氮化锇配合物离子[OsN(mnt)2]-的电子结构和光谱性质的理论研究

理论研究了离子型配合物[OsN(mnt)2]-[mnt=S2C2(CN)2)]的电子结构和光谱性质, 考察不同配体三价N、二硫氰烯S2C2(CN)2和金属Os的相互作用对光化学性质的影响. 分别在B3LYP/LANL2DZ和CIS/LANL2DZ水平上优化了配合物的基态和激发态结构. 与基态(1A1)相比, 激发态(3A2)的Os≡N 的键长缩短了0.0066 nm, 这与计算得到的频率增大一致, 使用TD-DFT方法计算得到了配合物的吸收和发射光谱. 计算得到的位于300 nm(f=0.1497)和262 nm(f=0.2890)的强吸收都来自1A1→1B1跃迁, 分别指认为SC→Os≡N+CN 和N+SC→Os≡N+CN的电子跃迁. 最低能量的吸收位于446 nm(f=0.0206) 处, 来自1A1→1B2的电子跃迁, 指认为N→Os和 N+SC→CN. 计算得到配合物在气态的磷光发射位于678 nm(A3A2→X1A1)处, 而在丙酮溶液中则蓝移到了625 nm处, 跃迁属性不变, 都是N→Os和S→Os的跃迁.     

Investigation on False Peak Phenomena in On-line Sweeping Technique in MEKC

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制备2，2′，4，4′-联苯四甲酸的新方法

氨基甲基苯甲酸;联苯四甲酸;合成;偶联;重氮盐     

Interlocking of molecular rhombi into a 2D polyrotaxane network via pi-pi interactions. Crystal structure of [Cu2(bpa)2(phen)2(H2O)]2.2H2O (bpa2- = biphenyl-4,4'-dicarboxylate,phen = 1,10-phenanthroline)

In the solid state, interlocking of the lateral phen ligands at the acute angle sites of the molecular [Cu2(bpa)2-(phen)2(H2O)]2 rhombi via aromatic pi-pi stacking interactions into the cavities of the adjacent rhombi generates laminated polyrotaxanes that are further assembled into a 3D network via similar interactions between the phen ligands at the obtuse angle sites.     

Theoretical studies of the spectroscopic properties of blue emitting iridium complexes

Electronic structures, absorptions and emissions of a series of (ppy)₂Ir(acac) derivatives (ppy = 2- phenylpyridine; acac = acetoylacetonate) with fluoro substituent on ppy ligands were investigated theoretically. The ground and excited states geometries were fully optimized at B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO is composed of d(Ir) and π(C^∧N), while the LUMO is localized on C^∧N ligand. The absorptions and emissions in CH₂Cl₂ media were calculated under the TD–DFT level with PCM model. The lowest-lying absorption of these complexes is dominantly attributed to metal-to-ligand and intraligand charge transfer (MLCT/ILCT) transitions and the emission of them originates from ³MLCT/³ILCT excited states. The absorption and emission of these complexes are blue-shifted by increasing the number of fluoro on phenyl, but the spectra are red-shifted by adding fluoro on pyridyl. While a single fluoro of different substituted site on phenyl results in different extent blue-shift to the spectra.     

Theoretical studies on structures and spectroscopic properties of photoelectrochemical cell ruthenium sensitizers, [Ru(Hmtcterpy)(NCS)3]n- (m = 0, 1, 2, and 3; n = 4, 3, 2, and 1)

A series of ruthenium(II) complexes, [Ru(tcterpy)(NCS)3](4-) (0H), [Ru(Htcterpy)(NCS)3](3-) (1H), [Ru(H2tcterpy)(NCS)3](2-) (2H), and [Ru(H3tcterpy)(NCS)3](-) (3H) (tcterpy = 4,4',4'-tricarboxy-2,2':6',2'-terpyridine), are investigated theoretically to explore their electronic structures and spectroscopic properties. The geometry structures of the complexes in the ground and excited states are optimized by the density functional theory and single-excitation configuration interaction methods, respectively. The absorption and emission spectra of the complexes in gas phase and solutions (ethanol and water) are predicted at the TDDFT(B3LYP) level. The calculations indicate that the protonation effect slightly affects the geometry structures of the complexes in the ground and excited states but leads to significant change in the electronic structures. In cases of both absorptions and emissions, the energy levels of HOMOs and LUMOs for 0H-3H decrease dramatically as a result of the introduction of the COOH groups. The protonation much stabilizes the unoccupied orbitals with respect to the occupied orbitals. Thus, both the absorptions and emissions are red-shifted from 0H to 3H. The phosphorescence of 0H-3H are attributed to tcterpyridine --> d(Ru)/NCS ((3)MLCT/(3)LLCT) transitions. The solvent media can influence the molecular orbital distribution of the complexes; as a consequence, the spectra calculated in the presence of the solvent are in good agreement with the experimental results. The MLCT/LLCT absorptions of 0H in ethanol and water are red-shifted relative to that in the gas phase. However, the MLCT/LLCT absorptions of the protonated complexes (1H-3H) are blue-shifted in ethanol and water with respect to the gas phase. Similarly, the solvent effect causes a blue-shift of the phosphorescent emission for 0H-3H.     

