Co-reporter:Anqi He, Xianzhe Zeng, Yizhuang Xu, Isao Noda, Yukihiro Ozaki, and Jinguang Wu
The Journal of Physical Chemistry A October 12, 2017 Volume 121(Issue 40) pp:7524-7524
Publication Date(Web):September 25, 2017
DOI:10.1021/acs.jpca.7b06621
The behavior of noise in asynchronous spectrum in generalized two-dimensional (2D) correlation spectroscopy is investigated. Mathematical analysis on the noise of 2D spectra and computer simulation on a model system show that the fluctuation of noise in a 2D asynchronous spectrum can be characterized by the standard deviation of noise in 1D spectra. Furthermore, a new approach to improve a signal-to-noise ratio of 2D asynchronous spectrum by a Butterworth filter is developed. A strategy to determine the optimal conditions is proposed. Computer simulation on a model system indicates that the noise of 2D asynchronous spectrum can be significantly suppressed using the Butterworth filtering. In addition, we have tested the approach to a real chemical system where interaction between berberine and β-cyclodextrin is investigated using 2D UV–vis asynchronous spectra. When artificial noise is added, cross peaks that reflect intermolecular interaction between berberine and β-cyclodextrin are completely masked by noise. After the method described in this article is utilized, noise is effectively suppressed, and cross peaks are faithfully recovered. The above result demonstrates that the approach described in this article is applicable in real chemical systems.
Co-reporter:Jin Zhang, Ran Guo, Anqi He, Shifu Weng, Xiuxiang Gao, Yizhuang Xu, Isao Noda, Jinguang Wu
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 Volume 182(Volume 182) pp:
Publication Date(Web):5 July 2017
DOI:10.1016/j.saa.2017.03.062
•Solubilization effect of PVP to artemisinin was proved by 1H NMR.•DAOSD approach was utilized to investigate interaction between artemisinin and NMP.•Dipole-dipole interaction occurs between specific groups of artemisinin and NMP.•Dipole-dipole interaction may account for the solubilization effect of PVP to artemisinin.In this work, we investigated the influence of polyvinylpyrrolidone (PVP) on the solubility of artemisinin in aqueous solution by using quantitative 1H NMR. Experimental results demonstrate that about 4 times of incremental increase occurs on the solubility of artemisinin upon introducing PVP. In addition, dipole-dipole interaction between the ester group of artemisinin and the amide group of N-methylpyrrolidone (NMP), a model compound of PVP, is characterized by two-dimensional (2D) correlation FTIR spectroscopy with the DAOSD (Double Asynchronous Orthogonal Sample Design) approach developed in our previous work. The observation of cross peaks in a pair of 2D asynchronous spectra suggests that dipole-dipole interaction indeed occurs between the ester group of artemisinin and amide group of NMP. Moreover, the pattern of cross peaks indicates that the carbonyl band of artemisinin undergoes blue-shift while the bandwidth and absorptivity increases via interaction with NMP, and the amide band of NMP undergoes blue-shift while the absorptivity increases via interaction with artemisinin. Dipole-dipole interaction, as one of the strongest intermolecular interaction between artemisinin and excipient, may play an important role in the enhancement of the solubility of artemisinin in aqueous solution.Download high-res image (282KB)Download full-size image
Co-reporter:Anqi He, Xiaoyan Kang, Yizhuang Xu, Isao Noda, Yukihiro Ozaki, Jinguang Wu
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017 Volume 185(Volume 185) pp:
Publication Date(Web):5 October 2017
DOI:10.1016/j.saa.2017.05.070
•UV–Vis spectra of berberine and berberine/β-cyclodextrin are recorded.•Intermolecular interaction between berberine and β-cyclodextrin has been investigated using 2D UV–Vis spectroscopy.•Comprehensive analysis has been performed on cross peaks around (420 nm, 420 nm) nm in a 2D spectrum.•Spectral behavior confirms that berberine enters the hydrophobic cavity of β-cyclodextrin.The interaction between berberine chloride and β-cyclodextrin (β-CyD) is investigated via 2D asynchronous UV–Vis spectrum. The occurrence of cross peaks around (420 nm, 420 nm) in 2D asynchronous spectrum reveals that specific intermolecular interaction indeed exists between berberine chloride and β-CyD. In spite of the difficulty caused by overlapping of cross peaks, we manage to confirm that the 420 nm band of berberine undergoes a red-shift, and its bandwidth decreases under the interaction with β-CyD. The red-shift of the 420 nm band that can be assigned to n-π* transition indicates the environment of berberine becomes more hydrophobic. The above spectral behavior is helpful in understanding why the solubility of berberine is enhanced by β-CyD.Download high-res image (374KB)Download full-size image
Co-reporter:Mo Chen, Ran Guo, Ying Zhao, Shifu Weng, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2016 Volume 1124() pp:244-248
Publication Date(Web):15 November 2016
DOI:10.1016/j.molstruc.2015.12.015
•Intermolecular interaction between diethyl ether and CH2Cl2 was investigated.•FT-IR spectra of the two compounds were measured in the gas phase.•A gas cell for the DAOSD approach was designed, fabricated and utilized.•Intermolecular interaction between the two compounds is manifested by cross peaks.•The approach extends the application range of DAOSD and relevant approaches.Intermolecular interaction between diethyl ether and dichloromethane was investigated by using double asynchronous orthogonal sample design (DAOSD) scheme. FT-IR spectra of the two compounds were measured in the gas phase. A gas cell that satisfied the requirement of the DAOSD approach was designed, fabricated and utilized. The appearance of cross peaks in a pair of asynchronous spectra demonstrated that intermolecular interaction occurred between two compounds. Interference from the spectra of solvent can be avoided by measuring the samples in gas phase, thereby extending the application range of DAOSD and relevant approaches.
Co-reporter:Xiaoyan Kang, Anqi He, Ran Guo, Jing Chen, Yanjun Zhai, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2016 Volume 1124() pp:228-237
Publication Date(Web):15 November 2016
DOI:10.1016/j.molstruc.2015.12.047
•Interaction between two solutes (P and Q) dissolved in solutions is characterized.•P occurs in two exchangeable states when it is dissolved alone in solutions.•DAOSD approach can be used to characterize interaction between P and Q reliably.•Spectral properties of cross peaks in different regions of 2D asynchronous spectra are discussed.•Cross peaks can be used to reflect intermolecular interaction at a network level.The spectral behavior of a pair of 2D asynchronous spectra generated by using the double asynchronous orthogonal sample design (DAOSD) approach on a chemical system is investigated. Two solutes (P and Q) are dissolved in the solution and intermolecular interaction between P and Q is characterized. In this particular system, P occurs in two exchangeable states when it is dissolved in the solutions. Results on mathematical analysis and computer simulation demonstrated that interference unrelated to the intermolecular interaction can be completely removed. Hence the resultant 2D asynchronous spectra generated by using the DAOSD approach can reflect intermolecular interaction reliably. Moreover, properties of cross peaks in different regions of the pair of asynchronous spectra are discussed. In our previous works, cross peaks generated by using the DAOSD and relevant techniques reflect variations on peak position, bandwidth or absorptivity of the characteristic peaks of solutes caused by intermolecular interaction. However, we find that cross peak can still be produced even if intermolecular interaction do not bring about any changes on the characteristic peaks of solutes. Mathematical analysis demonstrates that cross peaks are related to the variations of chemical systems caused by intermolecular interaction at a network level.
