苝二酸酐与嘧啶衍生物的氢键组装

用半经验AM1方法对苝二酸酐与嘧啶衍生物的1:1及1:2氢键复合物进行理论研究,表明随着氢键数目增多,弱相互作用能变大,主体上的供电基和客体上的吸电基有利于氢键相互作用,氢键导致电子从主体流向客体.用INDO/SCI方法计算配合物的电子光谱,表明其长波吸收峰与主体相比发生兰移,各配合物的长波吸收峰位置相差不大,与实验一致.讨论吸收峰兰移的原因并对电子跃迁进行理论指认,同时得到了配合物的双质子转移势能曲线,给出了相对于N-H键的过渡态和活化能.     

1-氨基萘印迹聚合物分子识别特性的光谱学研究

采用分子自组装印迹技术合成了一种对1-氨基萘有高度选择性的分子印迹聚合物新材料。应用紫外光谱、红外光谱、X射线光电子能谱和1H核磁共振波谱等研究了印迹聚合物的结合位点和识别机理。结果表明模板分子与功能单体通过氢键作用形成1:1型配合物,配合物的稳定常数K=5.537×104L/mol。1-氨基萘分子氨基上的氮原子是质子接受体,功能单体甲基丙烯酸分子羧基上的氢原子是氢键的质子给予体,是与1-氨基萘形成氢键作用的选择性识别位点。利用平衡吸附试验研究了印迹聚合物的结合特性,表明印迹聚合物对1-氨基萘分子具有特异的识别性能。     

花二酸酐与嘧啶衍生物的氢键组装(英文)

用半经验AM1方法对苝二酸酐与嘧啶衍生物的1∶1及1∶2氢键复合物进行理论研究,表明随着氢键数目增多,弱相互作用能变大,主体上的供电基和客体上的吸电基有利于氢键相互作用,氢键导致电子从主体流向客体。用INDO／SCI方法计算配合物的电子光谱,表明其长波吸收峰与主体相比发生兰移,各配合物的长波吸收峰位置相差不大,与实验一致。讨论吸收峰兰移的原因并对电子跃迁进行理论指认,同时得到了配合物的双质子转移势能曲线,给出了相对于N-H键的过渡态和活化能。     

可天宁印迹聚合物分子识别特性的光谱与XPS研究

以可天宁(COT)为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了一种新型的分子印迹聚合物。采用紫外光谱、X射线光电子能谱、红外光谱和1H NMR波谱研究了印迹聚合物的结合位点和识别机理。结果表明,该聚合物通过协同氢键作用形成1∶2型配合物,专一地结合可天宁分子。MAA分子羧基上的氢原子是氢键的质子给予体;COT分子吡啶环上的氮原子以及羰基上的氧原子是质子的接受体,是与MAA形成氢键作用的选择性识别位点。     

Cu+与N-[2-羟基-1(S)-甲基]-N-甲基甘氨酸间的C-H…Cu(Ⅰ)抓氢键

采用密度泛函B3LYP(Becke, three-parameter, Lee-Yang-Parr)/6-311G**理论水平研究了Cu+和Cu2+离子与N-[2-羟基-1(S)-甲基]-N-甲基甘氨酸根负离子配体（PT）形成的配合物的结构,重点讨论了配合物中的C-H Cu抓氢键结构. 计算表明, 当单个配体与Cu+结合时,配合物PT•••Cu(Ⅰ)结构中有C-H Cu抓氢键形成,C-H键伸缩振动频率显著红移,键长显著增大而被活化, 配体为三齿配体;当两个配体与Cu2+结合时,配合物PT•••Cu(Ⅱ)不存在C-H Cu抓氢键结构,配体为双齿配体. NBO及AIM理论分析均表明C-H Cu抓氢键属于一种较强的基团间相互作用,在强度和电子行为上与氢键弱相互作用有本质不同.     

