Pressure-induced formation of molecular B2X4(μ-X)2 (X = Cl, Br, I) species

Boron(III) halides (BX(3), where X = F, Cl, Br, I) at ambient pressure conditions exist as strictly monomeric, trigonal-planar molecules. Using correlated ab initio calculations, the three heavier halides (X = Cl, Br, I) are shown to possess B(2)X(4)(μ-X)(2) local minima, isostructural with the diborane molecule. The calculated dissociation barrier of the B(2)I(4)(μ-I)(2) species [≈14 kJ/mol with CCSD(T)/cc-pVTZ] may be high enough to allow cryogenic isolation. The remaining dimer structures are more labile, with dissociation barriers of less than 6 kJ/mol. All three dimer species may be stabilized by application of external pressure. Periodic density functional theory calculations predict a new dimer-based P1 solid, which becomes more stable than the P6(3)/m monomer-derived solids at 5 (X = I) to 15 (X = Cl) GPa. Metadynamics simulations suggest that B(2)X(4)(μ-X)(2)-based solids are the kinetically preferred product of pressurization of the P6(3)/m solid.     

Vibrational study of diphenylphosphorus halides Ph2PX (X  Cl,Br, I)

The Raman and i.r. spectra of diphenylphosphorus halides, Ph₂PX (X  Cl, Br, I), have been measured and concerted assignments have been made confirmed by an approximate normal coordinate analysis for the skeletal vibrations of Ph₂PCl using a three mass model for the phenyl group.     

MX2(AsH3)2(M=Pd,Pt;X=Cl,Br,I)的含时密度泛函理论研究

采用密度泛函方法(B3LYP)优化了MX2(AsH3)2[M=Pd；X=Cl(1)，Br(2)，I(3)和M=Pt；X=Cl(4)，Br(5)，I(6)]的基态结构，得到的几何参数与实验结果符合．以基态几何为基础，将TD-DFT方法用于计算标题配合物的电子吸收光谱．研究结果表明，金属的dx2-y2与配体所组成的反键轨道为LUMO轨道，从而该类配合物具有d-d跃迁属性的吸收带；在多数跃迁过程中，配体也有较大的贡献．     

Synthesis and crystal structures of π complexes of copper(I) halides with diallyl disulfide 2CuX · DADS (X = Cl, Br; DADS = CH2=CH-CH2-S-S-CH2-CH=CH2)

Compounds 2CuCl · DADS (I) and 2CuBr · DADS (II) (DADS is diallyl disulfide) are prepared by the ac electrochemical synthesis, and their crystal structures are determined. The complexes are isostructural, space group P2₁/n, Z = 4; I: a = 8.995(2) Å, b = 12.541(2) Å, c = 9.644(2) Å, β = 98.74(2)°, V = 1075.3(4) ų, II: a = 9.064(2), b = 12.878(3), c = 9.832(2) Å, β = 98.61(3)°, V = 1134.7(4) ų. In complexes I and II, the tetradentate DADS ligand is chelate-bridging and is coordinated by two crystallographically independent copper atoms of two inorganic Cu₄X₄ fragments. An insignificantly distorted tetrahedral environment of each of the two copper atoms consists of the olefin group, sulfur atom, and two halogen atoms. The complexes are stabilized additionally by the formation of C-H?S hydrogen bonds involved in characteristic seven-membered rings in the structures.     

Synthesis and structure of gold complexes [Ph3PR]+[Au(CN)2I2-trans]−, R = Et,CH2Ph,Ph

Russian Chemical Bulletin - Gold complexes [Ph3PR]+[Au(CN)2I2-trans]?, where R = Et (1), CH2Ph (2), Ph (3), were synthesized by the reaction of potassium dicyanodiiodoaurate with...     

固相配位化学反应研究(LXI)——[Cu(SC(Ph)NHPh)(PPh_3)_2X](X+Cl,Br,I)的固相合成和晶体结构(X=Cl)

SC(Ph)NHPh,CuX(X=Cl,Br,I)和PPh_3的固相反应产物经CS_2处理得红黄色立方晶体[Cu(SC(Ph)NHPh)(PPh_3)_2X],其中X=Cl的单晶用X射线衍射法收集晶胞参数,此晶体属单斜晶系,空间群P2_1/c,α=1.8013(5)nm,b=1.4588(5)nm,c=1.7222(4)nm,β=105.54(3)°,F=4.3601nm~3,Z=4。中心铜离子以扭曲四面体配位,Cu原子周围的平均键角为109.4°,其中Cu—S键、Cu—Cl键、Cu—P(1)键和Cu—P(2)键的键长分别为0.2352(3)nm、0.2375(4)nm、0.2297(4)nm和0.2282(3)nm.     

