TD-DFT

摘要： This work was undertaken to see how Ru II complexes can be suitable for photodynamic therapy through theoretical prediction. For that, four Ru II complexes, α-RuCl2(Azpy)2, ,  and  were used in unrestricted state by providing with no more energy than 2.68 eV. The unrestricted state allows the complex molecule to display each of its electrons in one orbital. All the calculations such as optimization, frequency and TD-DFT calculations were performed at WB97XD/Lanl2dz level. It resulted from this investigation that Ru II complexes are active for both mechanisms suitable for photodynamic therapy in presence or absence of 3O2. Moreover, this reaction was assumed to take place only with Guanine DNA base as demonstrated in literature. Therefore, Guanine is admitted as the base most reacting with ruthenium complexes for photodynamic therapy. This work confirms our prediction regarding metallic complexes that are assumed to be photosensitized in condition that an electron must be isolated to favor the excitation. Nevertheless, Ru II complexes are found suitable for superficial therapy while Ru III must be active for deep therapy.

摘要： 电子的运动与演化是贯穿许多物理化学过程的主线,而对这一过程的精确模拟和分析是发展有效的电子调控方法和应用的关键.传统方法,如TDHF(time-dependent Hartree-Fock)、TDDFT(time-dependent density functional theory)等,在模拟小尺度体系内的电子演化时表现优异,然而,在模拟大尺度体系时计算复杂度偏高,成本较大.在一些大尺度体系内,原子核位置相对固定,并且微扰对整体相互作用的哈密顿量影响较小.为此提出了一种简单有效的基于哈密顿矩阵的电子波函数演化方法,这一方法能处理远远大于TDDFT计算尺度的大体系.通过将该方法应用于四个不同的体系进行测试分析,验证了这一方法在处理大体系时的可行性,并为相关的电子调控应用提供了新的思路.

摘要： In this study, the first raw transition metals from V to Co complexes with benzene-1,2-dithiolate (L2-) ligand have been studied theoretically to elucidate the geometry, electronic structure and spectroscopic properties of the complexes. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods have been used. The ground state geometries, binding energies, spectral properties (UV-vis), frontier molecular orbitals (FMOs) analysis, charge analysis and natural bond orbital (NBO) have been investigated. The geometrical parameters are in good agreement with the available experimental data. The metal-ligand binding energies are 1 order of magnitude larger than the physisorption energy of a benzene-1, 2-dthiolate molecule on a metallic surface. The electronic structures of the first raw transition metal series from V to Co have been elucidated by UV-vis spectroscopic using DFT calculations. In accordance with experiment the calculated electronic spectra of these tris complexes show bands at 522, 565, 559, 546 and 863 nm for V3+, Cr3+, Mn3+, Fe3+ and Co3+ respectively which are mainly attributed to ligand to metal charge transfer (LMCT) transitions. The electronic properties analysis shows that the highest occupied molecular orbital (HOMO) is mainly centered on metal coordinated sulfur atoms whereas the lowest unoccupied molecular orbital (LUMO) is mainly located on the metal surface. From calculation of intramolecular interactions and electron delocalization by natural bond orbital (NBO) analysis, the stability of the complexes was estimated. The NBO results showed significant charge transfer from sulfur to central metal ions in the complexes, as well as to the benzene. The calculated charges on metal ions are also reported at various charge schemes. The calculations show encouraging agreement with the available experimental data.

摘要： 研究了一系列用于有机电致发光器件(OLED)的红色Ir(Ⅲ)配合物发光材料.从理论上探讨了它们的电子结构和光谱性质.采用密度泛函理论(DFT)研究了(piq)2Ir(acac)(1)和理论设计模型(piq)2 ir(dpis)(2)、(4Fpiq)2Ir(dpis)(3)、(4F5M-piq)2Ir(dpis)(4)、(4,5-2F-piq)2Ir(dpis)(5)以及(5-F-piq)2 Ir(dpis)(6)的几何构型、电子结构、吸收及磷光发射光谱.

