Übergangsmetall-Carbin-Komplexe: CIII. Aktivierung von Ethylisocyanid an elektronenreichen Metallzentren; Synthese von einkernigen Wolfram-Aminocarbin-Komplexen des Typs Tp′(CO)2 WCN(R)Et (R  Me,Et)

A large-scale, high-yield synthesis of the aminocarbyne complexes Tp′(CO)₂WCN(R)Et (5: R  Me; 6: R  Et) [Tp′ = hydridotris(3,5-dimethylpyrazol-1-yl)borate] is reported, starting from Tp′W(CO)₃I (2). The first step of the synthetic procedure involves thermal decarbonylation of 2 with EtNC to give cis-Tp′W(CO)₂(CNEt)I (3). Complex 3 is then reduced with Na/Hg to give the metallate Na[Tp′W(CO)₂(CNEt)] (4). Finally, complex 4 is alkylated with RI (R  Me, Et) exclusively at the isocyanide nitrogen to give the aminocarbyne complexes 5 and 6. In contrast, the metallates Na[(η⁵-C₅R′₅)W(CO)₂(CNEt)] (R′  H, Me) undergo alkylation with RI at the metal centre to afford the W^II alkyl complexes cis/trans-(η-C₅R′₅)W(CO)₂(CNEt)R. This difference in reactivity is ascribed to the steric demands of the Tp′ ligand, which shields the metal centre from the incoming electrophile.     

A diruthenium soft ferromagnet showing T(c) = 3.0 K: Mn4(H2O)16H[Ru2(CO3)4]2[Ru2(CO3)4(H2O)2]·11H2O

A three-dimensional CO(3)(2-)-bridged Mn(II)-Ru(2)(II,III) complex, Mn(4)(H(2)O)(16)H[Ru(2)(CO(3))(4)](2)[Ru(2)(CO(3))(4)(H(2)O)(2)]·11H(2)O (1), was synthesized by self-assembling Ru(2)(CO(3))(4)(3-) paddle-wheel precursors and Mn(2+) cations. It contains an unprecedented layer [Ru(2)(CO(3))(4)](n)(3n-) with (4,4) network. The ferromagnetic coupling between spin centers results in ordering below 3.0 K.     

Infrared Spectroscopy of Size-Selected Hydrated Carbon Dioxide Radical Anions CO2.−(H2O)n (n=2–61) in the C−O Stretch Region

Understanding the intrinsic properties of the hydrated carbon dioxide radical anions CO₂^.−(H₂O)_n is relevant for electrochemical carbon dioxide functionalization. CO₂^.−(H₂O)_n (n=2–61) is investigated by using infrared action spectroscopy in the 1150–2220 cm⁻¹ region in an ICR (ion cyclotron resonance) cell cooled to T=80 K. The spectra show an absorption band around 1280 cm⁻¹, which is assigned to the symmetric C−O stretching vibration ν_s. It blueshifts with increasing cluster size, reaching the bulk value, within the experimental linewidth, for n=20. The antisymmetric C−O vibration ν_as is strongly coupled with the water bending mode ν₂, causing a broad feature at approximately 1650 cm⁻¹. For larger clusters, an additional broad and weak band appears above 1900 cm⁻¹ similar to bulk water, which is assigned to a combination band of water bending and libration modes. Quantum chemical calculations provide insight into the interaction of CO₂^.− with the hydrogen-bonding network.     

Density functional investigations on the (H2O)n·CCH and (H2O)n·HCC complexes (n=1–3)

The electronic structures and energies of (H₂O)_n·CCH and (H₂O)_n·HCC complexes (n=1–3) between CCH and water have been theoretically investigated at the UB3LYP/6-311++G(2df,p)//UB3LYP/6-311G(d,p) level. The complexes with n=2–3 are cyclic structures with homodromic hydrogen-bond chain. The (H₂O)_n·CCH (n=1–3) complexes show increasing stabilities towards CCH- or H₂O-eliminations of 2.3, 5.8 and 7.6 kcal/mol and are energetically more stable than the corresponding (H₂O)_n·HCC complexes by 0.8, 2.7 and 3.4 kcal/mol, respectively, due to the charge-separation-enhanced hydrogen bonds within (H₂O)_n·CCH (n=2,3). Strong interactions between CCH and (H₂O)₂ and (H₂O)₃ clusters suggest special solvent effects of water on the chemical behavior of unsaturated radicals.     

