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.     

Polymerization of propylene catalyzed by α-diimine nickel complexes/methylaluminoxane: catalytic behavior and polymer properties

α-Diimine nickel dibromide complexes of dibromo[N,N’-bis(2,6-diisopropylphenyl)-2,3-butanediimine]nickel(II) (A) and dibromo[N,N’-(phenanthrene-9,10-diylidene)bis(2,6-diisopropylaniline)]nickel(II) (B) were synthesized under controlled conditions. The catalysts A, B and mixed of 1:1 weight ratio of them (C) were activated by methylaluminoxane and were used for propylene polymerization in a semi-batch reactor. In study of the catalytic systems behavior, activities, glass transition temperature (T _g) and viscosity average molecular weight (M _v) values related to the catalyst C were between those related to the catalysts A and B under same conditions. The highest and the lowest molecular weights of the obtained polymers were produced by the catalysts B and A which were about 80,000 and 70,000 (g/mol) under same conditions, respectively. The T _g of polypropylenes produced by the catalysts was about ?34 °C. The resulting polymers had similar behavior with ethylene-propylene copolymer which it could be due to formation of ethylene-type units in the polymer chain.     

Si6H6 revisited: The hexasilaprismane-to-hexasilabenzene and hexasila-dewarbenzene interconversion

Ab initio calculations on the parent hexasilaprismane (2) and its less stable valence isomers hexasilabenzene (1) and hexasila Dewarbenzene (3) have been performed. Calculated transition structures for the interconversion of the isomers indicate kinetic instability of the isomers1 and3.Ab initio (Cl(S) calculations on the S₁ photochemistry of the isomers explain the features of the recently observed UV spectra.     

Biosynthesis of Defensive Allomones in Leaf Beetle Larvae: Stereochemistry of Salicylalcohol Oxidation in Phratora vitellinae and Comparison of Enzyme Substrate and Stereospecificity with Alcohol Oxidases from Several Iridoid Producing Leaf Beetles

(7S)-[²H₅]-Salicylalcohol (3) and (7R)-[²H₁]-salicylalcohol (5) have been synthesized in order to examine the stereospecificity of salicylalcohol oxidase from the defensive secretion of the salicylaldehyde-producing leaf beetle Phratora vitellinae. Oxidation was found to proceed by selective removal of the C(7)-H_R hydrogen atom (Re-specificity) to yield salicylaldehyde. (7S)-[²H₆]-Benzylalcohol (9) was also oxidized Re-specifically to benzaldehyde, but in much lower yield, indicating the importance of the orthohydroxy group of salicylalcohol in substrate enzyme binding. The stereospecificities of terpenoid oxidases from six species of iridoid-producing leaf beetle were examined using (1R,8R)-[²H₂]-8-hydroxygeraniol (10), and were all found to oxidize the substrate Re-specifically. Cross-activity of oxidation was found in a number of species, with P. vitellinae able to oxidize terpenoid (10) and two of the iridoid-producing species able to oxidize salicylalcohol analogue (3), again with Re-specificity. However, when the two substrate analogs were presented together, in equal concentrations, preferential oxidation of the natural analog was observed in each case. The kinetics of oxidation for a number of terpenoid and aromatic alcohols by the defensive secretion of the iridoid-producing leaf beetle Phaedon armoraciae have been studied, revealing a large difference between the rate of (primary, allylic) terpenoid alcohol oxidation and the rate of salicylalcohol oxidation, thus accounting for the observed selectivity.     

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.     

Electroactive polymer actuator from highly doped permethylpolyazine dispersed in ethylene propylene diene elastomer

Structural, electronic, and optical properties of a series of ??-conjugated thiophene oligomers P1-P3 and CF ₃ P1-CF ₃ P3 have been theoretically investigated. P1-P3 contain the 2- (trifluoromethyl) thieno [3, 4-b] thiophene moiety as the centre and 1?C3 repeating thiophene units adjacent to its two sides respectively, while their corresponding derivatives CF ₃ P1-CF ₃ P3 with the CF₃ as end-caps. The geometric structures of the oligomers in the ground and excited state were optimized by PBE1PBE and CIS methods with 6?C31G (d) basis sets, respectively. All the oligomers exhibit zigzag arrangements. The absorptions and emissions were calculated by the time-dependent density functional theory method (TD-PBE1PBE). The lowest-lying absorptions of all the oligomers can be characterized as ??-??^* electron transition. For each series of oligomers, there is a progressive lowering in HOMO-LUMO gap with the increase of the repeating unit, being consistent with the red-shifted trend in the lowest-lying absorption and fluorescence from P1 to P3 and CF ₃ P1 to CF ₃ P3. To compare the P- and corresponding CF ₃ P-oligomers, the end-cap CF₃ group causes the slight blue shifts in absorption and emission spectra. The ionization potentials (IP_S), electron affinities (EAs), and reorganization energies (??) as well as the hole/electron extraction energies (HEP/EEP) of the oligomers were explored and those of the corresponding polymer were obtained by extrapolation method. The IP and HEP of P-polymer are lower than those of CF ₃ P-polymer, indicating that the P-polymer is more suitable for hole transport than CF ₃ P-polymer, while the higher EA and EEP for CF ₃ P-polymer suggest the better electron transfer property. For CF₃ end-caps, the CF ₃ P-polymer exhibits the equal reorganization energy between electron and hole, which is a precondition for the charge transfer balance.     

