Cl2/TiCl4体系引发IBVE活性阳离子聚合的研究(Ⅰ)——引发活性中心及其络合竞争

采用UV光谱法证明了IBVE/Cl₂/TiCl₁/甲苯聚合体系中同时存在着两种引发活性中心及络合竞争,研究了Cl₂/TiCl₁和H₂O/TiCl₁络合平衡,求出了20℃时2TiCl₁←Cl₂和TiCl₁←H₂O络合平衡不稳定常数.     

新型高活性催化剂乙烯气相聚合的研究(Ⅰ)──气相均聚和共聚反应及气相均聚动力学

研究了新型高活性乙烯气相聚合催化剂TiCl₄/MgCl₂/ZnCl₂/SiCl₄/醇/Al(i-Bu)₃体系中钛和醇组分含量对聚合反应和产物颗粒形态的影响。测定了乙烯气相聚合反应动力学曲线,确定了聚合动力学方程。用SEM、DSC、WAXD、¹³CNMR对催化剂及聚合物的形态、结构和性能进行了分析和表征。     

异相Ziegler-Natta催化剂的活性中心多分散性(Ⅰ)——钛催化体系聚合物分子量分布的研究

对TiCl₃及TiCl₄/MgCl₂-Al(C₂H₅)₃(或Al(i-C₄H₉)₃、Al(C₂H₅)₂Cl)催化体系合成的聚辛烯的分子量分布用SchulzeFlory"最可几分布"函数作拟合处理,将各种聚合条件下的实测分布分成了3～5个"最可几分布"的叠加,催化剂结构及聚合条件对这些"最可几分布"峰的位置、大小的影响较有规律,表明每个峰对应于一种活性中心。还测定了聚辛烯各级分的活性中心浓度。对各活性中心的差异作了分析。     

石墨烯吸附TiCl4分子的条件控制及光电性能的理论研究

为研究石墨烯吸附TiCl₄分子的影响因素及其光电性能,探索复合物应用于传感器及透明导电薄膜的可能性,采用第一性原理与蒙特卡罗方法研究TiCl₄气体分子在石墨烯表面的吸附条件控制与光电性能。结果表明：(1)石墨烯对TiCl₄气体分子具有较强的物理吸附作用,Cl原子吸附在其附近相距质心位置最远的碳原子顶位最稳定;(2)温度升高不利于TiCl₄气体分子吸附,气体逸度增加有利于吸附,TiCl₄气体分子插入石墨/双层石墨烯/多层石墨烯时宜将温度维持在TiCl₄沸点附近,并增加气体的压力;(3) TiCl₄的吸附对石墨烯的电子结构进行了调控,使费米能级附近的态密度显著提高,赝能隙减小,有效提高了导电性能;(4)在可见光区域,TiCl₄的吸附对体系的吸收性能影响不大,在提升透明导电薄膜导电性的同时未影响薄膜的光学性能。     

新型高活性催化剂乙烯气相聚合的研究(Ⅱ)──改性剂、预聚合和聚合条件对乙烯气相聚合的影响

研究了新型高活性乙烯气相聚合催化剂TiCl₄/MgCl₂/ZnCl₂/SiCl₄/醇/Al(i-Bu)₃体系中不同醇、不同C₂H₅OH/Ti摩尔比和正丁醚对聚合反应及产物颗粒形态的影响。研究了预聚合反应及乙烯气相聚合反应规律。用扫描电镜和图象分析对催化剂、预聚物及聚合产物的形态和颗粒分布的研究结果表明:新型高活性催化剂和经预聚合制得的乙烯气相聚合物的颗粒形态类似球形,颗粒长短轴比值和大小粒径比值相近。     

