Iron(III) amine-bis(phenolate) complexes as catalysts for the coupling of alkyl halides with aryl Grignard reagents

Catalytic cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing beta-hydrogens is achieved using Fe(III) amine-bis(phenolate) halide complexes.     

Interaction of NO2 with Model NSR Catalysts: Metal–Oxide Interaction Controls Initial NOx Storage Mechanism

Using scanning tunneling microscopy (STM), molecular‐beam (MB) methods and time‐resolved infrared reflection absorption spectroscopy (TR‐IRAS), we investigate the mechanism of initial NO_x uptake on a model nitrogen storage and reduction (NSR) catalyst. The model system is prepared by co‐deposition of Pd metal particles and Ba‐containing oxide particles onto an ordered alumina film on NiAl(110). We show that the metal–oxide interaction between the active noble metal particles and the NO_x storage compound in NSR model catalysts plays an important role in the reaction mechanism. We suggest that strong interaction facilitates reverse spillover of activated oxygen species from the NO_x storage compound to the metal. This process leads to partial oxidation of the metal nanoparticles and simultaneous stabilization of the surface nitrite intermediate.     

Gas phase vibrational spectroscopy of mass-selected vanadium oxide anions

The vibrational spectra of vanadium oxide anions ranging from V(2)O(6)(-) to V(8)O(20)(-) are studied in the region from 555 to 1670 cm(-1) by infrared multiple photon photodissociation (IRMPD) spectroscopy. The cluster structures are assigned and structural trends identified by comparison of the experimental IRMPD spectra with simulated linear IR absorption spectra derived from density functional calculations, aided by energy calculations at higher levels of theory. Overall, the IR absorption of the V(m)O(n)(-) clusters can be grouped in three spectral regions. The transitions of (i) superoxo, (ii) vanadyl and (iii) V-O-V and V-O single bond modes are found at approximately 1100 cm(-1), 1020 to 870 cm(-1), and 950 to 580 cm(-1), respectively. A structural transition from open structures, including at least one vanadium atom forming two vanadyl bonds, to caged structures, with only one vanadyl bond per vanadium atom, is observed in-between tri- and tetravanadium oxide anions. Both the closed shell (V(2)O(5))(2,3)VO(3)(-) and open shell (V(2)O(5))(2-4)(-) anions prefer cage-like structures. The (V(2)O(5))(3,4)(-) anions have symmetry-broken minimum energy structures (C(s)) connected by low-energy transition structures of C(2v) symmetry. These double well potentials for V-O-V modes lead to IR transitions substantially red-shifted from their harmonic values. For the oxygen rich clusters, the IRMPD spectra prove the presence of a superoxo group in V(2)O(7)(-), but the absence of the expected peroxo group in V(4)O(11)(-). For V(4)O(11)(-), use of a genetic algorithm was necessary for finding a non-intuitive energy minimum structure with sufficient agreement between experiment and theory.     

Analytic three-dimensional 'MLR' potential energy surface for CO(2)-He, and its predicted microwave and infrared spectra

A three-dimensional, analytic potential energy surface for CO(2)-He that explicitly incorporates its dependence on the Q(3) asymmetric-stretch normal-mode coordinate of the CO(2) monomer has been obtained by least-squares fitting new ab initio interaction energies to a new three-dimensional Morse/Long-Range (3D-MLR) potential function form. This fit to 2832 points has a root-mean-square (RMS) deviation of 0.032 cm(-1) and requires only 55 parameters. The resulting pure ab initio potential provides a good representation of the experimental microwave and infrared data: for 51 pseudo microwave and 49 infrared transitions the RMS discrepancies are 0.0110 and 0.0445 cm(-1), respectively. Scaling this surface using only two morphing parameters yields an order of magnitude better agreement with experiments, with RMS discrepancies of only 0.0025 and 0.0038 cm(-1), respectively. The calculated infrared band origin shift associated with the nu(3) fundamental of CO(2) is 0.109 cm(-1), in good agreement with the (extrapolated) experimental value of 0.095 cm(-1).     

Synthesis and Characterization of Gd2[Pt2(SO4)4(HSO4)2](HSO4)2

Red single crystals of Gd₂[Pt₂(SO₄)₄(HSO₄)₂](HSO₄)₂ (triclinic, , Z = 1, a = 844.02(9), b = 908.50(9), c = 939.49(8) pm, α = 107.73(1)°, β = 112.10(1)°, γ = 103.53(1)°) were obtained by the reaction of [Gd(NO₃)(H₂O)₇][PtCl₆]·4H₂O with sulfuric acid at 320 °C in a sealed glass ampoule. In the crystal structure, Pt₂ dumbbells are coordinated by four chelating sulfate groups and two monodentate hydrogensulfate ions. Two further HSO₄^? ions are not bonded to the Pt₂ dumbbell. The Gd³⁺ ions are eightfold coordinated by oxygen atoms. The IR data of Gd₂[Pt₂(SO₄)₄(HSO₄)₂](HSO₄)₂ are typical for these type of compounds. The thermal decomposition of the compound leads to elemental platinum and Gd₂O₃.