咪唑[4, 5-f] 1, 10-邻菲罗啉及其2-取代芳基衍生物的电子结构与光谱性质

分别采用B3LYP/6-31G(d)和CIS/6-31G(d)方法对咪唑[4, 5-f] 1, 10-邻菲罗啉(ip)及其8种2-取代芳基衍生物的基态(S0)和单重激发态(S1)的几何构型进行了全优化, 并采用含时的度泛函理论(TD-DFT)计算了上述化合物的电子吸收和电子发射光谱. 分析了取代基对咪唑[4, 5-f] 1, 10-邻菲罗啉的电子结构、前线分子轨道、电离势Ip、电子亲和势EA及电子光谱的影响. 计算结果表明, 取代基使8种取代衍生物前线分子轨道(LUMO-HOMO)能隙降低,导致其最大吸收和发射波长均发生了红移. 化合物1～8的跃迁类型均为分子内电荷转移（ICT）跃迁,且1～4和5～8的电子转移方向刚好相反. 溶剂对其电子光谱也有影响, 振子强度增大, 最大发射波长红移. 另外, 8种取代衍生物的电离势降低, 电子亲和势增大, 化合物1~4易于空穴的注入, 5~8易于电子的注入.     

咪唑[4, 5-f] 1, 10-邻菲罗啉及其2-取代芳基衍生物的电子结构与光谱性质

分别采用B3LYP/6-31G(d)和CIS/6-31G(d)方法对咪唑[4, 5-f] 1, 10-邻菲罗啉(ip)及其8种2-取代芳基衍生物的基态(S0)和单重激发态(S1)的几何构型进行了全优化, 并采用含时的度泛函理论(TD-DFT)计算了上述化合物的电子吸收和电子发射光谱. 分析了取代基对咪唑[4, 5-f] 1, 10-邻菲罗啉的电子结构、前线分子轨道、电离势Ip、电子亲和势EA及电子光谱的影响. 计算结果表明, 取代基使8种取代衍生物前线分子轨道(LUMO-HOMO)能隙降低,导致其最大吸收和发射波长均发生了红移. 化合物1～8的跃迁类型均为分子内电荷转移（ICT）跃迁,且1～4和5～8的电子转移方向刚好相反. 溶剂对其电子光谱也有影响, 振子强度增大, 最大发射波长红移. 另外, 8种取代衍生物的电离势降低, 电子亲和势增大, 化合物1~4易于空穴的注入, 5~8易于电子的注入.     

Zn2+-Schiff’s Base Complex as an “On–Off-On” Molecular Switch and a Fluorescence Probe for Cu2+ and Ag+ Ions

The present study presents a thorough theoretical analysis of the electronic structure and conformational preference of Schiff’s base ligand N,N-bis(2-hydroxybenzilidene)-2,4,6-trimethyl benzene-1,3-diamine (H₂L) and its metal complexes with Zn²⁺, Cu²⁺ and Ag⁺ ions. This study aims to investigate the behavior of H₂L and the binuclear Zn²⁺ complex (1) as fluorescent probes for the detection of metal ions (Zn²⁺, Cu²⁺ and Ag⁺) using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The six conformers of the H₂L ligand were optimized using the B3LYP/6–311?+??+?G** level of theory, while the L^?2-metal complexes were optimized by applying the B3LYP functional with the LANL2DZ/6–311?+??+?G** mixed basis set. The gas-phase and solvated Enol-cis isomer (E-cis) was found to be the most stable species. The absorption spectra of the E-cis isomer and its metal complexes were simulated using B3LYP, CAM-B3LYP, M06-2X and ωB97X functionals with a 6–311?+??+?G** basis set for C, O, N and H atoms and a LANL2DZ basis set for the metal ions (Zn²⁺, Cu²⁺ and Ag⁺). The computational results of the B3LYP functional were in excellent agreement with the experimental results. Hence, it was adopted for performing the emission calculations. The results indicated that metal complex (1) can act as a fluorescent chemosensor for the detection of Ag⁺ and Cu²⁺ ions through the mechanism of intermolecular charge transfer (ICT) and as a molecular switch “On–Off-On” via the replacement of Cu²⁺ by Ag⁺ ions, as proved experimentally.

