Metal–Organic Gels from Silver Nanoclusters with Aggregation-Induced Emission and Fluorescence-to-Phosphorescence Switching

Luminescent metal nanoclusters (NCs) are emerging as a new class of functional materials that have rich physicochemical properties and wide potential applications. In recent years, it has been found that some metal NCs undergo aggregation-induced emission (AIE) and an interesting fluorescence-to-phosphorescence (F-P) switching in solutions. However, insights of both the AIE and the F-P switching remain largely unknown. Now, gelation of water soluble, atomically precise Ag₉ NCs is achieved by the addition of antisolvent. Self-assembly of Ag₉ NCs into entangled fibers was confirmed, during which AIE was observed together with an F-P switching occurring within a narrow time scale. Structural evaluation indicates the fibers are highly ordered. The self-assembly of Ag₉ NCs and their photoluminescent property are thermally reversible, making the metal–organic gels good candidates for luminescent ratiometric thermometers.     

双核铂的Pt2（CN）4（CNC4H9）4的发光机制及Pt...Pt间互作用的从头计算研究

利用从头算ＭＰ２方法优化了Ｐｔ（ＣＮ）２（ＣＮＣＨ３）２,Ｐｔ（ＣＮ）２（ＣＮＣＨ３）２－（ＮＣＣＨ３）２．「Ｐｔ（ＣＮ）２．（ＣＮＣＨ３）２」２的在态几何结构,利用单激发的组态相互作用方法（ＣＩＳ）计算了固态和乙氰溶液中标题化合物的发射光谱,并对激发态的几何结构进行了优化,结果表明,基态时,Ｐｔ．．．ＮＣＣＨ３之间的距离较大（０．４０６ｎｍ）,说明溶剂分子与Ｐｔ原子之间存在较小的范德华作用;而激发时,Ｐｔ．．．ＮＣＣＨ３之间的距离减小（０．２５７ｎｍ）,说明此时Ｐｔ．．．ＮＣＣＨ３之间相互作用较强,由于这种作用使乙氰溶液中该物质的发光性质与不考虑溶剂效应时相比差异较大,其发射光谱不可我谱区,固态时,此化合物为直线链状结构,ＭＰ２计算得到：基态时「Ｐｔ（ＣＮ）２（ＣＮＣＨ３）２」２中Ｐｔ．．．Ｐｔ之间的距离为０     

Combinational simulations of free energy of polymer solution

It is conceptually proposed that the total entropy of polymer solution is contributed from two distinct parts: the positional and the oomformational. The former can be represented analytically, while the latter can be simulated with the random self-avoiding walk model on the simple cubic lattice for multichain systems. The obtained results indicated that both the conformational entropy and the mixing heat are consistent with the scaling laws wry well.     

X射线荧光与粒子激发X射线光谱分析

本文是《分析试验室》定期评述“Ｘ射线荧光光谱分析”系列评论第７篇,简述了１９９６年７月至１９９８年６月国内Ｘ射线荧光光谱分析技术发展的概况,从Ｘ射线荧光光谱仪的研制与改造、特殊激发方式的研究与应用、化学计量学与数据处理方法研究、化学态分析、标准物质与样品制备、测定方法研究与应用６个方面评述了国内Ｘ射线荧光与粒子激发Ｘ射线光谱分析进展。共收录国内学者论文及相关文集１４３篇。     

On the Scaling Study for the A_f-A_g Type Free Radical Polymerization

根据Ａｆ－Ａｇ自由基加聚反应的数量分布函数，导出凝胶点附近的渐进分布函数和高分子矩的表示式．进一步应用标度变换，得到了描述溶胶－凝胶相变的广义标度律，从而揭示了Ａｆ－Ａｇ自由基加聚的固化反应是一个相变过程．     

傅里哀变换红外发射光谱法研究金属氧化物催化剂——Ⅰ.实验建立及氧化钼的还原-氧化研究

本文报导了傅里哀变换红外发射光谱法研究多相氧化物催化剂的实验装置的建立及实验条件的考察。设计加工了一个温度范围宽,可在各种气氛和真空条件下原位研究氧化物催化剂的红外发射池。以MoO_3为例,考察了样品厚度,测试温度对发射光谱的影响。当样品量小于1mm·cm~(-2)时,随样品量增加,谱峰强度线性增加,但峰形不发生变化。当样品量高于1mg.cm~(-2)时,随样品量增加,谱图严重畸变。随样品温度升高,谱峰强度近似线性增加。并用该方法研究了MoO_3在还原和再氧化过程中表面氧物种的变化。结果表明桥式MO?O?Mo物种比端基Mo=O物种较易还原,再氧化时,Mo=O物种比Mo?O?Mo物种优先形成。