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1.
Medium-resolution spectra of the N 2 b 1Π u-X 1Σ g+ band system were recorded by 1 + 1 multiphoton ionization. In the spectra we found different linewidths for transitions to different vibrational levels in the b 1Π u state: Δν 0 = 0.50 ± 0.05 cm −1, Δν 1 = 0.28 ± 0.02 cm −1, Δν 2 = 0.65 ± 0.06 cm −1, Δν 3 = 3.2 ± 0.5 cm −1, Δν 4 = 0.60 ± 0.07 cm −1, and Δν 5 = 0.28 ± 0.02 cm −1. From these linewidths, predissociation lifetimes τ ν were obtained: τ 0 = 16 ± 3 ps, τ 1 > 150 ps, τ 2 = 10 ± 2 ps, τ 3 = 1.6 ± 0.3 ps, τ 4 = 9 ± 2 ps, and τ 5 > 150 ps. Band origins and rotational constants for the b 1Π uν = 0 and 1 levels were determined for the 14N 2 and 14N 15N molecules. 相似文献
2.
We have previously determined an analytical ab initio six-dimensional potential energy surface for the HCl dimer, and in the present paper we use this potential, with the HCl bond lengths held fixed, in a full (four-dimensional) close-coupling calculation to determine the energies of the lowest 24 vibrational states. These vibrational states involve the intermolecular stretch ν 4, the trans-bend tunneling vibration ν 5, and the torsion ν 6. The highest of the 24 levels is the (ν 4ν 5ν 6)=(111) state, for which we calculate an energy of 200 cm −1 above the (000) state. As well as determining tunneling energies up to 5ν 5=183 cm −1, we determine ν 4=49 cm −1, 2ν 4=93 cm −1, 3ν 4=134 cm −1, 4ν 4=172 cm −1, ν 6=137 cm −1 and ν 4+ν 6=178 cm −1, together with tunneling energies in all these states. Making allowance for the HCl stretching zero-point energy we determine the dissociation energy D0 as 390 cm −1 on this analytical surface. We determine that below 300 cm −1 there are 72 vibrational ( J=K=0) states, and below dissociation there are 162 vibrational ( J=K=0) states, for this potential surface. 相似文献
3.
The infrared absorption of mixtures of dimethyl ether and hydrogen halide (HX) in nitrogen at 13 K display relatively narrow bands in the range 650–800 cm −1 with an isotopic ratio ν H/ν D larger than 1.4 and weakly halogen dependent; these features are assigned to the antisymmetric O…H…O stretching within the [(CH 3) 2 O…H…O(CH 3) 2] +X − ion pair. With HI—ether mixtures, the intensity of the 660 cm −1 band decreases under infrared irradiation of the matrix, which might be due to the transfer of the proton back to the I − anion. 相似文献
4.
A Doppler-based velocity selection technique has been used to measure the relative velocity dependence of the cross sections σ ji,Δ(ν r) for rotationally inelastic collisions from level ji to ji + Δν 1 = 8,22,42) in 7Li *2 A 1Σ +u)—Xe. The σ jν±2(ν r) are strongly attenuated at a smaller ν r by “torque averaging” due to molecular rotation; in contrast, for large |Δ|, σ jiΔ = ν r−n (1 n 2). An empirical intermolecular potential which reproduces these types of behavior for 3-D classical trajectories is exhibited. 相似文献
5.
