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151.
We present a comparative study on the C-H stretching vibrations at air/DMSO (dimethyl sulfoxide) interface with both the free-induction decay (FID) coherent vibrational dynamics and the sub-wavenumber high resolution sum-frequency generation vibrational spectroscopy measurements. In principle the frequency-domain and time-domain spectroscopic measurements should generate identical information for a given molecular system. However, when the molecular systems are with several coupled or overlapping vibrational modes, obtain- ing detailed spectroscopic and coherent dynamics information is not as straightforward and rather difficult from either the time-domain or the frequency domain measurements. For the case of air/DMSO interface that is with moderately complex vibrational spectra, we show that the frequency-domain measurement with sub-wavenumber high-resolution sum-frequency generation vibrational spectroscopy is probably more advantageous than the time- domain measurement in obtaining quantitative understanding of the structure and coherent dynamics of the molecular interface. 相似文献
152.
Variation in the position of CF3 groups in several aromatic Group‐14 compounds was studied by 19F‐NMR spectroscopy. In these compounds RnECl4?n (n=1 or 2; E=Si, Ge, or Sn; R=2,4,6‐(CF3)3C6H2 (=Ar), 2,6‐(CF3)2C6H3 (=Ar′), or 2,4‐(CF3)2C6H3 (=Ar″)), Ar, Ar′, and Ar″ are all bulky, strongly electron‐withdrawing ligands. The 19F‐NMR studies of the variation in position of the CF3 substituents in these compounds as revealed by chemical shifts could be correlated with the electronegativities of the central elements E, and with intramolecular E–F interactions derived from single‐crystal X‐ray diffraction data. These interactions are considered to play an important role in the stabilization of these compounds. 相似文献
153.
LUO Ya-Nan XU Xian-Zhua YU Xiao-Yang ZHU Guang-Shan QU Xiao-Shu ZHANG Xiao YU Li-Ying 《结构化学》2013,(11):1667-1672
A new coordination polymer, {[CdL(en)]'DMF}n (1, H2L = 4-[(8-hydroxy-5- quinolinyl)azo]-benzenesulfonic acid, en = ethylenediamine, DMF = N,N-dimethylformamide), has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffrac- tion, infrared (IR) spectra, elemental analysis, powder X-ray diffractions (PXRD) and thermo- gravimetric analysis (TGA). Compound 1 crystallizes in monoclinic, space group P2Jc with a = 14.6525(9), b = 13.3917(9), c = 11.8838(8) A, β = 101.2290(10)°, V = 2287.2(3) A3, Z = 4, C20H24CdN6OsS, Mr = 572.91, Dc. = 1.664 mg-mm-3, F(000) = 1160, p = 1.091 mm-1, R = 0.0232 and wR = 0.0587 for 3597 observed reflections (I 〉 2σ(I)). Compound 1 exhibits a one-dimensional (1D) double-chain structure which is further connected through hydrogen bonding and π-π interactions into a three-dimensional (3D) supramolecular network. In addition, it exhibits blue fluorescence at room temperature in the solid state. 相似文献
154.
A new 1D chain copper coordination polymer [CuE(H2L)2(C10HsN2)(HEO)2]n'3n(H20) with 2,3-pyridinedi carboxylic acid (H2L) and 2,2'-bipyridine (2,2'-bipy) as ligands has been synthesized in the mixed ethanol and water solvents. Crystal data for this complex are as follows: monoclinic, space group P2Jc, a = 7.7713(7), b = 27.478(3), c = 13.2621(13)/1,, fl = 100.6940(10), V= 2782.8(5) A3, Dc = 1.722 g/cm3, Z = 4, p = 1.61 mm-1, F(000) = 1472, the final R = 0.0363 and wR = 0.0933. In the crystal structure, the whole molecule consists of two cooper ions, two H2L, one 2,2"-bipy molecule and six water molecules. Each central copper ion is coordinated with three oxygen atoms from two H2L and one water molecule, two nitrogen atoms from one 2,2'-bipy molecule and two H2L, giving a distorted tetragonal pyramidal geometry. Thermal stability properties of the complex were investigated. 相似文献
155.
Prof. Xuefeng Wang Prof. Lester Andrews Dipl.Chem. Felix Brosi Dr. Sebastian Riedel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(4):1397-1409
The reactions of laser‐ablated Au, Ag, and Cu atoms with F2 in excess argon and neon gave new absorptions in the M? F stretching region of their IR spectra, which were assigned to metal‐fluoride species. For gold, a Ng? AuF bond was identified in mixed neon/argon samples. However, this bonding was much weaker with AgF and CuF. Molecules MF2 and MF3 (M=Au, Ag, Cu) were identified from the isotopic distribution of the Cu and Ag atoms, comparison of the frequencies for three metal fluorides, and theoretical frequency calculations. The AuF5 molecule was characterized by its strongest stretching mode and theoretical frequency calculations. Additional evidence was observed for the formation of the Au2F6 molecule. 相似文献
156.
157.
The synthesis of two hydrophobic cavitands bearing four (1) and eight (2) thymidine residues covalently linked with triazole moieties is reported. Spectral evidence indicates the adoption of a hydrogen-bonded T-quartet assembly by 1 in chloroform at low temperature and a π-stacked quadruplex by 2 in DMSO under ambient conditions. 相似文献
158.
利用B3LYP/6-311+G(2d,p)方法对一种新型含能增塑剂双(2,2-二硝基丙基)甲缩醛进行几何优化,计算了其红外光谱、生成焓和爆轰特性. 分析了最弱键的键离解能和键级并预测了目标化合物的热稳定性. 结果表明双(2,2-二硝基丙基)甲缩醛中的四个N-NO2键的键离解能都为164.38 kJ/mol. 表明目标化合物是一个热力学性能稳定的化合物. 以凝聚相生成焓和分子密度为基础,采用Kamlet-Jacobs方法预测其爆速和爆压. 目标化合物的晶体结构属于P21空间群. 相似文献
159.
160.