Infra-Red Spectra of the Nitrogen-15 Labelled Triphosphonitrilic Chloride

Although the vibrational spectra of triphosphonitrilic chloride, (PNCl₂)₃ (1), have been studied by numerous investigators^1–8, there is no general agreement about the frequency of completely inactive A₂ ring vibration. Besides, assignment of some overtones and combination bands is doubtful.     

Vibrational Assignment of N-Phenylphthalimide and 15N-Phenylphthalimide

Abstract

The i.r. spectra of N-phenylphthalimide and ¹⁵N-phenylphthalimide have been measured in 4000–100 cm^?1 frequency range as KBr and polyethylene pellets and as chloroform solutions. The Raman spectra (4000–50) cm^?1 of microcrystalline powder of the of the same compounds have also been investigated.

A detailed assignment of most of the observed frequencies has been proposed on the basis of the group vibrational concept, isotopic shift data and analogies with the spectra of related molecules. Some literature data have been discussed and some frequencies are reassigned.     

Vibrational Assignment of 2-Benzoyl Pyridine and its 18O Labelled Isomer

Abstract

Vibrational spectra of 2-benzoyl pyridine and 2-benzoyl pyridine-¹⁸O have been recorded in the solid and molten state in the infrared (4000–100 cm^?1) and in the Raman (4000–50 cm^?1). Polarized Raman spectra in the molten state have also been measured. The assignment of the vibrational bands is performed using the group vibrational concept, isotopic shifts and polarization features of the normal modes.     

Nitrogen-15 NMR spectroscopy of proteins in solution

Experimental results from ¹⁵N NMR studies of selectively and uniformly labeled proteins with molecular weights ranging between 6000 and 155,000 Da in solution are described. These results demonstrate the resolution available in one- and two-dimensional ¹⁵N NMR spectra as well as the selection of particular ¹⁵N and ¹H resonances on the basis of the type of amino acid residue, the number of hydrogens bonded to a nitrogen, local dynamics, and amide hydrogen exchange kinetics.     

Vibrational Spectra of Some Substituted Benzene Derivatives

Abstract

The infrared spectra of 1,2,3-; 1,2,4- and 1,3,5-trimethylbenzenes have been recorded in the liquid phase in the region 250–4000 cm^?1 on a Perkin Elmer Grating Spectrophotometer model 521. Under the general symmetry considerations, the molecule 1,2,4-belongs to C_2v point group, the 1,2,3-isomer belongs to Cs and the 1,3,5-isomer to D_3h point group. The observed bands have been assigned to different modes of vibrations.     

The Raman Spectrum and Full Vibrational Assignment of Ethylenediamne Dihydrochloride

A full vibrational analysis was recently made for the H³N⁺CH₂CH₂N⁺H₃ ion, on the basis of infrared measurements, and a partial vibrational assignment proposed¹. The observed fundamentals were interpreted In terms of a C_2h, symmetry for the ion. There are thirty-six fundamentals (r - lla_g + 8A_u + 7B_g + 10B_u; A_g and B_g Raman-active only; A_u and B_u infrared-active only). In addition to the eighteen infrared-active vibrations, a number of bands was observed which were assigned as formally forbidden Raman-active modes, excited by strong hydrogen bonding causing departure from the exact site symmetry of the species.     

饱和一元醇类分子拉曼光谱振动峰的归属研究

选用B3LYP/6-31G(d)优化并计算了31种饱和一元醇类分子的拉曼光谱,以甲醇为例,考察了理论计算结果的准确性,分析了碳原子数小于7的直链饱和一元醇拉曼光谱振动峰的归属。研究结果显示,B3LYP/6-31G(d)用于饱和一元醇类分子拉曼光谱振动的模拟计算较为准确,通过饱和一元醇拉曼光谱振动峰归属分析,确认C—O伸缩振动引起的振动峰可作为饱和一元醇类分子拉曼光谱的特征峰;进一步研究还发现,饱和一元醇类分子拉曼光谱的特征峰与其极化率、热力学、能量等主要参数具有显著的相关性(sig.为0.015),为同系物的拉曼光谱研究提供了一定的参考价值。     

