LOW DENSITY POLYETHYLENE/CLAY NANOCOMPOSITES MODIFIED BY ETHYLENE COPOLYMERS： EFFECTS OF FUNCTIONALIZED SEGMENTS ON MORPHOLOGY

Melt extrusion was used to prepare binary nanocomposites of ethylene copolymers and organoclay and trinary nanocomposites of low-density polyethylene （LDPE）, ethylene copolymer and organoclay. X-ray diffraction （XRD） and transmission electron microscopy （TEM） were used to analyze the structure of the clay phase and the morphology of the nanocomposites. Influences of the comonomer in the copolymer and the content of the copolymer on the morphology of the resulting nanocomposites were discussed. The binary and the trinary composites may form intercalated or exfoliated structures depending on the interaction between the copolymer and the clay layers and the content of the copolymer.     

Supramolecular architectures with ladder and lamellar topologies using metal-ligand coordination units via C–H···Cl and O–H···Cl hydrogen bonding

New Mn^II/Cu^II/Zn^II complexes [(L¹)MnCl₂] (1), [(L²)CuCl₂]·0.5H₂O (2) and [(L²)ZnCl(H₂O)][ClO₄] (3), containing (2-pyridyl)alkylamine ligands, N-methyl-N,N-bis(2-pyridylmethyl)amine (L¹) and methyl[2-(2-pyridyl)ethyl](2-pyridylmethyl)amine (L²), have been prepared and characterized, including X-ray crystallography. The most striking feature of the structures of these complexes is the formation of molecular ladder and lamellar topology through the crystal packing arrangement, determined by both strong O–H···Cl and weak (however, multiple) C–H···Cl hydrogen-bonding interactions, to maintain the neutral/cationic metal-ligand coordination units linked to each other. In 3, additional secondary interactions are observed involving coordinated solvent and the counter-ion. The results presented here demonstrate that (i) the choice of organic ligands to provide flexibility and inherent potential to participate in hydrogen-bonding interactions, (ii) the coordination geometry preferences of metal ions, (iii) the number of metal-bound chloride ion and (iv) the presence of solvent/counter-anion have a great influence on supramolecular network topology.     

Synthesis and Spectroscopic Characterization of New Lead(II) Thiosaccharinates. Molecular Structure of Bis(thiosaccharinato)tetrakis(pyridine)dilead(II) and Thiosaccharinato‐bis(1,10‐phenantroline)lead(II) Thiosaccharinate

Four new lead(II) thiosaccharinate complexes: [Pb(tsac)₂H₂O] (1) (tsac: thiosaccharinate anion), [Pb₂(tsac)₄(py)₄] (2) (py: pyridine), [Pb(tsac)(o‐phen)₂](tsac)·CH₃CN (3) (o‐phen: 1,10‐phenantroline), and [Pb(tsac)₂(bipy)] (4) (bipy: 2,2′‐bipyridine) were prepared. The infrared and electronic spectra as well as the thermal analysis of all the compounds were recorded and discussed. The thiosaccharinate anion acts in three different coordination forms, one of then reported for the first time. The crystal structures of complexes 2 and 3 have been determined by single crystal X‐ray diffractometry. In complex 2 , two monomeric moieties are joined together forming a symmetric bis‐μ‐sulphur bridged dimer by interaction of two lead(II) atoms through the exocyclic sulphur atoms of two thiosaccharinate ligands. The seven‐fold coordination sphere of each lead atom is completed by two pyridine nitrogen atoms and by another sulfur and two nitrogen atoms of the thiosaccharinate anions. In complex 3 , the lead(II) atom is coordinated by four nitrogen atoms of two 1,10‐phenantroline molecules and by the sulfur and nitrogen atoms of one thiosaccharinate ion. The second anion has an electrostatic interaction with the nucleus.     

钴的二苯甲酰甲烷配合物：晶体结构及其轴向置换反应

Cobalt(Ⅱ) can form complexes with Hdbm in different environments. Hdbm reacted with cobalt nitrate to give complex 1 [Co(dbm)₂·2H₂O]. When complex 1 reacted with pyridine， α-stilbazole or 4，4′-bipyridine respectively， complex 2 [Co(DBM)₂Py₂] (Py=pyridine)， 3 [Co(DBM)₂Sbz₂] (Sbz=α-stilbazole) or 4 [Co(DBM)₂BPy]_n was obtained in turn through metathetical reaction. The coordination modes are octahedral polyhedrons. In the crystal structures， the two dbms take the plane position and two other donor molecules take the axial position. CCDC： 196070 for complex 2; 186859 for complex 3.     

