鲁米诺-二甲亚砜-氢氧化钠体系化学发光机理的理论研究

用密度泛函理论(DFT) B3PW91/6-31G**方法研究了鲁米诺-二甲亚砜-氢氧化钠化学发光反应体系中反应物、中间体和产物的分子结构和振动频率, 用B3PW91/6-311＋G(3df,2p)方法获得反应能量以及用时间相关(Time Dependent, TD)的B3PW91/6-311＋G(3df, 2p)方法进行电子激发能态分析. 研究结果支持了下列化学发光反应通道: LH₂(¹A)＋OH^－ →LH₂•OH^－(¹A)→LH^－(¹A)→L^·－(²A)→TS₁(³A)→LO₂^2－(³A)→TS₂(³A)→AP^2－*(?³A)→AP^2－(X³A)＋hν, 最后即AP^2－*回到基态发光; 或AP^2－*(?³A)→AP^2－*(?¹A)→AP^2－(a¹A)＋hν, 即激发态势能面交叉后的单重态跃迁发光. 它们在可见光区域主要有400～460和500～530 nm的强吸收谱带, 与实验结果符合. 研究还表明, 质子化的鲁米诺能量将大幅度降低, 说明酸性溶液导致鲁米诺的反应活性降低, 从理论上解释了鲁米诺化学发光体系的溶液须呈碱性, pH值影响发光反应的实验事实.     

开环茂金属成环及氢分子消除反应机理的理论研究

采用密度泛函方法(DFT)在M06-2X/def2-TZVPP//B3LYP/def2-TZVPP+ZPE水平下, 对以开环的(η⁵-C₅H₇)₂Ru为前驱体生成闭环(η⁵-C₅H₅)₂Ru的各种可能的反应路径进行了详细的研究. 最终确定其反应机理为: (η⁵-C₅H₇)₂Ru的一个η⁵-C₅H₇发生端碳成键的成环反应形成(η³-C₅H₇)Ru(η⁵-C₅H₇), 经过两步氢原子迁移到Ru原子上, 之后脱掉一个氢气分子形成(η⁵-C₅H₅)Ru(η⁵-C₅H₇), 而后另一个η⁵-C₅H₇再重复成环并进行两步氢迁移以及氢气分子消除而得到最终的产物(η⁵-C₅H₅)₂Ru.     

用GGA密度泛函及其长程、色散校正方法计算各类氢键的结合能

应用广义梯度近似(GGA) (PW91和PBE)、含动能密度的广义梯度近似(meta-GGA) (M06-L)、杂化泛函(hyper-GGA)(M06-2X、X3LYP和B3LYP)及其长程校正泛函LC-DFT(CAM-B3LYP、LC-ωPBE和ωB97X)和色散校正密度泛函(DFT-D)(ωB97X-D和B97-D),用多种基函数对15种不同强度的传统氢键和非传统氢键体系的结合能进行了系统的计算与分析.并与高精度的CCSD(T)/aug-cc-pVQZ结果比较发现:在上述各类泛函中,对于氢键结合能的计算M06-2X和ωB97X-D泛函较为精确与可靠,且没有必要使用过大的基函数,6-311++G(2d,2p)或aug-cc-pVDZ水平的基组就已足够,各类泛函所计算结合能的基组重叠误差(BSSE)均较小,除ωB97X和ωB97X-D外,其它9种泛函不经BSSE校正也能得到同样甚至更准确的结果.     

两个半夹心型聚吡唑硼酸盐羧酸钴配合物的合成、结构及催化活性

设计合成了2个结构新颖的半夹心单核聚吡唑硼酸盐羧酸配合物Tp^*Co(Hglu)(CH₃OH)(1)和Tp^*Co(Hsub)(H₂O)(2)[Tp^*=三聚(3,5-二甲基吡唑)硼酸根, H₂glu=戊二酸, H₂sub=辛二酸], 并通过元素分析、 红外光谱、 紫外-可见光谱和X射线单晶结构分析对标题配合物进行了表征. 结构分析表明, 在配合物1和2中, 配体Tp^*都是三齿配位, 配位模式相同; 戊二酸和辛二酸都以μ₁-η¹-η¹的端基配位模式与金属相连. 此外, 还对配合物的热稳定性进行了详细分析, 并初步探讨了配合物催化氧化环己烷的催化活性.     