139La-NMR chemical shifts were measured for several anionic complexes of formulae Li(C 4H 8O 2) 3/2 [La(ν 3-C 3H 5) 4], [Li(C 4H 8O 2) 2][Cp′ nLa(ν 3-C 3]H 5) 4−n] (Cp′ = Cp(ν 5-C 5H 5); n = 1, 2 and Cp′ = Cp * (ν 5-C 5Me5); N = 1) and Li[R nLa(ν 3-C 3H 4) 4− n] (R = N(SiMe 3) 2; n = 1, 2 and R = CCsIMe 3; n = 4), as well as for neutral compounds for formulae La(ν 3-C 3H 5) 3L n (L = (C 4H 8O 2) 1.5, (HMPT) 2, TMED), Cp′ nLa(ν 3-C 3H 5) 3−n (Cp′= Cp(ν 5-Cp 5H 5), Cp *(ν 5-C 5Me 5); n = 1, 2) and La(ν 3-C 3H 2) 2X(THF) 2 X = Cl, Br, I). Typical ranges of the 139La-NMR chemical shifts were found for the different types of complex independent of number and kind of organyl groups directly bonded to lanthanum. Zusammenfassung139La-NMR-Spektroskopie wurde an einer Reihe anionischer Allyllanthanat(III)-Komplexe der Zusammensetzung
]- [La)ν3-C3H5)4, [Li(C4H8)2][Cp′nLa(ν3-C3H5)4−n(Cp′ = Cp(ν5-C5H5); n = 1, 2 und Cp′ = Cp * (ν5-C5Me5); N = 1) und Li[RnLa(ν3-C3H5)4−n (R = B(SiMe3)2; n = 1, 2 und R = CCSiMe3; n = 4 sowie neutraler Allyllanthan(III)-Komplexe der Zusammensetzung La(ν3-C3H5)3Ln (Ln = (C4H8O2)1.5, (HMPT)2, TMED), Cp′n, La(ν3-C3H5)3−n (Cp′ = Cp(ν5-C5H5), Cp * (ν5- Cp5Me5); n = 1, 2) und La(ν3-Cp3H5)2X(THF)2 (X = Cl, Br, I) durchgefürt. In Abhängikeit von der Anzahl und der Art der am Lanthan gebundenen Gruppen wurden für die verschieden Komplextypen charakteristische Resonanzbereiche ermittelt. 相似文献
6.
The influence of intramolecular hydrogen bonding on the photodissociation of cis-HONO is probed via measurements on the OH fragment ejected by specific ---N=0 stretching (ν 2) vibrational levels of the à state. Due to hydrogen bonding between the H atom and the terminal oxygen, the ν 2 motion is coupled to the in-plane HON bend ν 3. Since the latter evolves into fragment rotation, the rotational energy and anisotropy of the OH product increases with the number of ν 2 quanta. By contrast, ν 2 in trans HONO is a relatively isolated ---N=O vibration and thus does not influence the OH photofragment's properties. 相似文献
7.
Two new alkaline metal borates containing 1D{B5}/{B6}oxoboron helical chains,namely Na0.5[B5O8(OH)2]0.5[B5O6(OH)2]0.5·0.5H3O(1)and NaKCs[B6O9(OH)3](2)were synthesized under solvothermal conditions.Compound 1 contains the interesting alternative left-and right-handed helical{[B5O8(OH)2][B5O6(OH)2]}2-({B5}-1 and{B5}-2)1D chains and compound 2 possesses the similar[B6O11(OH)3]7-({B6})chains.Their 1D chains are further assembled into 2D layers and 3D supramolecular frameworks through O-H…O hydrogen bonds.In addition,the UV cutoff edge of compounds 1 and 2 is both below 190 nm. 相似文献
8.
The Fourier transform infrared spectra of the H-bonded complexes between HCl and 4-aminopyridine, 4-aminopyrimidine, 4-hydroxypyridine, 2-hydroxypyridine, benzimidazole and purine were investigated in Ar matrices. From the analysis of these spectra, the H-bonds N HCl appear to be of the pseudosymmetric type II for 4-aminopyridine, 4-aminopyrimidine and 4-hydroxypyridine, while benzimidazole forms a slightly weaker complex. H-bonding of HCl with the bases 2-hydroxypyridine and purine is of the intermediate type I → II. In the case of 4-aminopyrimidine, additional bonding of the Cl atom of HCl to an amino N---H bond yields a closed complex which explains the type II behaviour. In all other cases, bonding of additional HCl molecules to the 1:1 complexes results in proton transfer towards N---H +…Cl −(HCl) π species, but n is much lower for type II than for the intermediate type I → II complexes. The results allow us to investigate the vibration correlation diagram and the isotopic ratio ν(HCl)/ν(DCl) for B - HCl complexes in Ar matrices into more detail. 相似文献
9.