Alcohol‐Vapor Inclusion in Single‐Crystal Adsorbents [MII2(bza)4(pyz)]n (M=Rh,Cu): Structural Study and Application to Separation Membranes

The vapor absorbency of the series of alcohols methanol, ethanol, 1‐propanol, 1‐butanol, and 1‐pentanol was characterized on the single‐crystal adsorbents [M^II₂(bza)₄(pyz)]_n (bza=benzoate, pyz=pyrazine, M=Rh ( 1 ), Cu ( 2 )). The crystal structures of all the alcohol inclusions were determined by single‐crystal X‐ray crystallography at 90 K. The crystal‐phase transition induced by guest adsorption occurred in the inclusion crystals except for 1‐propanol. A hydrogen‐bonded dimer of adsorbed alcohol was found in the methanol‐ and ethanol‐inclusion crystals, which is similar to a previous observation in 2 ?2EtOH (S. Takamizawa, T. Saito, T. Akatsuka, E. Nakata, Inorg. Chem. 2005 , 44, 1421–1424). In contrast, an isolated monomer was present in the channel for 1‐propanol, 1‐butanol, and 1‐pentanol inclusions. All adsorbed alcohols were stabilized by hydrophilic and/or hydrophobic interactions between host and guest. From the combined results of microscopic determination (crystal structure) and macroscopic observation (gas‐adsorption property), the observed transition induced by gas adsorption is explained by stepwise inclusion into the individual cavities, which is called the “step‐loading effect.” Alcohol/water separation was attempted by a pervaporation technique with microcrystals of 2 dispersed in a poly(dimethylsiloxane) membrane. In the alcohol/water separation, the membrane showed effective separation ability and gave separation factors (alcohol/water) of 5.6 and 4.7 for methanol and ethanol at room temperature, respectively.     

Synthesis, structures and reactivity of triosmium clusters containing terminal pyrazines, bridging hydroxy and methoxycarbonyl ligands

Four triosmium carbonyl clusters bearing terminal pyrazines, bridging hydroxy and methoxycarbonyl ligands of general formula [Os₃(CO)₉(μ-OH)(μ-OMeCO)L] (1, L = pyrazine; 2, L = 2-methylpyrazine; 3, L = 2,3-dimethylpyrazine; 4, L = 2,3,5-trimethylpyrazine) were synthesized by the reactions of [Os₃(CO)₁₂] with the corresponding pyrazine derivatives and water in the presence of a methanolic solution of Me₃NO in moderate yields. Compounds [Os₃(CO)₉(μ-OH)(μ-OMeCO)L] react with a series of two electron donor ligands, L′ at ambient temperature to give [Os₃(CO)₉(μ-OH)(μ-OMeCO)L′] (5, L′ = PPh₃; 6, L′ = P(OMe)₃; 7, L′ = ^tBuNC; 8, L′ = C₅H₅N) in good yields by the displacement of the pyrazine ligands. This implies that the pyrazine ligands in 1–4 are relatively labile. Compounds 2, 3, 4, and 8 were characterized by single crystal X-ray diffraction analyses. All the four compounds possess two metal–metal bonds and a non-bonded separation of two osmium atoms defined by Os(1)Os(3), which are simultaneously bridged by OH and MeOCO ligands and a heterocyclic ligand is terminally coordinated to one of the two non-bonded osmium atoms.     

Tertiary phosphine abstraction from a platinum(II) coordination complex with SeCN: Crystal and molecular structures of SePTA and [SePTA-Me]I · CH3OH

Reacting [PtCl(PTA)₃]Cl(PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.1^3,7]decane) with KSeCN in aqueous or MeOH medium results in the abstraction of the PTA ligands to yield SePTA. The reaction also proceeds quantitatively by direct reaction of PTA and KSeCN in water or methanol. The methylated PTA ligand, [PTA-Me]I (1-methyl-1-azonia-3,5-diaza-7-phosphatricyclo[3.3.1.1^3,7]decane iodide), reacts accordingly with KSeCN, albeit significantly slower. The crystal structure of SePTA, 1, and [SePTA-Me]I · CH₃OH, 2, revealed PSe bond distances of 2.0991(19) and 2.100(2) Å, respectively. The first order phosphorous selenium coupling constants, ¹J_P-Se (D₂O), of 722 and 788 Hz for SePTA and [SePTA-Me]I, respectively, indicates the latter is significantly less electron rich.     

