Time-resolved fluorescence spectra of a bichromophoric molecule, 2-methyl-1,2,3,4-tetrahydroisoquinoline in various media

Time-resolved fluorescence spectra of a title molecule (with benzene and aliphatic amine parts) in various media, after excitation by several lasers were observed to complement the previous work by conventional spectroscopy [N. Kanamaru, J. Tanaka, J. Phys. Chem. 95 (1991) 6441]. Though complex with many new features, the results were roughly consistent with the previous ones. The significant conclusions are as follows: (1) The emission to be ascribed to the amine (N) part, with more than one component (of nN and aN types) is observed not only for the acetonitrile solution (as previously reported) but also for all the other media. (2) Contrary to the case of a nonpolar hexane solution, both of N fluorescences in the other media reveal unusually long-lived decay components. This can be interpreted by assuming the so-called charge-transfer-to-solvent (CTTS) state that is nonfluorescent and lies just below the fluorescent state. (3) This observation in the protic media can also be taken as another evidence of the peculiar hydrogen bonding between this amine and the protic solvent molecules [N. Kanamaru, J. Tanaka, J. Phys. Chem. 95 (1991) 6441]. (4) Thus, the unexpectedly large quantum yields of N fluorescences in the polar media are now interpreted as arising due to the slow S₁^N→(CTTS)→S₀ internal conversions.     

Electrostatic potentials of molecules and prediction of the lewis acid-base properties of solvents,part I. General considerations

Summary Electrostatic potentials in the vicinity of isolated molecules of typical nonaqueous solvents were computed in the MNDO approximation. It was found that the calculated dipole moments are in good agreement with experimental values. However, it turned out that in many cases electrostatic interactions of ions with solvent molecules cannot be described in the frame of ion-dipole interactions. Thus, two computable parameters,UN andUP describing short-range electrostatic interactions of a solvent molecule with a cation or an anion of radiusR were proposed. The dependence ofUN andUP uponR is analyzed in the context of ion-solvent interactions.

---

Elektrostatische Potentiale von Molekülen und Voraussage von Lewis-Säure-Base-Eigenschaften von Lösungsmitteln, 1. Mitt.: Allgemeine Grundlagen

Zusammenfassung Es wurden die elektrostatischen Potentiale in der Umgebung von isolierten Molekülen typischer nichtwäßriger Lösungsmittel in der MNDO-Näherung berechnet. Die berechneten Dipolmomente waren in guter Übereinstimmung mit den experimentellen Werten. Es wurde jedoch beobachtet, daß in vielen Fällen die elektrostatischen Wechselwirkungen von Ionen mit Lösungsmittelmolekülen nicht im Rahmen von Ionen-Dipol-Wechselwirkungen beschrieben werden können. Dafür wurden zwei berechenbare ParameterUN undUP zur Beschreibung von elektrostatischen Wechselwirkungen im Nahbereich eines Lösungsmittelmoleküls mit einem Kationen- oder AnionenradiusR vorgeschlagen. Die Abhängigkeit vonUN undUP vonR wurde im Zusammenhang von Ionen-Solvens-Wechselwirkungen untersucht.

     

Schiff碱水杨醛苯甲酰腙的特性

研究了 Schiff碱水杨醛苯甲酰腙 (简称 SBH)晶体在 DMSO及其 DMSO- H2 O的混合溶剂中的红外光谱 ,通过 SBH氘代前后的 IR对比发现 ,羟基氢质子与混合溶剂 DMSO- H2 O(3∶ 1 ,V/ V)产生较大的相互作用。向溶有 SBH的 75 % DMSO- 2 5 % H2 O的溶液滴加 KOH发现 ,SBH分子上的 C O羰基基团先与 KOH作用 ,其后与 O H 羟基基团作用     

Trichloroisocyanuric acid as a novel oxidizing agent for the oxidation of 1,3,5-trisubstituted pyrazolines under both heterogeneous and solvent free conditions

Trichloroisocyanuric acid is used as an effective oxidizing agent for the oxidation of 1,3,5-trisubstituted pyrazolines to their corresponding pyrazoles under both heterogeneous and also solvent free conditions with good yields at room temperature.     

A polymer onium acting as phase-transfer catalyst in halogen-exchange fluorination promoted by microwave

A polymerized quaternary ammonium salt polydiallyldimethylammonium chloride, exhibiting high stability to heat and base, was prepared and applied as phase-transfer catalyst (PTC) in halogen-exchange (Halex) fluorination of chloronitrobenzenes to give excellent yields of corresponding fluoronitrobenzenes. Dimethyl sulfoxide was found to be the best solvent when microwave was applied as heating resource.     

双（十二烷基亚磺酰）乙烷溶剂萃取钯及其机理的研究

本文研究用双（十二烷基亚磺酰）乙烷萃取钯的性能，在ＫＩ存在下从７ｍｏｌ／Ｌ盐酸介质中用含有ＢＤＳＥ的氯仿能定量萃取钯，有机的钯可被硫脲或氨溶液反萃继之用ＴＭＫ－ＴｒｉｔｏｎＸ－１００光度法测定，研究了萃取的最佳条件及干扰情况，斜率法测得萃合物组成为Ｐｄ：Ｉ：ＢＤＳＥ＝１：２：１，红外光谱证实萃合物中ＢＤＳＥ的二个亚砜以硫原子与钯配位，萃合物为异位体络合物，提出了选择性萃取分离钯的新方法。     

Iodine‐Catalyzed Friedlander Quinoline Synthesis under Solvent‐Free Conditions

Polyfunctional quinolines were synthesized using Friedlander method catalyzed by molecular iodine in high yields at 60 °C under solvent‐free conditions.     

怎样写论文摘要

除论文标题之外 ,读者是通过摘要来决定是否继续阅读整篇论文 .因而摘要是一篇论文的窗口 .要在最小的空间内阐述问题、描述方法、总结贡献 ,是需要运用技巧与经验的 .一、摘要的内容摘要 (包括中、英文摘要 )的内容应包括目的、方法、结果、结论四个部分。重点应突出文章在结果和结论方面的创新之处 .二、摘要长度中文摘要长度一般不超过 30 0字 ,不少于 2 0 0字 ;英文摘要应比中文摘要有所扩展 ,以便使非汉语读者更多地了解文章的内容 .长度一般不超过 15 0 words,不少于 10 0 words。少数情况允许例外 ,但主题概念不得遗漏 .为了使在较短…     

高纯氧化钆中14种稀土杂质元素的柱色谱分离ICP-AES法测定

用Ｐ５０７萃淋树脂柱色谱法分离高纯氧化钆基体与稀土杂质。用ＩＣＰ－ＡＥＳ法测定高纯氧化钆中微量稀土杂质。选择了柱色谱分离的合适条件。优化了仪器测定参数。使本方法测定稀土总量下限小于１×１０－５％。可以满足９９．９９９９％高纯氧化钆的测定。此方法回收率在８５％－１１０％之间。相对标准偏差小于１８％。     

A hydrogen rearrangement of formamidine and the solvent effects thereupon

The nature of the 1,3 hydrogen rearrangement of formamidine (H₂N-CH=NH) and the solvent effects on that reaction are studied with ab initio molecular orbital calculations on the basis of the supermolecule model. The reaction path and the motion of the migrating hydrogen atom are traced by using the concept of the intrinsic reaction coordinate (IRC). Four types of orientation of one water molecule to formamidine at the transition state of reaction are examined and the results are discussed from the standpoint of the orbital interactions.