Structure and Two-dimensional Correlation Infrared Spectroscopy Study of a New One-dimensional Chain Compound: (4,4’-Hbpy)_3[NaMo_8O_(26)](4,4’- bpy)_2(H_2O)_4 (bpy = Bipydine)

A novel compound, （4,4＇-Hbpy）3[NaMo8O26]（4,4＇-bpy）2（H2O）4 1 （bpy=bipydine）, was synthesized by the hydrothermal method. Single-crystal X-ray diffraction shows that compound 1 belongs to the monoclinic system, space group C2/m with a=19.1921（5）, b=18.6931（6）, c=9.3821（3） A° β=104.8020（11）°, V=3254.22（17）A°^3 C50H51Mo8N10NaO30, Mr=2062.52, Z=2, F（000）=2016, μ=1.591 mm^-1 and Dc=2.105 g/cm^3. The final R=0.0283 and wR=0.0912 for 3118 observed reflections （I〉20（I））. Compound 1 contains the β-[Mo8O26]^4-anion, sodium ion, 4,4＇-bpy and lattice crystalline water molecules. The β-[MosO26] units link the sodium ion to form a chain structure. The infinitechains of [Na（Mo8O26）]^3- blocks are surrounded by protonized 4,4＇-bpy cations, 4,4＇-bpy and lattice crystalline water molecules. The 2D-IR correlation spectroscopy study indicates that the stretching vibrations of Mo=O occur more preferentially due to the thermal effect. The TGA analysis shows that compound 1 has high thermal stability.

Study on the Hydrogen Bond Interaction Between Soy Protein Isolate and Glycerol Using Two-Dimensional Correlation Fourier-Transform Infrared Spectroscopy

A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.

Phase transformation and nanograting structure on TiO2 rutile single crystal induced by infrared femtosecond laser

In this paper, TitaiJum dioxide （TiO2） rutile single crystal was irradiated by infrared femtosecond laser pulses with repetition rate of 250 kHz. For a P-polarized femtosecond laser, the periodic nanograting structure on the ablation crater surface was formed . The periodicity is much less than the laser wavelength. The direction of nanograting alignment depends on the polarization laser beam. Micro-Raman spectra show that the intensity of Eg Raman vibrating mode of rutile phase increases and that of Alg Raman vibrating mode decreases apparently within the ablation crater. With the increase of irradiation time and laser average power, the Raman vibrating modes of anatase phase emerged. Rutile phase of TiO2 single crystal is partly transformed into anatase phase.

Experimental Consideration of Two-Dimensional Fourier Transform Spectroscopy

Two-dimensional Fourier transform(2D FT) spectroscopy is an important technology that developed in recent decades and has many advantages over other ultrafast spectroscopy methods. Although 2D FT spectroscopy provides great opportunities for studying various complex systems, the experimental implementation and theoretical description of 2D FT spectroscopy measurement still face many challenges, which limits their wide application.Recently, the 2D FT spectroscopy reaches maturity due to many new developments which greatly reduces the technical barrier in the experimental implementation of the 2D FT spectrometer. There have been several different approaches developed for the optical design of the 2D FT spectrometer, each with its own advantages and limitations. Thus, a procedure to help an experimentalist to build a 2D FT spectroscopy experimental apparatus is needed.This tutorial review is intending to provide an accessible introduction for a beginner to build a 2D FT spectrometer.

Analysis and discrimination of ten different sponges by multi-step infrared spectroscopy

In this study,a convenient method using multi-step infrared spectroscopy,including Fourier transform infrared spectroscopy（FT-IR）,second derivative infrared spectroscopy（SD-IR） and two-dimensional correlation infrared spectroscopy（2DCOS-IR）,was employed to analyze and discriminate ten marine sponges from two classes collected from the Xisha Islands in the South China Sea.Each sponge had an exclusive macroscopic fingerprint.From the IR spectra,it was noted that the main ingredient of calcareous sponges was calcium carbonate,but that of demosponges was proteins.For sponges from the same genus or having highly similar chemical profile（IR spectral profile）,SD-IR and 2DCOS-IR were applied to successfully reveal the tiny differences.It was demonstrated that the multi-step infrared spectroscopy was a feasible and objective approach for marine sponge identification.

