FTIR studies of the CH3CN–BF3 complex in solid Ar, N2, and Xe: Matrix effects on vibrational spectra

FTIR spectra of the four isotopically substituted 1:1 complexes of acetonitrile and boron trifluoride were recorded in Ar, N₂ and Xe matrices. In Ar, previously unreported three vibrational modes of the complex were clearly observed. Several significant vibrational bands were also observed in N₂ and Xe. The observed frequency shifts on complexation, Δν, were qualitatively in good agreement with the computational results, which were calculated at the B3LYP/6-311++G(d,p) level using the optimized geometry of the C_3v eclipsed conformation. The observed magnitudes of Δν for most of the complex bands were larger than the calculated values. The BF₃ symmetric deformation mode is an exception. The observed frequency shits for this mode were smaller than the calculated values, especially in N₂. This suggests that even an inert matrix can significantly affect the vibrational spectrum of the complex.     

Reactivity of oxo-rhenium precursor trans-ReOCl3(OPPh3)(SMe2) with diaza heterocyclic congeners: Synthesis and spectroscopic characterization of mono and dinuclear compounds

The treatment of ReOCl₃(OPPh₃)(SMe₂) with an appropriate amount of [1,3]- and [1,4]-diaza heterocyclic ligands N  N (were N  N = pyrimidine (pym) and pyrazine (pyz)) in boiling acetonitrile under different reaction conditions yielded either the mononuclear ReOCl₃(OPPh₃)(pym) (1), ReOCl₃(OPPh₃)(pyz) (2) or dinuclear compounds [ReOCl₃(OPPh₃)]₂(μ-pym) (3), [ReOCl₃(OPPh₃)]₂(μ-pyz) (4). The new complexes were characterized in solution by means of NMR, IR, FIR, and UV–Vis spectroscopic methods. The molecular and crystal structures of 1, 3 and 4 were also determined by X-ray crystallography. All complexes adopt distorted octahedral geometries, with similar donor atoms arrangement, were axial positions are taken by terminal oxygen and triphenylphosphine oxide molecules. The equatorial planes are occupied by three chloride ligands and one nitrogen atom of the diaza ligand. The dinuclear complexes 3 and 4 comprise two equivalent six-coordinated monomeric units. Two halves of the dimer molecule are rotated about the Re–N  N–Re fragment: thus, an N-heterocyclic ring is stacked with two adjacent phenyl rings belonging to two triphenylphosphine oxide ligands. The preliminary results concerning the reactivity of the dimeric complexes point to their relative inertness in attempted further substitution towards synthesis of polynuclear complexes.     

Novel rhenium(III) complexes with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine: X-ray structures and DFT calculations for [ReCl3(OPPh3)(dppt)] and [ReCl3(PPh3)(dppt)] complexes

The reaction of [ReOCl₃(PPh₃)₂] with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt) has been examined and [ReCl₃(OPPh₃)(dppt)] has been obtained. The triphenylphosphine oxide can be easily replaced by PPh₃ in the reaction of [ReCl₃(OPPh₃)(dppt)] with an excess of triphenylphosphine. The [ReCl₃(OPPh₃)(dppt)] and [ReCl₃(PPh₃)(dppt)] complexes have been structurally and spectroscopically characterized. Their molecular orbital diagrams have been calculated with the density functional theory (DFT) method, and their electronic spectra have been discussed on the basis of time-dependent DFT calculations. The compound [ReCl₃(OPPh₃)(dppt)] has been studied additionally by magnetic measurement. The magnetic behavior is characteristic of mononuclear complexes with d⁴ low-spin octahedral Re(III) complexes (³T_1g ground state) and arise because of the large spin–orbit coupling (ζ = 2500 cm⁻¹), which gives diamagnetic ground state.     