芳基四硫富瓦烯与溴化铜电荷转移复合物的合成及晶体结构

采用溶液扩散的方法合成了硫原子桥联芳基取代四硫富瓦烯1～4与CuBr₂的4种电荷转移复合物(1^+·)(Cu₂Br₆)_0.5、(2^+·)(Cu₂Br₆)_0.5、(3^+·)(Cu₂Br₆)_0.5和(4^+·)(CuBr₂)。晶体结构研究表明,复合物中阴离子呈现2种构型：八面体型(Cu₂^ⅡBr₆)^2-和直线型(Cu^ⅠBr₂)^-,并且4种复合物呈现不同的堆积结构。通过调控芳基上卤素原子取代位置和大小,实现了对电荷转移复合物堆积结构和阴离子构型的有效调控。     

邻苯二甲酸单甲酯桥联双核铜(Ⅱ)配合物磁性的理论研究

采用对称性破损态方法结合密度泛函理论,选用典型的强反铁磁双核配合物作为研究对象,通过与实验数据相比较,探讨了不同密度泛函方法与基组对计算铜配合物[Cu2(mMP)4(H2O)2]·H2O交换耦合常数的准确度.结果表明,4种混合密度泛函DFT(B3LYP,B3P86,B3PW91和PBE0)的计算结果都能和实验所观察到的值-324cm-1符号一致,但B3PW91方法得到的结果和实验结果吻合程度最好,同时采用方法B3PW91方法计算所得的交换耦合常数Jab对基组的依赖性较大.研究表明,2个Cu(Ⅱ)离子之间的反铁磁相互作用主要源于单占据分子轨道SOMOs大的能量劈裂和桥联配体O-C-O轨道的重叠.     

Synthesis,Characterization and Theoretical Studies on a Thiocarbamide Derivative Containing Schiff Base Group

A thiocarbamide derivative containing Schiff base groups,1,5-bis[4-(dimethylamino)benzylidene]thiocarbonohydrazide,has been synthesized and characterized by elemental analysis,IR,1H NMR,UV and X-ray single-crystal diffraction.Density function theory(DFT) calculations at the B3LYP/6-31G* and PBE0/6-31G* levels for optimized geometries and electronic transition spectra have been performed.Comparative studies show that both B3LYP/6-31G* and PBE0/6-31G* methods can well reproduce the molecular structure,and the latter is more reliable than the former to simulate electronic spectra.NPA calculational results at the B3LYP/6-31G* level indicate the title compound to be a potential multidentate ligand to the metallic ions.Based on the vibrational analysis,thermodynamic properties at different temperatures have been obtained.     

双环金属铱(Ⅲ)异腈配合物的二阶非线性光学性质

采用密度泛函理论(DFT)方法对双环金属Ir(III)异腈配合物的非线性光学(NLO)性质进行计算研究。用B3PW91(UB3PW91)(金属原子采用LANL2DZ基组,非金属原子采用6-31G*基组)方法对配合物进行几何结构优化。在优化构型基础上,采用B3PW91(UB3PW91)和B3LYP(UB3LYP)方法计算了配合物的第一超极化率(βtot),并用CAM-B3LYP(UCAM-B3LYP)(金属原子采用LANL2DZ基组,非金属原子采用6-31G**基组)方法模拟配合物的吸收光谱。结果表明,主配体的取代基(R1)和副配体的取代基(R2)对第一超极化率值贡献不大。配合物发生氧化还原反应,电荷转移方式增多,电荷转移程度增大,使βtot值显著增加,其中1a+([(C∧N)2Ir(CNR)2]+(R=CH3))发生氧化反应和还原反应的βtot值分别增大了75倍和144倍。因此,这类双环金属铱(III)异腈配合物的氧化还原反应可以有效地调节其二阶NLO性质。     

碱式碳酸锌对[UO2(CO3)3]4-吸附机理的研究

用吸附法从海水中提铀的研究已引起了广泛的注意,碱式碳酸锌则是常用的吸附材料之一。本文报道用碱式碳酸锌对[UO₂(CO₃)₃]^4-吸附机理的研究结果。从不同碱度的碱式碳酸锌吸附[UO₂(CO₃)₄]^4-中铀的实验,得出在一定的—OH浓度范围内,碱式碳酸锌中—OH含量越高,对[UO₂(CO₂)₃]^4-中铀吸附率越大的结果。同时使用X射线衍射法与红外光谱法,亦对吸附机理进行了初步研究,由此扩大了研制新吸附剂的线索。     

8-羟基喹啉铍及其衍生物电子光谱性质的含时密度泛函理论研究

运用密度泛函理论(DFT)B3LYP方法和abinitioHF单激发组态相互作用(CIS)法分别优化了有机金属配合物8-羟基喹啉铍(BeQ₂)及其3种衍生物分子的基态及最低激发单重态几何结构.系统分析了分子结构、前线分子轨道特征和能级分布规律以探索电子跃迁机理.应用含时密度泛函理论(TD-DFT)计算分子的电子光谱,揭示了BeQ₂及其衍生物的发光源于配体中π→π^*电子跃迁,指出通过配体修饰可以有效地影响配合物前线分子轨道分布,调整发光波段,并有效提高电荷转移量.     

