New Routes to the Synthesis of Mes

New　Routes　to　the　Synthesis　of　Mes...     

Homoleptic 1-D iron selenolate complexes-synthesis, structure, magnetic and thermal behaviour of (1)(∞)[Fe(SeR)2] (R=Ph, Mes)

The first examples of polymeric homoleptic iron chalcogenolato complexes (1)(∞)[Fe(SePh)(2)] and (1)(∞)[Fe(SeMes)(2)] (Ph = phenyl = C(6)H(5), Mes = mesityl = C(6)H(2)-2,4,6-(CH(3))(3)) have been both prepared by reaction of [Fe(N(SiMe(3))(2))(2)] with two equivalents of HSeR (R = Ph, Mes) while (1)(∞)[Fe(SePh)(2)] was found to be also easily accessible through reactions of either FeCl(2), Fe(OOCCH(3))(2) or FeCl(3) with PhSeSiMe(3) in THF. In the crystal, the two compounds form one-dimensional chains with bridging selenolate ligands comprising distinctly different Fe-Se-Fe bridging angles, namely 71.15-72.57° in (1)(∞)[Fe(SePh)(2)] and 91.80° in (1)(∞)[Fe(SeMes)(2)]. Magnetic measurements supported by DFT calculations reveal that this geometrical change has a pronounced influence on the antiferromagnetic exchange interactions of the unpaired electrons along the chains in the two different compounds with a calculated magnetic exchange coupling constant of J = -137 cm(-1) in (1)(∞)[Fe(SePh)(2)] and J = -20 cm(-1) in (1)(∞)[Fe(SeMes)(2)]. In addition we were able to show that the ring molecule [Fe(SePh)(2)](12) which is a structural isomer of (1)(∞)[Fe(SePh)(2)] behaves magnetically similar to the latter one. Investigations by powder XRD reveal that the ring molecule is only a metastable intermediate which converts in THF completely to form (1)(∞)[Fe(SePh)(2)]. Thermal gravimetric analysis of (1)(∞)[Fe(SePh)(2)] under vacuum conditions shows that the compound is thermally labile and already starts to decompose above 30 °C in a two step process under cleavage of SePh(2) to finally form at 250 °C tetragonal PbO-type FeSe. The reaction of (1)(∞)[Fe(SePh)(2)] with the Lewis base 1,10-phenanthroline yielded, depending on the conditions, the octahedral monomeric complexes [Fe(SePh)(2)(1,10-phen)(2)] and [Fe(1,10-phen)(3)][Fe(SePh)(4)].     

M(bpy)2+3(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物Ｍ（ｂｐｙ）＾２＋３（Ｍ＝Ｆｅ,Ｒｕ,Ｏｓ）的量子化学密度泛函法研究的结果。Ｂ３ＬＹＰ／ＬａｎＬ２ＤＺ方法与基组的水平上进行计算,探讨Ｍ（ｂｐｙ）＾２＋３电子结构特征及相关性质,特别是中心原子对配合物的配位键长、光谱性质,电荷布局及化学稳定性等的影响规律,为该类配合物的合成,为分析光、电、催化作用机理提供理论参考。     

M(bpy)2+3(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物(M=Fe,Ru,Os)的量子化学密度泛函(DFT)法研究的结果.在B3LYP/LanL2DZ方法与基组的水平上进行计算,探讨的电子结构特征及相关性质,特别是中心原子对配合物的配位键长、光谱性质、电荷布居及化学稳定性等的影响规律,为该类配合物的合成,为分析光、电、催化作用机理提供理论参考.     

Unusually facile syntheses of [RuII(bpy)3]2+ (bpy = 2,2′-bipyridine) and [RuII(phen)3]2+ (phen = 1,10-phenanthroline)

The salts [Ru^II(L–L)₃](CF₃SO₃)₂ (L–L = bpy or phen) have been prepared in high yields via reactions of [Ru^II(DMF)₆](CF₃SO₃)₂ (DMF = N,N-dimethylformamide), generated in situ by reduction of [Ru^III(DMF)₆]-(CF₃SO₃)₃, with an excess of bpy or phen at room temperature in DMF solutions.     

M(bpy)_3~(2 )(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物M(bpy)2 M=Fe,Ru,Os)的量子化学密度泛函(DFT)法研究的结果.在B3LYP/LanL2DZ方法与基组的水平上进行计算 ,探讨M(bpy)32 的电子结构特征及相关性质 ,特别是中心原子对配合物的配位键长、光谱性质、电荷布居及化学稳定性等的影响规律 ,为该类配合物的合成 ,为分析光、电、催化作用机理提供理论参考.     