The crystal structure of the title compound has been determined. Crystals of [HgC1 2{μ-S(CH 2) 3NH(CH 3) 2}] are monoclinic, space group P2 1/ n, with a = 10.136(2), b = 6.519(1), c = 15.940(6) Å and β = 97.20(3)°. The structure consists of (---Hg---S---) n helicoidal chains linked by hydrogen bonding, which give rise to chemically unconnected layers along the (
02) planes. Each mercury is tetrahedrally coordinated to two terminal chlorine atoms and two bridging sulphur atoms. Assignments of ν as(SHgS) and ν s(SHgS) for this complex and its isostructural bromine analogue, and of ν s(C1HgC1) and ν s(BrHgBr) from IR and Raman spectroscopy are reported. Comparison of Hg---S frequencies with those reported for closely related compounds as well as correlation with Hg---S bond distances are made. 相似文献
10.
New zinc complexes [L 2ZnX 2] with X=Cl (I), Br (II), I (III) and NO 3 (IV), [L 3Zn(OClO 3)]ClO 4 (V) and [L 4Zn](ClO 4) 2 (VI) with 5-tert-butylpyrazole as ligand L were synthesized and characterized by infrared-, Raman-, mass- and NMR-spectroscopy. The assignment of the vibrational frequencies for the complexes in the range of 4000–80 cm −1 is proposed. Analysis of the IR spectra in the range of ν NH frequencies shows that 5-tert-butylpyrazole forms cyclic associates in the solid using intermolecular NHN hydrogen bonds. This was proven by a crystal structure determination, which showed that L exists as tetramers in the solid state. In solution there is an equilibrium between tetramers and monomers and, probably, dimers or trimers. In the complexes, the NH-groups of L form intramolecular H-bonds with the X-group. The intramolecular H-bond in VI has interionic character and partially dissociates in solution at high dilution. Ligand vibrations that are sensitive to the coordination and the dependence of their frequencies on the anionic group X has been revealed. 相似文献
11.
Infrared and Raman spectra of the BaF(HF 2) crystal and its 10 and 50% deuterated derivatives at 300 and 90 K have been investigated in the 4000 to 20 cm −1 range. An assignment of internal and lattice vibrations has been proposed. Vibrational spectra are consistent with a centrosymmetric P2 1/ m space group and Z=2. They show that the (FHF) − ion is not centrosymmetrical, in spite of a short F…F distance; a force field calculation has been performed in order to determine the F---H and H…F distances, which are equal to 1.08 and 1.20 Å, respectively, in agreement with the 1H and 19F NMR data. The ν 3(H)/ν 3(D) isotope frequency ratio indicates a negative or zero isotope effect on the F…F distance, which is observed for the first time for a strong asymmetric hydrogen bond. 相似文献
12.
The acid–base chemistry of some ruthenium ethyne-1,2-diyl complexes, [{Ru(CO) 2(η-C 5H 4R)} 2(μ 2-CC)] (R=H, Me) has been investigated. Initial protonation of [{Ru(CO) 2{η-C 5H 4R}} 2(μ 2-CC)] gave the unexpected complex cation, crystallised as the BF 4 salt, [{Ru(CO) 2(η-C 5H 4R}} 3(μ 3-CC)][BF 4] (R=Me structurally characterised). This synthesis proved to be unreliable but subsequent, careful protonation experiments gave excellent yields of the protonated ethyne-1,2-diyl complexes, [{Ru(CO) 2{η-C 5H 4R)} 2(μ 2-η 1:η 2-CCH)](BF 4) (R=Me structurally characterised) which could be deprotonated in high yield to return the starting ethyne-1,2-diyl complexes. 相似文献
13.