飞秒光学频率梳高精度气体吸收光谱技术进展

飞秒光学频率梳以其频谱宽、脉宽窄、频率稳定度高等优点,对光学频率计量、绝对距离测量、高精度光谱测定产生重大影响。飞秒光学频率梳的时域特性和频域特性溯源至微波频率基准,使得高精度气体吸收光谱探测成为可能。飞秒光学频率梳光谱技术具有测量速度快、光谱灵敏度高、分辨率高、信噪比高等优点,因此加大对飞秒光学频率梳光谱技术的研究力度将更好地服务于环境保护、工业生产、生物医学、科学研究等各领域。飞秒光频梳高精度气体吸收光谱主要可分为光频梳腔衰荡光谱、光频梳腔增强光谱和双光频梳多外差光谱。其中,根据采集方式不同,光频梳腔增强光谱又可分为梳齿游标测量法、虚拟成像相位阵列测量法和傅里叶变换测量法。目前,国外已广泛开展相关研究,而国内仍处于起步阶段。本文综述了飞秒光学频率梳高精度气体吸收光谱探测的主要技术方法,展示了不同测量方法典型的实验方案,分析了各探测方法的优缺点,并追踪了主要研究小组的前沿成果。

二羰基茂铁二聚体[CpFe(CO)2]2的中红外泵浦探测光谱

利用一维稳态红外光谱和5-μm泵浦探测红外光谱手段,结合量子化学计算,以非桥连三价羰基为探针,研究了二羰基茂铁二聚体[CpFe（CO）2]2在二氯甲烷中的结构和振动动力学.结果表明,[CpFe（CO）2]2两个主要结构（顺式cis和反式trans摩尔比为1.7）的振动态寿命和转动动力学都有一定不同.两种结构的两个羰基振动激发态的指数衰减过程都有一个〈1ps的快组分和一个-20ps的慢组分.我们认为前者与宽带激发所产生的振动相干态的快速失相过程有关,而后者属于典型的C≡O伸缩振动态寿命.此外,cis结构与溶剂的较强作用使得其转动衰减较慢.结果表明,非桥连羰基的红外吸收频率和振转动力学对分子结构和溶剂环境都非常敏感.

N-乙基丙酰胺的飞秒二维红外光谱

利用飞秒二维红外实验方法,结合稳态红外光谱实验和计算化学手段,对β-肽模型分子N-乙基丙酰胺(NEPA)的超快结构动力学进行了研究.结果表明,在水溶液中,NEPA具有类α-肽酰胺-I带的振动特征,并表现出对分子结构和化学环境的灵敏性.二维红外光谱动力学结果揭示了一个1ps左右的光谱扩散时间,与酰胺-水之间的氢键结构动力学时间尺度一致.

Anharmonic Vibrational Signatures of DNA Bases and Watson-Crick Base Pairs

Changes of molecular structure and associated charge distributions, and changes of anharmonic vibrational parameters from DNA base monomers to the Watson-Crick base pairs, have been investigated at the density functional theory level. Through examination of the NH2, N H, and C=O stretching vibrational modes that are involved in the multiple H-bonds in the base pairs, sensitivity of their diagonal and off-diagonal anharmonicities, as well as anharmonic vibrational couplings, to the structure change are predicted. Our results reveal the intrinsic connection between the anharmonic vibrational potentials, H-bonding, and electrostatic interactions in DNA bases.

