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La9Sb16Br3 and Ce9Sb16Cl3 compounds are synthesized from Ln, LnX3, and Sb under an Ar atmosphere at 950 degree Celsius. The results revealed that their electronic structure is valence-precise in the reduced halide part, but electron-deficient in the intermetallic part.

The thermodynamic properties, specifically the temperature dependence ofthe free energies, of ThCr2Si2 and CaBe2Ge2 type main group solids is investigated by using a Monte Carlo method based on the extended-Huckel tight-binding method. At room temperature, the ThCr2Si2 structure is more stable due to a more compact filled band and a lower Fermi level. At higher temperatures, the CaBe2Ge2 structure has a higher average energy than ThCr2Si2 types due to a smaller band gap for CaBe2Ge2.

A study is conducted to examine the chemistry of trifluoromethyl-substituted superelectrophiles generated in in superacid (C[F.sub.3]S[O.sub.3]H). The electrophilic character at cationic sites in superelectrophiles is enhanced by the strong electron-withdrawing properties of the trifluoromethyl group.

The chemistry of N-heterocyclic superelectrophiles and the examples of single electron transfer (SET) reactions involving these superelectrophiles are described. The studies have shown that besides the SET chemistry, oxazole-based superelectrophile has displayed high electrophilic reactivities with weak nucleophiles.

A series of mononuclear cis-diamineplatinum(II) pyrophosphato complexes containing ammine (am), trans-1,2-cyclohexanediamine (dcah), and 1,2-ethanediamine (en) the amine ligands are prepared and characterized by [super 31]P and [super 195]Pt NMR spectroscopy. The [super 195]Pt NMR spectrum of the ammine complex has showed coupling with two equivalent N atoms.

The single-crystal X-ray diffraction technique is employed to explain the synthesis and crystal structure of a hexanuclear zirconium glycine compound, which is grown in an aqueous solution via an extra stabilizer approach. The interactions of Zr with amino acids in these cluster compounds are also analyzed.

The synthesis of the first reduced rare earth halide with a group 12 endohedral compound, [Gd.sub.7][I.sub.12]Zn from Gd, Gd[I.sub.3] and Zn under Ar atmosphere at 850 degree Celsius is reported. The structure features isolated Zn-centered [Gd.sub.6] octahedral with all edges and corners capped by I atoms.

[La.sub.6][Br.sub.10]Fe is synthesized from La, La[Br.sub.3] and Fe under Ar atmosphere. The [La.sub.6]Fe octahedron is distorted and the La coordination by Br atoms is deviated from the common close-packing arrangements found in other reduced rare earth metal halides.

A demonstration that the highly active and catalytically useful Pd complexes could be easily assembled from readily available ligand precursors is presented. The approach of using an anionic carbocyclic carbene as ancillary ligand for palladium presents leads to new chances for the development of structurally unique carbene ligands for transition metal catalysis.

This Article presents the results from studies related to the chemistry of tricatiomc superelectrophiles. A series of triaryl methanols were ionized in Brønsted superacids, and the corresponding tricationic intermediates were formed. The trications are found to participate in two types of reactions; both are characteristic of highly charged organic cations. One set of reactions occurs through charge migration. A second set of reactions occurs through deprotonation of an unusually acidic site on the tricationic species. One of the tricationic intermediates has been directly observed by low temperature NMR spectroscopy. These highly charged ions and their reactions have also been studied using density functional theory calculations. As a result of charge migration, electron density at a carbocation site is found to increase with progression from monocationic to pentacationic structures. [ABSTRACT FROM AUTHOR]

Reaction of the charge-compensated carborane anion [9-SMe 2-7,8-C 2B 9H 10] −( 1−) with Me 2ECl 2and Me 3ECl (E = Si, Ge) leads to the carboranes η 1-8-EMe 2Cl-9-SMe 2-7,8-C 2B 9H 10( 2a, b) and (EMe 3)(9-SMe 2-7,8-C 2B 9H 10) ( 3a, b), respectively. Compound 3awas found to react readily with FeCl 2to form Fe(η 5-9-SMe 2-7,8-C 2B 9H 10) 2( 4). All products were characterized by NMR spectroscopy and chemical analysis. Compounds 2a, bwere additionally characterized by X-ray crystallography. The two compounds are isostructural with the carborane η 1-bonded to the Si or Ge through the cage carbon adjacent to the boron having the SMe 2substituent. [ABSTRACT FROM AUTHOR]