Vibrational Spectra of 4-Benzoylpiridine and the 18O Substituted Derivative

Abstract

Infrared and Raman spectra of 4-benzoylpiridine (4BP) and its ¹⁸O substituted derivative have been recorded in the solid and in the molten state. Polarized Raman spectra in the molten state have also been measured. The assignment of the vibrational bands is performed on the basis of isotopic shifts, group vibrational concept and polarization features of the normal modes. The previous assignment of the in- and out-of-plane deformations of the carbonyl group and the fundamentals below 700 cm^?1 are questioned and corrected.     

两种硝基苯甲酰胍化合物的振动光谱研究

酰胍基化合物具有抗菌活性高、毒性和副作用小的特点,广泛用于药物和药物中间体的合成。文章采用简单的方法合成了两种硝基苯甲酰胍类化合物,并对其振动频率进行了量化计算,运用Gaussian 98化学软件对其振动光谱进行了归属。结果表明：理论计算结果与实验结果相吻合,计算结果对实验数据的归属具有指导意义。     

“李时珍石”晶格振动光谱计算

“李时珍石”晶格振动光谱计算曾维杨，毛叔其，毛延哲（兰州大学物理系兰州７３００００）ＣａｌｃｕｌａｔｉｏｎｏｆＴｈｅＶｉｂｒａｔｉｏｎａｌＳｐｅｃｔｒｏｓｅｏｐｙｏｆＬｉｓｈｉｚｈｅｎｉｔｅ￥Ｗｅｉｙａｎｇ；Ｚｅｎｇｓｈｕｑｉ；ＭａｏａｎｄＹａｎｚｈ...     

Nitrogen-15 fractionation in the thermal decomposition of nitrous oxide of natural isotopic composition

The 15N fractionation in the thermal decomposition of nitrous oxide (N2O) of natural isotopic composition has been investigated in quartz reaction vessel in the temperature interval 888-1073 K. The formulas relating the observed experimentally 15N fractionations with the primary 15N kinetic isotope effect, (k14/k15)p for 14N15N16O, and secondary 15N kinetic isotope effect, (k14/k15)s for 15N14N16O, have been derived. The experimentally estimated 15N kinetic isotope effects have been compared with the primary and secondary 15N kinetic isotope effects calculated with the absolute rate theory formulations applied to linear three atom molecules. A good agreement was found for the primary 15N kinetic isotope effect, (k14/k15)p, in the temperature interval 888-1007 K. But at 1073 K the decompositions of N2O, accompanied by NO (nitric oxide) formation proceed with a twice times smaller primary kinetic isotope effect, (k14/k15)p of 1.0251 +/- 0.0009, only, suggesting the nonlinear transition state structures with participation of the fourth external atom at high temperature decompositions of nitrous oxide. The nitrogen isotope effects determined in this study correlate well with nitrogen isotope fractionations observed in the natural biological, earth and atmospheric processes.     

Nitrogen-15 Fractionation in the Thermal Decomposition of Nitrous Oxide of Natural Isotopic Composition

Abstract

The ¹⁵N fractionation in the thermal decompostion of nitrous oxide (N₂O) of natural isotopic composition has been investigated in quartz reaction vessel in the temperature interval 888–1073K. The formulas relating the observed experimentally ¹⁵N fractionations with the primary ¹⁵N kinetic isotope effect, (k ¹⁴/k ¹⁵)_p for ¹⁴N¹⁵N¹⁶O, and secondary ¹⁵N kinetic isotope effect, (k ¹⁴/k ¹⁵)_s for ¹⁵N¹⁴N¹⁶O, have been derived. The experimentally estimated ¹⁵N kinetic isotope effects have been compared with the primary and secondary ¹⁵N kinetic isotope effects calculated with the absolute rate theory formulations applied to linear three atom molecules. A good agreement was found for the primary ¹⁵N kinetic isotope effect, (k ¹⁴/k ¹⁵)_p, in the temperature interval 888–1007K. But at 1073K the decompositions of N₂O, accompanied by NO (nitric oxide) formation proceed with a twice times smaller primary kinetic isotope effect, (k ¹⁴/k ¹⁵)_p of 1.0251 ± 0.0009, only, suggesting the nonlinear transition state structures with participation of the fourth external atom at high temperature decompositions of nitrous oxide. The nitrogen isotope effects determined in this study correlate well with nitrogen isotope fractionations observed in the natural biological, earth and atmospheric processes.     