基于法布里-珀罗干涉仪的窄带宽激光脉冲产生及其应用

法布里-珀罗干涉仪的原理是多光束干涉,由于干涉仪内部是谐振腔结构(F-P腔),当入射光的频率满足共振条件时,透射频谱会出现很高的峰值.利用这一特性对输入的光信号进行频率筛选,从而得到理想的窄带宽脉冲信号.本文简要介绍了F-P腔的基本原理,以及利用F-P干涉仪产生窄带宽脉冲的过程,并介绍了该窄带宽脉冲在飞秒受激拉曼光谱、和频振动光谱和二维红外光谱等前沿光谱技术中的应用.

NIR assignment of isopsoralen by 2D-COS technology and model application in Yunkang Oral Liquid

Near infrared(NIR)assignment of Isopsoralen was performed using deuterated chloroform solvent and two-dimensional correlation spectroscopy(2D-COS)technology.Yunkang Oral Liquid was applied to study Isopsoralen,the characteristic bands by spectral assignment as well as the bands by interval partial least squares(iPLS)and synergy interval partial least squares(siPLS)were used to establish partial least squares(PLS)model.The coefficient of determination in calibration(R^(2)_(cal))were 0.9987,0.9970 and 0.9982.The coefficient of determination in cross validation(R^(2)_(val)) T were 0.9985,0.9921 and 0.9982.The coe±cient of determination in prediction(R^(2)_(pre)) T were 0.9987,0.9955 and 0.9988.The root mean square error of calibration(RMSEC)were 0.27,0.40 and 0.31 ppm.The root mean square error of cross validation(RMSECV)were 0.30,0.67 and 0.32 ppm.The root mean square error of prediction(RMSEP)were 0.23,0.43 and 0.22 ppm.The residual predictive deviation(RPD)were 31.00,16.58 and 32.41.It turned out that the characteristic bands by spectral assignment had the same results with the chemometrics methods in PLS model.It provided guidance for NIR spectral assignment of chemical compositions in Chinese Materia Medica(CMM).

Nanoscopy reveals surface-metallic black phosphorus

Black phosphorus(BP)is an emerging two-dimensional material with intriguing physical properties.It is highly anisotropic and highly tunable by means of both the number of monolayers and surface doping.Here,we experimentally investigate and theoretically interpret the near-field properties of a-few-atomic-monolayer nanoflakes of BP.We discover near-field patterns of bright outside fringes and a high surface polarizability of nanofilm BP consistent with its surface-metallic,plasmonic behavior at mid-infrared frequencies o1176 cm−1.We conclude that these fringes are caused by the formation of a highly polarizable layer at the BP surface.This layer has a thickness of~1 nm and exhibits plasmonic behavior.We estimate that it contains free carriers in a concentration of n≈1.1×10^(20) cm^(−3).Surface plasmonic behavior is observed for 10–40 nm BP thicknesses but absent for a 4-nm BP thickness.This discovery opens up a new field of research and potential applications in nanoelectronics,plasmonics and optoelectronics.

Microscopic study of binary mixtures between pyrrolidinium bis(triflorosulfonyl)imide and dimethyl sulfoxide/acetonitrile

Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis（triflorosulfonyl）- imide （[BMPyrr][TFSI]） with dimethyl sulfoxide （DMSO） and acetonitrile （AN） have been analyzed in this work. Attenuated total reflection Fourier transform infrared spectroscopy （ATR-FTIR） and density functional theory （DFT） calculations are used in the investigation, while excess infrared spectra and two-dimensional correlation spectroscopy are used to explore the data in detail. It has been found that the molecular solvents can interact with TFSI- （mainly with S=O and weakly with S-N-S group）. AN interacts feebly with BMPyrr＋ as compared with the strong interaction of DMSO. The strength of the interactions depends on the electron donating ability of the solvent. Upon mixing, hydrogen bonds regarding C-Hs in cation and S-N-S in anion are weakened, while that regarding S=O in anion is strengthened. Among the C-Hs which are connected directly with the N of the cation, Cl-H is the main interaction site for both DMSO and AN. This means that Cl-H is the most acidic hydrogen in pyrrolidinium cation.