Co-reporter:Ye Jiang, Junhui Xue, Xiaodong Wen, Yanjun Zhai, Limin Yang, Yizhuang Xu, Guozhong Zhao, Kuan Kou, Kexin Liu, Jia'er Chen, Jinguang Wu
Journal of Molecular Structure 2016 Volume 1109() pp:179-191
Publication Date(Web):5 April 2016
DOI:10.1016/j.molstruc.2016.01.005
•Novel Cs complexes with lactose, d- and l-arabinose are reported.•X-ray diffraction, IR, FIR, THz and Raman results are presented.•New coordination structures are observed.The novel cesium chloride–lactose complex (CsCl·C12H22O10 (Cs-Lac), cesium chloride-d-arabinose and l-arabinose complexes (CsCl·C5H10O5, Cs-D-Ara and Cs-L-Ara) have been synthesized and characterized using X-ray diffraction, FTIR, FIR, THz and Raman spectroscopies. Cs+ is 9-coordinated to two chloride ions and seven hydroxyl groups from five lactose molecules in Cs-Lac. In the structures of CsCl-d-arabinose and CsCl-l-arabinose complexes, two kinds of Cs+ ions coexist in the structures. Cs1 is 10-coordinated with two chloride ions and eight hydroxyl groups from five arabinose molecule; Cs2 is 9-coordinated to three chloride ions and six hydroxyl groups from five arabinose molecules. Two coordination modes of arabinose coexist in the structures. α-d-arabinopyranose and α-l-arabinopyranose appear in the structures of Cs-D-Ara and Cs-L-Ara complexes. FTIR and Raman results indicate variations of hydrogen bonds and the conformation of the ligands after complexation. FIR and THz spectra also confirm the formation of Cs-complexes. Crystal structure, FTIR, FIR, THz and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride–lactose, cesium chloride-D- and l-arabinose complexes.
Co-reporter:Xiaoyan Kang, Anqi He, Ran Guo, Yanjun Zhai, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2016 Volume 1124() pp:151-158
Publication Date(Web):15 November 2016
DOI:10.1016/j.molstruc.2016.02.064
We propose a substantially simplified approach to construct a pair of 2D asynchronous spectra based on the DAOSD approach proposed in our previous papers. By using a new concentration series, only three 1D spectra are used to generate a pair of 2D correlation spectra together with two reference spectra. By using this method, the previous problem of labor intensive traditional DAOSD approach has been successfully addressed. We apply the new approach to characterize intermolecular interaction between acetonitrile and butanone dissolved in carbon tetrachloride. The existence of intermolecular interaction between the two solutes can be confirmed by the presence of a cross peak in the resultant 2D IR spectra. In addition, the absence of cross peak around (2254, 2292) in Ψbutanone provides another experimental evidence to reveal the intrinsic relationship between the CN stretching band and an overtone band (δCH3+νC–C).
Co-reporter:Jingdan Wang, Anqi He, Ran Guo, Yongju Wei, Juan Feng, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2016 Volume 1124() pp:221-227
Publication Date(Web):15 November 2016
DOI:10.1016/j.molstruc.2016.01.047
•Study on 2D spectrum generated from a group of emission spectra is performed.•No cross peak appears in 2d spectrum as the solute occurs in single environment.•Appearance of cross peaks can be used to show the solute occurs in different environments.•The approach is applied to study the fluorescent behavior of anthracene.Properties of 2D asynchronous spectra generated from a series of fluorescence emission spectra are investigated. Variable excitation wavelengths are utilized as an external perturbation. Based on the results of mathematical analysis and computer simulation, we find that no cross peak will be produced on the 2D asynchronous spectrum if the fluorescent solute under investigation occurs in a single micro-environment. The observation of cross peaks implies that the fluorescent molecule may occur in different micro-environments in a solution. Based on these results, we use 2D asynchronous spectra to investigate the emission spectra of anthracene dissolved in cyclohexane. When the concentration of anthracene is low, no cross peak is produced in the resultant 2D asynchronous spectrum, confirming that anthracene is dissolved as single molecule in the solution. As the concentration elevated, cross peaks appear in the corresponding 2D asynchronous spectra. A plausible explanation of this phenomenon is that anthracene may undergo aggregation via π-π interaction or π-C-H interaction.
Co-reporter:Xiaopei Li, Anqi He, Kun Huang, Huizhou Liu, Ying Zhao, Yongju Wei, Yizhuang Xu, Isao Noda and Jinguang Wu
RSC Advances 2015 vol. 5(Issue 107) pp:87739-87749
Publication Date(Web):30 Sep 2015
DOI:10.1039/C5RA16062F
A new approach called “asynchronous spectrum with auxiliary peaks (ASAP)” is proposed for generating a 2D asynchronous spectrum to investigate the intermolecular interaction between two solutes (P and Q) dissolved in the same solution. In the ASAP approach, a virtual substance S with an isolated peak assumed to be at νS is introduced, while the characteristic peaks of P and Q are actually observed at νP and νQ. The concentrations series of P, Q and S are specifically designed so that a spectral portion that has nothing to do with the intermolecular interaction between P and Q is completely removed from the 2D asynchronous spectrum. Auxiliary cross peaks around (νP, νS) and (νQ, νS) can be used to reveal spectral variation caused by intermolecular interaction, which cannot be observed on conventional cross peaks appearing around the spectral coordinates (νP, νP), (νP, νQ), (νQ, νP), (νQ, νQ). For example, variation of the absorptivity of P caused by an intermolecular interaction between P and Q can be probed from the auxiliary cross peaks around (νP, νS) when Q does not even have any characteristic peak in the observed spectral range.
Co-reporter:Ye Jiang, Xiaoyan Kang, Danqing Gao, Anqi He, Ran Guo, Xiaokun Fan, Yanjun Zhai, Jinming Xia, Yizhuang Xu, Isao Noda and Jinguang Wu
RSC Advances 2015 vol. 5(Issue 28) pp:21544-21549
Publication Date(Web):18 Feb 2015
DOI:10.1039/C4RA13537G
Thin layer chromatography (TLC) coupled with infrared spectroscopic technique has great advantages in the separation and identification of different components in a mixture. However, determination of suitable separation condition is a tedious task. To improve the efficiency of finding suitable separation conditions, we propose a multi-narrow-band TLC approach. In this approach, a TLC plate containing several parallel narrow bands was utilized. In experiment, different pure substance was added on each of the narrow bands and TLC analysis was performed under same condition. Different substance exhibits different migration distance. Thus, it becomes much easier to separate substances with large difference in migration distance. This approach can be used to find multiple mixed sample pairs in a parallel manner. Consequently, a high-throughput method on selection of suitable mobile phase and separation conditions can be established.