The photo-induced decarbonylation of Cp′M(NO)(CO)2 (M = Cr,Mo, W) with diorgano dichalcogenides (R2E2; E = S,Se; R = Me,Ph)

The photo-induced decarbonylation of CpCr(NO)(CO)₂ (1a) in MeCN solution in the presence of R₂E₂ (E = S, Se; R = Me, Ph) leads to the formation of chalcogenolato-bridged binuclear complexes Cp₂Cr₂(NO)₂(-ER)₂ [E = S; R = Me (2a), Ph (3a); E = Se, R = Me (4a), Ph (5a)] while reactions between CpM(NO)(CO)₂ [M = Mo (1b), W (1c)] and Ph₂E₂ (E = S, Se) result in mononuclear complexes CpM(NO)(EPh)₂ [M = Mo; E = S (9b), Se (10b); M = W, E = S (11c), Se (12c)]. The corresponding reactions of (1b) with Me₂E₂ (E = S, Se) yielded both mono and binuclear complexes: CpMo(NO)(SeMe)₂ (8b), Cp₂Mo₂(NO)₂(-EMe)₂ [E = S (6b), Se (7b)]. The new complexes have been characterized by i.r., ¹H-, ¹³C-n.m.r. spectra and by electron-impact mass spectrometry.     

Complexes of group IIb metals with dithio oxamides—II. Vibrational analysis of ZnLX2(X = Cl,Br, I) complexes

With dithiooxamides, Zn(II) in acid media forms distorted tetrahedral complexes, which behave as non-electrolytes. The ligands act as bidentates with S, S coordination.A thorough vibrational analysis has been performed for the Zn(CH₃ NHCSCSNHCH₃)X₂(X = Cl, Br, I) and for the Zn[(CH₃)₂NCSCSN(CH₃)₂]X₂(X = Cl, Br, I) complexes.     

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.     

Photoelectron Spectroscopy and Structures of X−⋅⋅⋅CH2O (X=F,Cl, Br,I) Complexes

A combined experimental and theoretical approach has been used to investigate X⁻⋅⋅⋅CH₂O (X=F, Cl, Br, I) complexes in the gas phase. Photoelectron spectroscopy, in tandem with time-of-flight mass spectrometry, has been used to determine electron binding energies for the Cl⁻⋅⋅⋅CH₂O, Br⁻⋅⋅⋅CH₂O, and I⁻⋅⋅⋅CH₂O species. Additionally, high-level CCSD(T) calculations found a C_2v minimum for these three anion complexes, with predicted electron detachment energies in excellent agreement with the experimental photoelectron spectra. F⁻⋅⋅⋅CH₂O was also studied theoretically, with a C_s hydrogen-bonded complex found to be the global minimum. Calculations extended to neutral X⋅⋅⋅CH₂O complexes, with the results of potential interest to atmospheric CH₂O chemistry.     

The oxidative addition of 1-haloalkanes to monomeric trans-[Rh(X(CO)(PR3)2] (X  Cl,Br; R  aryl) and dimeric trans-[Rh(μ-X)(CO)(PPh3)]2 (XCl,I)

The oxidative addition of 1-bromopropane to trans-[RhBr(CO){P(p-EtC₆H₄)₃}₂] has been found to follow pseudo first-order kinetics and give only an acylrhodium(III) product. The reaction is not catalysed by added bromide ion in chloroform solution, indicating that an anionic intermediate such as [RhBr₂(CO){P(p-EtC₆H₄)₃}]⁻ does not play an important part in this reaction. The oxidative addition of iodomethane to trans-[Rh(μ-X)(CO)(PPh₃)]₂ (X  Cl and I) is pseudo first-order, the reactivity increasing on replacing chloride by iodide.     