低温相HI分子晶体振动光谱计算

低温相ＨＩ分子晶体振动光谱计算毛延哲曾维扬（兰州大学物理系兰州７３００００）ＣａｌｃｕｌａｔｉｏｎｏｆｔｈｅＶｉｂｒａｔｉｏｎａｌＳｐｅｃｔｒｏｓｃｏｐｙｏｆＣｒｙｓｔａｌｉｎｅＨｙｄｒｏｇｅｎＩｏｄｉｄｅＭａｏＹａｎｚｈｅ（Ｄｅｐｔ．ｏｆｆｕｎｄ...     

改进的三维分离变量表象方法计算振动光谱

用改进的三维分离变量表象(DVR3D)方法研究了基态电子态H2S和H2O的振动光谱。哈密顿形式在Jacobi坐标下给出,每个坐标都用一组DVR基函数表示.角度部分的DVR基组选择勒让德多项式形式,而径向坐标采用正弦函数形式.为了降低需要对角化的最终哈密顿矩阵的维数,采用连续对角化截断方法.用H2S和H2O振动能级的计算验证算法的正确性.     

Estimation of N Absorption and Secretion by Digesta Exchange between 15N Labelled and Unlabelled Pigs

Abstract

Three female pigs (LW～30 kg) were fitted with re-entrant cannulas in the duodenum and the ileum and with bladder catheters. Animal No. 1 was labelled by continuous infusion of [¹⁵N]leucine via a catheter into the vena jugularis. After reaching a steady state in the level of endogenous N (4–5 d after beginning of the infusion) the digesta of the labelled animal No. 1 and the two unlabelled animals were exchanged in a 3 day experiment. During this time the course of transit rates of digesta, digesta N and ¹⁵N through duodenum and ileum as well as the proportion of endogenous N: exogenous N were estimated. Using these data it was possible to calculate the secretion and absorption rates of endogenous and exogenous N in the three segments of the digestive tract: mouth-duodenum, duodenum-ileum, ileum-anus and in addition the reabsorption (intestinal recycling) of the endogenous N during its passage through the gut could be computed.     

苯并咪唑取代胺及其配合物光谱分析

本文阐述了用原子吸收光谱测定三（2－苯并咪唑亚甲基）胺和二（2－苯并咪唑亚甲基）胺与Cu2 的配合物中心原子,并对上述配体及配合物用紫外光谱法和红外光谱法进行了研究,从而解释了配合物分子结构。     

低温相HI分子晶体振动光谱计算

本文用弹性力常数模型计算了低温相ＨＩ晶体的振动光谱。利用９个可调参数计算出３７个晶格模式和８个内部模式晶场分裂谱线频率，结果与实验值甚符合，同时结合群论分析对晶体拉曼和红外光谱进行了全面指认，计算还给出晶体中各类相互作用力参数。     

Rotational Spectrum of the Excited Vibrational States of DCOOH and Assignment of Optically Pumped Laser Transitions

The rotational spectrum of DCOOH in the 175–335 GHz region was investigated. Analysis of the spectrum made it possible to assign several dozen transitions in the ν₆, ν₈, and ν₅vibrational states and to determine the rotational and centrifugal distortion constants. The derived parameters of the ν₆state allowed four optically pumped laser transitions to be assigned. In addition, the ground state parameters for DCOOH and D¹³COOH have been improved and for the first time those for DC¹⁸OOH and DCO¹⁸OH have been obtained.