Theoretical interpretation of spectral signs of an oxymethyl group in the IR spectrum of methyl-β-D-glucopyranoside

For the first time, we have assigned the observed absorption bands and interpreted the IR spectrum of methyl-β-D-glucopyranoside in detail in the 1500–800 cm⁻¹ region, based on a full calculation of the frequencies and absolute intensities of the normal vibrations of the molecule and their comparison with the experimental data. We have identified two groups of spectral signs indicating an oxymethyl substituent has replaced the hydroxyl group on the C₍₁₎ atom in the glucopyranoside: absorption bands of medium intensity due to the characteristic vibrations of the substituent, and intense bands due to an unusual “interaction” between many structural moieties. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 721–727, November–December, 2006.     

锂锰尖晶石红外光谱的研究

本文对锂锰尖晶石的红外光谱进行了研究。由于锂锰尖晶石的晶体结构属于Fd3m空间群,锂离子占据四面体空隙(8a位置),锰离子占据八面体空隙(16d位置)。根据群论的知识,对锂锰尖晶石晶体中离子的振动方式与红外活性之间的内在关系进行了讨论。并列出了锂锰尖晶石的红外光谱实验数据。通过理论分析,我们推断:位于618.6和501.5cm~(-1)的红外吸收带分别来源于Mn(Ⅳ)-O和Mn(Ⅲ)-O键在晶体中的不对称伸缩振动(单元为Mn(Ⅳ)O_6和Mn(Ⅲ)O_6八面体),位于1124cm~(-1)的弱红外吸收带来源于Li-O键的不对称伸缩(单元为LiO_4四面体)。还有一些低于400cm~(-1)的可能吸收带在400～4000cm~(-1)范围内未能检测到。这一结论的可靠性通过锂锰尖晶石和掺杂的锂锰尖晶石的红外光谱实验数据得到证实。     

Analysis of glucopyranoside trinitrate IR spectrum

The IR spectrum of 4-O-methyl-2,3,6-tri-O-nitromethyl-β-D-glucopyranoside has been interpreted in detail for the first time based on complete calculation of the normal vibration frequencies and absolute intensities of its IR absorption bands and a comparison of them with the corresponding experimental data. The results indicate that the location of the nitrates in cellulose nitrates can be determined experimentally from separate components of complicated absorption bands in the ranges 1700–1600 and 900–800 cm⁻¹ of the IR spectrum. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 43–51, January–February, 2008.     

Calculation and analysis of the frequencies of normal vibrations of 2,3-Di-O-nitro-methyl-β-D-glucopyranoside

A calculation of the frequencies and forms of the normal vibrations of the 31-atom molecule 2,3-di-O-nitromethyl-β-D-glucopyranoside has been performed. Particular emphasis has been placed on the interpretation of the strongest bands in the spectrum of 2,3-di-O-nitro-methyl-β-D-glucopyranoside, which are due to vibrations of the nitrate groups. The present work has been reported at the IV International Congress of theoretically competent chemists, Jerusalem (Israel), July 7–12, 1996. B. I. Stepanov Institute of Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 724–728, November–December, 1997.     

取代铁卟啉的拉曼及红外光谱分析

合成了系列取代铁卟啉化合物,研究了拉曼光谱及红外光谱.对二价铁卟啉RTPPFe(Ⅱ)和三价铁卟啉RTPPFeCl(Ⅲ)的红外光谱和拉曼光谱进行了对比分析,结果表明,二价铁卟啉在常温下是不稳定的,通常在其轴向位置上吸附氧分子而形成铁卟啉的超氧化物RTPPFe-O2,其稳定的立体构型为end-on式结构.采用量化软件对化合物的分子结构进行了模拟,得出了其分子结构参数,并结合化合物的红外及拉曼光谱,研究了分子结构对波谱位移的影响.不同结构的二价铁卟啉RTPPFe-O2拉曼及红外吸收峰的位置发生了不同程度的位移,其位移情况与分子的扭曲程度有关.即RTPPFe-O2的Fe-O2特征拉曼吸收峰以及红外特征吸收峰(Fe-O)的位置随着Fe-O-O角的增大而向高波数移动.     

Modeling of IR Spectra of Compounds on the Basis of Analogy between Fragmental Compositions of Structures

The possibility of using representations of the structures of compounds in the form of nonisomorphic k-vertex connective fragments for modeling IR spectra of compounds with a given structure on the basis of the spectra of their close structural analogs selected from a database is shown. Statistical justification of the approach and examples of modeled spectra are given.     

