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%.

Evolution of Two-Dimensional Correlation Spectroscopy

A number of useful techniques associated with two-dimensional correlation spectroscopy(2DCOS)to improve its performance and utility have been developed in the last 30years.Evolution of these 2DCOS techniques,including some of the very recent developments,is reviewed with examples.Topics include merged or modified asynchronous 2Dcorrelation spectrum,two-dimensional codistribution spectroscopy(2DCDS),Pareto scaling,and null-space projection treatment of spectral dataset.

Generalized two-dimensional correlation near-infrared spectroscopy and principal component analysis of the structures of methanol and ethanol

Liquid state methanol and ethanol under different temperatures have been investigated by FT-NIR(Fourier transform nearinfrared) spectroscopy,generalized two-dimensional(2D) correlation spectroscopy,and PCA(principal component analysis) . First,the FT-NIR spectra were measured over a temperature range of 30-64(or 30-71) °C,and then the 2D correlation spectra were computed.Combining near-infrared spectroscopy,generalized 2D correlation spectroscopy,and references,we analyzed the molecular structures(especially the hydrogen bond) of methanol and ethanol,and performed the NIR band assignments. The PCA method was employed to verify the results of the 2D analysis.This study will be helpful to the understanding of these reagents.

Structural characterization of steam-heat treated Tectona grandis wood analyzed by FT-IR and 2D-IR correlation spectroscopy

The properties of wood can be improved through steam-heat treatment.There are many studies about mechanical properties of steam-heat treated wood,but very few studies are on the aspects of chemical modifications.In this study,FT-IR spectra combined with SD-IR spectra,correlation coefficients and 2DIR spectra are employed to analyze the chemical modifications of teak[Tectona grandis L.F.） wood during steam-heat treatment under treatment temperatures from 120 ℃ to 220 ℃ at intervals of 20 ℃.Acetic acid,which is produced during steam-heat treatment,acts as a catalyst of condensation and degradation reactions of wood components.The changes of wood components are more and more intense with increasing the treatment temperature.The sensitivity of wood samples to thermal perturbation rises initially with increasing treatment temperature before falling back.The steam-heat treated wood under180℃ is the most sensitive.

Two-dimension fluorescence correlation spectroscopy to characterize the binding of organic ligands with zinc in eutrophic lake

Metal binding of organic ligands can definitely affect its environmental behavior in waters,while information on the binding heterogeneity with different organic ligands is still lacked till now.In this study,the binding of zinc with organic matters associated with cyanobacterial blooms,including dissolved organic matters（DOM） and attached organic matters（AOM）,were studied by using fluorescence quenching titration combined with two-dimensional correlation spectroscopy（2D-COS）.Metal-induced fluorescent quenching was obviously observed both for DOM and AOM,indicating the formation of metal-ligand complexes.Compared with the one-dimensional spectra,2D-COS revealed the sequences of metal-ligand interaction with the following orders：276 nm 〉 232 ran for DOM and232 nm 〉 276 nm for AOM.Furthermore,the modified Stern-Volmer model showed that the binding constant（logKM） of 276 nm in DOM was higher than that of 232 nm（4.93 vs.4.51）,while AOM was characterized with a high binding affinity for 232 nm（log KM：4.83）.The ranks of log KM values were consistent with the sequential orders derived from 2D-COS results both for the two samples.Fluorescence quenching titration combined with 2D-COS was an effective method to characterize the metal-ligand interaction.

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).

Comparing the Structures of Two Allomorphic Polyoxotungstates and the Difference in Weak Interactions by Thermal-dependent 2D-COS IR to Identify

A three-dimensional （3D） Keggin-type heteropolytungstate{Zn（phen）3}3[ZnW12O40]·9H2O 1 （phen = 1,10-phenanthroline） has been synthesized through a conventional hydrothermal synthesis and was characterized by X-ray single-crystal diffraction analysis, X-ray powder diffraction （XRD）, IR, UV-DRS, thermogravimetric analysis （TGA）, thermal-dependent 2D-IR correlation spectroscopy （2D-COS IR） and Raman spectrum. Crystal data for compound 1： trigonal system, space group R3 with a = b = 25.268（4）, c = 17.462（5） A, ）, = 120°, V= 9655（4） A3 and Z = 3. Compound 1 is allomorphic to {Co（phen）3}3[CoW12O40]·9H2O 2, which has been reported by Feng Chai et al. In compound 2, its prominent feature is that the decisive role of water molecules （O-H…O） builds a 3D supramolecular structure. However, in the structure of compound 1, the interlayer space is filled by Zn（phen）3]2＋ cations which linked the layers via C-H…O hydrogen bonding interactions to construct a three-dimensional framework. Two compounds are different in weak interactions, so we identify them by Thermal-dependent 2D-COS IR. Moreover, the fluorescence of compound 1 was also described.

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.

