A Series of Luminescent Lanthanide–Organic Complexes Constructed from In Situ Generated Dithiobenzoic Acid

Two types of lanthanide thiolato-carboxylate complexes, [Type I: [Yb(dtba) (Hdtba)] _n (1), Type II: [Ln(dtba)_1.5(biim)] _n (Ln = Pr (2a), Nd (2b), Sm (2c), Eu (2d), Gd (2e), Tb (2f), Dy (2g), H₂dtba = 2,2′-dithiodibenzoic acid, bimm = diimidazole)] have been obtained by hydrothermal method and characterized by the single-crystal X-ray diffraction, IR, 2D-COS IR, TG and the luminescence analysis. The H₂dtba ligand came from the in situ S–S function reaction of 2-mercaptobenzoic acid (H₂mba) under the hydrothermal condition. Complex 1 is a 2D bamboo-like sqr-topology layered structure, and the 3D (4, 4, 6)-connected supramolecular frameworks is produced by the hydrogen bonds of O–H···O. Complexes of type II (from 2a to 2g) are isostructural and they are assigned to 1D rope-like chains by introducing the chelating ligand of diimidazole. These 1D rope-like chains are further linked by N–H···O hydrogen bonds into a 3D supramolecular framework with CdSO₄-type topology. Photoluminescence studies reveal that complexes 2b, 2c, 2d, 2f, 2g exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.     

Electrocatalytic Performances of Carbon Supported Metallophthalocyanine and Pt/Metallophthalocyanine Catalysts Towards Dioxygen Reduction in Acidic Medium

Electrocatalytic performances of phthalocyanines (Pcs) involving N-benzyl-4-phenyloxyacetamide moieties, dispersed on a high-surface area carbon substrate, Vulcan XC-72 (VC) and Nafion (Nf), towards oxygen reduction in acidic medium were determined and compared. The VC/Nf/CoPc(5) catalyst showed much higher catalytic activity than those of the other Pc(1–4)-based catalysts (H₂Pc 1, ZnPc 2, NiPc 3 and CuPc 4) and that of unsubstituted CoPc-based one. The comparison of the performance of VC/Nf/Pt-5 dual catalyst with that of VC/Nf/Pt one indicated that the former can be a good alternative to the latter as a cathode catalyst both in direct methanol and H₂/O₂ fuel cell applications.     

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.     

Synthesis, Surface-Active Properties, and Anthelmintic Activities of New Cationic Gemini Surfactants Against the Gastrointestinal Nematode, Heligmosomoides polygyrus bakeri, In Vitro

A novel series of cationic dimeric surfactants was prepared involving the ketalization reaction, Williamson etherification, and regioselective oxirane ring opening with tertiary alkyl amines. The synthesized compounds were obtained in high purity by a simple purification procedure using column chromatography. The critical micelle concentration (CMC), effectiveness of surface tension reduction (??_CMC), surface excess concentration (??), and area per molecule at the interface (A) were determined and values indicate that the cationic series is characterized by good surface-active and self-aggregation properties. For the first time, we reported the anthelmintic activities against the rodent gastrointestinal nematode Heligmosomoides polygyrus bakeri, in vitro for cationic gemini compounds. In the series of five tested cationic compounds (4a?Ce), three of them (4a, 4b and 4d) were shown to have an excellent anthelmintic activity in vitro at different concentrations. The anthelmintic activity was found to be dependent on the type of cationic compound, concentration and incubation time. The cationic di-C₁₂ (4a) derivate of the series was the best anthelmintic agent, its use was optimal at a minimum concentration of 50?ppm and with 60?min of incubation.     