Co-reporter:Huizhen Li;Ran Guo;Yuhai Liu;Shaoxuan Liu;Edyta Proniewicz;Leonard M. Proniewicz;Ying Zhao;Jinguang Wu
Journal of Applied Polymer Science 2015 Volume 132( Issue 35) pp:
Publication Date(Web):
DOI:10.1002/app.42413
ABSTRACT
The effect of thermal treatment over a wide range of temperature (130–280°C) on the crystallization behavior of nylon 6 was studied by using DSC, FTIR, and polarized light microscope equipped with a hot stage. The crystallization and the subsequent melting behavior of the nylon 6 samples treated at different temperatures (Ts) were classified into four types. When Ts was higher than 236°C or lower than 213°C, the crystallization behavior of nylon 6 was insensitive to the variation of Ts. When Ts was in the range of 213–235°C, the crystallization behavior was sensitive to the change of Ts. The polarized light microscopic experiments have demonstrated that a large amount of tiny ordered nylon 6 segments/cluster persisted when nylon 6 film are heated to 231°C. Consequently, the fastest crystallization speed was observed. As Ts was between 214 and 223°C, both the Tm and the ΔHm were higher than those of the nylon 6 samples treated at other temperature. The polarized light microscopic investigations have also demonstrated that molten nylon 6 crystallizes by using the un-molten nylon 6 crystals as nucleation center at 220°C. Crystallization at higher temperature produces nylon 6 with thicker crystalline lamella. The above results are helpful for rational design of thermal treatment procedure to obtain nylon 6 with different crystalline features. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42413.
Co-reporter:Qian-Hong Jiang, Chun-Bo Zhang, Jian Yang, Ying Zhao, Yi-Zhuang Xu, Du-Jin Wang
Chinese Chemical Letters 2015 Volume 26(Issue 2) pp:197-199
Publication Date(Web):February 2015
DOI:10.1016/j.cclet.2015.01.015
Two-dimensional FT-IR correlation spectroscopy was used to reveal the structural changes of isotactic polypropylene (iPP) mesophase during the heating process. The co-relationship among the regular helical bands of iPP was discussed according to synchronous spectrum. The results show that the segments with different length-helixes were found to undergo a disordered process in the temperature range of 25–60 °C.Synchronous two-dimensional (2D) infrared correlation spectrum of quenched iPP in the range of 1000–800 cm−1.
Co-reporter:Yu-Hai Liu, Jia-Jia Shi, Dan-Qing Gao, Yun-Long Gao, Ran Guo, Xiao-Feng Ling, Shi-Fu Weng, Yi-Zhuang Xu, Isao Noda, Jin-Guang Wu
Chinese Chemical Letters 2015 Volume 26(Issue 2) pp:182-186
Publication Date(Web):February 2015
DOI:10.1016/j.cclet.2015.01.014
In this paper, 2D asynchronous spectra generated by using the DAOSD approach was utilized to probe interactions between Nd3+ and pyridinium dissolved in aqueous solution. A series of cross peaks in the resultant 2D asynchronous spectrum confirms the occurrence of intermolecular interaction between Nd3+ and pyridinium. However, no coordination occurs between Nd3+ and pyridinium. Interaction between π electron from aromatic system and f electron from lanthanide ions account for the appearance of cross peaks in 2D asynchronous spectra. Because of the interaction, the emission spectrum of pyridinium exhibits a significant change when neodymium perchlorate was introduced into the system.A series of cross peaks in the resultant DAOSD spectrum confirms the occurrence of intermolecular interaction between Nd3+ and pyridinium. However, no coordination occurs between Nd3+ and pyridinium. Interaction between π electron from aromatic system and f electron from lanthanide ions account for the appearance of cross peaks in 2D asynchronous spectra.
Co-reporter:Dan-Qing Gao, Xiao-Pei Li, Jia-Jia Shi, Xiao-Yan Kang, Ting-Guo Kang, Jin-Ming Xia, Xiao-Feng Ling, Shi-Fu Weng, Yi-Zhuang Xu, Isao Noda, Jin-Guang Wu
Chinese Chemical Letters 2015 Volume 26(Issue 2) pp:177-181
Publication Date(Web):February 2015
DOI:10.1016/j.cclet.2015.01.013
Two dimensional asynchronous spectra were used to characterize coordination between carbonyl group of butanone and metal ions by using an approach proposed in our recent paper. Spectral variation of n-π* transition band of carbonyl group is used to probe the coordination even if metal ions does not possess any characteristic peak in spectra. Experimental results indicate that Ca2+ and Al3+ show considerable ability to coordinate with the carbonyl group of butanone and bring about spectral variation of the n-π* transition band, which is manifested by cross peaks in 2D asynchronous spectra.Metal ions show considerable ability to coordinate with the carbonyl group of butanone and bring about spectral variation of the n-π* transition band, which is manifested by cross peaks in 2D asynchronous spectra.
Co-reporter:Jun-Hui Xue, Xiao-Hui Hua, Li-Min Yang, Wei-Hong Li, Yi-Zhuang Xu, Guo-Zhong Zhao, Gao-Hui Zhang, Ke-Xin Liu, Jia-Er Chen and Jin-Guang Wu
CrystEngComm 2014 vol. 16(Issue 33) pp:7711-7721
Publication Date(Web):12 Jun 2014
DOI:10.1039/C4CE00606B
Four kinds of coordination structures formed by lanthanide–picolinamide complexes, including [La(C6H6N2O)2(H2O)5]Cl3 (La–pa, Pr–pa, Nd–pa, Sm–pa and Gd–pa), [Er(C6H6N2O)2 (H2O)4]Cl3(H2O) (Er–pa), [Pr(C6H6N2O)2(H2O)5]Br3 (PrBr–pa) and [Nd(C6H6N2O)3(NO3)2] (C6H6N2O)(NO3) (NdN–pa) are reported. The crystal structures in the solid state vary with the change of anions and lanthanide ions as revealed by X-ray single crystal diffraction, FTIR, Raman, FIR and THz spectroscopy. In these crystal structures, the pyridyl nitrogen and carbonyl oxygen of picolinamide are coordinated to metal ions to form a five-membered ring structure or are hydrogen-bonded. The results indicate the differences in the coordination of different lanthanide ions (the Er ion is special for its small atomic radius), the changes of hydrogen bonds and the conformation of the ligands induced by complexation, and the influence of different anions. When nitrate ions are involved in the coordination structure, the coordination number of lanthanide ions is higher. Chloride and bromine ions do not coordinate to metal ions, so lanthanide bromine and lanthanide chloride–pa complexes have similar structures. The results provide models for the coordination structures of lanthanide ions with ligands that have amide groups.
Co-reporter:Xiaopei Li, Kun Huang, Yizhuang Xu, Huizhou Liu
Vibrational Spectroscopy 2014 Volume 75() pp:59-64
Publication Date(Web):November 2014
DOI:10.1016/j.vibspec.2014.10.001
Many papers have reported that salt ions can exert a great influence on the self-assembly behavior of PEO-PPO copolymers in the aqueous solution. Whereas the mechanism through which salt ions influence the self-assembly behavior of PEO-PPO copolymers is unclear and the dispute is mainly focused on whether the salt ions have a direct interaction with PEO-PPO copolymers. In this paper, the interaction of sodium and potassium ions with PEO-PPO copolymer was investigated by using FTIR, Raman and 23Na NMR spectroscopy. Experimental results reveal that direct interactions between salt cations and PEO-PPO macromolecular chains indeed occur in appropriate conditions. The present work highlights the role of cations in the self-assembly process of PEO-PPO copolymer.