Are the carbon monoxide complexes of Cp(2)M (M = Ca,Eu, or Yb) carbon or oxygen bonded? An answer from DFT calculations

DFT calculations have been performed on the CO adducts of the bivalent lanthanides, Cp(2)M(CO)(x), where M is Eu or Yb and x is 1 or 2, the alkaline earth metallocene Cp(2)Ca(CO), and the methylisocyanide adducts of Yb. The calculated nu(CO) values are in agreement with experiment for Cp(2)M(CO) when M is Ca or Eu, but in striking disagreement when the CO is bound to the metal by way of the carbon atom in CO in the case of Yb. The calculated nu(CO) values for M = Yb are brought into agreement with experiment when the CO is allowed to bond to Cp(2)Yb by way of the oxygen atom.     

OXO (X=Cl,Br)与X (2P3/2)反应机理的理论研究

用密度泛函B3LYP/6-311+G^**和高级电子相关的组态相互作用QCISD(T)/6-311+G^**方法研究了OXO与X(²P_3/2)双自由基反应的微观机理.研究结果表明:该反应存在两个反应通道,产物分别为XO和X₂+O₂.由于形成产物XO的活化势垒较低,因而是主要反应通道,这与实验观察到的结果是一致的.而形成X₂+O₂的通道从动力学上看是不利的.     

An MP2 study on pre-reactive complexes (CH_2)_2O … XY (X,Y = H,F,Cl,Br,I)

The structures, energies, atomic chaiges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means of ab initio molecular orbital theory at the second-order level of Moller-Plesset perturbation correction. It is found that the hydrogen bond O…H-X is non-linear. The attraction between X and the H atoms in oxirane ring causes O…H-X bond bending. The hydrogen bond slighdy weakens the bond strength of C-O, and leads the bending and stretching mode of IR to shift to the red. The calculation results show that there is no evidence of a significant extent of proton transfer to give (CH2)2OH …X- in the isolated complexes.     

H2C[P(Ph)2AUX]2和HC[P(Ph)2AUX]3(X=I,CI)型配合物的构象和Au (I)-Au(I)相互作用的从头算研究

根据配合物H₂C[P(Ph)₂AUX]₂(X=I,CI)和HC[P(Ph)₂AUX]₃(X=I,CI)的晶体结构对它们进行了从头算研究,在MP2近似水平下得到绕C-P旋转所产生构象的势能曲线,从而揭示AU(I)－AU(I)相互作用. 计算结果表明,在所研究的四个配合物中均存在AU(I)-AU(I)相互作用,该作用较弱,约为10. 0～16. 5kJ/mol,与Schmibaur的实验估计值和Pyykko等对其它模型配合物的计算结果接近.     

Nature of M-Ga bonds in dihalogallyl complexes (η5-C5H5)(Me3P)2M(GaX2) (M = Fe, Ru, Os) and (η5-C5H5)(OC)2Fe(GaX2) (X = Cl, Br, I): a DFT study

Density functional theory (DFT) calculations have been performed on the terminal dihalogallyl complexes of iron, ruthenium, and osmium (η(5)-C(5)H(5))(Me(3)P)(2)M(GaX(2)) (M = Fe, Ru, Os; X = Cl, Br, I) and (η(5)-C(5)H(5))(OC)(2)Fe(GaX(2)) (X = Cl, Br, I) at the BP86/TZ2P/ZORA level of theory. On the basis of analyses suggested by Pauling, the M-Ga bonds in all of the dihalogallyl complexes are shorter than M-Ga single bonds; moreover, on going from X = Cl to X = I, the optimized M-Ga bond distances are found to increase. From the perspective of covalent bonding, however, π-symmetry contributions are, in all complexes, significantly smaller than the corresponding σ-bonding contribution, representing only 4-10% of the total orbital interaction. Thus, in these GaX(2) complexes, the gallyl ligand behaves predominantly as a σ donor, and the short M-Ga bond lengths can be attributed to high gallium s-orbital character in the M-Ga σ-bonding orbitals. The natural population analysis (NPA) charge distributions indicate that the group 8 metal atom carries a negative charge (from -1.38 to -1.62) and the gallium atom carries a significant positive charge in all cases (from +0.76 to +1.18). Moreover, the contributions of the electrostatic interaction terms (ΔE(elstat)) are significantly larger in all gallyl complexes than the covalent bonding term (ΔE(orb)); thus, the M-Ga bonds have predominantly ionic character (60-72%). The magnitude of the charge separation is greatest for dichlorogallyl complexes (compared to the corresponding GaBr(2) and GaI(2) systems), leading to a larger attractive ΔE(elstat) term and to M-Ga bonds that are stronger and marginally shorter than in the dibromo and diiodo analogues.