紫外辐射诱导的C60聚合反应——共焦显微拉曼光谱研究

以表面增强拉曼效应的金面作为基底，用共焦显微拉曼光谱仪对Ｃ６０在紫外光辐射下拉曼光谱的变化进行了原位的跟踪考查。结果表明，在紫外辐射下，Ｃ６０发生了聚合，失去了分子所固有的球形对称结构；但聚合产物的笼状结构形式并无太大的变化，只是结构的共轭体系增大，整体的对称性降低。     

C_(60)在室温有机溶剂中荧光的研究

本文在室温下对C60分别在吡啶、甲苯和乙腈中的荧光了研究,实验表明:C60在吡啶中的荧光由以440nm、570nm和700nm为中心的三个荧光带组成;C60在甲苯中的荧光由以430nm和700nm为中心的两个荧光带组成;C60在乙腈中的荧光由以570nm和700nm为中心的两个荧光带组成。经比较分析发现C60-有机溶剂体系700nm区域的荧光带的发射与溶剂的种类无关,而440nm和570nm区域的荧光带及其精细结构可以反映C60与溶剂分子的特殊相互作用。进一步提出C60-吡啶体系以570nm为中心的荧光带是由吡啶分子通过含孤对电子的N与C60形成的电荷转移络合物发出的。     

C60-脱异丙基脱氢枞胺衍生物的NMR光谱分析

C_(60)与脱氢枞胺发生环加成反应可生成多种功能性富勒烯衍生物.该论文测定了目标化合物N,N-四氯邻苯二甲酰基-13-硝基-7,7-C_(60)-脱异丙基脱氢枞胺的~1H NMR和~(13)C NMR谱图,并利用~1H-~1H COSY、~1H-~1H ROESY、~1H-~(13)C HSQC和~1H-~(13)C HMBC等2D NMR技术,对其~1H和~(13)C NMR信号进行了归属,为表征类似化合物的结构提供了参考.     

电化学体系中吸附在金电极表面吡啶的紫外拉曼光谱研究

观察到波长为325nm的紫外光激发下吸附在金电极表面的吡啶的表面增强拉曼光谱(SERS)。结合其SERS谱随电位的变化关系,分析了其中的增强机制并表明随电位的负移吡啶的吸附方式发生改变。     

非水体系中C60在银电极上的表面增强拉曼光谱研究

采用表面增强拉曼光谱（SERS）技术研究了乙腈溶液中C60的悬液在银电极表面的光谱特征,得到了银电极表面C60团簇和表面吸附C60分子的光谱信息。结果表明,随着所加电势的改变,C60的SERS谱峰强度和位移皆有所变化。而且由于基底表面电磁场的改变直接影响着C60的分子结构,导致电势正扫和回扫时的还原电位和氧化电位之间出现400mV的滞后现象;由于扬-特勒变形的存在使C60分子的对称性降低,而导致其SERS谱图发生了变化。     

丙酮CO键在溶剂中频移变化的几种理论模型比较

测量了丙酮在16种溶剂中CO键的伸缩振动拉曼光谱,并且在Gaussian03程序下采用自恰反应场方法(SCRF)对丙酮在各种溶剂中的拉曼光谱进行了理论计算。用三种溶剂模型的电子给体-受体模型、Kirkwood模型和自恰反应场模型对实验结果进行了分析比较,结果表明Gutmann提出的电子给体-受体模型与实验结果符合的最好,而自恰反应场理论结果要好于Kirkwood模型。通过对三种模型的机理进行分析,得出给体-受体模型在解释电负性比较强的分子键振动光谱比较好,自恰反应场模型不但考虑了介电常数ε,而且考虑了分子大小、构型等因素的影响,模型复杂,计算量比较大,但是因为考虑的因素比较多,所以与实验结果也符合的比较好,而Kirkwood模型的主要参数为ε,模型简单,计算简便,能大致反映频移的趋势,说明介电常数是影响频移的一个主要因素。     

有机芳香烃掺杂控制C_(60)微/纳米晶形貌和发光

C60高度的分子对称性使其能带间的电子跃迁被禁止,导致其发光很弱。为了提高C60纳米晶的发光强度,采用挥发C60的芳香烃饱和溶液的方法,一步合成了芳香烃溶剂化的C60纳米晶。实验结果表明,有机溶剂的掺杂在不同程度上增强了C60纳米晶的发光,其原因可能是溶剂的掺杂破坏了C60的高度的分子对称性。     