The reactivity of [ReBr3(MeCN)(dppe)] towards gaseous nitric oxide. The X-ray structure of [ReBr3(MeCN)(dppe)] and [ReBr3(NO)(dppe)]0.57[ReOBr3(dppe)]0.43 and DFT calculations for [ReBr3(NO)(dppe)] and [ReOBr3(dppe)]

The [ReOBr₃(dppe)] (dppe=bis(diphenylophosphino)ethane) complex reacts with acetonitrile in the presence of excess of triphenylphpsphine to give a new monomeric nitrile rhenium(III) complex—[ReBr₃(MeCN)(dppe)] (1). The reaction of 1 with gaseous nitric oxide leads to the mixed [ReBr₃(NO)(dppe)]_0.57[ReOBr₃(dppe)]_0.43 complex (2) with rhenium atoms on +2 and +5 oxidation states. This paper presents the synthesis, spectroscopic characterisation and X-ray structure of 1 and 2. The geometries of [ReBr₃(NO)(dppe)] and [ReOBr₃(dppe)] have been optimized using the density functional theory (DFT) and the electronic transitions of [ReBr₃(NO)(dppe)] and [ReOBr₃(dppe)] have been calculated with the time-dependent DFT method (TDDFT). The UV–vis spectrum of 2 has been interpreted on the basis of the experimental data for [ReOBr₃(dppe)] and the calculated transitions for [ReOBr₃(dppe)] and [Re(NO)Br₃(dppe)].     

Photolysis of (Me2Si)6 in argon matrices doped with high concentrations (ca. 20%) of N2O or C2H4O: formation of (Me2SiO)6

Irradiation using a low pressure mercury lamp (λ=ca. 250 nm) of argon matrices containing ca. 1% (Me₂Si)₆ and ca. 20% ethylene oxide (C₂H₄O) or nitrous oxide (N₂O) for a period of ca. 20 h leads to the formation of the cyclic compound (Me₂SiO)₆. This has a 12-membered ring with alternating Si and O atoms. It is identified by comparison of its infrared spectrum with a spectrum of an authentic sample. The reaction appears to proceed by stepwise insertion of O atoms into Si---Si bonds.     

Synthesis,spectroscopic characterization,crystal and molecular structure of [ReOX2(bopyH)(PPh3)] complexes: DFT calculations for [ReOCl2(bopyH)(PPh3)]

The reactions of [ReOX₃(PPh₃)₂] (X = Cl, Br) with benzoylpyridine (bopy) have been examined and novel [ReOX₂(bopyH)(PPh₃)] oxocompounds have been obtained. The complexes were structurally and spectroscopically characterised. In the both structures two-electron reduced form of benzoylpyridine is coordinated to the central ion. The electronic structure of [ReOCl₂(bopyH)(PPh₃)] has been calculated with the density functional theory (DFT) method, and additional information about binding has been obtained by NBO analysis. The UV–Vis spectrum of the [ReOCl₂(bopyH)(PPh₃)] has been discussed on the basis of TDDFT calculations.     

The ternary system H2O–Fe(NO3)3–Co(NO3)2 isotherms 0 and 15 °C

The solid–liquid equilibria of the ternary system H₂O–Fe(NO₃)₃–Co(NO₃)₂ were studied by using a synthetic method based on conductivity measurements.

Two isotherms were established at 0 and 15 °C, and the stable solid phases which appear are the iron nitrate nonahydrate (Fe(NO₃)₃·9H₂O), the iron nitrate hexahydrate (Fe(NO₃)₃·6H₂O), the cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O) and the cobalt nitrate trihydrate (Co(NO₃)₂·3H₂O).     

Reactivity of [ReOX3(PPh3)2] and [ReOX3(AsPh3)2] towards 2-(2-hydroxyphenyl)-1H-benzimidazole: Synthesis, X-ray studies, spectroscopic characterization and DFT calculations for [ReOX2(hpb)(EPh3)] and [ReO(OMe)(hpb)2]·MeCN

The paper presents a combined experimental and computational study of mono- and disubstituted Re(V) oxocomplexes obtained in the reactions of [ReOX₃(EPh₃)₂] (X = Cl, Br; E = P, As) with 2-(2-hydroxyphenyl)-1H-benzimidazole (Hhpb). From the reactions of [ReOX₃(PPh₃)₂] with Hhpb in molar ratio 1:1 cis and trans stereoisomers of [ReOX₂(hpb)(PPh₃)] were isolated, whereas the [ReOX₃(AsPh₃)₂] oxocompounds react with Hhpb to give only cis-halide isomers. The [ReOX₂(hpb)(EPh₃)] and [ReO(OMe)(hpb)₂]·MeCN complexes have been characterized spectroscopically and structurally (by single-crystal X-ray diffraction). The DFT and TDDFT calculations have been carried out for the trans-[ReOBr₂(hpb)(PPh₃)], cis-[ReOBr₂(hpb)(AsPh₃)] and [ReO(OMe)(hpb)₂], and their UV–Vis spectra have been discussed on this basis.     

