钌联吡啶单配体双取代基效应

对钌联吡啶配合物及其单配体的4,4′ 双取代衍生物, 用量子化学密度泛函(DFT)方法在B3LYP/LanL2DZ水平上进行计算.探讨一些强的推电子基团(如－OCH3)和强的拉电子基团(如－NO2)的取代基效应对配合物的电子结构与相关性质,如配位键长、光谱性质等的影响规律,为该类配合物的合成,光、电、催化和生化作用机理分析提供理论参考.     

溶剂效应和取代基效应对2-(2-氨基苯基)苯并噻唑光谱性质及激发态分子内质子转移的影响

合成了多种2-(2-氨基苯基)苯并噻唑(APBT)氨基氢原子被供电子及吸电子基团取代的衍生物, 并用紫外光谱﹑荧光光谱等方法和密度泛函理论(DFT)计算研究了溶剂效应和取代基效应对衍生物的光谱性质及激发态分子内质子转移(ESIPT)的影响规律. 结果表明, 相比于非极性溶剂环己烷, 随溶剂极性的增加及APBT-溶剂分子间氢键的形成, APBT的紫外-可见最大吸收峰和荧光最大发射峰均发生了一定程度的红移, 并对APBT的ESIPT产生了影响. 在APBT分子的氨基氮原子上引入不同的吸电子或斥电子取代基, 对氮原子的电荷性质有较大的影响. 在环己烷溶剂中, 甲基取代后的APBT仅有单重荧光发射峰, 体系未发生ESIPT过程; 而COCH₂Cl等吸电子基团能促进APBT的ESIPT, 其荧光发射光谱出现了明显的双重峰, 表明体系发生了激发态分子内质子转移反应. 量子化学的理论计算较好地验证了光谱实验结果.     

1,10-邻菲咯啉衍生物La(III)配合物的电子结构与抗癌活性

对一系列1,10-邻菲咯啉衍生物La(III)配合物,用密度泛函(DFT)法,在B3LYP/LanL2DZ水平进行理论研究.探讨了配合物的电子结构与其抗癌活性的关系,发现偶极矩(μ)和原子净电荷(Q)都对配合物的抗癌活性有影响,但不起决定性作用,而配合物的LUMO的能量(ELUMO)是决定其抗癌活性强弱的主要因素.并且揭示了配体上侧链烷基链的增长并不是获得高活性分子的最佳途径,而侧链上苯环引入却为设计活性更强的分子提供了可能性.基于理论研究结果,设计了三个具有更高抗癌活性的新配合物.     

茂金属配合物[2,5-(Me3Si)2MeC5H2FeI(CO)2]的电子结构研究

运用G98W程序，采用Lan12dz基组，对茂金属配合物[2,4-(Me3Si)2MeC5H2F3I(CO)2]进行从头算研究，探讨了配合物结构单元的稳定性，分子轨道能量，原子净电荷布居规律，以及一些前线分子轨道组成特征等，结果表明，标题配合物在能量上可作为结构单元而稳定存在，该结构单元为茂金属配合物的合成，分子组装分析和催化活性研究提供理论依据。     

取代基效应对环金属Rh(Ⅲ)配合物二阶非线性光学性质影响的DFT研究

本文采用密度泛函理论(DFT)方法对系列环金属Rh(Ⅲ)配合物的结构与二阶非线性光学性质进行了计算研究.结果显示，配体中取代基的改变对配合物的几何结构和Wiberg键级影响不大.当主配体上的—H被其他强的供/吸电子基团取代时，配合物的极化率增大.其中，对于配合物1-6,主配体或副配体中强供/强吸电子基团的引入均有效地提高了配合物的第一超极化率(β_tot).而在配合物7-12中，配体中取代基的改变对配合物的β_tot值也有所提高，但幅度不大.此外，计算所得的配合物动态超瑞利散射超极化率(β_HRS)值与β_tot值的变化规律一致.对配合物的电子结构与吸收光谱的分析表明，体系具有较大的β_tot值与其吸收光谱的明显红移，较低的电子跃迁能，以及方向一致的电荷转移模式相关.     

单核Cu(Ⅱ)配合物C_(18)H_(12)CuN_4O-2的密度泛函研究

用量子化学从头算方法,在ROB3LYP/LANL2MB水平上,对单核配合物C18H12CuN4O2进行了理论计算,优化得到了该配合物的平衡几何构型,并计算了它的谐振动频率.结果表明:该配合物分子是可以稳定存在的,电子自旋布居主要集中在Cu原子及配体原子上,Cu原子和配体原子的自旋布居符号相同,说明体系中存在较强的自旋离域效应.体系的前沿轨道主要由Cu原子的d轨道和配体原子的p轨道组成,这种组成有利于配体与磁中心之间的电子转移.计算结果与实验符合得较好.     