Direct Synthesis and Crystal Structure of Dehydrated State in Vapochromic MMX-type Quasi-One-Dimensional Iodide-Bridged Platinum Complexes

The dehydrated vapochromic 1D coordination polymer, (H₃NC₄H₈NH₃)₂[Pt₂(pop)₄I] (1) was synthesized directly from methanol solution. Although vapochromic 1 · 4H ₂ O has been synthesized, dehydrated high-temperature structure has never been determined because of lowering the quality of crystal by dehydration. The crystal structure of 1 was determined by X-ray crystal structure analysis, and we confirmed that it was identical to the dehydrated high-temperature structure of 1 · 4H ₂ O by comparing the powder X-ray diffraction (XRD) patterns. The Pt–I–Pt distance (d(Pt–I–Pt)) of compound 1 · 4H ₂ O was shortened for approximately 1.1 Å by desorption of water to form compound 1, accompanied with phase transition in electronic states. The other crystal including methanol molecule as lattice solvent, 1 · 2MeOH, was also obtained as by-product. The synthesis from various kinds of organic solvent has the great potential to develop the field of vapochromism accompanying phase transition of electronic state.     

Metallopolymer Films Exhibiting Three-Color Electrochromism in the UV/Vis and Near-IR Region: Remarkable Utility of Trimetallic Clusters Bearing Thienyl Pendants and Their Mixed-Valent Charge Transfer Transitions

Novel oxo-centered, acetate-bridged trinuclear ruthenium clusters functionalized with two pyridine ligands with thienyl substituents, [Ru₃O(CH₃COO)₆(CO)(L1)₂] (1) and [Ru₃O(CH₃COO)₆(CO)(L2)₂] (2), where L1 = 4-(2-thienyl)pyridine and L2 = 4-(2,2′-bithienyl)pyridine, have been synthesized and characterized. The molecular structure of 2 has been determined by single-crystal X-ray diffraction. One-electron oxidation of 2 with silver(I) cation has led to the isolation of a CO-dissociated product, [Ru₃O(CH₃COO)₆(H₂O)(L2)₂]PF₆ (3·PF ₆ ), and subsequent reaction with 4-dimethylaminopyridine (dmap) gave [Ru₃O(CH₃COO)₆(dmap)(L2)₂]PF₆ (4·PF ₆ ). Linear metallopolymers containing the {Ru₃O(CH₃COO)₆} groups have been deposited onto indium-tin oxide surface via oxidative electropolymerization of 2, 3·PF ₆ , and 4·PF ₆ . These metallopolymer thin films exhibit three-color electrochromism in the UV/Vis and near-IR region associated with the Ru₃ ^II,III,III, Ru₃ ^III,III,III, and Ru₃ ^III,III,IV oxidation states.     

Use of Glycerol Carbonate in an Efficient, One-Pot and Solvent Free Synthesis of 1,3-sn-Diglycerides

An efficient solvent-free synthesis of a variety of highly pure 1,3-sn-diglycerides (1,3-sn-diacylglycerols) in a two-step one pot process is described. Heating glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one) with fatty acid anhydrides 2a–d affords 1:1 mixtures of glycerol carbonate fatty esters 3a–3d and the corresponding fatty acids. Further heating the reaction mixtures in the presence of catalytic amounts of 1,4-diazabicyclo[2.2.2]octane (DABCO) at 195–200 °C yields highly pure 1,3-sn-diglycerides 4a–4d.     

Hydrothermal Synthesis, Crystal Structures and Fluorescent Properties of Two New d10 Metal Coordination Polymers with Two Mixed Flexible Ligands

Two complexes, [Zn(qda)(bpp)] _n (1) and {[Cd(qda)(bpp)₂]·2H₂O} _n (2), (H₂qda?=?hydroquinone-O,O′-diacetic acid, bpp?=?1,3-bis(4-pyridyl)propane), were hydrothermally synthesized and characterized by single crystal X-ray diffraction analysis, FTIR and elemental analysis. Both compounds exhibit two-dimensional structures. The qda anions in compound 1 adopt two different trans conformations, coordinating to Zn²⁺ ions in a monodentate fashion, while in compound 2 they adopt only one trans conformation yet keeping the same coordination fashion as in compound 1. The bpp molecules show same anti-gauche coordination conformation in both 1 and 2. In addition, photoluminescence for 1 and 2 has been investigated in the solid state at room temperature.     