Co-reporter:Junhui Xue, Xiaohui Hua, Limin Yang, Weihong Li, Yizhuang Xu, Guozhong Zhao, Gaohui Zhang, Liming Liu, Kexin Liu, Jia’er Chen, Jinguang Wu
Journal of Molecular Structure 2014 Volume 1059() pp:108-117
Publication Date(Web):5 February 2014
DOI:10.1016/j.molstruc.2013.11.001
•Novel Co and Sr complexes with three isomers are reported.•The ligands are nicotinamide, isonicotinamide and picolinamide.•X-ray diffraction, IR, FIR, THz, Raman and UV–Vis results are presented.•New coordination structures are observed.Novel coordination structures formed by cobalt(II) and strontium(II) complexes with nicotinamide (na), isonicotinamide (ina) and picolinamide (pa) are reported. The structures of these complexes (CoCl2·(C6H6N2O)2·6H2O (Co-na), CoCl2·(C6H6N2O)2 (Co-ina), CoCl2·(C6H6N2O)2·2H2O, (Co-pa), SrCl2·(C6H6N2O)2·4H2O (Sr-na), SrCl2·(C6H6N2O)2·3H2O (Sr-ina) and SrCl2·C6H6N2O·H2O (Sr-pa)) in the solid state have been characterized by X-ray single crystal diffraction, FTIR, FIR, THz, Raman and UV–Vis spectroscopies. Pyridyl nitrogen of nicotinamide is coordinated to Co2+, but pyridyl nitrogen and carbonyl oxygen are used for coordination to Sr2+, and each Sr2+ is coordinated to four ligands. For isonicotinamide, pyridyl nitrogen is coordinated to Co2+, carbonyl oxygen is coordinated to Sr2+ and the ligand is also hydrogen-bonded in Sr-ina. Pyridyl nitrogen and carbonyl oxygen of picolinamide are coordinated to Co2+ to form a five-membered ring structure, but the carbonyl oxygen is coordinated to two Sr2+ ions in Sr-pa. Some of the complexes can form chain or network structures. The experiments results indicate the differences of the coordination of Co and Sr ions, the changes of hydrogen bonds and conformation of the ligands induced by complexation.Graphical abstractNovel cobalt(II) and strontium(II) complexes with nicotinamide (na), isonicotinamide (ina) and picolinamide (pa) complexes are reported. New coordination structures were observed.
Co-reporter:Jun-Hui Xue, Xiao-Hui Hua, Li-Min Yang, Wei-Hong Li, Yi-Zhuang Xu, Guo-Zhong Zhao, Gao-Hui Zhang, Ke-Xin Liu, Jia-Er Chen, Jin-Guang Wu
Chinese Chemical Letters 2014 Volume 25(Issue 6) pp:887-891
Publication Date(Web):June 2014
DOI:10.1016/j.cclet.2014.01.012
The novel coordination structures of europium and terbium chloride-picolinamide complexes (EuCl3·(C6H6N2O)2·5H2O, Eu-pa and TbCl3·(C6H6N2O)2·5H2O, Tb-pa) are reported. The crystal structures in the solid state are characterized by X-ray single crystal diffraction, FTIR, Raman, FIR, THz and luminescence spectroscopy. In the crystal structures, the pyridyl nitrogen and carbonyl oxygen atoms in picolinamide are coordinated to the metal ions to form a five-membered ring structure. The experimental results indicate the similar coordination structures of Eu and Tb-pa complexes and the changes of hydrogen bonds and conformation of the ligands induced by complexation. The results provide models for the coordination structures of lanthanide ions with ligands having amide groups.The crystal structures, FTIR, Raman, FIR, THz and luminescence spectroscopy are presented for Eu and Tb-picolinamide complexes.
Co-reporter:Hui-zhen Li, Dong-liang Tao, Jian Qi, Jin-guang Wu, Yi-zhuang Xu, Isao Noda
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2014 Volume 124() pp:697-702
Publication Date(Web):24 April 2014
DOI:10.1016/j.saa.2013.12.110
•“Orthogonal Sample Design Scheme” was used to construct 2D spectroscopy.•Dipole–dipole interactions of DMF/CH3COOC2H5, C60/CH3COOC2H5 in CCl4 were probed.•Interactions were studied using FT-IR and combination of UV–Vis/FT-IR spectra.•2D synchronous spectrum can be used to characterize dipole–dipole interaction.Two-dimensional (2D) synchronous spectroscopy together with a new approach called “Orthogonal Sample Design Scheme” was used to study the dipole–dipole interactions in two representative ternary chemical systems (N,N-dimethyllformamide (DMF)/CH3COOC2H5/CCl4 and C60/CH3COOC2H5/CCl4). For the first system, dipole–dipole interactions among carbonyl groups from DMF and CH3COOC2H5 are characterized by using the cross peak in 2D Fourier Transform Infrared Radiation (FT-IR) spectroscopy. For the second system, intermolecular interaction among π–π transition from C60 and vibration transition from the carbonyl band of ethyl acetate is probed by using 2D spectra. The experimental results demonstrate that “Orthogonal Sample Design Scheme” can effectively remove interfering part that is not relevant to intermolecular interaction. Additional procedures are carried out to preclude the possibilities of producing interfering cross peaks by other reasons, such as experimental errors. Dipole–dipole interactions that manifest in the form of deviation from the Beer–Lambert law generate distinct cross peaks visualized in the resultant 2D synchronous spectra of the two chemical systems. This work demonstrates that 2D synchronous spectra coupled with orthogonal sample design scheme provide us an applicable experimental approach to probing and characterizing dipole–dipole interactions in complex molecular systems.Graphical abstract
Co-reporter:Jun Liu, Yunlong Gao, Lirong Zheng, Danqing Gao, Anqi He, Yuhai Liu, Shifu Weng, Ying Zhao, Zhanlan Yang, Limin Yang, Xiaodong Wen, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2014 1069() pp: 217-222
Publication Date(Web):8 July 2014
DOI:10.1016/j.molstruc.2014.02.036
•We applied the DAOSD approach to probe weak coordination between Co2+ and acetone.•Subtle spectral variation on carbonyl band and d–d transition band are revealed.•The spectral variation suggests coordination occur between acetone and Co2+.•Coordination between acetone and Co2+ is further confirmed by EXAFS results.We applied a newly developed technique of the DAOSD (Double Asynchronous Orthogonal Sample Design) approach to probe weak coordination between Co2+ ions and acetone. Subtle spectral variation on the carbonyl band of acetone and d–d transition band are revealed via cross peaks of 2D asynchronous spectra generated by using the DAOSD approach. These results suggest that coordination occur between cobalt ions and the carbonyl group of acetone. To confirm whether coordination occur between cobalt ions and acetone, EXAFS experiments are utilized. The EXAFS results reveal that a Co2+ is coordinated by six methanol molecules in anhydrous CoCl2/methanol solution. Upon addition of acetone in into the anhydrous CoCl2/methanol solution, the coordination number of Co2+ ion becomes four, and one coordinating oxygen atom is replaced by a chlorine atom. We infer that the decrease in coordination number of Co2+ ion is due to the participation of the carbonyl oxygen of acetone in the coordination since the size of acetone is larger than methanol. This result provides an alternative evidence to support the conclusion that Co2+ ions coordinate with acetone, which is separately obtained from the 2D asynchronous spectra generated by using the DAOSD approach.