含混合配体双核铜（I）配合物的合成及荧光光谱

合成了含双二苯基膦甲烷（dppm)和邻菲咯啉（phen)混合配体的双核铜（I）配合物[Cu(dppm)(phen)]2(NO3)21,并经X射线单晶结构分析表征了配合物的结构，研究了配合物的荧光光谱特征，配合物1的结构分析表明，dppm作为桥式双齿配体、phen作为双齿配体分别与铜原子形成四面体配位结构，硝酸根离子位于配合物外界。     

配合物Cu(phen)2 (dca)2的合成及晶体结构

合成了配合物Cu(phen)2 (dca)2(phen=C12H8N2为1,10-邻菲啰啉,dca-为二氰基氨基阴离子),用IR对其结构进行了初步表征,并测定了配合物的晶体结构.该晶体属单斜晶系,空间群为P21/c;晶胞参数a=0.8869(2)nm,b=1.4691(2)nm,c=1.9298(2)nm,β=100.90(1)°;V=2.4691(8)nm3,Z=4,F(000)=1132.00,Dc=1.496g/cm3,R=0.051,RW=0.068.中心铜(Ⅱ)离子分别与两个phen中的四个N原子和两个dca-的两个N原子配位,形成六配位的变形八面体结构.     

茂金属配合物[(eat5-C5H4R)Mo(CO)3 ]2(R: SiMe3 ,Si2Me5)的电子结构研究

运用G98W,采用Lanl2dz基组,对茂金属配合物[(eat5-C5H4R)Mo(CO)3]2 (R: SiMe3, Si2Me5)进行从头算研究,探讨配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律,以及一些前沿分子轨道的组成特征等,结果表明,标题配合物结构在能量上是稳定的,作为结构单元而存在.     

[Fe(phen)_3]·2ClO_4·2CH_2OH和[Cd(phen)_2(NO_3)_2]的合成及其晶体结构

以4-氨基苯甲酸和1,10-菲啰啉(phen)与高氯酸铁或硝酸镉反应,得到了两个邻菲啰啉的配合物:[Fe(phen)3]·2Cl O4·2CH2OH(1)和[Cd(phen)2(NO3)2](2)。并利用元素分析、红外光谱和X射线单晶衍射分析进行了表征。晶体结构分析表明,配合物(1)和(2)晶体属单斜晶系,C2/c空间群,其晶胞参数分别为:(1)a=35.708(3),b=15.903(2),c=12.204(1),β=102.504(6),V=6766(1)3,Z=8。(2)a=11.6887(6),b=15.2569(8),c=13.4630(10),β=105.9650(10),V=2310.5(2)3,Z=4。配合物(1)中phen上的氢原子与来自高氯酸根和乙二醇的氧原子形成氢键,并且相邻phen的吡啶环之间形成π~π堆积,从而使整个晶体扩展为三维网状超分子结构;配合物(2)中phen上氢原子与硝酸根的氧原子之间通过氢键使整个晶体扩展为三维网状超分子结构。     

Studies on 4,7-di-substitution effects of one ligand in [Ru(phen)3]2+ with DFT method

Studies on the complex [Ru(phen)3]2+ (phen = 1,10-phenanthroline) and its derivatives with 4,7-di-substitution on one ligand(phen) were carried out using the DFT method at the B3LYP/LanL2DZ level of theory. The trends in the substituent effects caused by the electron-pushing group (OH) and the electron-withdrawing group (F), on the electronic structures and the related properties, for example, the energies and the components of some frontier molecular orbitals, the spectroscopy properties, and the net charge populations of some main atoms of the complexes, etc., have been investigated. The computational results show that the substituents have some interesting effects on the electronic structures and the related properties of the complexes. First, according to the analysis of components of LUMO of the complexes, the electron-withdrawing group (F) can activate the main ligand (the substituted ligand, i.e., 2R-phen) and passivate the coligands, on the contrary, the electron-pushing group (OH) can activate the coligands and passivate the main ligand in the first electronic excited states of complexes. Second, both the electron-pushing group (OH) and the electron-withdrawing group (F) can cause a red shift in the electronic ground bands. Third, the characteristics of the atomic net charge populations on the main ligand can also be analyzed in detail by means of a schematic map expressed by several series of arrowheads based on the law of polarity alternation and the idea of polarity interference. The most negative charges are populated on N1, the next most net negative charges are populated on C3 among the skeleton atoms for the three complexes, etc. The computational results can be better used to explain some experimental phenomena and trends.     