Preparation, spectroscopic properties and thermal stabilities of organomercury compounds containing the bulky ligand (Me3Si)3C or (PhMe2Si)3C

Mercury compounds of the types HgR¹R (R¹ = C(SiMe₃)₃; R = Me, ⁱPr, Bu, ^tBu or Ph) and HgR²R(R² = C(SiMe₂Ph)₃; R = Me, Bu, CH₂Ph or Ph) have been prepared. Those containing R¹ were made by reactions of the bromides HgR¹Br with the Grignard reagents MgRX, and those containing R² by reaction of HgR²Cl with LiR or, for R = CH₂Ph, with Mg(CH₂Ph)Cl. Replacement of one R group in HgR₂ by the bulky R¹ or R² group leads to a large increase in thermal stability, a marked shift in the ¹⁹⁹Hg resonance to lower frequency and an increase in the coupling constant ¹J(¹³C---¹⁹⁹Hg) for the Hg---R bond. The compound HgR²Cl does not react further with LiR² in tetrahydrofuran, but with LiR¹ gives HgR¹R²; the arrangement of the SiMe₂Ph groups in the latter in solution in CH₂C12 at low temperature appears to be different from that in the solid.     

Platination of [3-X-7,8-Ph2-7,8-nido-C2B9H8] (X=Et, F): Synthesis and characterisation of slipped and 1,2→1,7 isomerised products

The reaction of the labelled carborane ligand [3-Et-7,8-Ph₂-7,8-nido-C₂B₉H₈]²⁻ with a source of {Pt(PMe₂Ph)₂}²⁺ affords non-isomerised 1,2-Ph₂-3,3-(PMe₂Ph)₂-6-Et-3,1,2-closo-PtC₂B₉H₈ (1). The analogous reaction between [3-F-7,8-Ph₂-7,8-nido-C₂B₉H₈]²⁻ and {Pt(PMe₂Ph)₂}²⁺ yields 1,8-Ph₂-2,2-(PMe₂Ph)₂-4-F-2,1,8-closo-PtC₂B₉H₈ (3). Compound 1 has a heavily slipped structure (Δ 0.72 Å), which to some degree obviates the need for C atom isomerisation. However, that it is a kinetic product of the reaction is evident from the fact that it reverts to isomerised 1,8-Ph₂-2,2-(PMe₂Ph)₂-4-Et-2,1,8-closo-PtC₂B₉H₈ (2) slowly at room temperature but more rapidly with gentle warming. The heteroatom and labelled-B atom positions in the isomerised compounds 2 and 3 may be explained most simply by the rotation of a CB₂ face of an intermediate based on the structure of 1. Compounds 1–3 were characterised by a combination of spectroscopic and crystallographic techniques.     

Some further studies of estertin compounds. crystal structures of [NEt4][MeO2CCH2CH2Sn(dmio)2] (dmio = 1,3-dithiole-2-one-4,5-dithiolato) and (MeO2CCH2CH2)2SnX2[X2 = I2, (NCS)2 or Cl, Br]