The reactions of [Fe2(η-C5H5)2(CO)4−n(CNMe)n] (n = 0–4) complexes with halogens and mercury(II) salts

Halogens, X₂, and HgY₂ (X = Cl, Br, I; Y = X, F, NO₃, BF₄) cleave the metalmetal bonds in [Fe₂(η-C₅H₅)₂(CO)_4−n(CNMe)_n] complexes (n = 0–4). Typically, e.g., when n = 2, X₂ electrophiles give [Fe(η-C₅H₅)(CO)(CNMe)X] (a) and [Fe(η-C₅H₅)(CO)(CNMe)₂]X (b) in relative yields which depend on X, the reaction solvent and n, but HgY₂ give equimolar amounts of [Fe(η-C₅H₅)(CNMe)₂Y] (c and [Fe(η-C₅H₅)(CO)₂HgY] only. Hg(CN)₂ reacts more slowly than other HgY₂, and [Hg(PPh₃)₂I₂] does not react at all. It is suggested that the reactions which give rise to products of type (a), (b) or (c) are all two-electron oxidation which proceed by way of adducts containing μ-CA → X₂ or μ-CA → HgX₂ groups (Ca = CO or CNMe). One of these adducts has been isolated, namely [Fe₂(η-C₅H₅)₂(CNMe)₂{μ-CN(Me)HgCl₂}₂] · CHCl₃.     

Photoelectron spectroscopy of (CO2)n(H2O) m − clusters

Photoelectron spectra of (CO₂)_nH₂O^? (2≤n≤8) and (CO₂)_n(H₂O) ₂ ^? (1≤n≤2) were measured at the photon energy of 3.49 eV. The spectra show unresolved broad features, which are approximated by Gaussians. The vertical detachment energies (VDEs) were determined as a function of the cluster size. For (CO₂)_nH₂O^?, the VDE-n plots exhibit a sharp discontinuity between n=3 and 4; the VDE value is ≈3.5 eV at n=3, while it drops down abruptly to 2.59 eV at n=4. This discontinuity in VDE is ascribed to "core switching" at n=4; a C₂O ₄ ^? dimer anion forms the core of (CO₂)_nH₂O^? for n≤3, while a monomer CO ₂ ^? is the core for n≥4. The (CO₂)₂(H₂O) ₂ ^? ion has a VDE of 2.33 eV, indicating the presence of a CO ₂ ^? monomer core in the binary clusters containing two H₂O molecules.     

ChemInform Abstract: Unique Seven-Node Rare-Earth Octacyanomolybdate(IV) Three-Dimensional Molecular Frameworks: {[Er(H2O)5(Er (H2O)4)3] [Mo(CN)8]3·11H2O}n and {[Eu(H2O)5(Eu (H2O)4)3] [Mo(CN)8]3·11H2O}n.

Good quality single crystals of the title compound are obtained by reaction of H₄[Mo(CN)₈] with the rare earth carbonates.     

Pressure tuning spectroscopy of [Pt3(CO)6]2−n (n=3–5)

The pressure shifts of the first three bands appearing in the visible spectra of [Pt₃(CO)₆]²⁻_n (n = 3–5) have been measured in solution over the range 0–10 kbar. Previous electronic calculations performed on the dimer in conjunction with these results afford a possible set of assignments for the first three bands appearing in the visible spectrum for the dimer.     

