波浪形一维链状镉配合物的合成、结构及分子识别性能

以四水合硝酸镉(Cd(NO_3)_2·4H_2O)与2-(邻溴)苯基-4,5-咪唑二羧酸(o-BrPhH_3IDC)和草酸铵通过水热反应,合成了一个波浪形一维链状配合物{[Cd(o-BrPhH_2IDC)_2(H_2O)]·H_2O}_n(1)。并通过元素分析、傅里叶变换红外光谱、热重分析和单晶X射线衍射等技术手段对配合物1进行了表征。结果表明,配合物1为正交晶系,Pbca空间群。配合物1在316 nm波长激发下,在356 nm处有最大的荧光发射峰。配合物1对小分子具有识别性能,乙腈使配合物荧光强度明显增强,甲醇、乙醇使配合物荧光强度明显减弱,而吡啶处理后的样品在356 nm附近的发射峰消失,显示对吡啶有识别作用。     

惰性气体原子与HF分子相互作用的分子形貌动态研究

研究了惰性气体原子(Rg=He,Ne,Ar和Kr)分别向HF分子两端原子接近过程中分子形貌的动态变化,使用MELD精密从头算方法中的CISD/6-311++G(2d,2p)方法,计算了FH-Rg和HF-Rg2个二聚体的单电子作用势、分子平面的边界轮廓以及相应界面上的电子密度.研究表明,惰性气体原子Rg分别向HF的两端接近时,双方的外形在接近的方向上均有伸手欢迎的表示,分子的前沿电子密度也相应的发生变化,对惰性键提供了一种新的认识.     

以Eu(DBM)3Bipy为荧光探针的温敏漆的制备及性能表征

利用氯化铕（EuCl₃）、二苯甲酰甲烷（DBM）和联吡啶（Bipy）为原料合成了Eu（DBM）₃Bipy探针分子,并将探针分子掺入到甲基丙烯酸甲酯（MMA）中,在过氧化苯甲酰（BPO）引发剂的作用下聚合,获得温敏漆Eu（DBM）₃Bipy/PMMA。采用红外光谱仪、紫外吸收光谱仪、扫描电子显微镜和荧光光谱仪对探针分子的结构、形貌、发光性能和温敏漆的温度猝灭性能进行了表征。红外及紫外吸收光谱分析发现稀土离子Eu³⁺与配体配位成键,成功合成Eu（DBM）₃Bipy探针分子;扫描电镜及能谱分析表明Eu（DBM）₃ Bipy探针分子呈碎片状,大小约为150 nm,且主要由C、N、O和Eu四种元素组成;荧光光谱表明,在367 nm激发下,Eu（DBM）₃ Bipy探针分子的最佳发射波长位于612 nm,且第二配体Bipy对Eu（DBM）₃的荧光发射具有增益作用。在不同温度下测试温敏漆的荧光发射特性,发现温敏漆Eu（DBM）₃Bipy/PMMA在40~90℃温度区间内具有良好的荧光温度猝灭特性,测温灵敏度最高的温度区间位于40~60℃。     

Fluorescence resonance energy transfer (FRET) in chemistry and biology: Non-F?rster distance dependence of the FRET rate

Fluorescence resonance energy transfer (FRET) is a popular tool to study equilibrium and dynamical properties of polymers and biopolymers in condensed phases and is now widely used in conjunction with single molecule spectroscopy. In the data analysis, one usually employs the F?rster expression which predicts (l/R ⁶) distance dependence of the energy transfer rate. However, critical analysis shows that this e_xpression can be of rather limited validity in many cases. We demonstrate this by explicitly considering a donor-acceptor system, polyfluorene (PF₆)-tetraphenylporphyrin (TPP), where the size of both donor and acceptor is comparable to the distance separating them. In such cases, one may expect much weaker distance (as l/R ² or even weaker) dependence. We have also considered the case of energy transfer from a dye to a nanoparticle. Here we find l/R ⁴ distance dependence at large separations, completely different from F?rster. We also discuss recent application of FRET to study polymer conformational dynamics. Dedicated to Prof J Gopalakrishnan on his 62nd birthday.     

Periodane—An unexpectedly stable molecule of unique composition

Structure, bonding characteristics, and reaction energies as well as optical, vibrational, and nuclear magnetic resonance (NMR) properties of the hitherto unknown molecule LiBeBCNOF, called periodane, have been calculated by quantum chemical methods. It can be shown that periodane is stable enough to be produced and identified experimentally. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

Coupled Rearrangement Channel Calculation of the Hyperfine Structure of the dtμ Molecule

Hyperfine structure splittings are calculated for the J = v = 1 state of the dtμ molecule. The splittings are determined by the accurate three-body wave function obtained by coupled rearrangement channel method using the updated physical constants. The result obtained is in good agreement with the previous calculation within ∼0.07 meV. The discrepancy is due to the accuracy of the three-body wave function. This revised version was published online in August 2006 with corrections to the Cover Date.     

Resonant tunnelling of the magnetization in molecular crystal of [（Mn1-xCrx）12O12 （CH3COO）16（H2O）4]·2CH3COOH·4H2O（x=0,0.03,0.04,0.05）

The quantum tunnelling of magnetization （QTM） in single crystals of the single molecule magnet （Mn1-xCrx）12- Ac （x=0, 0.03, 0.04, 0.05） has been investigated. In comparison with its parent Mnl2-Ac, a greater rate of magnetization relaxation and a lower effective potential-energy barrier have been observed in Cr-doping samples. This modulation of QTM due to the Cr-doping could be attributed to the small change of Sz due to the smaller spin of Cr itself and additional intrinsic but distributed transverse and longitudinal anisotropy raised by a subtle change of the local environment in the magnetic Mn12 core.     

Investigation on Molecular Non-covalent Interaction in the Sodium Dodecyl Benzene Sulfonate-polychrome Blue B-protein Replacement Reaction

Introduction Supramolecular assembly is always an importantresearch direction for chemists and biochemists.1-5 It isvery helpful for us to accurately analyze the physico-chemical action and process occurring inside biologicalcell, for example, function of a drug, damage of a toxi-cant, detection of oncogene and so on. Understandingthe chemical, physical, biological and pharmacologicalactivity of a complex system requires knowledge of thestate of molecular aggregation of the system compo-ne…     

TF分子基态（X’∑^＋）势能函数

电子相关耦合族方法CCSD（T）和QCISD（T）以及基组6—311＋＋G＊＊和cc—pvdz是目前最可靠的单参考组态方法。利用其对TF分子的基态进行优化计算，使优化的平衡间距分别为0．091599872nm，0．091971495nm，0．091623623nm，0．091978183nm。它们与实验值0．091760000nm基本吻合，误差小于0．00022。采用标准Murrell—Sorbie函数进行非线性最小二乘法拟合，得到了TF分子势能函数的解析表达式。这样计算所得的力常数及光谱常数与实验数据符合得相当好。