The metal-organic frameworks (MOF) with low and medium specific surface areas (SSA) were shown to be able to adsorb hydrogen via bridged spillover at room temperature (RT) up to an amount of full coverage of hydrogen in the MOF. Anomalous small-angle X-ray scattering was employed to investigate the key relationship between the structures and storage properties of the involved materials. It was found that the tunable imperfect lattice defects and the 3D pore network in the MOF crystal are the most critical structures for RT hydrogen uptake rather than the known micropores in the crystal, SSA, and Pt catalyst structure.
A collaborative experimental and theoretical study of rotationally inelastic collisions of CH(A 2Δ,v=0) resolved rotational/fine-structure levels with argon is presented. Experimental state-to-state rate constants were extracted from CH A 2Δ→X 2Π fluorescence spectra upon laser excitation to individual levels in the A 2Δ state in the presence of Ar. Fluorescence detection of the collision-induced population permits resolution of the fine-structure levels at low N, but no Λ-doublet discrimination. For the lowest value of N (N=2), the dominant process is the ΔN=0 fine-structure-changing transition, and the efficiency of this transition decreases markedly with increasing N. There is an increasing preference for conservation of the fine-structure label in ΔN≠0 transitions as N increases. These rate constants have been compared to and interpreted with theoretical rate constants computed through quantum coupled-states calculations of cross sections based on ab initio CH(A 2Δ)–Ar potential energy surfaces determined by Kaledin and Heaven (to be published). The tendency to conserve the fine-structure label is attributed to the Hund’s case (b) nature of the CH(A 2Δ) state, for which the electron spin is a spectator in the collision.
Preparations of novel unsymmetrical, tridentate nitrogen ligand precursors, PhN=C(CMe2)(NPh)C=N(CH2)2NMe2(1) and PhN=C(CMe2)(NPh)C=N(CH2)Py (2), are described. Treatment of 1 with 1 molar equiv. (COD)PdCl2 in the presence of NEt3 or with 1 molar equiv. Pd(OAc)2 affords orthometallated palladium(II) complexes, [PhN=C(CMe2)(N-eta1-Ph)C=N(CH2)2NMe2]PdX (X=Cl (3); X=OAc (4)), respectively. Compound can be yielded via the reaction of with an excess of LiCl in methanol. Treatment of with 1 molar equiv. of (COD)PdCl2, Pd(OAc)2 or Pd(TFA)2 affords orthometallated palladium(II) complexes, [PhN=C(CMe2)(N-eta1-Ph)C=NCH2Py]PdX (X=Cl (5); X=OAc (6); X=TFA (7)), respectively. The crystal and molecular structures are reported for compounds 2, 3, 5 and 6. The application of these novel palladacyclic complexes to the Heck reaction with aryl halide substrates was examined.
Two pendant oxalic amidine compounds [C6H5N=C{NH(CH2)(2)OMe}-C{NH(CH2)(2)OMe} = NC6H5] (1) (oxam(OMe)(2)H-2) and [C6H5N=C{NH(CH2)(2)NMe2} - C{NH(CH2)(2)NMe2} = NC6H5] (2) (oxam(NMe2)(2)H-2) are described. Reactions of 1 or 2 with two molar equivalents of AlMe3 in toluene give the bimetallic complexes [(Me-2)Al(oxam(OMe)(2)) Al(Me-2)] (3) and [(Me-2)Al(oxam(NMe2)(2)) Al(Me-2)] (4), respectively. Treatment of 1 or 2 with two molar equivalents of MeMgBr in THF affords the bimetallic complexes [(Br)(THF) Mg(oxam(OMe)(2))Mg( THF)(Br)] (5) and [(Br)(THF) Mg(oxam(NMe2)(2)) Mg(THF)(Br)] (6) respectively. The crystal and molecular structures are reported for compounds 1, 2, 3, 5 and 6
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