Co-reporter:Xiaopei Li, Xiaokun Fan, Kun Huang, Huizhou Liu, Ying Zhao, Yongju Wei, Cuige Liu, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2014 1069() pp: 127-132
Publication Date(Web):8 July 2014
DOI:10.1016/j.molstruc.2014.01.046
•A method is proposed to probe intermolecular interaction of two solutes where a solute has no peak.•2D asynchronous spectrum can be used reliably to characterize intermolecular interactions.•This approach is proved to be applicable for real chemical systems.We explore whether it is possible to use 2D correlation spectrum to characterize intermolecular interactions between two solutes dissolved in the same solution when one substance does not possesses any characteristic peak. We demonstrate that the interaction can be manifested by characteristic cross peaks in 2D asynchronous correlated spectrum. The above cross peaks reflect the subtle spectral variations on the characteristic peak of another solute under intermolecular interaction. On the other hand, 2D synchronous spectrum is not suitable to characterize intermolecular interaction since the cross peaks contain irremovable interfering parts. The terbium-chloride/benzamide/methanol system is used to demonstrate that this approach is applicable in the real chemical system.
Co-reporter:Quan Bi, Jing Chen, Xiaopei Li, Jia-Jia Shi, Ran Guo, Yanjun Zhai, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2014 1069() pp: 211-216
Publication Date(Web):8 July 2014
DOI:10.1016/j.molstruc.2014.02.004
•Under intermolecular interaction, peak position, bandwidth may change simultaneously.•Change on both peak position and bandwidth will produce butterfly cross peaks.•A method is set up to estimate change of peak position, bandwidth from cross peaks.•The validity of the approach is confirmed by computer simulation.Subtle spectral variations caused by intermolecular interactions, which are hardly observed in the original one-dimensional spectra or the second derivative spectra, can be distinctly visualized via spectral patterns in two-dimensional spectra generated by using double asynchronous orthogonal sample designed scheme (DAOSD). If intermolecular interaction only brings about band-shift on a characteristic peak, a pair of cross peaks appears in the corresponding near diagonal region. If intermolecular interaction induces variation of bandwidth only, a cluster of cross peaks forms a diamond pattern in the near diagonal region. In both cases, the variation of peak position or bandwidth can be deduced quantitatively from the pattern of cross peaks. If intermolecular interaction causes variations on both peak position and bandwidth, four cross peaks form a butterfly pattern. In this case, however, it is not straightforward to estimate the variation of peak position and bandwidth directly from the patterns of the cross peaks. In this paper, we propose an algorithm to estimate the variations of peak position and bandwidth of a characteristic peak caused by intermolecular interactions. The validity of this approach was confirmed by computer simulation on several model systems.
Co-reporter:Yunlong Gao, Jun Liu, Yuhai Liu, Jia-jia Shi, Shifu Weng, Limin Yang, Xiaodong Wen, Tingguo Kang, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2014 1069() pp: 205-210
Publication Date(Web):8 July 2014
DOI:10.1016/j.molstruc.2014.03.047
•We applied the DAOSD to probe coordination between Nd3+ ions and ethyl acetate.•Cross peaks reveal subtle spectral change related to coordination between Nd3+ and the ester group.•A peak at 177.8 ppm in 13C NMR supports coordination between Nd3+ and ethyl acetate.We applied a newly developed technique of DAOSD (double asynchronous orthogonal sample design) approach to probe weak coordination between Nd3+ ions and ethyl acetate. Cross peaks from the 2D asynchronous spectra are successfully used to reveal subtle spectral variation on carbonyl band of ethyl acetate and f–f transition peak of Nd3+, which is relevant to the coordination between Nd3+ and the ester group of ethyl acetate. In addition, we also use 13C NMR spectra to investigate the Nd3+/ethyl acetate system. The appearance of new weak carbonyl peak around 177.8 ppm provides alternative evidence of the weak coordination between Nd3+ and ester group of ethyl acetate.
Co-reporter:Haijian Hu ; Junhui Xue ; Xiaodong Wen ; Weihong Li ; Chao Zhang ; Limin Yang ; Yizhuang Xu ; Guozhong Zhao ; Xiaoxia Bu ; Kexin Liu ; Jia’er Chen ;Jinguang Wu
Inorganic Chemistry 2013 Volume 52(Issue 22) pp:13132-13145
Publication Date(Web):October 31, 2013
DOI:10.1021/ic402027j
The novel cesium chloride–d-ribose complex (CsCl·C5H10O5; Cs-R) and cesium chloride–myo-inositol complex (CsCl·C6H12O6; Cs-I) have been synthesized and characterized using X-ray diffraction and FTIR, FIR, THz, and Raman spectroscopy. Cs+ is eight-coordinated to three chloride ions, O1 and O2 from one d-ribose molecule, O1 from another d-ribose molecule, and O4 and O5 from the third d-ribose molecule in Cs-R. For one d-ribose molecule, the oxygen atom O1 in the ring is coordinated to two cesium ions as an oxygen bridge, O2 is cocoordinated with O1 to one of the two cesium ions, and O4 and O5 are coordinated to the third cesium ion, respectively. O3 does not coordinate to metal ions and only takes part in forming hydrogen bonds. One chloride ion is connected to three cesium ions. Thus, a complicated structure of Cs–d-ribose forms. For Cs-I, Cs+ is 10-coordinated to three chloride ions, O1 and O2 from one myo-inositol molecule, O3 and O4 from another myo-inositol molecule, O5 and O6 from the third myo-inositol molecule, and O6 from the fourth myo-inositol molecule. One metal ion is connected to four ligands, and one myo-inositol is coordinated to four Cs+ ions, which is also a complicated coordination structure. Crystal structure results, FTIR, FIR, THz, and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride–d-ribose and cesium chloride–myo-inositol complexes.
Co-reporter:Fang Wang, Haijun Wu, Qing Zhu, Kun Huang, Yongju Wei, Cuige Liu, Yanjun Zhai, Zhanlan Yang, Shifu Weng, Yizhuang Xu, Isao Noda and Jinguang Wu
Analytical Methods 2013 vol. 5(Issue 16) pp:4138-4144
Publication Date(Web):15 May 2013
DOI:10.1039/C3AY40128F
The present paper focuses on the development of narrow-band thin-layer chromatography (TLC) coupled with Fourier transform Infrared spectroscopy (FTIR) technique. We adopted a new method to prepare a narrow-band TLC plate by using silver iodide as stationary phase. The narrow-band TLC plate exhibits a variety of advantages: the preparation time is about 20 minutes, while 3–7 days are needed to prepare a common TLC plate suitable for TLC/FTIR analysis by using “settlement volatilization method”. Furthermore, the usage of stationary phase in narrow-band TLC plates decreases by about one order of magnitude in comparison with that of common TLC plates. This is very important for an expensive stationary phase such as silver iodide. In addition, experimental results of TLC/FTIR analysis on mixed samples containing rhodamine B and bromocresol green demonstrate the detection limit significantly improves by using the narrow-band TLC technique.