C60/C70在空气中高温状态下的聚合

Ｃ６０（含Ｃ７０）固体在空气中封闭,在８５０－９００℃高温下处理１０分钟,红外光吸收光谱分析发现Ｃ６０（７０）在氮氧的作用下产生聚合。     

The Influence of Temperature on C153 Steady-State Absorption and Fluorescence Kinetics in Hydrogen Bonding Solvents

In a recent paper (J Fluoresc (2011) 21:1547–1557) a temperature induced modulation of Coumarin 153 (C153) fluorescence lifetime and quantum yield for the probe dissolved in the polar, nonspecifically interacting 1-chloropropane was reported. This modulation was also observed in temperature dependencies of the radiative and nonradiative rates. Here, we show that the modulation is also observed in another 1-chloroalkane—1-chlorohexane, as well as in hydrogen bonding propionitrile, ethanol and trifluoroethanol. Change in the equilibrium distance between S ₀ an S ₁ potential energies surfaces was identified as the source of this modulation. This change is driven by temperature changes. It leads to a modulation of the fluorescence transition dipole moment and it is the primary source of the experimental effects observed. Additionally, we have found that proticity of the solvent induces a rise in the fluorescence transition dipole moment, which leads to a shortening of the fluorescence lifetime. Hydrogen bonds are formed by C153 also with hydrogen accepting solvents like propionitrile. We show that while such bonds do not affect the transition probability, they do change the S₀ an S₁ energy gap which in turn implies a change in non-radiative transition rate in a similar way as in protic solvents, as well as in the fluorescence spectrum position. Finally, the influence of temperature on the energies of hydrogen bonds formed by C153 when acting as hydrogen donor or acceptor is reported.     

Negative ions of hydrogenated and deuterated C60 fullerenes

This paper reports on the results of mass spectrometric and theoretical investigations of hydrogenated and deuterated fullerene derivatives C₆₀H(D)_x. The formation and decay (through electron autodetachment) of negative molecular ions of the C₆₀H₁₈ and C₆₀D₁₈ hydrofullerenes are discussed. A comparative analysis of these processes is performed for different fullerene derivatives.     

不同激发波长下C_(60)/C_(70)的荧光研究(英文)

在室温吡啶溶液中得到了较以往丰富的C6 0 /C70 荧光谱,研究了其荧光谱随激发波长的变化,并且比较了C6 0 和C70 的荧光谱     

Negative group velocity in C60 due to RSA effect

We experimentally observed negative group velocity in C₆₀ toluene solution at the wavelength of 532 nm for the first time. The observed time advancement of the modulated signal appears to be due to the RSA (reverse saturable absorption) effect of the C₆₀ molecule. The largest time advancement of 71.65 ms was obtained with a C₆₀ sample of 1.5-mm length with the concentration of 1.39×10^-3 mol/l; the corresponding group velocity was -0.021 m/s. We could control the group velocity by adjusting the modulation frequency and the input intensity. PACS 42.65.-k; 42.50.Ct; 41.20.Jb     

Effect of C60 molecular rotation on nanotribology

The effect of C60 molecular rotation on the nanotribological properties of C60 single crystal surfaces has been studied by atomic/frictional force microscopy. The orientational order-disorder phase transition, in which the high temperature C60 free rotation is reduced to a low temperature hindered rotation, is shown to give rise to an abrupt change in friction and adhesion. This change in frictional force is quantitatively consistent with the observed change in adhesion. The similar slopes of the friction versus load curves in both phases indicate that the friction coefficient in the two phases remains about the same. Hence the C60 rotation does not provide an additional energy dissipation channel in the friction process.     

不同浓度维生素C对DNA紫外损伤的影响

分别检测了DNA与不同浓度维生素C的混合物经10和30 min紫外辐射的拉曼光谱,紫外线的辐射照度为18.68 W·m-2。实验表明,维生素C对DNA损伤的影响与其浓度密切相关。低于0.35 mmol·L-1的维生素C对紫外线诱发的DNA损伤具有明显的保护作用,且保护效果随着其浓度的增大越来越好,0.35 mmol·L-1时保护效果最佳。当维生素C的浓度高于0.35 mmol·L-1时,在10 min的紫外辐射中,维生素C不仅没有保护DNA,反而促进了DNA的损伤,DNA被损伤的程度随着维生素C浓度的增加而增加;但在30 min的紫外辐射中,相对于不加VC的紫外辐射,维生素C对DNA仍起保护作用。