聚合温度对负载型Ziegler-Natta催化剂催化丁二烯-异戊二烯共聚合的影响

非均相TiCl₄/MgCl₂-AlR₃型Ziegler-Natta(非均相Z-N)催化剂是聚烯烃工业最重要的催化剂,经烷基铝活化的非均相Z-N催化剂具有复杂的活性中心结构,改变聚合温度、聚合时间、烷基铝种类及浓度等均会影响活性中心结构与催化性能.本文研究了不同聚合温度下TiCl₄/MgCl₂-AlEt₃(三乙基铝)催化丁二烯(Bd)和异戊二烯(Ip)的共聚合动力学,研究发现,随着聚合时间的延长,聚合活性先升高然后降低,在50℃聚合活性最高.采用核磁共振波谱(¹H NMR)、紫外荧光定硫仪和凝胶渗透色谱(GPC)研究了共聚物的微观结构、活性中心数和分子量及其分布,发现随着聚合时间的延长及聚合温度的升高,活性中心数、共聚物中反式-1,4-结构、分子量及分子量分布均发生不同规律的变化.本文研究结果可为进一步理解非均相Z-N催化剂在不同聚合温度下催化共轭二烯烃聚合的动力学及其关键影响因素提供参考.     

异相Ziegler-Natta催化剂的活性中心多分散性(Ⅱ)——4种活性中心的聚合动力学参数

测定了络合Ⅱ型TiCl₃-Al(C₂H₅)₃催化1-辛烯聚合中不同时间的产物分子量分布,用4个Schulz-Flory“最可几”分布函数叠加,较好地拟合了实测分布,从而确定此体系有4种活性中心。从拟合及动力学测定结果确定了4种活性中心的聚合速率、浓度及链增长速率常数、链转移速率常数等,讨论了各活性中心的结构及聚合机理。     

三种不同碳桥联双核茂钛配合物的合成及催化乙烯聚合研究

合成了3种不同结构的CnH₂n桥联双核茂钛配合物(CH₃)₂C[(C₅H₄)TiCl₂(C₅H₅)]₂(3),(CH₂)_n[(C₅H₄)TiCl₂(C₅H₅)]₂(6,n=3;7,n=4),并用1HNMR进行了表征.发现以甲苯为溶剂时,不仅提高了产率,而且有效地避免了副产物Cp₂TiCl₂的生成.研究了化合物7/MAO(甲基铝氧烷)催化乙烯聚合的反应,考察了反应条件对催化体系的影响.结果表明,催化活性随着n(Al)/n(Cat.)比的增大而提高,聚乙烯的分子量在n(Al)/n(Cat.)=500和50℃时达到最高值9.0102×10⁴;随着聚合时间的延长,催化活性下降,而产物分子量不断升高;随着温度的上升,50℃时催化活性和聚乙烯的分子量最高,分别为2.4074×10⁵gPE/(molTi·h)和6.8679×10⁴.随着桥联双核茂钛配合物碳桥的增长,催化活性增加,所得聚乙烯的分子量降低.     

硅桥连双(三甲硅基环戊二烯基)钛化合物的合成及脱硅基反应

硅桥连双(三甲硅基环戊二烯基)双锂盐与TiCl₄·2THF反应,生成相应的钛化合物[E(C₅H₃SiMe₃)₂]TiCl₂[E=Me₂SiSiMe₂(3),Me₂SiOSiMe₂(5)],同时还分离到了脱一个三甲硅基的产物[E(C₅H₄)(C₅H₃SiMe₃)]TiCl₂[E=Me₂SiSiMe₂(4),Me₂SiOSiMe₂(6)].其中四甲基二硅氧桥连配体更容易发生这种脱硅基反应.通过元素分析、MS和¹HNMR谱表征了化合物3-6的分子结构.     

1-辛烯的Ziegler-Natta聚合动力学(Ⅱ)——速率增长期的动力学及其机理

用膨胀计研究了络合Ⅱ型TiCl₃-烷基铝催化1-辛烯聚合的非稳态期动力学,发现速率增长期随[TiCl₃]、[M]₀的增大及温度升高而变短。通过显微镜观察发现增长期中催化剂大颗粒逐步破碎成较小颗粒。对此提出了聚合物促使催化剂颗粒破碎从而增大活性表面的增长期机理模型,用此模型解释了大部分实验现象。     

Inverse phase transfer catalysis: kinetics of the pyridine-1-oxide-catalyzed two-phase reactions of methyl-, methoxy-, iodo-, and nitro-benzoyl chlorides and benzoate ions