氮化硼薄膜的红外光谱研究

用磁控溅射法制备六角氮化硼薄膜,在衬底温度、衬底偏压、工作气压等条件一定的情况下改变工作气体(氮气+氩气)中氮气的比例,以制备高质量的六角氮化硼薄膜,薄膜以红外吸收光谱标识。实验结果表明,工作气体中氮气的比例对制得的六角氮化硼薄膜有很大影响,在氮气比例为20%时得到理想的六角氮化硼薄膜。     

Calculation of Normal Vibrations and Interpretation of the Quasiline Spectra of Tetraazachlorin

Quasiline fluorescence and fluorescence-excitation spectra of tetraazachlorin and its N-deuterated derivative in n-octane at 77 K have been investigated and the frequencies of the normal vibrations for the electronic states S ₀ and S ₁ have been determined. Calculation of the normal vibrations of these molecules has been done and used to interpret the experimental data. Based on the results of analysis of the intensities in the spectra, the change in the structure of the molecule in the electronic state S ₁ is discussed.     

Analysis of the Resonance Raman Scattering Spectra and Line Spectra of Tetrabenzoporphin Metal Complexes

On the basis of the calculations of normal vibrations of Zn– and Cu–tetrabenzoporphin, the literature spectra of resonance Raman scattering of the above compounds and the fluorescence spectra of Zn–tetrabenzoporphin are interpreted. The nonmirror character of the fluorescence and fluorescence excitation spectra is noted for some B _1g symmetry type vibrations of the point group of symmetry D _4h caused by the symmetry breakdown of a molecule in its electronic state S ₁ due to the Jahn–Teller effect.     

Method for assigning absorption bands in IR spectra of polyatomic molecules with respect to internal vibrational coordinates

A method is proposed for assigning absorption bands in IR spectra of polyatomic molecules. An algorithm is developed and a Fortran program is written based on this method. The method is illustrated for the example of the toluene molecule. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 169–173, March–April, 2007.     

Calculation of Normal Vibrations of the Tetraazaporphin Molecule and Interpretation of Quasiline Spectra

Quasiline fluorescence and fluorescence-excitation spectra of tetraazaporphin and its N-deuterated derivative in n-octane at 77 K have been investigated, and the frequencies of normal vibrations in electronic states S ₀ and S ₁ have been determined. Calculation of normal vibrations of these molecules has been done and, on its basis, the experimental data are interpreted. It is shown that in the spectra, predominantly the totally symmetric vibrations of type A _g symmetry of the point D _2h symmetry group are active. Some activation of the nontotally symmetric B _1g vibrations in the fluorescence-excitation spectra is explained by the nonadiabatic interaction of the vibrational sublevels of the excited electronic state S ₁ with the purely electronic level S ₂.     

Substituent Effects on Electronic Spectra of Vicinally Substituted 2-, 3- and 4-Aminopyridines

The electronic spectra of forty vicinally substituted 2-, 3- and 4-aminopyridines have been discussed. The low-energy transition of 17 derivatives was analyzed with the help of CNDO/S calculations. In general, the experimental band corresponds to two theoretical transitions. The dual substituent parameter approach (DSP) quite well explains the frequency of one transition in the long-wavelength region of the experimental spectrum.     

水化与非水化－2－乙基己基磷酸单－2－乙基己基酯钠盐的红外吸收强度研究

本文对水化与非水化２－乙基己基磷酸单－２－乙基已基酯钠盐在简化结构的假定下进行了简正分析，给出了谱带的指认；并利用ＣＮＤＯ／２方法进行了红外吸收强度计算。结果表明该分子在水化后Ｐ＝Ｏ和Ｐ—Ｏ—Ｃ谱带的吸收强度都增加，经过四个实际样品的检验证明港带强度增加的计算值与实验值符合很好。这一结果为应用极性基团红外谱带强度变化来研究其水化作用提供了理论基础。     

Quantum - Chemical Study of the Relation Between Electronic Structure and IR Spectra of Neutral Molecules,Anion - Radicals,and Dianions of Aromatic Nitriles

The relation between the IR data and the quantum-chemical indices. calculated by the CNDO/2 method has been studied. The linear relationship between the experimentally measured °C≡N and the corresponding Wiberg bond index (W_C≡N) has been found for the series of conjugated nitriles including neutral molecules. anion - radicals and dianions.

The changes in the intensity of the stretching C≡N vibration on transition from a neutral molecule into anion - radical and dianion have been investigated by the CNDO/2 method. The calculated values for δμ/δQ_CN show that in the order: neutral molecule, anion - radical and dianion the IR intensity of the stretching C≡N vibration significantly increases.     