Synthesis,crystal, molecular,and electronic structure of [ReOCl3(bpzm)] complex

The [ReOCl₃(OAsPh₃)(AsPh₃)] and [ReOCl₃(PPh₃)₂] complexes react with bis(pyrazol-1-yl)methane (bpzm) to give [ReOCl₃(bpzm)]. The compound has been studied by IR, UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagram of the oxocomplex has been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of [ReOCl₃(bpzm)] have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the title compound has been discussed on this basis.     

Syntheses and X-ray crystallographic studies of {[Ni(en)2(pot)2]0.5CHCl3} and [Ni(en)2](3-pytol)2

Two novel Ni(II) complexes {[Ni(en)₂(pot)₂]0.5CHCl₃} (3) {pot = 5-phenyl-1,3,4-oxadiazole-2-thione} (1) and [Ni(en)₂](3-pytol)₂ (4) {3-pytol = 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol} (2) have been synthesized using en as coligand. The metal complexes have been characterized by physical and analytical techniques and also by single crystal X-ray studies. The complexes 3 and 4 crystallize in monoclinic system with space group P21/a and P121/c, respectively. The complex 3 has a slightly distorted octahedral geometry with trans (pot)⁻ ligands while 4 has a square planar geometry around the centrosymmetric Ni(II) center with ionically linked trans (3-pytol)⁻ ligands. The π?π (face to face) interaction plays an important role along with hydrogen bondings to form supramolecular architecture in both complexes.     

A novel rhenium(III) complex with bis(pyrazol-1-yl)methane: X-ray structure and DFT calculations for [ReCl3(bpzm)(PPh3)]

The [ReCl₃(MeCN)(PPh₃)₂] complex reacts with bis(pyrazol-1-yl)methane (bpzm) to give [ReCl₃(bpzm)(PPh₃)]. This compound has been studied by IR, UV–Vis spectroscopy, magnetic measurement and X-ray crystallography. The molecular orbital diagram of [ReCl₃(bpzm)(PPh₃)] has been calculated with the density functional theory (DFT) method. The spin-allowed triplet–triplet electronic transitions of [ReCl₃(bpzm)(PPh₃)] have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the title compound has been discussed on this basis. The magnetic behavior is characteristic of a mononuclear d⁴ low-spin octahedral Re(III) complex (³T_1g ground state) and arises because of the large spin–orbit coupling (ζ = 2500 cm⁻¹), which gives a diamagnetic ground state.     

Oxorhenium(V) complexes with quinoline-2-carboxylate ligand. X-ray structure of [ReOCl2(quin-2-c)(PPh3)] and [ReOBr2(quin-2-c)(AsPh3)] complexes: DFT and TD-DFT calculations for [ReOCl2(quin-2-c)(PPh3)]

Novel [ReOX₂(quin-2-c)(EPh₃)] complexes (X = Cl, Br; E = As, P; quin-2-c = quinoline-2-carboxylate ion) have been prepared by treatment of [ReOX₃(EPh₃)₂] with quinoline-2-carboxylic acid in acetone at room temperature. All the complexes were characterised by IR, UV–Vis spectroscopy and elemental analysis. The crystal and molecular structures have been determined for [ReOCl₂(qiun-2c)(PPh₃)] (1) and [ReOBr₂(qiun-2c)(AsPh₃)] (4). The electronic structure of 1 has been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 have been calculated with the time-dependent DFT method.     

New oxorhenium complexes with 2-(2′-hydroxyphenyl)-2-benzoxazolinato ligand. X-ray structure and DFT calculations for [ReOX2(hbo)(AsPh3)] and [ReOX2(hbo)(PPh3)] complexes

The reactions of [ReOX₃(AsPh₃)₂] and [ReOX₃(PPh₃)₂] with 2-(2′-hydroxyphenyl)-2-benzoxazoline (Hhbo) have been examined and [ReOX₂(hbo)(AsPh₃)] and [ReOX₂(hbo)(PPh₃)] (X = Cl, Br) complexes have been obtained. The crystal and molecular structures of [ReOCl₂(hbo)(AsPh₃)] (1) and [ReOBr₂(hbo)(PPh₃)] (4) have been determined. The electronic structures of 1 and 4 have been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 and 4 have been calculated with the time-dependent DFT method, and the UV–Vis spectra of these complexes have been discussed.     