The title compound was synthesized from La, LaBr3, and Fe under Ar atmosphere at 800 °C. It crystallizes in space group P41 (No. 76) with lattice constants a = 8.255(1) A and c = 30.033(6) A. The structure features an isolated Fe-centered La6 octahedron with all corners, 9 of its 12 edges, and 3 of its 8 triangular faces coordinated, bridged, or capped by Br atoms. The La6Fe octahedron is significantly distorted, and the La coordination by Br atoms deviates from the common close-packing arrangements found in other reduced rare earth metal halides. Band structure, bonding, and physical properties of the compound have been investigated. [ABSTRACT FROM AUTHOR]

The reactions of nido-2-R-3-(Me3Si)-2,3-C2B4H6(R Me3Si, 1; R Me, 2) with 5-2,4-(Me)2C5H53M in a molar ratio of 1:1, in toluene at elevated temperature (70 °C), produced mixed-ligand dimeric lanthanacarboranes of the type (5-2,4-(Me)2C5H5)(5-2-R-3-(Me3Si)-2,3-C2B4H4)M2(3, M Y, R Me3Si; 4, M Y, R Me; 5, M Gd, R Me3Si; 6, M Gd, R Me; 7, M Tb, R SiMe3; 8, M Tb, R Me; 9M Dy, R Me3Si; 10, M Dy, R Me; 11, M Ho, R Me3Si; 12, M Ho, R Me; 13, M Er, R Me3Si; 14, M Er, R Me; 15, M Tm, R SiMe3; 16, M Tm, R Me; 17, M Lu, R Me3Si; 18, M Lu, R Me) as crystalline solids in 75−88% yields. All the compounds were characterized by IR spectroscopy and elemental analyses. While the diamagnetic species 3, 4, 17, and 18were characterized by 1H, 13C, and 11B NMR spectroscopy, compounds 3−8, 10,12−14, and 18were also characterized by single-crystal X-ray diffraction analyses. On the basis of the reactivity pattern and isolated products, an intramolecular H-transfer reaction mechanism is proposed for the formation of these species. [ABSTRACT FROM AUTHOR]

The title compounds were synthesized from Ln, LnX3 (Ln = La, Ce; X = Cl, Br), and Sb under an Ar atmosphere at 950 °C. They crystallize in the space group P63/m (No. 176) with lattice constants a = 21.232(5) and 20.862(2) Å and c = 4.323(2) and 4.2728(7) Å for La9Sb16Br3 and Ce9Sb16Cl3, respectively. The solids are the most metal-rich members in the reduced rare earth metal halide family and contain partial structures which are characteristic of reduced halides and intermetallic phases. These are the [Ln6X6]∞ hexagon stars, Sb-centered [Ln3Sb] ∞ trigonal prismatic columns, and stripes of Sb square meshes. Computational analysis indicates that their electronic structure is valence-precise in the reduced halide part, but electron-deficient in the intermetallic part. Susceptibility and resistivity measurements reveal the metallic nature of the compounds. [ABSTRACT FROM AUTHOR]

The compounds Ce[sub 10]CI[sub 4]Ga[sub 5] and Ln[sub 3]CIGa[sub 4] (Ln = La, Ce) were synthesized from stoichiometric mixtures of Ln, LnCIs3, and Ga under Ar atmosphere in sealed Ta ampules at 910-1020 °C for 25-26 days. Ce[sub 10]Cl[sub 4]Ga[sub 5] is isostructural to La[sub 10]CI[sub 4]Ga[sub 5] (space group I4/mcm, No. 140) with lattice constants a = 7.9546(11) Å c = 31.793(6) Å. Ln[sub 3]CIGa[sub 4] represents a new structural type, also in the space group I4/mcm, with a = 8.1955(8) and 8.1123(11) Å, c = 11.363(2) and 11.229(2) Å, respectively, for Ln = La and Ce. Ce[sub 10]Cl[sub 4]Ga[sub 5] features building blocks of Ga-centered Ce[sub 6] trigonal prisms and distinctive two-dimensional intermetallic CuAI[sub 2] and U[sub 3]Si[sub 2] type nets. Its electronic structure falls within the realm of reduced rare-earth halides. Ln[sub 3]CIGa[sub 4] also contains the intermetallic CuAI[sub 2] type nets, but the interstitials are inverted: The building blocks are Cl-centered Ln[sub 6] octahedra. Its electronic structure is characterized by strong peripheral Ln-Ga bonding stabilizing the Ln[sub 6]CI octahedron which normally would have its Ln-Ln antibonding orbitals filled with electrons from interstitials beyond chalcogen. Magnetic susceptibility and conductivity measurements confirm the metallic nature of all three compounds. [ABSTRACT FROM AUTHOR]