The substitution reactions of XC₆H₄COCl [X=2-, 3-, or 4-CH₃; 2-, 3-, or 4-CH₃O; 2-, or 4-I; or 2-, 3-, or 4-NO₂] and YC₆H₄COONa [Y=2-, 3-, or 4-CH₃; 2-, 3-, or 4-CH₃O; 2-I; 4-NO₂; or H] in a two-phase H₂O/CH₂Cl₂ medium using pyridine-1-oxide (PNO) as an inverse phase transfer catalyst were investigated. In general, the kinetics of the reaction follows a pseudo-first-order rate law, with the observed rate constant being a linear function of the concentration of PNO in the water phase. In contrast to other analogous reactions, the hydrolysis reaction of 2-, 3-, or 4-NO₂C₆H₄COCl in H₂O/CH₂Cl₂ medium is catalyzed considerably by PNO and reaches an equilibrium. In the PNO-catalyzed reaction of XC₆H₄COCl and XC₆H₄COONa in H₂O/CH₂Cl₂ medium, the order of reactivities of XC₆H₄COCl toward reaction with PNO in CH₂Cl₂ is 2-IC₆H₄COCl>4-IC₆H₄COCl>(C₆H₅COCl,3-CH₃OC₆H₄COCl)>3-CH₃C₆H₄COCl>(2-CH₃C₆H₄COCl,4-CH₃C₆H₄COCl)>4-CH₃OC₆H₄COCl>2-CH₃OC₆H₄COCl. Combined with the results of other analogous reactions, good Hammett correlations with positive reaction constant were obtained for the meta- and para-substituents, which supports that the XC₆H₄COCl–PNO reaction in CH₂Cl₂ is a nucleophilic substitution reaction.     

Third-order Optical Nonlinearities of a Series of Compounds Derived from a Keplerate Type Molybdenum-oxide-based Polyoxometalate

Abstract By reacting the unique Keplerate type molybdenum-oxide based polyoxometalate （NH4）42·[MoI320372·（CH3COO）30（H2O）y2]·ca.300H2·ca. 10CH3COONH4（1） with tetramethylammonium bromide, a new derivative （NH4）26[TMA]16{MoI32O372（H2O）72（CH3COO）30}·ca.7NH4CH3COO·ca.189H2O（2, TMA=tetramethylammonium） was prepared. Compound 2 was characterized by Fourier transform infrared spectroscopy（FTIR）, UV-Vis, elemental and thermogravimetric analyses. By the well-established Z-scan technique, investigations on the nonlinear opti- cal（NLO） properties of the series of compounds derived from the Keplerate type molybdenum-oxide-based poly- oxometalate, namely, the newly prepared compound 2, the three previously reported compounds, included compound 1, （NH4hs（TBA）24{Mo132O372（H2O）72（CH3COO）30}·ca.7NH4CH3COO·ca. 173H2O（3, TBA=tetrabutylammonium） and （DODA）40（NH4）2[（H2O）nMo132O372（CH3COO）3o（H20）72]（4, DODA=dimethyldioctadecylammonium）, reveal that the third-order nonlinearity[x（3）] values of compounds 1, 2 and 3 in the DMF/H2O solution and compound 4 in chloro- form are almost the same, which indicates that the counter cations with different length of alkyl chains show ignora- ble impacts on the NLO susceptibility. In other words, the remarkable third-order nonlinearities[x（3）≈10 19 m2/V2] mainly come from the [MoI32O372（CH3COO）30（H2O）72]42 anions. This fact reveals that the applications of the NLO active polyoxometalates in various environments（such as hydrophilic, hydrophobic, polar, apolar, etc.） can be achieved by simply varying cations to meet the demands in the design of diverse devices. Keywords Keplerate type polyoxometalate; Nonlinear optical property; Z-Scan technique; Self-defocusing; Reverse saturable absorption     

Four Coordination Polymers Assembled with a New Biscarboxyl-functionalized Schiff Base Ligand