微波场作用下的溶质扩散通量

微波场协同溶质扩散机理是强化传质研究的苇要内容,由于微波热效应的干扰,微波场协同极性分子扩散的实验研究尚未取得大的进展.基于液体扩散机制,利用微波场对偶极分子的作用以及分子间相互作用能的影响,建立了微波场协同溶质分子扩散的关系式,得出了微波协同极性分子扩散是通过改变分子间的相互作用能来增强溶质分子扩散的结论.微波场的协同作用依赖分子的电偶极矩,温度较高时,电偶极矩越人强化效果越明显.微波场还可以通过削弱分子问动态氢键来增大扩散通量.该结论可为微波强化传质的理论和实验研究提供参考.     

分子间相互作用对核酸碱基中17O屏蔽张量与四极耦合常数影响的理论计算研究

通过高精度量子化学理论计算的方法研究了分子间弱的非键相互作用对胸腺嘧啶、尿嘧啶、胞嘧啶和鸟嘌呤四种核酸碱基中~(17)O核的屏蔽张量(σO)和四极耦合常数(QCC)的影响.计算结果表明分子间强的氢键作用以及弱的范德华(vd W)相互作用都对~(17)O核的化学位移(δO)具有较大的影响.随着分子间氢键作用的逐渐增强,δO逐渐减小,当采用包含所有弱相互作用的周期性模型进行计算时,理论结果与实验值吻合.进一步的电荷分析显示,~(17)O核化学位移的减小主要是由于分子间氢键作用强度增加导致~(17)O原子的负电荷密度逐渐增加.此外,计算结果表明碱基中分子间氢键网络和弱的范德华作用对碱基~(17)O QCC也具有显著的影响.周期性模型下,碱基上氧原子的局域结构环境得到平衡,~(17)O QCC达到最小值,与实验结果最为接近.以核酸碱基为例,说明了分子间的氢键网络以及分子间弱的相互作用对于准确计算生物样品的核磁共振(NMR)参数非常重要,以小的团簇模型来计算生物体系的核磁参数将会产生较大的偏差.     

全国第一次波谱学与原子分子物理学学术会议在北京召开

1980年3月5日至10日在北京召开了全国第一次波谱学与原子分子物理学学术会议.到会代表共70人.会议由中国科学院二局主持. 波谱学是一门基础学科.波谱学的研究导致了微波放大器研制成功,为量子电子学的发展奠定了基础,直接促进了激光器的产生.利用原子、分子谱线的恒定性,确定原子时间频率标准;精确地测量原子、分子的物理常数,不断地揭示了物理学理论和实验之间的矛盾,推动着理论的发展.例如辐射场和原子相互作用引起的原子内部结构变异的测定,为量子场论奠定了实验基础. 这次会议收到的磁共振及电子自旋共振的论文共42篇,反映了在固体物哩…     

甲胺磷分子印迹聚合物的结合机理及其分子识别特性的光谱学研究

采用分子自组装印迹技术合成了一种新的对甲胺磷农药分子有高度选择性的分子印迹聚合物。在预聚合阶段,通过1H NMR,FTIR和UV光谱法研究了分子印迹聚合物的形成机理。结果表明模板分子和功能单体通过协同氢键作用形成1∶2型氢键配合物,配合物稳定常数K＝2.894×106 L2·mol-2,稳定性好。运用红外光谱法研究了印迹聚合物对模板分子的特异性识别作用,进一步表明印迹聚合物通过协同氢键作用特异性地识别模板分子。     

久效磷分子印迹聚合物分子识别特性的光谱研究

采用分子印迹技术合成了对有机磷农药久效磷有高度选择性的聚合物,通过1H NMR和紫外光谱研究了印迹聚合物的结合机理和识别特性。结果表明,该聚合物通过协同氢键作用形成1∶2型氢键配合物专一地结合久效磷。聚合物红外光谱研究表明,聚合物表面存在可与印迹分子相互作用的官能团。     

Intermolecular hydrogen bonds, rotational spectrum, and structure of van der Waals complexes of (CH3)2O?CF2CH2 and (CH3)2O?CF2CHF