具有螺旋结构的新型硼磷酸盐化合物:(NH4)0.5(H3O)0.5Mg(H2O)2BP2O8

利用水热方法合成新型硼磷化合物:(NH4)0.5(H3O)0.5Mg(H2O)2BP2O8,单晶X射 线衍射分析证明化合物属六方晶系,空间群为P6522,a=0.94507(19)nm,c=1.5803(5) nm,γ=120°,V=1.2224(5)nm^3,Mr=279.06,Dc=2.258g/cm^3,Z=6,F(000)=834,μ =0.663mm^-1。结构中BO4,PO4基团形成∞^1{[BP2O8]^3-}的螺旋带与MgO6相连构 成八面体-四面体空间骨架,元素分析、IR光谱、热重差热分析和电荷平衡计算证 明晶体中含有NH4^+和质子。NH4^+占据螺旋带螺旋纹内,质子化的水分靠近螺旋带 通道的内侧,两者均起到平衡电荷和稳定骨架的作用。     

Theoretical study of [Ni (H2O)n]2+(H2O)m (n ≤ 6, m ≤ 18)

The [Ni-(H(2)O)(n)](2+)(H(2)O)(m) (n ≤ 6, m ≤ 18) complexes were studied by means of first-principles all-electron calculations performed with the BPW91 gradient corrected functional and the 6-311+G(d,p) basis sets for the H, O, and Ni atoms. Triplet states were found as low-lying states for each (n, m) combination. The estimated Ni(2+)-(H(2)O)(n) binding energies (112.8-57.4 kcal/mol for the first layer and 52.0-23.0 kcal/mol for the second one) decreases and the Ni(2+)-OH(2) bond lengths lengthen as n + m increases. With six H(2)O moieties the Ni(2+) ion furnishes its first coordination sphere of octahedral geometry. Further water addition renders the formation of the second layer. The effect of Ni(2+) on the (H(2)O)(n)···(H(2)O)(m) hydrogen bond formation for several "n" and "m" combinations was studied, revealing an enhancement of this kind of bonding, which is of key importance for the stabilization and growth of the clusters. For some n + m isomers the second layer appears before the first octahedral layer is fully formed. For example, the square planar Ni(2+)-(H(2)O)(4) core originates two-dimensional 4 + 2 and 4 + 4 isomers, where each outer water molecule accepts two H-bonds, lying 2.0 kcal/mol above the 6 and 6 + 2 ground states. The clusters were also studied by IR spectra; the OH stretching vibrational frequencies allowed us to identify the outer solvation shells by the presence of red-shifted hydrogen bond regions.     

Übergangsmetall-carbin-komplexe: CII. Alkylierung von Na[CpMo(CO)2(CNtBu)]; einfluβ des isocyanid-substituenten auf den reaktionsablauf

Reduction of cis / trans-CpMo(CO)₂(CN^tBu)I (1a/1b) (Cp  η⁵C₅H₅) with an excess of sodium gives the Mo⁰-metallate Na[CpMo(CO)₂(CN^tBu)] (2) in quantitative yield. Complex 2 is alkylated by Et₃OBF₄ at both the metal center and the isocyanide nitrogen. Reaction at the metal center leads to a mixture of the Mo^II, isomers cis- and trans-CpMo(CO)₂(CN^tBu)(Et) (3a, 3b), while reaction at the isocyanide nitrogen gives the aminocarbyne complex Cp(CO)₂MoCN(Et)^tBu (4). The ethyl complexes 3a and 3b rearrange in refluxing THF to give a mixture of the iminoacyl complex Cp(CO)₂Mo[η²C(N^tBu)Et] (5) and the 1-azaallyl complex Cp(CO)₂MO[η³-CH(Me)

CH

N^tBu] (6). A comparison of the product distribution obtained in the reaction of the metallates Na[CpMo(CO)₂(CNR)] (R  Et, ^tBu) with Et₃OBF₄ shows a strong effect of the isocyanide substituent R on the orientation of electrophilic attack in these compounds.     