The encounter complex C 2H 4…ClF was isolated by using a fast-mixing nozzle before chemical reaction could occur between the components and was characterised by Fourier-transform microwave spectroscopy. Rotational constants, centrifugal distortion constants, Cl nuclear quadrupole constants and Cl spin-rotation constants were determined for the isotopomers C 2H 4… 35ClF and C 2H 4… 37ClF. The complex has C 2v symmetry with the ClF subunit perpendicular to the plane of C 2H 4 and oriented so that Cl is closer to C 2H 4. Both the centrifugal distortion constant Δ J and the Cl nuclear quadrupole coupling constants indicate that the complex is relatively weakly bound and it is concluded that the interaction between the subunits is largely electrostatic in origin. 相似文献
14.
Zeeman spectral data are presented for the 2Π 3/2: J = 7/2 → J= 9/2, 2Π 3/2: J= 7/2→ 2Π 1/2: J= 5/2 and 2Π 3/2 J= 3/2→ J = 5/2 transitions in OD. Data for the 2Π 3/2. J=3/2→ J= 5/2 and 2Π 3/2 J= 5/2 → 2Π l/2 : J= 3/2 transitions in OH, taken under similar conditions, are included. 相似文献
15.
The reaction of 1,2-bis(diphenylthioylphosphino)hydrazine (L) with copper(I) and mercury(II) halides affords the complexes, [{CuLX} 2] (X = I, Br or Cl), [HgLX 2] (X = Cl or Br) and the tetrametallic complex, [{L(HgI 2) 2} 2]. Single crystal X-ray structures have been performed on the uncoordinated ligand, L, as well as the complexes [{CuLX} 2] (X = I, Br and Cl), [HgLBr 2] and [{L(HgI 2) 2} 2. The molecules of L exist as dimers as a result of pairs of N–HS hydrogen bonds. The copper(I) complexes are centrosymmetric dimetallic species, the two copper atoms being bridged by L and the X atoms. In all cases the coordination sphere around the Cu atoms is approximately trigonal pyramidal with an ‘S 2X 2’ donor set. The complex, [HgLBr 2], is a distorted tetrahedral monomer with an ‘S 2Br 2’ donor set and L acting as a bidentate thus forming a seven-membered chelate ring. The tetramercury iodo complex, [{L(HgI 2) 2} 2], contains two ‘L(HgI 2) 2’ units linked centrosymmetrically via an I atom from each moiety. The geometry around the Hg atoms is distorted tetrahedral. The influence of hydrogen bonding between the hydrazine backbone hydrogens of L and the coordinated halide ions in for the structures of the metal complexes is discussed. 相似文献
16.
Reactions of FcCCH (a), HCCCCFc (b) and FcCCCCFc (c) with Ru 3(CO) 10(NCMe) 2 (all) and Ru 3(μ-dppm)(CO) 10 (b and c only) are described. Among the products, the complexes Ru 3(μ 3-RC 2R′)(μ-CO)(CO) 9 (R=H, R′=Fc 1, CCFc 2; R=R′=Fc 5), Ru 3(μ-H)(μ 3-C 2CCFc)(μ-dppm)(CO) 7 3, Ru 3(μ 3-FcC 2CCFc)(μ-dppm)(μ-CO)(CO) 7 6 and Ru 3{μ 3-C 4Fc 2(CCFc) 2}(μ-dppm)(μ-CO)(CO) 5 7 were characterised, including single-crystal structure determinations for 1, 3, 5 and 7; that of 7 did not differ significantly from an earlier study of a mixed CH 2Cl 2–C 6H 6 solvate. 相似文献
17.
The spectrum of CD 2HF was measured by high-resolution interferometric Fourier-transform IR (FTIR) spectroscopy (apodised instrumental band with:0.004 cm −1 fwhm) between 800 and 1200 cm −1 covering the four lowest fundamentals. A complete rotational analysis using a semi-automatic assignment procedure yields accurate band centres (ν 9: 912.2028 cm −1, ν 6:964.4994 cm −1, ν 5: 1050.5104 cm −1, ν 4: 1093.8632 cm −1) and a complete set of first-order Coriolis coupling constants. The most important couplings occur between ν 9 and ν 6 (ξ a= 1.069 cm −1, ξ c= −0.3535 cm −1) and between ν 5 and ν 4 (ξ b= −0.80606 cm −1). The analysis was guided by and compared with results from our ab initio calculations for Coriolis constants and transition moments using CADPAC at TZP/MP2 level. 相似文献
18.