The Inclusion of Organometallic Derivatives of Cyclotriphosphazenes Inside SiO2 Matrix and Their Conversion to Nanostructured Metal-Oxides and Phosphates

Organometallic derivatives of the cyclotriphosphazene N₃P₃[OC₆H₄CH₂CN·TiClCp₂]₆ (1), N₃P₃(O₆H₅)₅[OC₆H₄N·W(CO)₅] (2), N₃P₃[OC₆H₄CH₂CN·Mo(CO)₅]₆ (3), [N₃P₃(O₆H₅)₅(OC₅H₄N·CpRu(PPh₃)₂)][PF₆] (4), [N₃P₃(O₂C₁₂H₈)₂OC₅H₄N·Ag(PPh₃)][OSO₂CF₃] (5), N₃P₃[OC₆H₅]₅ [OC₅H₄N·Cu][PF₆] (6) and N₃P₃[OC₆H₄CH₂CN·CuCl]₆[PF₆]₆ (7),were incorporated inside SiO₂ through the sol–gel method. The metal–organic nanocomposites of the general formula N₃P₃[OC₆H₄CH₂CN·TiClCp₂]₆·nSiO₂ (G ₁ ), N₃P₃[OC₆H₄N·W(CO)₅]·nSiO₂ (G ₂ ), N₃P₃[OC₆H₄CH₂CN·Mo(CO)₅]₆·nSiO₂ (G ₃ ), N₃P₃(O₆H₅)₅OC₅H₄N·CpRu(PPh₃)₂][PF₆]·nSiO₂ (G ₄ ), [N₃P₃(O₂C₁₂H₈)₂OC₅H₄N·Ag(PPh₃)][OSO₂CF₃]·nSiO₂ (G ₅ ), N₃P₃[OC₆H₅]₅[OC₅H₄N·Cu][PF₆]·(SiO₂) _n (G ₆ ), and N₃P₃[OC₆H₄CH₂CN·CuCl]₆[PF₆]₆·(SiO₂) _n (G ₇ ), were characterized by IR spectroscopy; ¹²C, ³¹ P and ²⁹Si MAS NMR measurements as well as UV–Visible diffuse reflectance spectra, indicating the presence of the respective organometallic derivatives of the cyclotriphosphazene incorporated into SiO₂. Pyrolysis of these nanocomposites under air at 800 °C gives rise to nanostructured metal-oxides and metal phosphates incorporated into amorphous SiO₂, with the presence in some cases of complexes phase mixtures. From some precursors, we obtained metal-oxides/phosphates nanoparticles separated from the SiO₂ nanoparticles instead the oxides/phosphates nanoparticles inside the SiO₂ matrix. Additionally and for comparison purposes, we used the compound N₃P₃[NH(CH₂)₃Si(OEt)₃]₆ as gelator. Nanocomposites (G′ ₁ ), (G′ ₂ ) and (G′ ₃ ) exhibited mainly morphological differences while in some cases composition differences when using TEOS as gelator. Some simple metal-containing compounds as (O₃SCF₃)Ag(PPh₃)(HOC₅H₄N), [CuCl₂·NC₅H₄OH] and [CuCl₂·NCCH₂C₆H₄OH]—which are useful models of the most complexes (G ₅ ), (G ₆ ) and (G ₇ ) were also prepared and incorporated in amorphous silica. Their pyrolytic products were compared with those of more complex cyclotriphosphazene analogous. Interestingly, the pyrolysis of the nanocomposite [(O₃SCF₃)Ag(PPh₃)(HOC₅H₄N)][SiO₂] _n affords the firstly-reported materials containing Ag₂O along with SiO₂ nanoparticles.     

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.     

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.     

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.     