Analysis of Transformer Oil Using IR Analyzers

Spectral characteristics of samples of transformer oil that differ in technical grade, service life, and content of an antioxidant additive and dissolved water are investigated. It is suggested to determine service deterioration of insulating oils from absorption in the region 1710 cm^–1 using IR filter analyzers.     

Theoretical analysis of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside

A detailed interpretation of the IR spectrum of methyl-3,4-anhydro-α-D-talohexopyranoside that is based on complete calculation of normal vibration frequencies and absolute IR absorption band intensities of the molecule and a comparison of the results obtained with the corresponding experimental data is given for the first time. The influence of the epoxy group on the absorption bands characteristic of the pyranose ring has been analyzed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 597–605, September–October, 2008.     

金属掺杂纳米固体超强酸SO_4~(2-)/ZrO_2的IR考察

首先采用sol gel法制备出ZrO(OH) 2 ,再分别用Ni2 + ,Al3 + ,Sn4+ ,Ag+ ,Sn2 + 金属盐溶液和H2 SO4稀溶液浸渍ZrO(OH) 2 的方法合成了一系列金属离子掺杂的SO2 -4/ZrO2 纳米固体超强酸。并用XRD ,TEM和IR技术考察了各样品的性能。结果发现 ,经不同金属掺杂的SO2 -4/ZrO2 颗粒具有固体超强酸的IR谱特征。经Ni2 + ,Sn4+ 掺杂的样品中Zr—O和 SO 键振动吸收峰明显蓝移 ,Zr—O的νZr—O由SO2 -4/ZrO2 的4 85cm-1增大到Ni2 + ,Sn4+ 掺杂样品的 5 0 0cm-1,SO的νas由 1390cm-1增大到 14 0 5和 14 0 0cm-1,而Sn2 + 掺杂的样品变化不大。说明Ni2 + ,Sn4+ 金属离子的掺杂增强了样品的超强酸性。同时还发现 ,随着样品焙烧温度的提高 ,经Ni2 + 和Al3 + 掺杂的SO2 -4/ZrO2 纳米颗粒 ,Zr—O和 SO 键振动吸收峰明显蓝移 ,而Ag+ 掺杂的样品在焙烧温度达到 10 73K时IR谱只是吸收强度减弱 ,振动频率不变。     

基于密度泛函理论的左旋延胡索乙素的红外、拉曼光谱研究

研究了左旋延胡索乙素的红外光谱(IR)、固体常规拉曼光谱(NRS)以及以新型Ag/Cu纳米材料为基底的表面增强拉曼光谱(SERS)。以密度泛函理论(DFT),B3LYP/6-311+G(d,p)基组对其红外光谱和拉曼光谱进行了计算,给出了对应的光谱振动图,并利用Gauss view 5.0可视化软件对其峰位进行了全面归属。左旋延胡索乙素在3 300～2 500和1 800～600 cm-1波数范围内有明显的红外和拉曼峰,在左旋延胡索乙素的SERS中,Ag/Cu纳米基底利用SnCl₂和PVP作为结构导向剂,采用循环浸泡的方法,最终生成分散较好的银纳米颗粒,实现了很好的增强效应,分子获得了信号较强的选择性增强散射峰,其中1 500～1 400和1 000～700 cm-1波数范围内的增强效应最明显,经分析,该分子的亚甲基与银纳米表面吸附,苯环与银衬底夹角接近90°。左旋延胡索乙素的红外、拉曼光谱的理论计算和实验结果基本一致,存在一定差异的原因可能是因为分子之间的作用力等因素。可视化软件直观形象展示出了该分子的结构特征和分子基团振动情况,对其振动峰位的归属提供了重要的依据。左旋延胡索乙素是一种重要的中药试剂,包含于多种养心安神类药物当中,该研究为左旋延胡索乙素的快速、特征、痕量监测提供了依据,也为中枢抑制性镇痛药物的生物作用研究提供了重要参考。     

Calculation of the Band Intensities of the IR Spectra of Oriented Polymers

An attempt has been made to extend the theory of IR spectra of polymers to oriented polymers. Formulas for the absorption-band intensities in polarization IR spectra of oriented polymers reflecting the dependence of the polarized absorption-band intensity on the structural and orientation characteristics of polymers have been obtained. These formulas permit calculating the intensity of polarized absorption bands at different degrees of orientation of the polymer.