     

4氢-吡喃-4-硫酮1(n-π*),1Ag-(π→π*)和1Bu+(π→π*)等的激发态特征

理论上4氢-吡喃-4-硫酮的激发态特征用量子化学方法以及二维实空间分析法和三维立体实空间分析法加以研究.理论上的结果揭示1(n→π*)和1Ag-(π→π*)激发态是分子内电荷转移(ICT)激发态,而1Bu (π→π*)激发态是离域激发态.它们的跃迁偶极矩的强度和方向用三维密度跃迁(TD)加以解释,用三维电荷密度差(CDD)观察分子间电荷转移(ICT)的激发态特征或局部激发态特征.用二维实空间分析法研究电子.空穴相关性,离域化和激子的尺寸.     

4氢-吡喃-4-硫酮~1(n→π*),~1A_g~-(π→π*)和~1B_u~+(π→π*)等的激发态特征(英文)

理论上4氢-吡喃-4-硫酮的激发态特征用量子化学方法以及二维实空间分析法和三维立体实空间分析法加以研究.理论上的结果揭示^1（n→π^＊）和^1Ag^-（π→π^＊）激发态是分子内电荷转移（ICT）激发态,而^1Bu^＋（π→π^＊）激发态是离域激发态.它们的跃迁偶极矩的强度和方向用三维密度跃迁（TD）加以解释,用三维电荷密度差（CDD）观察分子间电荷转移（ICT）的激发态特征或局部激发态特征.用二维实空间分析法研究电子-空穴相关性,离域化和激子的尺寸.     

含苯丙氨酸席夫碱结构姜黄素衍生物的量化模拟

采用量子化学密度泛函理论在B3LYP/6-311G**水平对标题化合物可能存在的A、B、C三类互变异构体进行全优化,采用AIM 2000程序包计算了分子内氢键及相应的成键临界点电荷密度和关键原子的电荷;在计算的基础上,分析了异构体几何构型、相对稳定性和电荷分布,讨论分子内质子转移的难易程度. 采用含时密度泛函理论在相同水平上对其进行了电子吸收光谱研究. 为模拟真实条件,计算还考虑了水溶液对电子结构和光谱性质的影响. 研究结果表明：烯胺式B为最稳定结构,三个异构体稳定性为BAC. A、B、C的λmax均来源于     

含苯丙氨酸席夫碱结构姜黄素衍生物的量化模拟

采用量子化学密度泛函理论在B3LYP/6-311G**水平对标题化合物可能存在的A、B、C三类互变异构体进行全优化，采用AIM 2000程序包计算了分子内氢键及相应的成键临界点电荷密度和关键原子的电荷；在计算的基础上，分析了异构体几何构型、相对稳定性和电荷分布，讨论分子内质子转移的难易程度. 采用含时密度泛函理论在相同水平上对其进行了电子吸收光谱研究. 为模拟真实条件，计算还考虑了水溶液对电子结构和光谱性质的影响. 研究结果表明：烯胺式B为最稳定结构，三个异构体稳定性为BAC. A、B、C的λmax均来源于     

Theoretical study of the optical and charge transport properties in non-peripherally octasubstituted phthalocyanine–tetrabenzoporphyrin hybrids

The charge transfer rate of seven non-peripherally phthalocyanine–tetrabenzoporphyrin hybrids was investigated theoretically at the level of B3LYP/6-31+G(d,p) using density functional theory. The results showed that the hybrids are semiconductor molecules, which have a certain absorption in the visible region. The hole or electron transport capability of a non-peripherally substituted octamethyl phthalocyanine molecule is obviously better than that of phthalocyanine or non-peripherally substituted octafluorine, octamethoxy phthalocyanine molecules at 300 K, whereas the holes or electron transport capabilities of four non-peripherally substituted octamethoxy phthalocyanine–tetrabenzoporphyrin hybrids are basically the same. Overall, the hole transport capability of hybrids is superior to their electron transport capability. The charge transfer rate constant and the carrier mobility rate of three representative molecules using three methods, that is the long range-corrected functionals CHB-B3LYP and WB97XD, the metahybrid GGA M06-2X functional, are consistent with the use of the density functional B3LYP method.     

钴络合物催化甲醇羰基化制甲酸甲酯反应的理论研究

本文运用密度泛函理论B3LYP方法,对C、O、H采用6-311+G(2d,p)基组,计算研究了钴络合物催化甲醇羰基化制甲酸甲酯反应的微观机理,优化了各反应物、中间体和过渡态的构型特征,用频率分析方法和内禀反应坐标方法对过渡态进行了验证,同时对各中间体进行电荷分析.对比了催化过程与非催化过程的能垒.结果表明,有催化剂参与后反应活化能明显降低.     