Synthesis of molecular ferromagnetics [R3R′X]MCr(C2O4)3 (X = N,R = Bun,R′ = Prn,Et, Me; X = P,R = Ph,R′ = Bun; M = Mn,Fe, Co,Ni, Cu)

The synthesis, IR spectra, and the temperatures of the transition into a ferromagnetic state (T _c) of layered ferromagnetics [R₃RX[MCr(C₂O₄)₃ (M = Mn, Fe, Co, Cu, and Ni) with the [Ph₃BuP]⁺, [Bu₃RN]⁺ (R = Pr, Et, and Me) cations capable of subsequently changing the distances between metallooxalate layers have been considered. The temperatureT _c has been found to be independent of the size of the organic cation. It is believed that the determining factors in the transition to a ferromagnetic state are exchange interactions inside the metallooxalate layer.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2327–2330, September, 1996.     

Fluorescence lifetime studies of no a 2Σ+(ν = 5, N = 9), B2Π32(ν = 8, J = 8.5), CwΠ32(ν = 1, J = 8.5), D2Σ+ (ν = 0, N = 5) and D2Σ+(ν = 1, N = 9)

Fluorescence decay profiles of NO excited levels slightly above the dissociation limit have been measured by a single-photon counting technique with nanosecond pulse excitation using an iodine flash lamp. Three iodine atomic lines in the vicinity of 180 nm are found to bring NO molecules into the levels A²Σ⁺(ν = 5, N = 9), B²²Π_{$\text{3}\text{2}$}(ν = 8, J = 8.5), C²Π_{$\text{3}\text{2}$}(ν = 1, J = 8.5), D²Σ⁺(ν = 0, N = 5) and D²Σ⁺(ν = 1, N = 9). Extrapolated zero-pressure lifetimes for single rotational levels are obtained, except for the C state where only a lifetime of ⩽0.4 ns was obtained. Self-quenching rate constants are also determined under higher-pressure conditions. Helium was found to quench the NO A²Σ⁺(ν′ = 5) fluorescence very efficiently.     

Theoretical Study of Decomposition Pathways for Rare-gas-containing Compounds HRgX （Rg = He, Ne, Ar, Kr; X = Cl, Br）

1 INTRODUCTION transfer species with common formula H-Rgδ -Xδ, where X represents a strongly electrone-gative atom Since xenon hexafluoraplatinate, XePtF6 , the [1] or fragment, and Rg is a rare-gas atom. These species first rare gas-containing compound was discovered have linear equi- librium geometries and are mainly by Bartlett in 1962, rare gases are getting more and bound up by strong columbic attraction between (H- more attention and have been found to be possible to Rg) and…     

Interactions of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1)

The coupled cluster singles and doubles method with perturbative treatment of triple excitations is applied to calculate the potentials of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1). The bond functions and the basis set superposition errors are considered to obtain accurate interaction energies. The potential energy curves of all complexes are obtained. The vibrational energy levels and the spectroscopic parameters for these complexes are determined. The analytical potential energy functions are also fitted based on the potential energies.     

Structures and Aromaticity of Three-membered BeXP （X = C,Si, Ge） and CYP （Y = O,S, Se） Rings

Three-membered BeXP （X = C, Si, Ge） and CYP （Y = O, S, Se） rings are theoretically investigated using density functional theory （DFT） methods at the B3LYP/6-311＋G^＊ and B3PW91/6-311＋G^＊ levels of theory. The research results show that the size of atoms has a great influence on the structural stability of these species. The wiberg bond indexs （WBIs） suggest the existence of delocalization in these structures. Negative nucleus-independent chemical shift （NICS） values for these species indicate that a strong ring current exists in these three-membered structures （Cs symmetry）. A detailed molecular orbital （MO） analysis further reveals that a delocalized π MO strengthens the structural stability and makes these species show strong aromatic characters.     