Demonstrates the synthesis of a novel ternary chromium sulfide, BaCrS2. Crystallization of the solid state compound in the orthorhombic, centrosymmetric space group; Comparison of the structures of BaCrS2 and BaNiS2; Distortion of the square pyramidal coordination of the novel compound; Computational study of the novel compound.

The title compound features a five-membered Ru5 ring embedded in a La14 hexagonal wheel-like cage, an incommensurate combination of the two building units. A formal electron partition of (La3+)14(Cl-)20(Ru5)22- results in a (Ru5)22- ring isoelectronic to (Cd5)2-. However, computational studies show that there is significant electron back-donation from the Ru5 ring to the La14 wheel. This interaction strongly stabilizes the Ru5 ring. The resistivity and magnetic susceptibility of the compound have also been investigated. [ABSTRACT FROM AUTHOR]

A highly luminescent three-dimensional microporous metal-organic framework, [Zn2(oba)2(bpy)]·DMA, demonstrates unique selectivity for the detection of high explosives and other aromatics via a fluorescence quenching and enhancement mechanism. [ABSTRACT FROM AUTHOR]

The reactions of Ln(NO[sub 3])[sub 3] (Ln = La, Er) with 1,4-phenylendiacetic acid (H[sub 2]PDA) under hydrothermal conditions produce isostructural tanthanide coordination polymers with the empirical formula [Ln[sub 2](PDA)[sub 3](H[sub 2]O)]·2H[sub 2]O. The extended structure of [Ln[sub 2](PDA)[sub 3](H[sub 2]O)]·2H[sub 2]O consists of Ln-COO triple helixes cross-linked through the -CH[sub 2]C[sub 6]H[sub 4]CH[sub 2]-spacers of the PDA anions, showing 1D open channels along the crystallographic c axis that accommodate the guest and coordinated water molecules. Evacuation of [Er[sub 2](PDA)[sub 3](H[sub 2]O)]·2H[sub 2]O at room temperature and at 200 °C, respectively, generates [Er[sub 2](PDA)[sub 3](H[sub 2]O)] and [Er[sub 2](PDA)[sub 3]], both of which give powder X-ray diffraction patterns consistent with that of [Er[sub 2](PDA)[sub 3](H[sub 2]O)]· 2H[sub 2]O. The porosity of [Er[sub 2](PDA)[sub 3](H[sub 2]O)] and [Er[sub 2](PDA)[sub 3]] is further demonstrated by their ability to adsorb water vapor to form [Er[sub 2](PDA)[sub 3](H[sub 2]O)]·2H[sub 2]O quantitatively. Thermogravimetric analyses show that [Er[sub 2](PDA)[sub 3]] remains stable up to 450 °C. The effective pore window size in [Er[sub 2](PDA)[sub 3]] is estimated at 3.4 Å. Gas adsorption measurements indicate that [Er[sub 2](PDA)[sub 3]] adsorbs CO[sub 2] into its pores and shows nonporous behavior toward Ar or N[sub 2]. There is a general correlation between the pore size and the kinetic diameters of the adsorbates (CO[sub 2] = 3.3 Å, Ar = 3.40 Å, and N[sub 2] = 3.64 Å). That the adsorption favors CO[sub 2] over Ar is unprecedented and may arise from the combined differentiations on size and on host-guest interactions. [ABSTRACT FROM AUTHOR]

The article presents a study on the N-heterocyclic superelectrophiles and on the structural electron transfer (SET) reactions involving these superelectrophiles. It states that SET chemistry takes place in reactions of ferrocene with oxazole, thiazole, and pyridine-based superelectrophiles. It mentions that bothy low-lying LUMOs and energetically favorable single-electron reductions are regarded important to the success of this SET chemistry.