Based on a new biscarboxyl-functionalized Schiff base ligand 1,2-cyclohexanediamino-N,N'-bis[3-methoxyl-5-(p-carboxyl-phenylazo)] salicylidene(H₄L), four polymers,[(CH₃)₂NH₂]₂·[Mn₃(L)₂(H₂O)₄]·2DMF(CP1),[Fe₂(L)(H₂O)(DMF)](CP2),[(CH₃)₂NH₂]·[Cu(HL)]·H₂O(CP3) and[Ni₂(L)(teta)]·2DMF·H₂O(CP4), have been synthesized(teta=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). In CP1, both of the internal[N₂O₂] pocket and the external carboxylate groups of L^4- anion are ligated by Mn²⁺ ions, and the structure displays a layer. In CP2, the Fe²⁺ cations are linked by L^4- anions to form a binuclear double chain. CP3 displays a[Cu₂(HL)₂] dimer. In CP4, the Ni²⁺ ions are connected by L^4- anions to form a chain. The structures are further linked by hydrogen bonds to form 2D or 3D supramolecular architectures, respectively. CP1 exhibits adsorption ability to three organic dyes.     

Syntheses and structural characterization of trivalent lanthanide complexes of p-sulfonatothiacalix[4]arene

The X-ray crystallographic studies are reported for the water-soluble trivalent lanthanide complexes of the macrocyclic p-sulfonatothiacalix[4]arene [Gd(H₂O)₆((CH₃)₂SO)(p-sulfonatothiacalix[4]arene)]·H₃O⁺·5H₂O (1) and Na[Nd(H₂O)₆((CH₃)₂SO)(p-sulfonatothiacalix[4]arene)]·3H₂O (2). The complexes are isostructural and belong to monoclinic system, C2/m space group. The Ln³⁺ metal ion is coordinated by the thiacalixarene ligand via the sulfonato group, and also ligated by an oxygen atom of a dimethyl sulfoxide (DMSO) molecule that occupies the cavity of the thiacalixarene and six aqua ligands. The thiacalixarenes are linked by the coordinated water molecules through hydrogen bonding to form a 2D polymer. The p-sulfonatothiacalixarenes maintain the clay-like bi-layer structure in the coordination network.     

Preparation, properties, and reactions of metal-containing heterocycles: Part CV. Synthesis and structure of polyoxadiphosphaplatinaferrocenophanes

A series of novel heterobimetallic crown ether-like polyoxadiphosphaplatinaferrocenophanes cis-[1,1′-Fc(CH₂O(CH₂CH₂O)_nCH₂CH₂PPh₂)₂]PtCl₂ (n=1–3) (4a–c) was synthesized in good yield by cyclization of the bis(phosphine) ligands 1,1′-Fc(CH₂O(CH₂CH₂O)_nCH₂CH₂PPh₂)₂ (n=1–3) (3a–c) and (PhCN)₂PtCl₂ under high dilution conditions in CH₂Cl₂. The bisphosphines 3a–c are obtained by reaction of the corresponding diols 1,1′-Fc(CH₂O(CH₂CH₂O)_nCH₂CH₂OH)₂ (n=1–3) (1a–c) with: (i) CH₃SO₂Cl in CH₂Cl₂ and (ii) LiPPh₂ in THF. Although the X-ray crystal structure of 4a shows that the cavity is large enough for the encapsulation of small metal cations, inclusion experiments of 4a–c with Group 1 cations, and Mg²⁺, or NH₄⁺ in solution applying NMR titration and cyclovoltammetric methods reveal no evidence for the formation of host–guest complexes for 4a,b. In the case of 4c only the addition of Na⁺ or K⁺ leads to an insignificant effect.     