Preparation and crystal structure of members of the solid solution phase Ba5Ru2−xAl1+x−yCuyO11 with x=0.378, y=0.085 and x=0.5, y=0

Single crystals of the new phase Ba₅Ru_2−xAl_1+x−yCu_yO₁₁ (x=0.378, y=0.085) have been grown from a powder mixture of BaCO₃, RuO₂ and CuO in an alumina crucible. The new compound crystallizes isostructurally to Ba₅Ir₂AlO₁₁. The crystal structure was determined by X-ray single-crystal diffraction technique and refined to a composition of Ba₅Ru_1.622(8)Al_1.29(1)Cu_0.085(6)O₁₁ (orthorhombic, Pnma (No. 62), a=18.615(4) Å, b=5.771(1) Å, c=11.098(2) Å, Z=4, R₁=0.048, wR₂=0.075). The composition of the new compound obtained from crystal structure refinement is in good agreement with the result of electron probe microanalysis using wavelength-dispersive X-ray spectroscopy. Octahedra [RuO₆] are connected via faces forming pairs. The central positions of the octahedra pairs are statistically occupied by Ru and Al atoms. These octahedra pairs are interconnected to one-dimensional chains extending along [010] via tetrahedra [Al_1−yCu_yO₄]. Isotypic Ba₅Ru_1.5Al_1.5O₁₁ is a further member of the solid solution with the lattice parameters a=18.6654(5) Å, b=5.7736(1) Å, c=11.0693(3) Å according to Rietveld refinement on a microcrystalline sample.     

Bridge Cleavage Reactions of Dinuclear Diselenolenes: Preparation of Palladium Complexes of Novel Chelating Selenolato/Selenide Ligands, [PdX(Se{R′}CnH2n−4Se)(PR3)](n = 6, 7, 8; R = Ph,Bu; X = Br,I; R′ = Me,Et, etc.)

Abstract

The dinuclear palladium diselenolenes [Pd₂(Se₂C_nH_2n?4)₂(PR₃)₂] react with haloalkanes, via electrophilic attack at the bridging selenium atoms, to yield the neutral mononuclear square planar palladium(II) complexes [PdX(Se{R′}C_nH_2n?4Se)(PR₃)] (n = 6, 7, 8; R = Ph, Bu; X = Br, I; R′ = Me, Et, etc.), containing a novel chelating selenolato/selenide ligand, in which the alkylated selenium and halogen donor atoms occupy cis-positions. The products have been characterised by mass spectrometry and multinuclear NMR spectroscopy; the molecular structure of the compound with n = 8, R = Ph, R′ = Et has been determined by X-ray crystallography.     

Structures and Aromaticity of Planar XY2Z （X = Li,K, Y - P,As and Z = C,Si, Ge） Clusters

Clusters XY2Z species are theoretically investigated with density functional theory （DFT） method. The results show that for LiP2C, LiAs2Ge and KAs2C species, the C2v isomer is the most stable planar structure, while for other species the Cs isomer is the most stable planar structure at the B3LYP/6-311＋G＊ level. Wiberg Bond Index （WBI） and Nucleus-Independent Chemical Shift （NICS） values indicate the existence of delocalization in stable planar structures. A detailed Molecular Orbital （MO） analysis further reveals that planar isomers of these species have strong aromatic character, which strengthens the structural stability and makes them closely connect with the concept of aromaticity.     

Copper-Catalyzed Chemoselective Asymmetric Hydrogenation of C=O Bonds of Exocyclic α,β-Unsaturated Pentanones

A highly chemoselective earth-abundant transition metal copper catalyzed asymmetric hydrogenation of C=O bonds of exocyclic α,β-unsaturated pentanones was realized using H₂. The desired products were obtained with up to 99 % yield and 96 % ee (enantiomeric excess) (99 % ee, after recrystallization). The corresponding chiral exocyclic allylic pentanol products can be converted into several bioactive molecules. The hydrogenation mechanism was investigated via deuterium-labelling experiments and control experiments, which indicate that the keto-enol isomerization rate of the substrate is faster than that of the hydrogenation and also show that the Cu−H complex can only catalyze chemoselectively the asymmetric reduction of the carbonyl group. Computational results indicate that the multiple attractive dispersion interactions (MADI effect) between the catalyst with bulky substituents and substrate play important roles which stabilize the transition states and reduce the generation of by-products.     

The First-principlies Calculations of the Electronic Structures and Optical properties of Ⅱ-Ⅲ2-Ⅵ4 （Ⅱ=Zn,Cd; Ⅲ= In; Ⅵ=Se,Te）

The electronic structures and optical properties of II-III2-VI4 （II = Zn, Cd; III = In; VI = Se, Te） compounds are studied by the density functional theory （DFT） using the Vienna ab initio simulation package （VASP）. Geometrical optimization of the unit cell is in good agreement with the experimental data. Our calculations show that the valence band maximum （VBM） and conduction band minimum （CBM） are located at G resulting in a direct energy gap. The optical properties are analyzed, and the independent second harmonic generation （SHG） coefficients are determined. By an analysis of the band structure, we can get that SHG response of the system can be attributed to the transitions from the bands near the top of valence band that are derived from the Se/Te p states to the unoccupied bands contributed by the p states of In atoms.     