鱼粉、豆粕样本-样本二维相关近红外光谱判别

为了探讨利用二维相关近红外光谱法快速判别鱼粉和豆粕饲料原料的可行性,共收集了52个鱼粉、60个豆粕样品,其中34个鱼粉和40个豆粕样品作为定标集,其余18个鱼粉和20个豆粕样品作为独立验证集,用Spectrum400型近红外光谱仪扫描获取光谱,并对其特征峰进行解析。采用样本-样本二维相关分析方法定性判别鱼粉、豆粕,当预处理方法为一阶导数时,判断正确率为100%。与偏最小二乘判别分析方法相比,二者均可正确检测鱼粉、豆粕,其中二维相关方法的建模及验证算法简单、计算量小、运算速度快。

乙醇丙酮体系的广义二维相关近红外光谱分析

利用近红外及二维相关光谱进行了丙酮乙醇两种试剂体系的结构分析。首先检测30~50℃范围内（每隔2℃）的近红外光谱,结合近红外光谱、二维相关光谱及相关文献,对乙醇丙酮体系的分子结构（特别是氢键）进行了分析。近红外光谱的特征峰在一维图上变化不明显,借助于二维相关分析,提高了分辨率和可解释性。特别是分析了两种氢键羟基的存在,发现了烯醇羟基形成氢键及甲基与羰基形成氢键的证据,确定了不同分子结构之间的变化先后顺序,并进行了本体系近红外峰的归属。研究结果将有利于更深刻地理解该类试剂,为其进一步研究和使用提供参考。

原位检测组织非特异碱性磷酸酶活性的二维相关分析校正

在以人成骨肉瘤细胞株(Saos-2)为模型,利用α-D-葡萄糖-1-磷酸(α-G-1-P)为生理底物,原位检测组织非特异性碱性磷酸酶(TNAP)活力时,红外(IR)光谱峰位选取不准确和谱带严重重叠无法分辨/分离等都将给酶活力的测试结果带来偏差。二维相关分析与IR光谱的结合使用将在一定程度上改进上述问题,将在文中具体阐述。

Syntheses,Crystal Structures and Intermolecular Interactions of Cu(Ⅱ) Complexes with Methyl- benzoic Acid(MBA) and 1,10-Phenanthroline

Two cupric complexes containing methylbenzoic acid have been prepared and crystallized by solvent evaporation method in DMF. The single-crystal X-ray crystallographic analysis reveals that they are dicaryon complexes. Complex I with formula of [Cu2（m- MBA）4DMF2] crystallizes in monoclinic with space group of P21/c and complex 2 with formula of [Cuz（o-MBA）ffo-phen）2]·NO3·H2O crystallizes in triclinic with space group of P I. The weak interactions including C-H...O hydrogen bonds, C-H…π interactions and π-π stacking in the structures of two complexes are observed from the X-ray crystallographic data. In addition, there are still classical hydrogen bonds in 2. The different strength of intermolecular interaction in the structure is reflected on their different thermal stability measured by thermal gravimetric analysis and 2D-1R correlation spectroscopy of two complexes. The study of weak interactions is meaningful to provide supporting data for supramolecular chemistry theory and potential applications in molecular biology.

Synthesis and characterization of a new catalyst for RhB degradation constructed by[SiMo_(12)O_(40)]^(4-) anionic cluster

A Keggin-type polyoxomolybdate[H2biim]{Ni（biim）3（SiMO12O40）}[biim =1H,1＇H-[2,2＇]biimidazolyl]has been synthesized under hydrothermal condition and characterized by XRD,temperature-dependent IR,TG,temperature-induced and magnetism-induced 2D infrared correlation spectroscopy（2D-IR COS）and UV-vis DRS in order to explore the relationship between structure and properties.Temperatureinduced 2D-IR COS spectroscopy indicates that the terminal Mo-Oμ/υbonds are more sensitive than the bridging Mo=Ot,bands to temperature variation,which is in agreement with the conclusion of temperature-dependent IR.Magnetism-dependent 2D-IR COS spectroscopy reveals the stretching vibration of the Mo=Ot,occurs prior to the stretching vibration of the Mo-Oμ/υ,which is due to the coordination environment and the valence of the Si atom.The stability of compound 1 is investigated via TG and temperature-dependent IR.In RhB degradation,compound 1 shows good photocatalytic abilities.

Evolution of humic substances in polymerization of polyphenol and amino acid based on non-destructive characterization

Abiotic humification is important in the formation and evolution of organic matter in soil and compost maturing processes.However,the roles of metal oxides in abiotic humification reactions under micro-aerobic remain ambiguous.The aim of this study was to use non-destructive measurement methods to investigate the role of MnO_(2) in the evolution of humic substances(HSs)during oxidative polymerization of polyphenol-amino acid.Our results suggested a synergistic effect between MnO_(2) and O_(2) in promoting the polymerization reaction and identified that MnO_(2) alone had a limited ability in accelerating the transformation of fulvic acid(FA)to humic acid(HA),whereas O_(2) was the key factor in the process.Two-dimensional correlation spectroscopy(2D-COS)showed that the evolution in the UV-vis spectra followed the order of 475–525 nm>300–400 nm>240–280 nm in the humification process,indicating the formation of simple organic matter followed by FA and then HA.13C nuclear magnetic resonance(13C NMR)analysis revealed that the products under both air and N2 conditions in the presence of MnO_(2) had greater amounts of aromatic-C than in the absence of MnO_(2),demonstrating that MnO_(2) affected the structure of the humification products.The results of this study provided new insights into the theory of abiotic humification.

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.