Structural Variations in Coordination Polymers of Sodium and Cesium Dicarboxylates

The coordination polymer {[Na₂L(μ-H₂O)(H₂O)₃]·H₂O} _n (1) derived from 2,2′-(phenylmethylidene-bis(3,5-methyl-2-phenyleneoxy)] diacetic acid (H₂ L) has repeat units comprising of hexa-coordinate diaqua-bridged dinuclear sodium complex ions. These units are connected through intervening mononuclear complex parts having penta-coordinated sodium ions. The sodium ions adopt repeated hexameric chair-like arrangement in the polymer. The cesium salt of H₂ L namely [Cs(HL)(μ-H₂O)(H₂O)] _n (2) is a coordination polymer. In this case one acid group of the ligand is deprotonated and 2 form self-assembly by intermolecular hydrogen bonds between the free carboxylic acid groups. The fluoro-substituted ligand 2,2′-(2-fluorophenylmethyledene-bis(3,5-methyl-2-phenyleneoxy)] diacetic acid (H ₂ L _f ) forms disodium salt with a composition [{Na₂L_f(μ-H₂O)(H₂O)₃}·H₂O] _n (3); which is a two dimensional coordination polymer. On the other hand the corresponding cesium salt of H ₂ L _f has a composition [{(H₂O)Cs(μ-H₂O)(μ-L_f)Cs(H₂O)₂}] (4); which is also a 2-D coordination polymer. The cesium ions are six or nine coordinate in the polymer and the coordination polymer possesses unusual Cs···F–C coordination bond.     

Synthesis, Crystal Structures and Luminescent Properties of pH-Dependent Zn (II) Coordination Polymers

Two new coordination polymers [Zn(L)(bib)] _n (1) and [Zn(L)(bib)_0.5] _n (2) [L = 5-hydroxyisophthalic acid and bib = 1,4-bis(2-methyl-imidazol-1-yl)butane] have been synthesized and characterized. X-ray single crystal diffractions show that complex 1 is a 2D layered structure and complex 2 is a 3D 6-connected topological net. Complex 1 are further assembled into a 3D supramolecular structure by intermolecular hydrogen bonding. Complex 2 features a two-fold interpenetrated pcu topology. Moreover, the fluorescent properties of complexes 1 and 2 were studied in the solid state at room temperature.     

Characterization,synthesis, and behavioral responses to sex attractiveness pheromones of red-sided garter snakes (Thamnophis sirtalis parietalis)

The sex attractiveness pheromone of the red-sided garter snake,Thamnophis sirtalis parietalis, has been characterized as a mixture of 13 long-chain (C₂₉-C₃₇) saturated and monounsaturated methyl ketones. Samples of the major unsaturated ketones in the mixture, (Z)-24-tritriaconten-2-one (7) and (Z)-26-pentatriaconten-2-one (10), and their saturated analogs, 2-tritriacontanone (8) and 2-pentatriacontanone (11) were prepared by unambiguous synthesis. In field bioassay tests, male garter snakes were presented with natural and synthetic pheromone components both individually and as a mixture. Males exhibited courtship behavior to the synthetic compounds approximating the natural blend.     

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.     

From 5-Hydroxymethylfurfural (HMF) to Polymer Precursors: Catalyst Screening Studies on the Conversion of 1,2,6-hexanetriol to 1,6-hexanediol

1,6-hexanediol (1) is an important polymer precursor for the polyester industry. In this paper, exploratory catalyst screening studies on the synthesis of 1 from 1,2,6-hexanetriol (2) are described via two different routes. The latter is available by a two-step procedure from 5-hydroxymethylfurfural (HMF, 3), a promising bio-based platform chemical. In the first approach, the direct catalytic hydrodeoxygenation of 2 to 1 with heterogeneous catalysts and molecular hydrogen was explored. Best results were obtained using a Rh?CReO_x/SiO₂ catalyst in water (180?°C, 80?bar H₂, 20?h reaction time), leading to full conversion of 2 and 73?% selectivity to 1, the main byproduct being 1,5-hexanediol (4). In a second approach, 2 was first converted to tetrahydropyran-2-methanol (2-THPM, 5) in quantitative yield using triflic acid as catalyst (125?°C, 30?min). Various catalysts were explored for the subsequent ring opening/hydrodeoxygenation of 5 to 1 using a hydrogenation protocol and the best results were obtained with a Rh?CReO_x/SiO₂ catalyst, viz. 96?% selectivity to 1 at 26?% conversion (120?°C, 80?bar H₂, 20?h).     

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.     

A Two-Dimensional Semiconductive Cu2I2-Based Layered-Structure with Rigid Conjugated Tris-Bidentate Tripodal Schiff-Base Chelator

A two-dimensional (2D) layered structure 1 with (6,3) topology was constructed from Cu₂I₂ dimer and rigid conjugated tripodal tris-bidentate Schiff-base chelator L, wherein Cu₂I₂ dimer acts as a two-connecting inorganic node and L ligand works as a triangular three-connecting synthon. Compound 1 has been well structurally elucidated by single-crystal X-ray diffraction. Solid-state diffuse-reflectance UV–Vis spectra show that compound 1 exhibits a much lower optical band gap (Eg) of 1.85 eV compared to its individual components (Eg(CuI) = 3.1 eV, Eg(L) = 2.87 eV).     

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.     

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.     

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.