isomers of sordidin 1c + 1d or 1a?1d. Although addition of the minor naturally occurring isomers of sordidin (1a and 1b) to pseudostem traps increased capture rates above controls, these compounds did not increase attraction of pseudostem traps to the same extent as 1a?1d. In comparison tests with conventional pseudostem traps, significantly more adults were trapped in water-containing pitfall traps baited with 1a?1d.     

Hydrothermal Syntheses and Crystal Structures of Three Zn(II) Coordination Compounds Constructed with 3,5-Pyrazoledicarboxylic Acid

Three novel metal–organic coordination compounds, [Zn(Hdcp)(H₂O)₄]·1.5H₂O (1), [Zn(Hdcp)(H₂O)₂]_∞ (2) and [Zn₃(dcp)₂(H₂O)₅]_∞ (3) with the ligand 3,5-pyrazoledicarboxylic acid were prepared by the hydrothermal method. The complexes were structurally characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. Compound 1 is a mononuclear molecule that is linked into a 3D supramolecular framework via N–H···O and O–H···O hydrogen bonds. In 2, two types of carboxylic bridges were found between Zn^II ions to form a 1D double-chain. The 1D chains were further construct into a 3D structure by hydrogen bonds. Trinuclear 3 consists of 1D bi-infinite parallelogram chains of [Zn₃(dcp)₂(H₂O)₃] trimers. In the basic trinuclear unit a further bridging mode of the ligand is seen where two dcp^3? ligands chelate three Zn^II ions by utilizing five donors of the dcp^3? ligand. The photoluminescent properties of 1, 2 and 3 were investigated.     

Targeted Highly-Thermostable Metal–Organic Frameworks Directed by Imidazole: Syntheses, Structures, Thermal Behaviors and Luminescent Properties

Three new isostructural 3D lanthanide MOFs (Ln(HBPTC)(H₂O)) (Ln = Tb (1), Pr (2), Nd (3); H₄BPTC = 3,3′,4,4′-biphenyltetracarboxylic acid) have been synthesized under hydrothermal conditions using imidazole as a structure-directing agent, and characterized by elemental analyses, IR, thermogravimetric analyses (TGA) and powder X-ray diffraction (PXRD) analyses. Topologically, compounds 1–3 demonstrate an intriguing 3D (6, 6)-connected network with the Schläfli symbol of (4¹⁰·6⁵)(4⁹·6⁶); and if the dinuclear (Ln₂) clusters are considered as the single 8-connected nodes, they can be described as a scarcely reported (4, 8)-connected alb net constructed from two intertwining sqp-4 nets. TGA and PXRD analyses reveal that compounds 1–3 exhibit high thermal stability, at least being stable up to 410 °C. Furthermore, the luminescence studies were performed on compound 1 and its dehydrated phase in the solid state at room temperature. The results demonstrate that compound 1 displays intense green emission, implying its potential application as fluorescence material. And the luminescence of 1 is quenched when removing the coordinated water molecules.     

Thermal and Fluorescence Properties of New Nanostructured Hg(ll) -2,2′-Bipyridine Derivative Complexes

Two new nano-structured Hg(II) supramolecular complexes, [Hg(5,5′-di-t-but-bpy)(μ-Br)Br]₂[Hg(5,5′-di-t-but-bpy)Br₂](1) and [Hg(5,5′-di-t-but-bpy)I₂] (2) were synthesized by the sonochemical method. The structures of 1 and 2 were characterized by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR spectroscopy and single crystal X-ray diffraction. Their thermal stabilities were studied by thermogravimetric and differential thermal analyses. Solid-state luminescent spectra of 1 and 2 indicate a fluorescent broad emission band between 304 and 404 nm with excitation at 284 nm. These nanostructured coordination polymers were characterized by scanning electron microscopy, elemental analysis, and IR spectroscopy.