Synthesis and crystal structure of a complex bearing interesting structural motifs: [Cu (C4H7N3) H2O (4,4′-Hbpy)]·SO4·NO3

A new complex [Cu (C₄H₇N₃) H₂O (4,4′-Hbpy)]·SO₄·NO₃ was synthesized and X-ray characterized. Elemental analysis, X-ray diffraction and infrared spectroscopy of the complex were performed. The crystal system is orthorhombic. Crystal data: Fw=498.98, spacegroup: P212121. Z=4, a=14.952(3), b=20.491(4), c=6.713 Å. V=2056.7(9) Å. λ(Mo-K)=0.71070 Å. μ=12.18 cm⁻¹, D_calc=1.66 g/cm³, F₀₀₀=1032.00, R=0.062, Rw=0.087. X-ray analysis illustrated that 4,4′-bpy is mono-protonated and that there are two kinds of anions in one molecule, which give rise to the hydrogen interaction between the molecules in the crystal. Then an extended three-dimensional network is formed along the hydrogen bonds and π–π bonds between the pyridine rings.     

硫酸亚铈催化的芳香化合物与苄基醇、烯丙醇类化合物以及苄基氯的傅-克烷基化反应研究

硫酸亚铈作为一种便宜的和有效的催化剂催化芳香化合物与苄基醇、烯丙醇类化合物和苄基氯的傅-克烷基化反应. 在1～10 mol%的硫酸亚铈存在下, 芳香化合物分别与苄基醇、烯丙醇类化合物和苄基氯能够顺利有效地进行傅-克烷基化反应. 此外, 催化剂能回收, 再次使用三次也没有明显地失去催化活性.     

Synthesis,spectroscopic investigation,structural characterization and DFT calculation of the complexes [ReX2(N2COPh)(4-PhPyr)(PPh3)2] (X = Cl, Br)

The reactions of [ReX₂(η²-N₂COPh-N′,O)(PPh₃)₂] with 4-phenylpyrimidine have been performed. As a result, the two complexes [ReX₂(N₂COPh)(4-PhPyr)(PPh₃)₂] (X = Cl, Br) (4-PhPyr = 4-phenylpyrimidine), isostructural in the solid state, have been obtained. The crystal and molecular structures of ([ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂])₂·CHCl₃ (1) and ([ReBr₂(N₂COPh)(4-PhPyr)(PPh₃)₂])₂·CHCl₃ (2) have been determined. The electronic structure of [ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂] has been examined using the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of [ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂] has been discussed on this basis.     

FTIR spectra of (HF)2 and (HF)3 species in solid argon at 12K

Condensation of argon/HF mixtures at 12 K revealed sharp new 3825.5 and 3702.0 cm^?1 absorptions which exhibited different growth behaviour on sample warming. Mixed HF/DF samples revealed a single mixed isotopic satellite near the DF counterpart of the former band assigned to (HF)₂ and a group of satellites for the latter band assigned to (HF)₃.     

UV and IR absorption spectra of C3 embedded in solid para-hydrogen

This paper presents the UV and IR absorption spectroscopy of small carbon molecules of C₃ observed using a high-resolution Fourier-transform spectrometer. The C₃ molecules were produced by irradiation of dimers or larger clusters of acetylene with an ArF laser (λ=193 nm). Sharp UV absorption features with multiple structures were observed in the electronic transition of C₃. The sharp UV absorption demonstrates the potential of solid para-hydrogen as a matrix for high-resolution spectroscopy of UV–vis electronic transitions.     

Synthesis and thermodynamic properties of a metal-organic framework: [LaCu6(μ-OH)3(Gly)6im6](ClO4)6

A metal-organic complex, which has the potential property of absorbing gases, [LaCu₆(μ-OH)₃(Gly)₆im₆](ClO₄)₆ was synthesized through the self-assembly of La³⁺, Cu²⁺, glycine (Gly) and imidazole (Im) in aqueous solution and characterized by IR, element analysis and powder XRD. The molar heat capacity, C_p,m, was measured from T = 80 to 390 K with an automated adiabatic calorimeter. The thermodynamic functions [H_T − H_298.15] and [S_T − S_298.15] were derived from the heat capacity data with temperature interval of 5 K. The thermal stability of the complex was investigated by differential scanning calorimetry (DSC).