A novel three-dimensional coordination polymer [Cd2(C3H2O4)2(H2O)2(μ 2-hmt)] n (hmt = hexamethylenetetramine): synthesis and crystal structure

The self-assembly of the Cd^II ion, hexamethylenetetramine (hmt) and malonate ligand yields a three-dimensional (3D) coordination polymer [Cd₂(C₃H₂O₄)₂(H₂O)₂( ₂-hmt)] _n with channels. The Cd^II ion is located in a octahedral coordination environment, composed of four oxygen atoms from three malonates, one oxygen atom of water and one nitrogen atom of hmt. Two oxygen atoms of each malonate coordinate to the same Cd^II ion and the other two oxygen atoms connect to adjacent two Cd^II ions respectively to form a two-dimensional infinite network, these networks are bridged by ₂-hmt coordinated to Cd^II ions to product a 3D architecture.     

Synthesis and structure of [Zn8(HPO4)8(H2PO4)8]•[(C2H8N)8]•4H2O

A chain-like zincophosphate [Zn₈(HPO₄)₈(H₂PO₄)₈]•[(C₂H₈N)₈]•4H₂O was obtained at room temperature from a ZnO/P₂O₅/dimethylamine/H₂O mixture. The crystal structure was determined by single crystal X-ray diffraction. The symmetry is monoclinic a=1.26450(7)nm, b=1.08477(5)nm, c=1.46311(4)nm, β=98.793(5)°, space group Cc. The structure consists of chains of zinc-corner-sharing Zn₂P₂O₄ four rings. The negative charge of the chains is compensated by the protonated dimethylamine. The characterization by ³¹P solid state nmr spectroscopy is also reported.     

Unique seven-node rare-earth octacyanomolybdate(IV) three-dimensional molecular frameworks: {[Er(H2O)5(Er(H2O)4)3][Mo(CN)8]3·11H2O}n and {[Eu(H2O)5(Eu(H2O)4)3][Mo(CN)8]3·11H2O}n

The crystal structure analyses of {[Er(H₂O)₅(Er(H₂O)₄)₃][Mo(CN)₈]₃·11H₂O}_n (1) and {[Eu(H₂O)₅(Eu(H₂O)₄)₃][Mo(CN)₈]₃·11H₂O}_n (2), show that they are not only new neutral three-dimensional rare-earth octacyanomolybdate(IV) molecular frameworks, but that they also belong to an unknown structure type having seven different nodes. To the best of our knowledge this is different to any other known molybdenum(IV) octacyanide complexes published to date. Both compounds crystallize in the triclinic system, space group P-1, and are isostructural and isotypic. The coordination polyhedra of the molybdenum atoms in the three different [Mo(CN)₈]⁴⁻ anions are trigonal prisms, with two additional atoms. A new bridging mode for octacyanometallates is also observed with five of the eight cyanide groups involved in bridging either three or four rare-earth atoms, while the three remaining cyanide groups are terminal and are involved in hydrogen bonding. The four rare-earth atoms in 1 and 2 have different coordination polyhedra in the form of trigonal prisms with two additional atoms. The three-dimensional structures are made up of infinite two-dimensional slabs linked by one of the rare-earth metal atoms. In both compounds, apart from the 17 coordinated water molecules, there are 11 lattice water molecules of crystallization present in the cavities of the three-dimensional frameworks. The 28 water molecules and the terminal CN⁻ groups are involved in an extensive O–H⋯O and O–H⋯N hydrogen bonding network.     