Optical Properties of Neutral and Charged Low Band Gap Alternating Copolyfluorenes: TD-DFT Investigation

用含时的密度泛函(TD-DFT)方法研究了低带隙的中性和带电的交替共聚芴(Green 1),该化合物是由烷基取代芴和(1,2,5-噻吩基-3,4-硫重氮基)喹喔啉噻吩(T-TDQ-T)单元交替重复组成,对他们的激发态特性用二维(2D)和三维(3D)实空间分析方法做了进一步分析．对于中性的Green 1,分别得到其带隙、键能、激子结合能和核驰豫能．用3D跃迁密度方法对中性和带电的Green 1的跃迁偶极矩进行比较可显示出跃迁偶极矩的取向和强度;用3D电荷差异密度方法显示出激发后的中性和带电的Green 1电荷重新分布和比较,用2D实空间分析方法(跃迁密度矩阵)来研究中性和带电的Green1处于激发态时的电子空穴相干性．中性Green 1的激发态特性分别用TD-DFT和ZINDO两种方法进行了计算,比较得出电子-电子相互作用(在TD-DFT中)对激发态性质的重要影响．     

铱催化甲醇羰基化制乙酸循环反应的理论探究

采用密度泛函理论DFT-B3LYP方法,对铱、碘元素采用相对论校正赝势基组SDD,对C、O、H采用6-311+G(2d,p)基组,优化了各反应物、中间体和过渡态的构型特征,通过能量和振动分析证实了过渡态的真实性.理论研究了阴离子循环中铱催化甲醇羰基化制乙酸的循环反应机理.运用能量跨度模型获得了反应的动力学信息,确定了各反应的决速中间体和决速过渡态和各催化剂的能量跨度和转化频率.通过对cis-[Ir(CO)_2I_2]~-和trans-[Ir(CO)_2I_2]~-催化剂电荷密度的分析比较,得到中心金属的富电子性提高了其催化能力,以上计算结论与文献假设相符.     

铱催化甲醇羰基化制乙酸循环反应的理论探究

采用密度泛函理论DFT-B3LYP方法, 对铱、碘元素采用相对论校正赝势基组SDD, 对C、O、H采用6-311+G(2d, p)基组, 优化了各反应物、中间体和过渡态的构型特征, 通过能量和振动分析证实了过渡态的真实性. 理论研究了阴离子循环中铱催化甲醇羰基化制乙酸的循环反应机理. 运用能量跨度模型获得了反应的动力学信息, 确定了各反应的决速中间体和决速过渡态和各催化剂的能量跨度和转化频率. 通过对cis-[Ir(CO)2I2]- 和 trans-[Ir(CO)2I2]-催化剂电荷密度的分析比较, 得到中心金属的富电子性提高了其催化能力, 以上计算结论与文献假设相符.     

Transition Dipole,Charge Transfer,and Electron-hole Coherence in Two-photon Absorption: Visualizations with Two Dimensional Site and Three Dimensional Cube Representations

采用二维和三维实空间分析方法可视化了双光子吸收特征,包括跃迁距、电荷转移和电子空穴相干性. 跃迁密度的三维实空间分析揭示了跃迁距的强度和方向,电荷差异密度显示双光子吸收过程中的电荷转移方向. 跃迁密度矩阵的二维实空间分析可视化了电子和空穴的相干性. 二维和三维实空间分析有助于清晰地理解双光子吸收的电荷转移过程和激发的分子单元对双光子吸收的贡献.     

2-取代芳基菲并咪唑类化合物的电子结构和光谱性质的理论研究

运用密度泛函理论,在B3LYP/6-31G(d)水平上对菲并咪唑(PI)及其8种2-取代芳基衍生物的结构进行了全优化,探讨了取代基对分子结构、电离势(I_P)、电子亲和势(E_A)、电荷转移、前线分子轨道能量和电子吸收光谱等方面的影响.采用含时的度泛函理论(TD-DFT)计算了各分子的气相及液相的电子吸收光谱,计算结果与实验值十分接近.并用GaussSum2.1程序模拟吸收光谱和态密度(DOS)图,结果表明,芳基4′-位上取代基对菲并咪唑(PI)和苯环的骨架结构没有很大的扰动,但它们重新调整了菲并咪唑环和苯环中原子电荷分布,前线分子轨道(LUMO)-HOMO)能隙降低,导致8种取代的化合物的吸收波长均发生了红移.     