摘要： The dye sensitized solar cells (DSSCs) have been extensively studied due to their low production cost and simple fabrication process. Dye co-sensitization broadens the absorption spectrum of the sensitizer;thus enhances light harvesting efficiency;and contributes to the improvement of the DSSCs overall efficiency. In this study we performed theoretical design of complex molecule (C45H32N2O4) through combination (esterification reaction) of the natural dye lawsone and synthetic metal free indoline dye D131. The excitation energies, vibration spectra, molecular structures, electronic absorption spectra and electron transitions in individual dyes and complex molecule were investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT) B3LYP5 methods, with 3-21G, 6-31G and 6-31G(d,p) basis sets. The UV-Vis absorption spectra of the individual dyes and their mixture in chloroform solution were measured using spectrophotometer. For the complex formation reaction, enthalpy, entropy and Gibbs free energy were calculated and the results indicated the reaction was endothermic and non-spontaneous. Electron density distribution of the frontier and adjacent molecular orbitals and energy levels alignment were used for analysis of the electronic spectra and mechanism of transitions. The results indicated that the designed complex molecule satisfied the requirements for good photosensitizer of DSSCs.

摘要： 为了研究三个来源于高等真菌的化合物的绝对构型,采用理论计算与实验数据相结合的方法.运用时间依赖密度泛函理论(TDDFT)计算了这三个新化合物的电子圆二色谱(ECD)并与实验所测ECD谱图作比较,最终确定了它们的绝对构型.

摘要： 采用密度泛函理论B3LYP/6 31G(d)方法优化计算以香豆素作为发色基团,胺基为氢键供体形成的化合物(1)及其在氟离子作用下生成的新化合物(2)的分子结构.应用含时密度泛函理论(TD-DFT)计算它们的气相和液相电子光谱,研究了计算方法和溶剂模型对理论光谱的影响.从理论上解释香豆素基化合物可用于识别氟离子的作用机理.在考虑溶剂效应条件下,采用B3LYP/6-31(d)方法优化分子构型后,利用TDDFT方法获得的电子光谱与实验光谱吻合很好.%The molecular geometries of two compounds were optimized with B3LYP/6-31G(d) method,which based on coumarin,amino compounds for the formation of hydrogen bond donor by 1 and the fluoride ions generated under the action of the molecular structure of the new compound 2.The theoretical electronic spectra were calculated with TD-DFT in gas phase and solution phase.Explaining the mechanism of action to identify fluoride based on coumarin in theory.The influences of solvent model and calculation methods on the electronic absorption spectra were also probed.The obtained result suggest that electronic spectra calculated by TD-DFT on the bases of geometries optimized with B3LYP/6-31G(d) are in agreement with experimental ones,and can account for the different spectroscopic properties.

摘要： 采用量子力学的密度泛函B3LYP/6-31G(d)方法,研究含有不同取代基的三种7-乙酰氨基-1,8-萘啶衍生物分子的结构与理论光谱.分别在气相和液相中,对三种7-乙酰氨基-1,8-萘啶衍生物分子进行结构优化,并计算其紫外可见吸收光谱.不管在气相还是在液相,三种衍生物HOMO和LOMO能极差?E均很小.并且与气相的B3LYP/6-31G(d)计算所得到的结果相比较,液相B3LYP/6-31G(d)计算得到的的三种衍生物的最大吸收波长全部都产生了不同程度的红移.

摘要： Focusing our DFT calculations on the carboxylic acid drugs such as ibuprofen drug (IBF), it has been concluded that the anions of these types of drugs have the spontaneous electron donor character to all the carcinogenic cells of electron deficiency in their nuclei. Due to the spontaneity of electron transfer of anions, it has been found clinically that ibuprofen drug cures cancers of colon, protostate, lung and breast. The breast cancer treatment of Matthew Gdovin group in two hours by injection of ethanolic solution of nitrobenzaldehyde in the breast tumor in presence of uv-irradiation has been studied from TD-DFT point of view;the excited states of these molecules in presence of uv-irradiation act as electron donors to the cancerous cells to compensate the electron deficiency. Finally, it has been concluded that the electron transfer is the main cause of the breast cancer treatment which is the most aggressive type of cancers and is one of the hardest to treat.

摘要： 实验测量了1，1＇-联萘-2，2’-二胺（BINAM）的红外吸收光谱、可见光激发普通拉曼光谱、紫外共振拉曼光谱．用电子密度泛函方法计算了BINAM的基态几何构型、振动频率、普通拉曼和近共振拉曼强度．通过实验和理论计算对比，对所得红外和拉曼提出了详细的指认，并且分析了各振动模式的特征．BINAM的紫外共振拉曼光谱与普通拉曼光谱相比较，发现有若干拉曼谱带出现了选择性共振增强．基于共振拉曼强度分析，讨论了BINAM可能的激发态几何结构的变形．