A computational study of the effectiveness of the frontier molecular orbital formalism in predicting conformational isomerism in (p-RC6H4NC)2W(dppe)2

Ab initio electronic structure calculations on a series of ligands, p-RC6H4NC:, indicate, that the energy of the LUMO correlates with the electron-withdrawing/donating capabilities of the substituent group, which determines the relative pi-acidity of the ligand. Depending on the nature of the para substituent group on the aryl isocyanide ligand, bis(aryl isocyanide) complexes of tungsten-containing bulky bidentate arylphosphine ligands adopt either cis or trans conformations. The frontier molecular orbital formalism predicts that strong pi-acids, which contain electron-withdrawing groups, tend to polarize sufficient charge density away from the metal center to effect the formation of the sterically less favorable but electronically stabilized cis conformer. Density functional theory calculations on similar complexes containing phosphines which do not impose severe steric contraints indicate that the balance between steric and electronic stabilization can be effectively predicted by comparing the relative energies of the ligand LUMOs.     

The effects of the substitution on the imidazole ligand on the photochemical properties of fac-[Mn(CO)3(phen)(Imidazole)](SO3CF3) complexes

Photochemical and photophysical data are reported for a series of fac-[Mn(CO)(3)(phen)(Im-R)](SO(3)CF(3)) complexes, where phen is 1,10-phenanthroline and Im is imidazole. Intraligand and metal-to-ligand charge transfer (MLCT) transitions are observed in the electronic absorption spectra of these complexes and are sensitive to the nature of the ligand substituent. At room temperature the emission spectra show a clear progression from broad structureless MLCT to highly structured pi-pi* emission on going from R = -H, -CH(3), -C(6)H(5), to -Metro, where Metro is 2-methyl-5-nitroimidazole. Even at low temperatures the latter complexes show only the pi-pi* emission. The trend in the photophysical properties found in the emission spectra parallels the changes in the photochemical properties with the electron-donating or electron-withdrawing power of the substituent on the imidazole ligand. Although MLCT irradiation of the complexes with R = -H, -CH(3) leads to the mer-[Mn(CO)(3)(phen)(Im-R)](+) isomers, the complexes with the imidazole ligand substituted by -C(6)H(5) or -Metro release the Im-R ligand and produce the stereoretentive fac-[Mn(CO)(3)(phen)(S)](+) complexes. The stereochemical fate and mechanistic implications of the photolysis reactions are discussed in terms of the nature of ligand substitution.     

Photophysical study of a family of [Ru(phen)2(Me n dpq)]2+ complexes in different solvents and DNA: a specific water effect promoted by methyl substitution

The synthesis and spectroscopic characterisation of a family of ruthenium complexes [Ru(phen)(2)(Me(n)dpq)](2+)(n= 0, 1, 2) are reported and the photophysical effect of the progressive methyl substitution on the dpq ligand ascertained in a range of solvents and in the presence of DNA: [Ru(phen)(2)(dpq)](2+)(1), [Ru(phen)(2)(Medpq)](2+)(2) and [Ru(phen)(2)(Me(2)dpq)](2+)(3)(where dpq is dipyrido[3,2-f:2',3'-h]-quinoxaline; Medpq is 2-methyldipyrido[3,2-f:2',3'-h]-quinoxaline; Me(2)dpq is 2,3-dimethyldipyrido[3,2-f:2',3'-h]-quinoxaline and phen is 1,10-phenanthroline). The increase in electron density following substitution renders the quinoxaline nitrogen atoms more basic in the ground state to yield pK(a) values of -1.9, -2.3, and -2.7 for 3, 2, and 1, respectively. The methyl groups have a pronounced effect on the excited state photophysics of 1-3. In organic solvents, the non-radiative decay constant correlates well with the solvent polarity parameter pi*, with the effect being more pronounced with increasing methyl substitution. On the contrary, in aqueous solution there is a ca. four-fold decrease in the non-radiative decay constant upon methyl substitution. This "specific water effect" may be explained in terms of deactivation of the excited state by hydrogen bonding interactions between water and the quinoxaline nitrogen atoms, which is reduced on moving from 1 to 3. The excited state lifetimes and luminescence intensities for substantially increase when bound to DNA in aerated aqueous solutions, with a six-fold increase, compared to a more moderate three-fold increase for 2 and 3.     

M(bpy)_3~(2 )(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物M(bpy)2 M=Fe,Ru,Os)的量子化学密度泛函(DFT)法研究的结果.在B3LYP/LanL2DZ方法与基组的水平上进行计算 ,探讨M(bpy)32 的电子结构特征及相关性质 ,特别是中心原子对配合物的配位键长、光谱性质、电荷布居及化学稳定性等的影响规律 ,为该类配合物的合成 ,为分析光、电、催化作用机理提供理论参考.     