Estertn compounds, (MeO₂CCH₂CH₂)₂SnX₂ [X₂ = I₂ (2); X₂ = Br₂ (9); X₂ = Cl, Br (4)) or X₂ = (NCS)₂ (3)] have been obtained by halide exchange reactions of (MeO₂CCH₂CH₂)₂SnCl₂. Crystal structure determinations of 2–4 revealed chelating MeO₂CCH₂CH₂ units with distorted octahedral geometries at tin. The Sn---O bond lengths in the isothiocyanato complex, 3, are shorter [2.390(11) to 2.498(12), mean 2.439 Å], with the chelate bite angles, C---Sn---O, larger [74.3(7) to 78.2(6), mean 76.0°] than those in the halide analogues 2 and 4 [Sn---O = 2.519(2) to 2.541(8), mean 2.530 Å; C---Sn---O 72.8(3) to 73.9(4), mean 73.3°]. ¹H, ¹³C and ¹¹⁹Sn NMR and IR spectra of 2–4 and 9 were determined in CDCl₃ solution: the NMR spectra of (MeO₂CCH₂CH₂)₂SnX₂ show the following trends: (i) both δ¹H and δ¹³C, increase and (ii) both ²J (Sn---H) and ¹J(Sn---C) decrease in the sequence X₂ = (NCS)₂, Cl₂, ClBr, Br₂ and I₂. The MeO₂CCH₂CH₂ and dmio groups (dmio = 1,3-dithiole-2-one-4,5-dithiolato) are all chelating groups in (MeO₂CCH₂CH₂)₂Sn(dmio) (5). As shown by X-ray crystallography, the tin atom in the anion of solid [Q][MeO₂CCH₂CH₂Sn(dmio)₂] 6 (Q = NEt₄) forms 5 strong bonds [to C and the 4 thiolato S atoms, Sn---S 2.459(2) to 2.559(2) Å], arranged in a near trigonal bipyramidal array. There is an additional Intramolecular but weaker, interaction with the carbonyl oxygen atom [Sn---O = 3.111(5) Å]; v(C=O) = 1714 cm⁻¹ in solid 6 (Q = NEt₄). NMR spectra of 5 and 6 are also reported.     

Simulated T ← S spectra of benzaldehydes as a function of the energy gap between the ππ and nπ levels

The T_1,2 ← S₀ spectra of benzaldehydes have been studied as a function of the energy separation between the vibrationless levels. It is shown that the spectra are very complicated in the region of ΔE[T₂⁰(nπ^*)-T₁⁰(ππ^*)] = 250–400 cm⁻¹, reflecting effective vibronic interferences between T₂⁰(0-0) and each of the ν₃₆-ν₃₃ out-of-plane vibrational levels of T₁⁰(ππ^*). The simulated spectra correspond to the observed spectra. In the case of T₁⁰ = ³nπ^* and T₂⁰ = ³ππ^* the spectral change is not so drastic as in the reverse case loc. cit. because the optical intensity generally concentrates in the longest wavelength band, i.e., the origin band of the T₁(nπ^*) ← S₀ transition. The simulation spectra are useful for interpretation of the absorption spectra in similar electronic structure systems of substituted benzaldehydes.     

Darstellung von metallkomplexen des thio- und selenoacetaldehyds sowie die kristallstruktur von C5H5Rh(η-CH3CHSe)P(i-Pr)3

The compounds C₅H₅Co(η²-CH₃CHS)PMe₃ (I) and C₅H₅Co(η²-CH₃CHSe)PMe₃ (II) are prepared from C₅H₅Co(CO)PMe₃, CH₃CHBr₂ and NaSH or NaSeH, respectively. The synthesis of the corresponding rhodium complexes C₅H₅Rh(η²-CH₃CHS)P(i-Pr)₃ (VI) and C₅H₅Rh(η²-CH₃CHSe)P(i-Pr)₃ (VII) has been achieved through hydrogenation of C₅H₅Rh(η²-EC=CH₂)P(i-Pr)₃ (E = S, Se), using RhCl(PPh₃)₃ as a catalyst. The crystal structure of VII has been determined.     

DFT and TD-DFT investigation of the ground and excited states for dinuclear and mononuclear copper(I) and silver(I) complexes of 3,5-bis(trifluoromethyl)pyrazole and related bis(pyrazolyl)borate

The ground-state and low-lying excited electronic states in mononuclear, {H₂B[3,5-(CF₃)₂Pz]₂M(2,4,6-Cn)} (M₁) and dinuclear {[3,5-(CF₃)₂Pz]M(2,4,6-Cn)}₂, (M₂) (Pz = pyrazole, Cn = collidine and M = Cu, Ag), are studied using DFT approach. Electronic properties are calculated using B3LYP, while excited singlet and triplet-states are examined using TD-B3LYP. All the calculated low-lying transitions are categorized as ¹MLCT transitions. A good agreement was found between experimental spectra and predicted emission wavelengths (λ_em), the corresponding emissive states being assigned as ³MLCT for Cu₁ and Ag₂, ³MLLCT for Ag₁ and ³LLCT for Cu₂.     