DFT and TD-DFT calculations on the electronic structures and spectroscopic properties of cyclometalated platinum(II) complexes

The electronic structures and spectroscopic properties of the three tridentate cyclometalated Pt(II) complexes Pt(N/\N/\C)C(triple bond)CPh (N/\N/\CH = 6-phenyl-2,2'-bipyridine) (1), Pt(N/\N/\S)C(triple bond)CPh (N/\N/\SH = 6-thienyl-2,2'-bipyridine) (2), and Pt(N/\N/\O)C(triple bond)CPh (N/\N/\OH = 6-furyl-2,2'-bipyridine) (3) were investigated theoretically using the density functional theory (DFT) method. The geometric structures of the complexes in the ground and excited states were explored at the B3LYP and UB3LYP levels, respectively. The absorption and emission spectra of the complexes in CH2Cl2 and CH3CN solutions were calculated by time-dependent density functional theory (TD-DFT) with the PCM solvent model. The calculated energies of the lowest singlet state and lowest triplet state in the three complexes are in good agreement with the results of experimental absorption and luminescence studies. All of the lowest-lying transitions were categorized as LLCT combined with MLCT transitions. The 623-nm emission of 1 from the 3A' --> 1A' transition was assigned as 3LLCT and 3MLCT transitions, whereas the 657- and 681-nm emissions of 2 and 3, respectively, were attributed to 3ILCT perturbed by 3MLCT transitions. NLO response calculations revealed that the nonzero values of the static first hyperpolarizability (beta0) for 1-3 are greatly enhanced through the introduction of the metal Pt(II) into the cyclometalated ligands, an effect that is determined by MLCT and LLCT transitions.     

Anion-selective interaction and colorimeter by an optical metalloreceptor based on ruthenium(II) 2,2'-biimidazole: hydrogen bonding and proton transfer

A new anion sensor [Ru(bpy)2(H2biim)](PF6)2 (1) (bpy = 2,2'-bipyridine and H2biim = 2,2'-biimidazole) has been developed, in which the Ru(II)-bpy moiety acts as a chromophore and the H2biim ligand as an anion receptor via hydrogen bonding. A systematic investigation shows that 1 is an eligible sensor for various anions. It donates protons for hydrogen bonding to Cl-, Br-, I-, NO3-, HSO4-, H2PO4-, and OAc- anions and further actualizes monoproton transfer to the OAc- anion, changing color from yellow to orange brown. The fluoride ion has a high affinity toward the N-H group of the H2biim ligand for proton transfer, rather than hydrogen bonding, because of the formation of the highly stable HF2- anion, resulting in stepwise deprotonation of the two N-H fragments. These processes are signaled by vivid color changes from yellow to orange brown and then to violet because of second-sphere donor-acceptor interactions between Ru(II)-H2biim and the anions. The significant color changes can be distinguished visually. The processes are not only determined by the basicity of anion but also by the strength of hydrogen bonding and the stability of the anion-receptor complexes. The design strategy and remarkable photophysical properties of sensor 1 help to extend the development of anion sensors.     

模板剂在分子筛合成过程中的作用机理

启用分子模拟途径,通过Lennard-Jones势对模板剂分子与分子筛骨架间非成键作用的能学分析,论证n=5、6的双季铵盐［(CH₃)₃N(CH₂)_nN(CH₃)₃］Br₂在ZSM-50分子筛骨架合成过程中所起的模板作用。     

Self-Assembled Three-Dimensional Coordination Polymers with Unusual Ligand-Unsupported Ag−Ag Bonds: Syntheses,Structures, and Luminescent Properties

A staggered arrangement like that of the hydrogen atoms in ethane is exhibited by the six phenol groups about each pair of silver atoms in the self-assembled three-dimensional coordination networks [Ag₂(H₂L)₃]_nX_2n (H₂L=N,N′-bis(salicylidene)-1,4-diaminobutane; X⁻=NO₃⁻ or ClO₄⁻); the former is depicted (for clarity the H₂L ligands are represented by long rods and the Ag atoms by hatched circles). These solids contain short ligand-unsupported metal–metal bonds and display intense blue photoluminescence at room temperature.