Synthesis, crystal structure, and luminescent properties of novel Eu3+ heterocyclic beta-diketonate complexes with bidentate nitrogen donors

New tris(heterocyclic beta-diketonato)europium(III) complexes of the general formula Eu(PBI)3.L [where HPBI = 3-phenyl-4-benzoyl-5-isoxazolone and L = H2O, 2,2'-bipyridine (bpy), 4,4'-dimethoxy-2,2'-bipyridine (dmbpy), 1,10-phenanthroline (phen), or 4,7-diphenyl-1,10-phenanthroline (bath)] were synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy (FT-IR), 1H NMR, high-resolution mass spectrometry, thermogravimetric analysis, and photoluminescence (PL) spectroscopy. Single-crystal X-ray structures have been determined for the complexes Eu(PBI)3.H2O.EtOH and Eu(PBI)3.phen. The complex Eu(PBI)3.H2O.EtOH is mononuclear, and the central Eu3+ ion is coordinated by eight oxygen atoms to form a bicapped trigonal prism coordination polyhedron. Six oxygens are from the three bidentate HPBI ligands, one is from a water molecule, and another is from an ethanol molecule. On the other hand, the crystal structure of Eu(PBI)3.phen reveals a distorted square antiprismatic geometry around the europium atom. The room-temperature PL spectra of the europium(III) complexes are composed of the typical Eu3+ red emission, assigned to transitions between the first excited state (5D0) and the multiplet (7F0-4). The results demonstrate that the substitution of solvent molecules by bidentate nitrogen ligands in Eu(PBI)3.H2O.EtOH richly enhances the quantum yield and lifetime values. To elucidate the energy transfer process of the europium complexes, the energy levels of the relevant electronic states have been estimated. Judd-Ofelt intensity parameters (Omega2 and Omega4) were determined from the emission spectra for Eu3+ ion based on the 5D0 --> 7F2 and 5D0 --> 7F4 electronic transitions, respectively, and the 5D0 --> 7F1 magnetic dipole allowed transition was taken as the reference. The high values obtained for the 4f-4f intensity parameter Omega2 for europium complexes suggest that the dynamic coupling mechanism is quite operative in these compounds.     

M(bpy)2+3(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物Ｍ（ｂｐｙ）＾２＋３（Ｍ＝Ｆｅ,Ｒｕ,Ｏｓ）的量子化学密度泛函法研究的结果。Ｂ３ＬＹＰ／ＬａｎＬ２ＤＺ方法与基组的水平上进行计算,探讨Ｍ（ｂｐｙ）＾２＋３电子结构特征及相关性质,特别是中心原子对配合物的配位键长、光谱性质,电荷布局及化学稳定性等的影响规律,为该类配合物的合成,为分析光、电、催化作用机理提供理论参考。     

[Ru(bpy)2L]2+、[Ru(phen)2L]2+(L=pytp,pztp)电子结构与抗癌活性研究

Theoretical studies on the complexes Ru(bpy)2L2+, Ru(phen)2L2+ (L=pytp,pztp) were carried out by using the density functional theory (DFT) method at B3LYP/LanL2DZ level. The relation between electronic structures and anti-cancer activities of complexes was investigated. The increasing of N in the main ligand can strengthen the interaction of complexes with DNA and anti cancer activities of complexes. The calculation results show that for complexes I-IV, their energies of LUMO orbital are in the order of εI>εII, εIII>εIV, the electron cloud components of LUMO come mainly from main ligands and the content distributing is in the order of I相似文献   

Effects of protonation on the spectroscopic properties of tetrapyridoacridine (TPAC) mono- and dinuclear Ru(II) complexes in their ground and (3)MLCT excited states

The spectroscopic behavior of mono- and dinuclear Ru(II) complexes (P, T, PP and TT, Figure 1) that contain the extended planar ligand tetrapyrido[3,2-a:2',3'-c:3' ',2' '-h:2' ',3' '-j]acridine (TPAC) and either 1,10-phenanthroline (phen) or 1,4,5,8-tetraazaphenanthrene (tap) as ancillary ligands is examined in water and as a function of the pH. These four complexes luminesce in aqueous solution. The analyses of the data in absorption lead to the pKa values in the ground state, and the data in emission show that the excited 3MLCT states are much more basic than the ground state. When the complex contains tap ligands (T and TT), a decrease in pH transforms the luminescent excited basic form into another luminescent excited protonated species, which emits more bathochromically. In contrast, with phen ancillary ligands (P and PP), the protonated excited state does not luminesce. The rate constant of first protonation of the 3MLCT state is diffusion controlled, except for the dinuclear PP complex, whose protonation takes place on the nitrogen of the acridine motif. For P, in which the protonation process is the fastest, it would take place on the nitrogen atoms of the nonchelated phen moiety of the TPAC ligand. These results allow also us to gain information on the localization of the excited electron in the 1MLCT state populated upon absorption as well as in the relaxed 3MLCT emissive state. Moreover as these complexes are interesting for their study with DNA, it can be concluded from these data that a portion of the excited species in interaction with DNA will be protonated.