A case study in performance evaluation of Density Functional Tight Binding method in two-layer ONIOM method

A performance evaluation of Density Functional Tight Binding (DFTB) in the two-layer ONIOM method is presented in an effort to estimate DFTB effectiveness as an inexpensive low level quantum mechanical layer. Ground state geometries, geometry error, S-values and energy error for: (H₂O)_x(MeOH)_y, [(η⁵-C₅Me_nH_5−n)₂Ti]₂(μ₂, η²,η²-N₂), n = 4, and complexes of Cu⁺ with tyrosine, were compared to target calculations at B3LYP level of theory for all three of the systems and second order Moller-Plesset (MP2) target level of theory for the first two systems. The calculated root-mean-square errors (RMS) of the ONIOM optimized geometries relative to the target are found to be small. The DFTB level of theory was unable to reproduce the target geometry structure for one of the isomers of tyrosine–Cu⁺ complex, while the ONIOM combinations were able to reproduce all target structures. The absolute value of the geometry error was determined to be smaller then the corresponding energy error except for the (H₂O)_x(MeOH)_y system at the ONIOM(MP2/6-31G(d,p):DFTB) level of theory. The S-values were relatively small and close in value contributing to relatively small energy errors. Both method combinations ONIOM(MP2:DFTB) and ONIOM(DFT:DFTB) show similar performance compared to the corresponding target level of theory. The results also suggest that it is safe to use ONIOM(DFT:DFTB) for investigations of [(η⁵-C₅Me_nH_5−n)₂Ti]₂(μ₂, η²,η²-N₂) complexes.     

自由基照相体系的ESR波谱研究

本文用自旋捕获剂t-BuNO(2-甲基2-亚硝基丙烷)与ESR技术结合的方法研究了CBr₄-φ₂NH、CBr₄-LCV及CBr₄-LMG体系的光化学过程。从ESR谱的超精细结构及其随组分浓度的变化,证实了上述体系中除有Br^·外,还分别形成了 自由基。由这些体系在避光条件下的UV谱,证明溶液中存在(HX…CBr₄)型的部分电荷转移络合物。因此,上述自由基照相体系的光引发反应既包括CBr₄的光解,又包括(HX…CBr₄)^*的光解。     

Synthesis and properties of some diruthenium acetate compounds

The compound [Ru₂(μ-O₂CCH₃)₄(THF)₂]BF₄ (I) containing the Ru₂⁵⁺ unit was prepared by reaction of Ru₂Cl(μ-O₂CCH₃)₄ with AgBF₄ in THF. This compound, in contrast with Ru₂Cl(μ-O₂CCH₃)₄, is soluble in several polar organic solvents and reacts in THF with OPPh₃ and PPh₃ giving [Ru₂(μ-O₂CCH₃)₄(OPPh₃)₂]BF₄·CH₂Cl₂ (II) and [Ru(μ-O₂CCH₃)(O₂CCH₃)(PPh₃)]_n (III), respectively. The complex II has been also obtained as hexafluorophosphate [Ru₂(μ-O₂CCH₃)₄(OPPh₃₂]PF₆·CH₂Cl₂ (IV) by treatment of Ru₂Cl(μ-O₂CCH₃)₄ with an excess of NOPF₆ and PPh₃ in methanol. In this reaction the triphenylphosphine oxide is generated by oxidation of the triphenylphosphine.     

Tricarbonylrhenium(I) complexes of phosphine-derivatized amines, amino acids and a model peptide: structures, solution behavior and cytotoxicity

Modified Mannich reactions of amines, amino acids and a model peptide with Ph₂PH and CH₂O gave bis(diphenylphosphinomethyl)amines (Ph₂PCH₂)₂NR [R=Ph (1), CH₂CH₂OH (2), CH₂COOCH₂Ph (3), CH₂CONHCH₂COOCH₂Ph (4), CH₂COOH (5)] and (Ph₂PCH₂)₂NCH₂CH₂N(CH₂PPh₂)₂ (6). Reaction with [ReBr₃(CO)₃]²⁻ under mild conditions led to [ReBr(CO)₃]{(Ph₂PCH₂)₂NR} [R=Ph (7), CH₂CH₂OH (8), CH₂COOCH₂Ph (9), CH₂CONHCH₂COOCH₂Ph (10), CH₂COOH (11)] and [ReBr(CO)₃(Ph₂PCH₂)₂NCH₂]₂ (12). All new complexes have been characterized by NMR and IR spectroscopy and for 7, 9 and 10, single-crystal X-ray diffraction analyses. Electrospray mass spectrometric studies show that the rhenium–phosphine chelates are very stable, especially in neutral methanolic solution. Hydrolysis of the ester and amide linkages slowly occur in acidic and basic solutions over several weeks; displacement of the bromide ligand also occurs in basic medium. Cytotoxicity testing of 7–10 and 12 showed that all the complexes are active against specific tumor cell lines, especially MCF-7 breast cancer and HeLa-S³ suspended uterine carcinoma.