Co-reporter:Junhui Xue, Xiaohui Hua, Limin Yang, Yizhuang Xu, Weihong Li, Guozhong Zhao, Gaohui Zhang, Jinguang Wu
Journal of Molecular Structure 2013 Volume 1052() pp:93-101
Publication Date(Web):25 November 2013
DOI:10.1016/j.molstruc.2013.08.044
•Lanthanide–isonicotinamide complexes were synthesized and characterized.•X-ray diffraction, IR, FIR, THz and Luminescence results were presented.•Four kinds of structures, with or without chloride coordination in the coordination spheres were observed for lanthanide–isonicotinamide complexes.The coordination of amide groups to metal ions is important because it may be involved in the interactions between metal ions and proteins. The synthesis and characterization of nine novel lanthanide–isonicotinamide (ina) complexes, including LaCl3, PrCl3, NdCl3, SmCl3, EuCl3, GdCl3, TbCl3, ErCl3 and PrBr3 complexes are reported. The structures of these complexes in the solid state have been characterized by X-ray single crystal diffraction, FTIR, FIR, THz and Luminescence spectroscopy. Isonicotinamide has only one coordination mode in four structures as O-monodentate ligand to coordinate to metal ions, but four kinds of topological structures are observed for lanthanide–isonicotinamide complexes, including LnCl3⋅(C6H6N2O)2⋅4H2O (La, Pr, Nd and Sm), EuCl3⋅(C6H6N2O)2⋅7H2O, LnCl3⋅(C6H6N2O)2⋅6H2O (Gd, Tb and Er) and PrBr3⋅(C6H6N2O)2⋅7H2O. Chloride ions can coordinate to metal ions or hydrogen-bonded. FTIR spectra indicate the formation of four kinds of lanthanide–ina complexes, the extensive hydrogen bond networks after complexation and the coordinations and the changes of the conformation of the ligand. FIR and THz spectra also confirm the formation of lanthanide ion–ina complexes. Luminescence spectra of Eu and Tb-ina complexes have the characteristics of Eu and Tb ions.Four kinds of structures, with or without chloride coordination in the coordination spheres were observed for lanthanide–isonicotinamide complexes.
Co-reporter:Xiaopei Li, Quan Bi, Shaoxuan Liu, Jing Chen, Shijuan Yue, Yongju Wei, Kun Huang, Ying Zhao, Huizhou Liu, Yanjun Zhai, Yizhuang Xu, Isao Noda, Jinguang Wu
Journal of Molecular Structure 2013 Volume 1034() pp:101-111
Publication Date(Web):27 February 2013
DOI:10.1016/j.molstruc.2012.08.050
In this paper, a modified reference spectrum is utilized to generate 2D asynchronous spectra constructed by using the AOSD approach that is developed in our previous work. Mathematical analysis suggests that it is possible to enhance the intensity of cross peaks by using the modified reference spectrum. Computer simulation indicates that both intensity of cross peaks and signal-to-noise ratio of 2D spectra are improved significantly by adopting the modified reference spectrum. As a result, 2D asynchronous spectrum can be used to probe weak intermolecular interactions under the influence of spectral noise. Furthermore, experiments on acetonitrile/butanone/CCl4 system demonstrate that intensities and signal-to-noise ratio of cross peaks that reflect intermolecular interactions between acetonitrile and butanone can be enhanced remarkably by using the modified reference spectrum.Highlights► A modified reference spectrum is used to construct 2D asynchronous spectra. ► Computer simulation show intensities and s/n ratio of cross peaks are improved. ► Experiments on real chemical system show intensities of cross peaks are enhanced.
Co-reporter:Xiuxiang Gao, Yufeng Liu, Huizhen Li, Jiang Bian, Ying Zhao, Ye Cao, Yuezhi Mao, Xin Li, Yizhuang Xu, Yukihiro Ozaki, Jinguang Wu
Journal of Molecular Structure 2013 1040() pp: 122-128
Publication Date(Web):22 May 2013
DOI:10.1016/j.molstruc.2013.02.017
We have investigated a cooperative hydrogen bonding system with a CH⋯O hydrogen bond in ofloxacin by using NMR, UV–Vis spectra together with quantum chemistry calculation. Both pH-dependent NMR experiments and DFT calculation indicate that the intra-molecular CH⋯O hydrogen bond between an aromatic proton and an oxygen atom from the carboxyl group is formed. Notably, the CH⋯O hydrogen bond forms a cooperative hydrogen bonding system with a neighboring OH⋯O hydrogen bond between the carboxyl group and the keto oxygen. The cooperative hydrogen bonding system makes the formation and disruption of the OH⋯O and CH⋯O hydrogen bonds in a synergistic manner. Comparison on the pKa value of the carboxylic group in different fluoroquinolones compounds indicates that the CH⋯O hydrogen bond plays a significant role in stabilizing the OH⋯O hydrogen bond. In addition, the formation and disruption of the cooperative hydrogen bonding system could regulate the conformation of the carboxyl group, which affects the size of the conjugated system and spectral behavior of π–π transition of ofloxacin.Highlights► Intra-molecular CH···O hydrogen bond is formed between an aromatic proton and a carboxyl oxygen in ofloxacin. ► The CH⋯O hydrogen bond forms a cooperative hydrogen bonding system with a neighboring OH⋯O hydrogen bond. ► Formation/disruption of the cooperative hydrogen bonds regulates the conformation and π–π transition of ofloxacin.
Co-reporter:Shaoxuan Liu, Chengfeng Zhang, Edyta Proniewicz, Leonard M. Proniewicz, Younkyoo Kim, Jun Liu, Ying Zhao, Yizhuang Xu, Jinguang Wu
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2013 Volume 115() pp:783-788
Publication Date(Web):November 2013
DOI:10.1016/j.saa.2013.06.056
•Decomplexation of PA6/CaCl2 produces porous PA6 with different crystalline forms.•PA6 in γ form is obtained by soaking PA6/CaCl2 in water at room temperature.•Decomplexation of PA6/CaCl2 in boiling water produces PA6 in α form.•If PA6/CaCl2 is soaked in methanol, PA6 microsphere in α crystalline form is formed.•Changing solvents and experimental condition can adjust the morphology of porous PA6.In this work, we developed a new method to prepare porous PA6 with different morphologic feature and crystalline forms via the decomplexation of PA6/CaCl2 composite. The structures and morphology of thus obtained materials were characterized by vibrational spectroscopy (FT-IR and Raman) and scanning electron microscope (SEM) method. When amorphous PA6/CaCl2 composite films were treated in water at room temperature, PA6 re-arranges into γ form. However, decomplexation of the PA6/CaCl2 composite in boiling water produces PA6 in α crystalline form. If the PA6/CaCl2 composite is soaked in methanol, part of PA6 is dissolved or swollen in methanol/metal salt solutions. As a result, a dissolve/precipitation process occurred during the decomplexation process, which led to the formation of PA6 in α crystalline form. Further investigation demonstrates that the morphologies of the porous PA6 could be adjusted by using different solvents and/or different decomplexation conditions.
Co-reporter:Limin Yang, Xiaohui Hua, Junhui Xue, Qinghua Pan, Lei Yu, Weihong Li, Yizhuang Xu, Guozhong Zhao, Liming Liu, Kexin Liu, Jia’er Chen, and Jinguang Wu
Inorganic Chemistry 2012 Volume 51(Issue 1) pp:499-510
Publication Date(Web):December 8, 2011
DOI:10.1021/ic2019605
The coordination of carbohydrate to metal ions is important because it may be involved in many biochemical processes. The synthesis and characterization of several novel lanthanide-erythritol complexes (TbCl3·1.5C4H10O4·H2O (TbE(I)), Pr(NO3)3·C4H10O4·2H2O (PrEN), Ce(NO3)3·C4H10O4·2H2O (CeEN), Y(NO3)3·C4H10O4·C2H5OH (YEN), Gd(NO3)3·C4H10O4·C2H5OH (GdEN)) and Tb(NO3)3·C4H10O4·C2H5OH (TbEN) are reported. The structures of these complexes in the solid state have been determined by X-ray diffraction. Erythritol is used as two bidentate ligands or as three hydroxyl group donor in these complexes. FTIR spectra indicate that two kinds of structures, with water and without water involved in the coordination sphere, were observed for lanthanide nitrate-erythritol complexes. FIR and THz spectra show the formation of metal ion-erythritol complexes. Luminescence spectra of Tb-erythritol complexes have the characteristics of the Tb ion.
