absorption and phosphorescent mechanism of three Au（III） complexes, Au（2,5-F2C6H3-C^CAC）（C = C-C6H4N（C6Hs）2 [Au25FPh], Au（3,5-F2C6Ha-CACAC）（C=C-C6H4N（C6Hs）2 [Au35FPh], and Au（3,5-F2C6H3-CAC^C）（C=C-C6H4N（1H- indole）2 [Au35FID], are calculated and compared using density functional theory （DFT） and time-dependent DFT （TDDFT）. The calculated results reveal that enlarging the center CACAC ligand will result in the enhanced LMCT participation. This theoretical contribution allows design of new Au（III） complexes with higher phosphorescence efficiency.
通过系统的使用完全活化空间自洽场(CASSCF)和多组态二阶微扰理论(CASPT2)方法结合ANORCC(TZP)基组研究了CH_3Se自由基的低能电子态相关性质,计算过程中,采用Cs对称性.实验结果表明,该自由基的Jahn-Teller效应不明显(69 cm^(-1)),基态电子态1~2A'与其简并态1~2A″形成8 cm^(-1)的微小劈裂,这一点与实验值形成较好的吻合.计算所得基态电子态的C—Se的拉伸频率ν_6(a')为554.1 cm^(-1)与实验值的600±60 cm^(-1)吻合良好.另外计算中发现CH_3Se在0.025 e V、3.661 e V和7.322 e V处存在1~2A'→1~2A″、1~2A'→2~2A'(1~2A1)和1~2A'→1~2A″三处比较强烈的激发光谱.
通过系统的使用完全活化空间自洽场(CASSCF)和多组态二阶微扰理论(CASPT2)方法结合ANORCC基组对CH_3SS自由基的低能电子态进行理论研究.对于CH_3SS的基态X2A″的研究,计算S—S的伸缩模式与实验报告相一致.垂直激发能的计算结果显示,CH_3SS自由基在1.176 e V和3.422 e V两处存在比较强的激发,分别对应着X^2A″→1~2A'和X^2A″→2~2A″电荷跃迁.
A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru（dcbpyH2）2（NCS）2]（N3,dcbpy=4,4＇-dicarboxy2,2＇-bipyridine;NCS=thiocyanato）.Density functional theory（DFT） based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT（TD-DFT） results indicate that the ancillary ligand dominates the molecular orbital（MO） energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO（HOMO） to the lowest unoccupied MO（LUMO） and LUMO to LUMO＋1 orbital.If the gap between LUMO-LUMO＋1 is small enough,the higher efficiency of dye-sensitized solar cell（DSSC） should be expected.
The electronic structures and spectroscopic properties of heteroleptic cyclometalated iridium（Ⅲ） complexes were investigated. The geometries, electronic structures, and the lowest-lying excited states of （DBQ）2Ir（acac） and （MDQ）2Ir（acac） were investigated via density functional theory-based approaches. A series of designed models of （DBQ）2Ir（dpis）, （DBQ）2Ir（tpip）, （MDQ）2Ir（dpis） and （MDQ）2Ir（tpip） was also calculated for comparison. The structures in the ground and excited states were optimized via B3LYP method. The lowest absorptions and emissions spectra were evaluated via TD-B3LYP and TD-PBE1PBE methods, The computational results reveal that the emission peaks of the designed complexes are at around 585-640 nm, which belong to the orange-yellow wavelength. The frontier molecular orbital properties indicate that the Ir（Ⅲ） complexes have low efficiency roll-off.
SONG MingxingHUANG JianBAI FuquanWANG ChunxuLIU HongboWANG JinLI DongfeiQIN Zhengkun
A variety of heteroleptic ruthenium sensitizers have been engineered and synthesized because of their higher light-harvesting efficiency and lower charge-recombination possibility than the well known homoleptic N3 dye. As such, a great deal of atten- tion has been focused on sensitizers with the general formula Ru（ancillary-ligand）（anchoring-ligand）（NCS）2, among which important examples are Ru（4,4＇-bis（5-hexylthiophen-2-yl）-2,2＇-bipyridine）（4,4＇-carboxylic acid-4＇-2,2＇-bipyridine）（NCS）2 （C101） and Ru（N-（4-butoxyphenyl）-N-2-pyridinyl-2-pyridinamine）（4,4＇-carboxylic acid-4＇-2,2＇-bipyridine）（NCS）2 （J13）. In order to simulate experimental conditions with different pH values, the photosensitizing processes of these sensitizers pos- sessing different degrees of deprotonation （2I-I, lit to OH） have been explored theoretically in this work. Their ground/excited state geometries, electronic structures and spectroscopic properties are first calculated using density functional theory （DFT） and time-dependent DFT （TDDFT）. The absorption and emission spectra of all the complexes in acetonitrile solution are also predicted at the TDDFT （B3LYP） level. The calculated results show that the ancillary ligand contributes to the molecular or- bital （MO） energy levels and absorption transitions. It is intriguing to observe that the introduction of a thiophene group into the ancillary ligand leads directly to the increased energy of the absorption transitions in the 380-450 nm region. The calcula- tions reveal that although deprotonation destabilizes the overall frontier MOs of the chromophores, it tends to exert a greater influence on the unoccupied orbitals than on the occupied orbitals. Consequently, an obvious blue shift was observed for the absorptions and emissions in going from 21-1, 1H to OH. Finally, the optimal degree of deprotonation for C101 and J13 has al- so been evaluated, which is expected to lead to further improvements in the perfo