The results of molecular beam Fourier transform microwave (FTMW) investigations of the van der Waals complexes of dimethyl ether with 1,1-difluoroethene/trifluoroethene are reported. The rotational parameters of the complexes have been interpreted in terms of a C_s geometry with the two methyl groups lying out of the σ_v symmetry plane of complexes. The complexes are bound with three hydrogen bonds of which one is the stronger O?HC type and two are the weaker F?HC types. Some additional information on the structure and the hydrogen bond has been obtained from ab initio calculations.     

d^10组态金属离子与邻菲罗啉衍生物配位反应的^1H NMR研究

通过研究ｄ＾１０组态金属离子Ｚｎ＾２＋，Ｃｄ＾２＋，Ｈｇ＾２＋与邻菲罗啉及其衍生物发生配位时配体的＾１Ｈ ＮＭＲ谱的变化，对配离子的种类进行了讨论，给出了配离子中配键稳定性的比较，提出了一种通过实验直接研究溶液中的ｄ＾１０组态离子为中心离子的配合物的方法。     

Softening of ionic crystals as a result of a change in the spin states of structural defects under paramagnetic resonance conditions

The purpose of this work was to investigate the plastic properties of Ca-or Eu-doped NaCl and KCl single crystals in crossed constant and microwave magnetic waves under paramagnetic resonance conditions. It was found that when the photon energy of the microwave field equals the Zeeman splitting of the electronic spin sublevels, resonance softening of the crystals, manifested as an increase in the free path of individual dislocations and the macroplastic flow velocity as well as a decrease of the microhardness of the crystals, is observed. It was established that metastable Ca-and Eu-impurity complexes, which are also sensitive to the constant magnetic field in the absence of the microwave field, as well as complexes formed by dislocations and point defects are responsible for resonance softening.     

压缩空气微波等离子体发射光谱的实验研究

利用微波等离子体发生装置,以压缩空气为工作气体,在1～5 atm气压下激发了微波等离子体。使用光谱测量系统,对不同气压和不同入射微波功率情况下的压缩空气微波等离子体的发射光谱进行了实验研究。结果显示,在其他条件不变时,随着气压升高,压缩空气微波等离子体的带状连续谱特征逐渐减弱;随着入射微波功率降低,带状连续谱强度逐渐减弱而带状连续谱特征依然显著。实验结果为了解压缩空气微波等离子体的光谱特性和NO活性基团的产生条件提供了实验依据。     

Computational study of the cooperative effects between tetrel bond and halogen bond in XCN⋅⋅⋅F2CO⋅⋅⋅YCN complexes (X = H,F, Cl,Br; Y = F,Cl, Br)

ABSTRACT

Ab initio calculations have been accomplished to study the cooperativity between the halogen bond and tetrel bond in the XCN???F2CO???YCN (X = H, F, Cl, Br; Y = F, Cl, Br) complexes. F₂CO at the same time plays the role of Lewis acid with the π-hole on the C atom and Lewis base with the O atom to participate in the tetrel bond and in halogen bond, respectively. According to the geometry survey, the effect of a tetrel bond on a halogen bond is more pronounced than that of a halogen bond on a tetrel bond and the intermolecular distances in the triads are always smaller than the corresponding values in the dyads. In all cases, the halogen bond and tetrel bond in the termolecular complexes are stronger compared with those in the bimolecular complexes. So, from the intermolecular distances, interaction energies and many-body interactions demonstrate that there is positive cooperativity between the halogen bond and tetrel bond. The molecular electrostatic potential, atoms in molecules and natural bond orbital methodologies are used to analyse the nature of interactions of the complexes.     