Co-reporter:Junhui Xue, Xiaohui Hua, Weihong Li, Limin Yang, Yizhuang Xu, Guozhong Zhao, Gaohui Zhang, Chunping Li, Kexin Liu, Jia’er Chen, Jinguang Wu
Carbohydrate Research 2012 Volume 361() pp:12-18
Publication Date(Web):1 November 2012
DOI:10.1016/j.carres.2012.07.026
Three novel lanthanum chloride–erythritol complexes (LaCl3·C4H10O4·5H2O (LaE(I)), LaCl3·C4H10O4·3H2O (LaE(II)), and LaCl3·1.5C4H10O4 (LaE(III)) were synthesized and characterized by single crystal X-ray diffraction, FTIR, far-IR, THz, and Raman spectroscopy. The coordination number of La3+ is nine. LaE(I) and LaE(II) have similar coordination spheres, but their hydrogen bond networks are different. Erythritol exhibits two coordination modes: two bidentate ligands and tridentate ligands in LaE(III). Chloride ions and water coordinate with La3+ or participate in the hydrogen-bond networks in the three complexes. Crystal structures, FTIR, FIR, THz, and Raman spectra provide detailed information on the structures and coordination of hydroxyl groups to metal ions in the metal–carbohydrate complexes.Graphical abstractHighlights► Five lanthanide chloride erythritol complexes are reported in the literature. ► Three new LaCl3–erythritol complexes have been synthesized and characterized. ► X-ray diffraction, IR, FIR, THz, and Raman results are presented.
Co-reporter:Jing Chen, Quan Bi, Shaoxuan Liu, Xiaopei Li, Yuhai Liu, Yanjun Zhai, Ying Zhao, Limin Yang, Yizhuang Xu, Isao Noda, and Jinguang Wu
The Journal of Physical Chemistry A 2012 Volume 116(Issue 45) pp:10904-10916
Publication Date(Web):October 11, 2012
DOI:10.1021/jp300918g
This paper introduces a new approach called double asynchronous orthogonal sample design (DAOSD) to probe intermolecular interactions. A specifically designed concentration series is selected according to the mathematical analysis to generate useful 2D correlated spectra. As a result, the interfering portions are completely removed and a pair of complementary sub-2D asynchronous spectra can be obtained. A computer simulation is applied on a model system with two solutes to study the spectral behavior of cross peaks in 2D asynchronous spectra generated by using the DAOSD approach. Variations on different spectral parameters, such as peak position, bandwidth, and absorptivity, caused by intermolecular interactions can be estimated by the characteristic spectral patterns of cross peaks in the pair of complementary sub-2D asynchronous spectra. Intermolecular interactions between benzene and iodine in CCl4 solutions were investigated using the DAOSD approach to prove the applicability of the DAOSD method in real chemical system.
Co-reporter:Kun Huang, Hui Zhou, Anqi He, Yan Sun, Yufeng Liu, Xiuxiang Gao, Ying Zhao, Shaoxuan Liu, Zhihong Li, Tiandou Hu, Xiaopei Li, Cuige Liu, Yongju Wei, Limin Yang, Juan Feng, Yuanli Cai, Zhanlan Yang, Yizhuang Xu, Isao Noda, and Jinguang Wu
The Journal of Physical Chemistry B 2011 Volume 115(Issue 24) pp:7823-7829
Publication Date(Web):May 26, 2011
DOI:10.1021/jp109551z
We report the discovery of a potentially useful superconcentrated HCl at ambient temperature and pressure by using a simple surfactant-based reversed micelle system. Surprisingly, the molar ratios of H+ to H2O (denoted as nH+/nH2O) in superconcentrated HCl can be larger than 5, while the maximum achievable nH+/nH2O value for conventional saturated HCl aqueous solution (37 wt %) is only about 0.28. Furthermore, both NMR and FT-IR results indicate that a significant amount of HCl remains in the molecular form rather than being ionized into H+ and Cl–. The superconcentrated HCl may promote some organic reactions that are not feasible by using conventional 37 wt % HCl solution. For example, addition reaction between C═C and HCl occurs in superconcentrated HCl solution without using catalysts.
Co-reporter:Huizhen Li, Yanjie Wu, Harumi Sato, Lei Kong, Chengfeng Zhang, Kun Huang, Dongliang Tao, Jing Chen, Xuexin Liu, Ying Zhao, Yizhuang Xu, Jinguang Wu and Yukihiro Ozaki
Macromolecules 2009 Volume 42(Issue 4) pp:1175-1179
Publication Date(Web):January 27, 2009
DOI:10.1021/ma8019333
In this study, we develop a new facile method to prepare nylon-6 with special features (denoted as vp-nylon-6). The key strategy for the method is to make the crystallization of nylon-6 be performed in a slow and near-equilibrium manner by diffusing the vapor of precipitator into a nylon 6/formic acid solution at ambient temperature and pressure. Differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD) have demonstrated that the crystallinity and crystalline perfection of vp-nylon-6 are significantly improved by the new method. Scanning electron microscope (SEM) observations have shown that vp-nylon-6 exhibits versatile morphological features including ribbon, bowknot, flower, semisphere, and dumbbell which are the result of the assembly of crystalline lamellae. The crystalline lamellae occur in a discrete fashion rather than being embedded in an amorphous matrix even if concentrated nylon solutions are used. Selected area electron diffraction (SAED) in transmission electron microscope (TEM) shows that the crystalline lamellae are composed of single crystals.
Co-reporter:ChengFeng Zhang;YuHai Liu;ShaoXuan Liu
Science China Chemistry 2009 Volume 52( Issue 11) pp:
Publication Date(Web):2009 November
DOI:10.1007/s11426-009-0242-5
Recently we have successfully produced fine denier PA6 fibers by using additives containing lanthanide compounds. Meanwhile, crystallization and phase transition of PA6 fibers during spinning and drawing processes were investigated. During the spinning process, β phase crystal could be obtained in as-spun PA6 fibers which were produced with relatively high melt draw ratio, while γ phase crystal predominated when the melt draw ratio was relatively low. β phase crystal, whose behaviors are similar with those of γ phase by FT-IR and XRD characterization, could be transformed to α form easily when PA6 fibers are immersed in boiling water. However, γ phase crystal of PA6 remains unchanged in boiling water. Thus, β and γ phase crystals of PA6 can be differentiated by the crystalline behaviors of PA6 fibers after treatment in boiling water. Further experiments demonstrate that the β phase can also be produced during a drawing process where a phase transformation from γ to α occurs. In other words, β phase may act as an intermediate state during the phase transformation.
Co-reporter:Jian Qi, Kun Huang, Xiuxiang Gao, Huizhen Li, Shaoxuan Liu, Ying Zhao, Yizhuang Xu, Jinguang Wu, Isao Noda
Journal of Molecular Structure 2008 Volumes 883–884() pp:116-123
Publication Date(Web):30 July 2008
DOI:10.1016/j.molstruc.2008.01.036
Weak interactions between lanthanide (III) ions and organic ligands in solution mixtures are studied by using two-dimensional synchronous spectroscopy together with “Orthogonal Sample Design” (OSD) scheme that can effectively remove the interfering cross peaks in 2D synchronous spectrum. Two representative chemical systems are investigated and discussed here: (1) PrCl3/butanone in ethanol solution, where weak coordinative interaction between Pr3+ and carbonyl group from butanone is characterized by using 2D UV/IR heterogeneous spectroscopy; and (2) NdCl3/5-sulfosalicylic acid in aqueous solution, where the interaction between Nd3+/5-sulfosalicylic acid is investigated by using 2D UV spectra. The cross peaks occurred in the 2D spectra confirm the weak interactions between lanthanide (III) ions and corresponding molecules where no observable variation occurs in conventional 1D spectra.