Synthesis and Crystal Structure of Organic Salt (H_2Bpy)(cda)_2 (cda = Carbamyldicyano-methanide Anion; H_2bpy = Hydrogen 4,4''''-Bipyridyl Divalent Cation)

1 INTRODUCTION Polynitrile compound Na(cda) is a very useful ligand and its complexes have been synthesized[1～3], in which the two-dimensional Eu(III) complex exhi- bits the strongest fluorescence and non-linear optic property[4]. We originally want to…     

Synthesis and Characterization of Organosilyl Derivatives of Keggin Polyoxometalates [XW11O40（SiR）2]n- CX=CoIII, P; R=CH=CH2, OH）

以CoIIIW11和有机硅烷为原料,在pH=1,乙醇-水（体积比=2∶1）的混合溶剂中,首次合成了Keggin型有机硅取代的钨钴酸盐[CoIIIW11O40（SiR）2]5-（CoIIIW11（SiR）2,R=CH=CH2,OH）.这里,乙醇作为共溶剂增加硅烷在溶液中的溶解度,使CoIIIW11在转化为饱和结构之前能够快速与硅烷相遇并反应.产物的组成和结构用IR,UV-Vis,NMR,TG-DTA,元素分析等技术进行了全面表征.结果显示,两个SiR基团进入了CoIIIW11的空位,并形成Si—O—Si桥,得到与先前报道的硅取代钨硅酸盐和钨磷酸盐相似的结构.还运用此条件成功合成了以往需要在固-液相转移条件下合成的[PW11O40（SiR）2]3-[PW11（SiR）2,R=CH=CH2,OH],进一步证明了此方法在合成有机硅取代的多金属氧酸盐方面的可行性和通用性.     

Hydrothermal Synthesis,Crystal Structure,Magnetic Properties and Network Topology of a Novel Binuclear Co(Ⅱ) Coordination Polymer_∞~1[Co_2(4,4'-bpy)_2(L)_4](bpy = Bipyridine,HL = 2-Fluorbenzoic Acid)

One novel binuclear Co(Ⅱ) coordination polymer 1[Co2(4,4'-bpy)2(L)4](1, bpy = bipyridine, HL = 2-fluorbenzoic acid) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR and X-ray single-crystal diffraction. Complex 1 crystallizes in the monoclinic system, space group P21/c with a = 11.163(2), b = 21.943(4), c = 9.6381(19)?, β = 113.92(3)°, V = 2158.2(7) ?_3, Z = 4, Dc = 1.518 g/cm3, Mr = 493.31, F(000) =1004, R = 0.0303 and w R = 0.0808 for 3614 observed reflections(I 2σ(I)). Complex 1 exhibits a 3D Schlafli symbol(4.62)(4.66.83) topological framework, and the magnetic characterization shows weak antiferromagnetic coupling exchange between two Co ions.     

Syntheses,Structures and Band Gaps of KLnSiS4 （Ln = Sm,Yb）

Two new quaternary sulfides, KSmSiS4 （1） and KYbSiS4 （2）, have been synthesized by high-temperature solid-state reaction. Single,crystal X-ray diffraction analyses indicate that both compounds crystallize in the space group P21/m, and the crystal data are as follows： a = 6.426（11）, b = 6.582（11）, c = 8.602（15）A, β= 107.90（13）°, Z = 2, V= 346.2（10） A^3, Dc = 3.317 g/cm^3, F（000） = 318,μ（MoKα） = 10.334 mm^-1, the final R = 0.0559 and wR = 0.1370 for 1; and α= 6.3244（10）, b = 6.5552（10）, c = 8.5701（15）A, β= 108.001（13）°, Z = 2, V = 337.91（9） A^3, De= 3.621 g/cm^3, F（000） = 334, μ（MoKα） = 15.737 mm^-1, the final R = 0.0422 and wR = 0.0960 for 2. The KLnSiS4 （Ln = Sm, Yb） structure consists of corrugated ∞^2 [LnSiS4]^- layers which are formed by edge-sharing LnS8 bicapped trigonal prisms and SiS4 tetrahedra. The K^＋ cations are located in the cavities defined by S2 anions between the ∞^2[LnSiS4]^- layers. Band-gap analyses show that compounds 1 and 2 are semiconductors with optical band-gaps of 2.40 and 2.34 eV, respectively.