Mixed Solvothermal Synthesis of a New Heterometallic Coordination Polymer Containing Two Distinct Inorganic Cd–O–Ca Chains

A new heterometallic coordination polymer, namely [Cd₂Ca₂(PBDC)(H₂O)₂(e-urea)(DMF)]_n·2n(DMF) (1 H₂PBDC = terephthalic acid, DMF = N,N-dimethylformamide, e-urea = ethyleneurea) has been synthesized by combining the PBDC ligand with Cd(II) and Ca(II) salts under mixed solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 is an extended three-dimensional framework containing two distinct inorganic Cd–O–Ca chains, and can be simplified into a 4-connected topological network based on three unequivalent nodes. Luminescent study reveals that 1 exhibits strong, ligand-centred luminescence in the solid-state at room temperature.     

Construction of Three New Coordination Polymers Based on Dicarboxylate and Different Organic N-Donor Ligands

Three new metal coordination polymers, {[Ni₂(L₁)₂(bip)₂]·H₂O} _n (1), [Zn₂(L₂)₂(bih)_0.5] _n (2) and [Cd(L₂)(bih)_0.5] _n (3) [H₂L₁?=?2-(3-carboxyphenoxy)benzoic acid, H₂L₂?=?2-(4-carboxyphenoxy) benzoic acid, bip?=?4,4??-bis(2-imidazol-1-ylmethyl) biphenyl and bih?=?1,6-bis(2-methylimidazol-1-yl) hexane], have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Compound 1 is a one-dimensional ladder-like chain structure. Compound 2 is a two-dimensional layer structure. In compound 3, the alternate arrangement of the right- and left-handed helical chains through bih ligands interactions, which lead to form a two-dimensional framework. In compound 1, 2 and 3, the L₁ and L₂ ligands act as bridging ligands, exhibiting three coordination modes to link metal ions: bis-monodentate, bidentate chelating and monodentate modes. Moreover, the luminescent properties of compound 2 and 3 were also investigated in this work.     

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.     

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.     

An insight on the effect of rubbing textile fiber on morphology of some semi-alicyclic polyimides for liquid crystal orientation

Two semi-alicyclic PIs were prepared from bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BOCA) and the aromatic diamines: 4,4′-oxydianiline (ODA) or 4-(4-{[4-(4-aminophenoxy)phenyl]sulfonyl}phenoxy)aniline (pBAPS). The obtained films are transparent in visible domain, having a cut-off wavelength of 294 nm for poly(BOCA–ODA) and 264 nm for poly(BOCA– p BAPS), respectively. Atomic force microscopy images indicate a better surface organization after rubbing with cotton velvet (V_C) comparatively with cellulose diacetate (V_CD). Contact angle measurements reveal a slight increase of hydrophobicity after patterning as a result of dipolar forces intensification and geometrical constraints of the macromolecular chains. The alignment properties of both PIs, tested with N-(4-methoxybenzylidene)-4-butylaniline, are more obviously for processing with V_C. Also, the contrast between the dark and bright states is higher for poly(BOCA– p BAPS)/V_C comparatively with poly(BOCA–ODA)/V_CD, since its larger surface malleability generates deeper microgrooves.     

Three New Coordination Polymers Constructed from Mixed Ligands: Syntheses,Luminescence and Magnetism

Three new coordination polymers, namely, {[Cd(H₂bptc)(IP)(H₂O)]·2H₂O} _n (1), {[Mn₂(IP)₂(dstc)]·6H₂O} _n (2) and {[Zn₂(IP)₂(dstc)]·3H₂O} _n (3) (IP = 1H-imidazo[4,5-f][1,10]-phenanthroline, H₄bptc = 3,3′,4,4′-benzophenonetetracarboxylic acid, and H₄dstc = 3,3′,4,4′-diphenylsulfonetetracarboxylic acid) have rationally designed and characterized by single crystal X-ray diffraction. Polymer 1 shows a 1D ribbon-like structure. Although compounds 2 and 3 feature 2D grid networks, the coordinative modes of dstc ligand and the arrangements of IP ligand are very different. Furthermore, the luminescence properties for 1 and 3, as well as the magnetism of 2 are explored in detail.     