Theoretical investigation on the excited state intramolecular proton coupled charge transfer phenomenon for a novel fluorophore

We theoretically investigate the excited state behaviors of the novel fluorophore tetraphenylethene‐2‐(2′‐hydroxyphenyl)benzothiazole (TPE‐HBT), which was designed based on the intersection of TPE and HBT, using density functional theory and time‐dependent density functional theory methods. Compared with previous experimental results about fluorescence peaks, our calculated results are in good agreement with experimental data, which further confirms that the theoretical level we used is reasonable. Furthermore, our results confirm that the excited state intramolecular proton transfer (ESIPT) process happens upon photoexcitation, which is distinctly monitored by the infrared spectra and the potential energy curves. In addition, the calculation of highest occupied molecular orbital and lowest unoccupied molecular orbital reveals that the electron density change of proton acceptor because of the intramolecular charge transfer (ICT) process in the S₁ state induces the ESIPT. Moreover, the transition density matrix is worked out to facilitate deeper insight into the ESIPT coupled ICT process. It is hoped that the present work not only elaborates the ESIPT coupled ICT phenomenon and corresponding mechanisms for the TPE‐HBT but also may be helpful to design and develop new materials and applications involved in TPE‐HBT systems in future.     

Theoretical study on the influence of ancillary ligand on the energy and optical properties of heteroleptic phosphorescent Ir(III) complexes

The geometries, energies, and electronic properties of a series of phosphorescent Ir(III) complexes including FIrpic, FIrmpic, FIrpca, and FIrprza have been characterized within density functional theory DFT calculations, which can reproduce and rationalize experimental results. The properties of excited states of the Ir(III) complexes were characterized by the configuration interaction with single-excitation (CIS) method. The ground- and excited-state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. The absorption and phosphorescence wavelengths were computed based on the optimized ground- and excited-state geometries, respectively, by the time-dependent density functional theory (TD-DFT) methods. All the energies have been calculated by B3LYP method. The predictions revealed that the nature of the ancillary ligands can influence the distributions of frontier molecular orbitals and their energies, resulting in impact on the transition character and change in the emission color. In addition, the charge of transport quality has been estimated approximately by the predicted reorganization energy (λ). Our result also indicates that the substituent groups and different auxiliary ligand not only change the character of transition but also affect the rate and balance of charge transfer.     

Is the (hfac)Cu(I)–(tmvs) bond intrinsically weak?

Density functional theory studies were performed to study the structure and bonding of (hexafluoroacetylacetonate)-copper(I)-(trimethylvinylsilane) [Cu(hfac)(tmvs)], an ideal and important Cu(I)-CVD compound. A popular three-parameter hybrid density functional (B3LYP) with 6-311+G(d,p) and an effective core potential included LanL2DZ basis set was utilized for this purpose. The (hfac)Cu–(tmvs) bond energy of approximately 30?kcal?mol^?1 obtained at the B3LYP/6-311+G(d,p) level of theory reveals that the Cu–olefin bond in Cu(hfac)(tmvs) is not as weak as previously estimated/assumed and, hence, that the substrate plays a vital role in copper film formation from Cu(hfac)(tmvs). Bonding analysis reveals that fairly strong (hfac)Cu–(tmvs) bonding is the result of DCD-model σ-donation and π-back-bonding between the copper and tmvs in Cu(hfac)(tmvs).     

Quantum Chemical Calculations on 4-[2-(Tert-Butylamino)-1-Hydroxyethyl]-2-(Hydroxymethyl)Phenol by Density Functional Theory

Density functional theory (DFT) calculations have been carried out for the compound 4-[2-(tert-butylamino)-1-hydroxyethyl]-2-hydroxymethyl) phenol (4BAHEHMP) by using the B3LYP method at the 6-311++G (d,p) basis set level. The electric dipole moment (μ) and the first hyperpolarizability (α) values of the investigated molecule were computed. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis were presented. HOMO and LUMO energies confirm that charge transfer occurs within the molecule. In addition Molecular Electrostatic Potential (MEP), Natural Bond Orbital analysis (NBO) and Non- Linear Optical (NLO) properties are studied.     

The geometry structures and electronic properties of Li_mB_n(m+n=12) clusters

The geometric structures, electronic properties, total and binding energies, harmonic frequencies, the highest occupied molecular orbital to the lowest unoccupied molecular orbital energy gaps, and the vertical ionization potential energies of small LimBn （m＋ n = 12） clusters were investigated by the density functional theory B3LYP with a 6-31 I＋G （2d, 2p） basis set. All the calculations were performed using the Gaussian09 program. For the study of the LimBn clusters, the global minimum of the B 12 cluster was chosen as the starting point and the boron atoms were gradually replaced by Li atoms. The results showed that as the number of Li atoms increased, the stability of the LimBn cluster decreased and the physical and chemical properties became more active. In addition, on average there was a large charge transfer from the Li atoms to the B atoms.