[Bi2Cl10(H2-Norf)4(H2O)8](H-Norf是诺氟沙星)

CommentDuringinvestigationsonvariousmetalcomplexeswithH鄄Norf[1,2],complexationwithBiwasinvestigated.Fig.1showsthestructureofthefirstBi髥complexcontainingtheantibacterialdrugNorfloxacin○,[Bi2Cl10(H2鄄Norf)4(H2O)8].Thisisanioniccompoundcompris鄄ingfour[H2     

State-to-state reactive scattering in six dimensions using reactant-product decoupling: OH + H2 → H2O + H (J = 0)

We extend to full dimensionality a recently developed wave packet method [M. T. Cvitas? and S. C. Althorpe, J. Phys. Chem. A 113, 4557 (2009)] for computing the state-to-state quantum dynamics of AB + CD → ABC + D reactions and also increase the computational efficiency of the method. This is done by introducing a new set of product coordinates, by applying the Crank-Nicholson approximation to the angular kinetic energy part of the split-operator propagator and by using a symmetry-adapted basis-to-grid transformation to evaluate integrals over the potential energy surface. The newly extended method is tested on the benchmark OH + H(2) → H(2)O + H reaction, where it allows us to obtain accurately converged state-to-state reaction probabilities (on the Wu-Schatz-Fang-Lendvay-Harding potential energy surface) with modest computational effort. These methodological advances will make possible efficient calculations of state-to-state differential cross sections on this system in the near future.     

Theoretical study of H2 elimination from [B n H n + 1]− monoanions (n = 6–9, 11)

Transition states of elementary reactions of H₂ molecule elimination from [B _n H _{n + 1}]^? anions (n = 6–9, 11) in which nucleophilic/electrophilic vacancies form at boron atoms have been localized by the density functional theory method (in the B3LYP/6-311++G** approximation). For a series of [B _n H _{n + 1}]^? anions (n = 6–12), the activation barriers to H2 elimination have been compared to consider the possibility of substitution for exopolyhedral hydrogen atoms by the mechanism with the first rate-limiting stage of formation of [B _n H _{n ? 1}]^? (n = 6–12) intermediates with a vacant “bare” vertex of the boron cluster. For the [B _n H _n ]^2?, [B _n H _{n + 1}]^?, and [B _n H _{n ? 1}]^? anions (n = 6–12), the electronic chemical potential μ and Pearson hardness η have been evaluated since these characteristics make it possible to assess the propensity of different reagents to react with each other in terms of the empirical HSAB principle (soft with soft and hard with hard). The application of this principle is exemplified by the interaction of the [B₁₀H₉]^? and [B₁₂H₁₁]^? anions with acetonitrile CH₃CN, furan C₄H₄O, and 18-crown-6.     

H3+O和H3+O(H2O)n(n=1,2,3)阳离子振动力场和光谱频率的理论计算

本文利用多原子分子振动力场的模型势函法对H₃⁺O和H₃⁺O(H₂O)_n(n=1～3)阳离子的振动力场作了理论计算,并对其光谱频率进行了预测.H₃⁺O和H₉⁺O₄的振动频率的结果优于从头算梯度法的结果.本文首次给出了H₅⁺O₂、H₇⁺O₃伸缩振动频率的理论预测值.     

17O, 13C, 1H NMR and IR spectroscopic investigations of (CH3)nC5H5–nRe(CO)3 analogues (n = 0–5)

¹³C, ¹H NMR investigation of the (CH_3nC₅H_5–nRe(CO)₃ Me_nCpReT) n = 0–5 analogous series showed that the signals of almost all magnetic nuclei shift upfield with increase n, which also occurs in (Me_nCp)₂M compounds (M = Fe²⁺, Co³⁺; n = 0–5). The smaller value of the C(CH₃) signal (1.5 ppm.) shifts upfield when a further methyl group is introduced into the vicinal position, this shift can be attributed to the absence of the second methyl cyclopentadienyl ring. It is noteworthy that methyl cyclopentadienyl ring coordination to the transition-metal atom results in the downfield shift of the substituted carbon atom (C_key) signal. One of the reasons for such a shift might be the reduction in screening effect of the central CpM bond π-electron current on C_key owing to nodal properties of Cp ring e-orbitals. The δ ¹³C(CO), δ ¹⁷O(CO), and v(CO) values reflect successive increases of Re → CO π-back donation with increase in n.