Synthesis and Structural Characterization of Two New Nano-Coordination Compounds Based on Mercury(II) NN Donor Schiff Base

Two new nano mercury(II) coordination compounds, [Hg₂(μ-L1)(μ-I)₂I₃]_n (1) and [Hg(L2)(I)₂] (2) {L1?=?(E)-N′-(pyridin-2-ylmethylene)isonicotinohydrazide and L2?=?(E)-N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide} have been synthesized by a sonochemical method. The new nano-structures were characterized by scanning electron microscopy, X-ray powder diffraction, elemental analysis and IR spectroscopy. The compounds were also characterized by single crystal X-ray diffraction and the results indicate a 1D fishbone-like structure containing dinuclear units for 1 and a mononuclear structure for 2. In coordination polymer 1, the two Hg(II) centers are four coordinate into a chain-axis and also in the terminal linkages. In complex 2, the Hg(II) center is four coordinate. The chains of polymer 1 interact with each other through π–π stacking interactions which create a 3D framework.     

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.     

Hydrothermal Synthesis, Crystal Structures and Fluorescent Properties of Two Complexes Based on 1,2-Phenylenedioxydiacetic Acid and Polypyridyl Ligands

Hydrothermal reactions of flexible 1,2-phenylenedioxydiacetic acid (H₂pda) with zinc nitrate or cadmium nitrate in the presence of auxiliary 4,4′-bypyridine (bpy) or 1,3-bis(4-pyridyl)propane (bpp) ligands gave rise to two coordination polymers, {[Cd₂(pda)₂(bpy)(H₂O)₂]·4H₂O} _n (1) and [Zn(pda)(bpp)] _n (2). The polymers were characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction methods. Compound 1 shows 1D ribbon structure and compound 2 displays twofold parallel interpenetrated 2D?→?2D architecture. The different conformations of pda anions in these two compounds are mainly induced by different metal coordination configurations in compound 1 and 2. In addition, the photoluminescence emission of 1 and 2 has been investigated in the solid state at room temperature.     

Cu(II) and Zn(II)-Pyridine-2,3-Dicarboxylate Complexes with 2-Methylimidazole: Syntheses, Crystal Structures, Spectroscopic and Thermal Analyses

Two new Cu(II) and Zn(II)-pyridine-2,3-dicarboxylate (pydc) complexes with 2-methylimidazole (2-Meim), [Cu(pydc)(2-Meim)₃]·H₂O (1) and {[Zn(μ-pydc)(H₂O)(2-Meim)]·H₂O}_n (2) have been synthesized and characterized by elemental, spectral (IR and UV–Vis.) and thermal analyses. The molecular structures of mononuclear (1) and polynuclear (2) complexes have been determined by the single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic P ? 1 space group, while compound 2 crystallizes in the monoclinic P2₁/c space group. The pyridine-2,3-dicarboxylate ligand acts in two different coordination modes; namely, bidentate-(N,O) for 1 and μ-tridentate-(N,O,O) for 2, the latter displaying a 1D polynuclear structure. The crystal packing of the complexes exhibit 3D supramolecular frameworks including channels by C–H···π, π···π, and N–H···O interactions. Water molecules occupy the channels by O–H···O hydrogen bonds.     

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.     

Synthesis, Crystal Structures and Luminescence of Organic-Lanthanide Complexes with Nicotinic Acid and Adipic Acid Ligands

Two new lanthanide coordination polymers, [Sm₂(nic)₃(ad)_0.5(H₂O)(μ₃-O)₂] (1), [Pr(nic)(ad)]·2H₂O (2) (nic?=?nicotinic acid, ad?=?adipic acid) have been synthesized hydrothermally from the self-assembly of the lanthanide ions (Ln³⁺) with rigid nicotinic acid and the flexible adipic acid. They were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Structural analyses reveal that both of the complexes crystallize in triclinic, space group P-1 and have different framework characterization. Because of different coordination modes of nicotinate, complexes 1 and 2 exhibit 2D and 3D framework structure, respectively. In 1, the Sm1 and Sm2 atoms and their corresponding centrosymmetric atoms are connected by bridging oxygen atoms to form a 1D Sm₂(μ₃ -O)₂ polymeric chain along [010] direction. The photoluminescent properties of 1 and thermogravimetric analysis of 1 and 2 are discussed in detail.