Correlation of Dative Bond Length and Donor Proton Affinity in Adducts of SO3: A Good Predictor for HCCCN-SO3

The rotational spectrum of HCCCN-SO₃ has been observed using Fourier transform microwave spectroscopy. The vibrationally averaged structure is that of a symmetric top, with the HCCCN axis along the C₃ axis of the SO₃, and the nitrogen end near the sulfur. The N-S bond length is 2.567(13) Å, which is slightly shorter than the sum of the van der Waals radii. The NSO angle is 91.7(4)°, indicating a small but distinct distortion of the SO₃ from planarity, and the N-S interaction can be described as a chemical bond in an early stage of its formation. The N-S bond lengths in a series of SO₃ adducts with amines, nitriles, and pyridine are shown to correlate well with the proton affinities of the bases. In addition, for the bases considered here, the proton affinities vary in a regular manner with the ionization energies corresponding to removal of a lone pair electron. Thus, the trend in proton affinities follows the variation in energy gap between donor and acceptor orbitals in these complexes, accounting for the utility of the proton affinity in correlating aspects of structure and bonding across the series.     

Microwave spectrum of (CH3)3CCN-SO3

Eight rotational transitions of the complex (CH₃)₃CCN-SO₃ have been recorded using pulsed-nozzle Fourier transform microwave spectroscopy and a series of ab initio calculations has been performed. The complex is a symmetric top with free or nearly free internal rotation of the SO₃ and (CH₃)₃CCN subunits. The nitrogen-sulfur bond distance is determined to be 2.394(19) Å. Calculations at the MP2/aug-cc-pVTZ level/basis, which are in excellent agreement with the experimental results, give a binding energy of 11.0 kcal/mol relative to (CH₃)₃CCN and SO₃. Physical properties of the system, including N-S bond length, N-S-O angle, binding energy, and the degree of electron transfer (obtained from Townes and Dailey analysis of the ¹⁴N nuclear quadrupole coupling constant) are compared with those of similar complexes. The proton affinity of the base is a useful parameter for ordering complexes in the series.     

Application of Microwave Nonstationary Spectroscopy for Noninvasive Medical Diagnostics

We consider an application of the method of microwave nonstationary gas spectroscopy for analytical studies of multicomponent gas mixtures using exhaled air as an example. The methods used for studying multicomponent gas mixtures are reviewed. We describe subterahertz and terahertz nonstationary gas spectrometers based on the effect of freely damped polarization. The results of test measurements of nitric oxide (NO) in the 2-mm wavelength range are presented. Methods for studying the response dynamics are developed. The prospects of using the method of microwave nonstationary gas spectroscopy in the subteraherz and teraherz ranges are shown. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 6, pp. 545–551, June 2008.     

低温微波近场显微镜及其在材料研究中的应用

微波近场技术是研究材料表面区域电磁性质的有效手段,结合低温技术则可将这种技术的应用拓展到更广的范围.本文报道了我们研制的低温扫描微波近场显微镜系统,它由微波近场显微镜和与之配合的可变温样品台构成,可以在液氮温度和室温之间工作.利用该系统我们详细研究了YBaCuO超导薄膜、NdSrMnO磁性薄膜在不同温度条件下的电磁性质,给出了相关实验结果.研究表明微波近场技术与低温技术的结合为电子材料和器件低温下局域电磁性质的研究提供了有力的手段.     

Competition between hydrogen bond and σ-hole interaction in SCS-HArF and SeCSe-HArF complexes

A computational study of the complexes formed between HArF and XCX (X?=?O, S, and Se) has been performed at the MP2/aug-cc-pVTZ level. Two types of complexes were found. One is formed through a hydrogen bond with XCX as the electron donor and the other is formed through the σ-hole interaction with XCX as the electron acceptor. The OCO-FArH complex is more stable than the OCO-HArF complex, whereas the XCX-HArF (X?=?S and Se) complex is more stable than the XCX-FArH complex. The distant H-Ar bond is shortened and exhibits a blue shift, but the associated one displays a red shift in SCS-HArF and SeCSe-HArF complexes. When compared with XCX-HF complex, the structure of the complex suffers a great effect from the inserted noble gas atom. The natural bond orbital (NBO) and atoms in molecules (AIM) have been performed for a better understanding of the interactions.