Reaction of [Ru 3(CO) 12 with (CF 3) 2P---P(CF 3) 2 in p-xylene at 140°C yielded the compounds [Ru 4(CO) 13{μ-P(CF 3) 2} 2] (1), [Ru 4(CO) 14{μ-P(CF 3) 2} 2] (2) and [Ru 4(CO) 11{μ-P(CF 3) 2} 4] (3). Reaction with [(μ-H) 4Ru 4(CO) 12] under similar conditions yielded [(μ-H) 3Ru 4(CO) 12{μ-P(CF 3) 2}] (4). All four compounds have been characterised by X-ray crystallography. The fluxional behaviour of the hydrides in 4 has also been studied by variable-temperature NMR spectroscopy. Compounds 1, 2 and 4 were also obtained from the reactions of Ru 3(CO) 12 with (CF 3) 2PH in dichloromethane at 80°C. 相似文献
19.
High resolution vibration-rotation spectra of 13C 2H 2 were recorded in a number of regions from 2000 to 5200 cm −1 at Doppler or pressure limited resolution. In these spectral ranges cold and hot bands involving the bending-stretching combination levels have been analyzed up to high J values. Anharmonic quartic resonances for the combination levels ν 1 + mν 4 + nν 5, ν 2 + mν 4 + ( n + 2) ν 5 and ν 3 + ( m − 1) ν 4 + ( n + 1) ν 5 have been studied, and the l-type resonances within each polyad have been explicitly taken into account in the analysis of the data. The least-squares refinement provides deperturbed values for band origins and rotational constants, obtained by fitting rotation lines only up to J ≈ 20 with root mean square errors of ≈ 0.0003 cm −1. The band origins allowed us to determine a number of the anharmonicity constants xij0. 相似文献
20.
Sn(CH 3) 2Cl 2 exerts its antitumor activity in a specific way. Unlike anticancer cis-Pt(NH 3) 2Cl 2 drug which binds strongly to the nitrogen atoms of DNA bases, Sn(CH 3) 2Cl 2 shows no major affinity towards base binding. Thus, the mechanism of action by which tinorganometallic compounds exert antitumor activity would be different from that of the cisplatin drug. The aim of this study was to examine the binding of Sn(CH 3) 2Cl 2 with calf thymus DNA and yeast RNA in aqueous solutions at pH 7.1–6.6 with constant concentrations of DNA and RNA and various molar ratios of Sn(CH 3) 2Cl 2/DNA (phosphate) and Sn(CH 3) 2Cl 2/RNA of 1/40, 1/20, 1/10, 1/5. Fourier transform infrared (FTIR) and UV–visible difference spectroscopic methods were used to determine the Sn(CH 3) 2Cl 2 binding mode, binding constant, sequence selectivity and structural variations of Sn(CH 3) 2Cl 2/DNA and Sn(CH 3) 2Cl 2/RNA complexes in aqueous solution. Sn(CH 3) 2Cl 2 hydrolyzes in water to give Sn(CH 3) 2(OH) 2 and [Sn(CH 3) 2(OH)(H 2O) n] + species. Spectroscopic evidence showed that interaction occurred mainly through (CH 3) 2Sn(IV) hydroxide and polynucleotide backbone phosphate group with overall binding constant of K(Sn(CH 3) 2Cl 2–DNA)=1.47×10 5 M −1 and K(Sn(CH 3) 2Cl 2–RNA)=7.33×10 5 M −1. Sn(CH 3) 2Cl 2 induced no biopolymer conformational changes with DNA remaining in the B-family structure and RNA in A-conformation upon drug complexation. 相似文献
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