Visual observation of contact-induced intercrystalline migration of aromatic species adsorbed in zeolites by fluorescence microscopy.

Intercrystalline migration and a migration-assisted chemical reaction of adsorbed aromatic species between zeolite particles in physical contact were visualized by fluorescence microscopy coupled with a particle manipulation technique. The luminescence color characteristics of particular zeolite particles originating from the specific photochemistry of adsorbed species was exploited to follow the migration of the molecules. Two examples are shown that are relevant to the visualization of the time-dependent migration process: A one guest-two sets of zeolite crystals system: chrysene (Chry)-loaded zeolite Na+ -X (the sodium form of zeolite X) crystals were placed in contact with unloaded Tl+ -X (thallium-exchanged X) crystals and allowed to stand at room temperature. Initially, the blue fluorescence of Chry was detected only from the Na+ -X particles, but later, the development of green phosphorescence emission was discernible from the Tl+ -X which suggests that Chry migrated from the Na+ -X to the Tl+ -X crystals. A two guest-species systems: Electron-donating Chry-loaded Na+ -X crystals were placed in contact with electron-accepting 1,2,4,5-tetracyanobenzene (TCNB)-loaded Na+ -X or Na+ -Y crystals. With time, the former system (Chry/Na+ -X and TCNB/Na+ -X) gave rise to the emission of Chry-TCNB charge-transfer complexes resulting mainly from the migration of Chry while the latter system (Chry/Na+ -X and TCNB/Na+ -Y) afforded the same emission resulting largely from the migration of TCNB. The present investigation reveals that there is a certain direction for guest migration depending on the zeolite host and the nature of host-guest or guest-guest interaction.     

3-Substituted Sydnone Derivatives. Structures of 3-Cyclohexylsydnone and of Two Forms of 3-(3-Pyridyl)sydnone

The crystal and molecular structures of three sydnone derivatives are reported. The compound 3-cyclohexylsydnone crystallizes in space group C2/c of the monoclinic system with sixteen molecules in a cell of dimensions a = 19.326 (3), b = 9.471 (2), c = 20.005 (4)Å, β = 106.85(1)°. The structure has been refined to a final value of 0.0581 for the conventional R-factor based on 2222 independent observed intensities. Form I of 3-(3-pyridyl)sydnone crystallizes in space group P2/n of the monoclinic system with eight molecules in a cell of dimensions a = 7.317(2), b = 9.283 (2), c = 20.891 (6) Å, β = 99.61(2)°. The structure has been refined to a final value of 0.0514 for the conventional R-factor based on 1208 independent observed intensities. Form II of 3-(3-pyridyl)sydnone crystallizes in space group P2₁/c of the monoclinic system with eight molecules in a cell of dimensions a=9.073 (2), b = 22.267 (5). c = 7.494(2)Å, β = 112.15 (2)°. The structure has been refined to a final value of 0.0462 for the conventional R-factor based on 1330 independent observed intensities. Each of the three structures contains two crystallographically independent molecules in the cell. In the case of 3-cyclohexylsydnone, one of the independent molecules exhibits disorder around the exocyclic bond at N(3). A comparison of bond lengths indicates that the (electron donating) cyclohexyl group brings about enhanced electron density in the N(3)-C(4) bond, and possibly in the N(3)-N(2) bond. All three structures studied here exhibit intermolecular hydrogen bonding involving C(4)-H(4)…O(6) interactions. Although there are no stacking interactions in the cyclohexyl derivative, there is evidence for such interactions in the 3-pyridyl derivatives.     

Neue ternäre Phosphide und Arsenide des Caesiums mit Elementen der 8. Nebengruppe

New Ternary Phosphides and Arsenides of Cesium and Element of the 8th Transition Metal Group In the ternary systems Cesium/8^th transition metal group/5^th main group some new compounds were found and investigated. By single crystal measurements CsRh₂P₂ was found to crystallize in the space group 14/mmm with the lattice constants a = 390.11 pm and c = 1429.36 pm. The new compounds with the formula CsM₂X₂ (M = Fe, Co, Ru, Rh, Ir; X = P or As) crystallize in the ThCr₂Si₂-type structure, compounds of the formula Cs₂MX₂ (M = Ni, Pd, Pt; X = P or As) can be placed in a line with the K₂PdP₂-type structure.