Co-reporter:Yuhai Liu, Chengfeng Zhang, Shaoxuan Liu, Ying Zhao, Dujin Wang, Jinguang Wu, Yizhuang Xu, Isao Noda
Journal of Molecular Structure 2008 Volumes 883–884() pp:124-128
Publication Date(Web):30 July 2008
DOI:10.1016/j.molstruc.2007.12.025
In our previous work, we proposed an approach called orthogonal sample design (OSD) scheme, which was successful in eliminating interfering cross peaks in 2D synchronous spectrum. As a result, intermolecular interactions, which cause a deviation from the Beer–Lambert law, can be manifested in the form of the appearance of cross peaks in 2D synchronous spectra. However, the complex relationship between the deviation term and the intensity of the cross peak sometimes makes it possible that no cross peak appears even if an intermolecular interaction actually occurs in the system. In this paper, we propose a modified OSD approach based on a new concentration series, which can be applied on two-dimensional (2D) synchronous spectroscopy. The new approach greatly simplifies the relationship between the intensity of the synchronous cross peak and the deviation terms caused by intermolecular interactions. Accordingly, a protocol is proposed to check whether the absence of cross peaks in 2D synchronous spectra is indeed caused by the absence of intermolecular interactions or not. Therefore, a solid and unambiguous relationship between of the cross peak in 2D synchronous spectrum and intermolecular interaction can be established. That is to say, the appearance of cross peaks reflects genuine intermolecular interactions, while the disappearance of cross peak means no intermolecular interactions.
Co-reporter:Jing Chen, Chengfeng Zhang, Huizhen Li, Yufeng Liu, Weihong Li, Yizhuang Xu, Jinguang Wu, Isao Noda
Journal of Molecular Structure 2008 Volumes 883–884() pp:129-136
Publication Date(Web):30 July 2008
DOI:10.1016/j.molstruc.2008.01.052
A computer simulation is applied on a model chemical system to study patterns of cross peaks in 2D synchronous spectrum generated by using orthogonal sample design scheme. Variations on different spectral parameters, such as peak position, bandwidth, and absorptivity, caused by intermolecular interactions result in rich and complex behavior in 2D synchronous spectrum. Subtle spectral variations that are hard to be observed in 1D spectra can be clear observed in 2D synchronous spectra. The results suggest that the cross peaks in 2D synchronous spectrum generated by using orthogonal sample design (OSD) can act as a resolution enhancement tool that can differentiate highly overlapping bands.
Co-reporter:Zhiqiang Su;Ying Zhao;Ning Kang;Xiuqin Zhang;Jinguang Wu;Dujin Wang;Charles C. Han;Duanfu Xu;Ying Zhao;Ning Kang;Jinguang Wu;Xiuqin Zhang;Dujin Wang;Zhiqiang Su;Duanfu Xu;Charles C. Han
Macromolecular Rapid Communications 2005 Volume 26(Issue 11) pp:895-898
Publication Date(Web):2 JUN 2005
DOI:10.1002/marc.200500075
Summary: High-resolution FT-IR spectroscopy has been used for the first time to characterize the variation of the unit cell dimensions of high-density polyethylene (HDPE). In combination with the unit cell parameters of HDPE measured at different temperatures by Swan using wide-angle X-ray diffraction, the relationship between the rocking band shift (730 cm−1) and the change of the unit cell volume of HDPE has been established.
Co-reporter:Yizhuang Xu;Yanjie Wu;Duanfu Xu;Dujin Wang;Ying Zhao;Shifu Weng;Jinguang Wu
Journal of Applied Polymer Science 2004 Volume 91(Issue 5) pp:2869-2875
Publication Date(Web):14 JAN 2004
DOI:10.1002/app.13495
FT-IR spectroscopy has been utilized to study nylon 66/lithium salt systems. The results show that coordination between nylon 66 and lithium ions brings about significant variation in the FT-IR spectra: (1) a stronger hydrogen bond is formed in the systems; (2) the interaction induces obvious conformational changes of the nylon 66 chains. A coordination model has been proposed to rationalize the observed spectral phenomena. The interaction between amide groups and lithium ions is a feasible approach to modify the performance of nylon 66. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2869–2875, 2004
Co-reporter:Yizhuang Xu Dr.;Jinguang Wu ;Wenxiu Sun Dr.;Dongliang Tao Dr.;Limin Yang Dr.;Zengfu Song ;Shifu Weng ;Zhenhua Xu ;Roger D. Soloway ;Duanfu Xu ;Guangxian Xu
Chemistry - A European Journal 2002 Volume 8(Issue 23) pp:
Publication Date(Web):13 NOV 2002
DOI:10.1002/1521-3765(20021202)8:23<5323::AID-CHEM5323>3.0.CO;2-E
Strong electronic Raman bands corresponding to the transition between 4I9/2 and 4I11/2 manifolds of Nd3+, caused by a Raman-enhancement effect, are observed in the FT-Raman spectrum of Nd2O3. Neither resonance enhancement (RR) nor surface enhancement (SERS) accounts for the Raman enhancement observed here. We propose a new mechanism of Raman enhancement called the “feed-back” mechanism. A YAG laser excites the final state of the Raman transition (4I11/2 of Nd3+) to the 4F3/2 state and causes a significant decrease in the population of Nd3+ at the 4I11/2 state. This causes the population ratio of Nd3+ at 4I9/2 and 4I11/2 to deviate from the value required by Boltzmann's law. To restore equilibrium, Raman scattering is enhanced so that more Nd3+ ions are brought from the 4I9/2 state to the 4I11/2 state. This hypothesis gets support from the temperature-variable FT-Raman spectroscopic results. Additionally, obvious differences between the Stokes and anti-Stokes Raman spectrum of Nd3+ provide further evidence to support the feed-back mechanism. The Raman-enhancement effect confers on the electronic Raman bands a special ability to reflect the variation of coordinated structure around metal ions. The structural variations in polymer–metal ion composites and biomineralization systems have been investigated by using the electronic Raman bands.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 16) pp:NaN4144-4144
Publication Date(Web):2013/05/15
DOI:10.1039/C3AY40128F
The present paper focuses on the development of narrow-band thin-layer chromatography (TLC) coupled with Fourier transform Infrared spectroscopy (FTIR) technique. We adopted a new method to prepare a narrow-band TLC plate by using silver iodide as stationary phase. The narrow-band TLC plate exhibits a variety of advantages: the preparation time is about 20 minutes, while 3–7 days are needed to prepare a common TLC plate suitable for TLC/FTIR analysis by using “settlement volatilization method”. Furthermore, the usage of stationary phase in narrow-band TLC plates decreases by about one order of magnitude in comparison with that of common TLC plates. This is very important for an expensive stationary phase such as silver iodide. In addition, experimental results of TLC/FTIR analysis on mixed samples containing rhodamine B and bromocresol green demonstrate the detection limit significantly improves by using the narrow-band TLC technique.