Interaction of antitumor drug Sn(CH3)2Cl2 with DNA and RNA

Sn(CH₃)₂Cl₂ exerts its antitumor activity in a specific way. Unlike anticancer cis-Pt(NH₃)₂Cl₂ drug which binds strongly to the nitrogen atoms of DNA bases, Sn(CH₃)₂Cl₂ shows no major affinity towards base binding. Thus, the mechanism of action by which tinorganometallic compounds exert antitumor activity would be different from that of the cisplatin drug. The aim of this study was to examine the binding of Sn(CH₃)₂Cl₂ with calf thymus DNA and yeast RNA in aqueous solutions at pH 7.1–6.6 with constant concentrations of DNA and RNA and various molar ratios of Sn(CH₃)₂Cl₂/DNA (phosphate) and Sn(CH₃)₂Cl₂/RNA of 1/40, 1/20, 1/10, 1/5. Fourier transform infrared (FTIR) and UV–visible difference spectroscopic methods were used to determine the Sn(CH₃)₂Cl₂ binding mode, binding constant, sequence selectivity and structural variations of Sn(CH₃)₂Cl₂/DNA and Sn(CH₃)₂Cl₂/RNA complexes in aqueous solution. Sn(CH₃)₂Cl₂ hydrolyzes in water to give Sn(CH₃)₂(OH)₂ and [Sn(CH₃)₂(OH)(H₂O)_n]⁺ species. Spectroscopic evidence showed that interaction occurred mainly through (CH₃)₂Sn(IV) hydroxide and polynucleotide backbone phosphate group with overall binding constant of K(Sn(CH₃)₂Cl₂–DNA)=1.47×10⁵ M⁻¹ and K(Sn(CH₃)₂Cl₂–RNA)=7.33×10⁵ M⁻¹. Sn(CH₃)₂Cl₂ induced no biopolymer conformational changes with DNA remaining in the B-family structure and RNA in A-conformation upon drug complexation.     

Luminescent properties of carbon-rich starburst gold(I) acetylide complexes. Crystal structure of [TEE][Au(PCy3)]4 ([TEE]H4=tetraethynylethene)

Two carbon-rich starburst gold(I) acetylide complexes [TEE][Au(PCy₃)]₄ (3, [TEE]H₄=tetraethynylethene) and [TEB][Au(PCy₃)]₃ (6, [TEB]H₃=1,3,5-triethynylbenzene) were prepared and their UV–vis absorption, emission and excitation spectra have been recorded. In fluid CH₂Cl₂ solutions, 3 exhibits prompt ¹(ππ*) fluorescence with λ_0–0 and λ_max at 413 and 428 nm, respectively, while 6 displays ³(ππ*) phosphorescence with λ_0–0 and λ_max at 446 and 479 nm, respectively. The crystal structure of 3·CH₂Cl₂ has been determined.     

New Supramolecular Networks Based on Paratungstate with N-Donor Bridging Ligands

Three new supramolecular networks based on paratungstate and N-donor bridging ligands, [H₂bpmp]_2.5H[H₂W₁₂O₄₀]2H₂O(1), [H₂(bpp)]₂[H(py―CH₃)]_0.25[H(py―C₂H₅)]_0.25H_1.5[H₂W₁₂O₄₀]·4H₂O(2) and [H₂pip]₃[H₂W₁₂O₄₀](3)[bpmp=N,N'-bis(4-pyridylmethyl)piperazine; bpp=1,3-bis(4-pyridyl)propane; py=pyridine; pip=piperazine] were prepared by the hydrothermal synthesis and characterized by elemental analysis, infrared(IR), thermogravimetric(TG) analysis and single-crystal X-ray diffraction(XRD). All the compounds show high-dimen- sional supramolecular networks based on [H₂W₁₂O₄₀]^6- and the protonated N-donor ligands via the N―H···O―W hydrogen bonds and/or π···π stacking interactions. Their luminescent properties were investigated.     

系列Sm3+配合物的合成、结构及光物理性能

采用水热方法合成了4种Sm³⁺配合物, 即{[SmZn(2,5-pdc)₂(tp)_0.5(H₂O)]·2H₂O}_n(1), [Sm₂Zn₂(C₆H₅COO)₁₀(Imh)₂(H₂O)₂](2), {[Sm₂(NO₂C₆H₄COO)₆(H₂O)₄]·H₂O}_n(3)和{[SmN(CH₂COO)₃(H₂O)₂]·H₂O}_n(4)[2,5-pdc=2,5-吡啶二羧酸根, tp=对苯二甲酸根, C₆H₅COO=苯甲酸根, Imh=咪唑, NO₂C₆H₄COO=对硝基苯甲酸根, N(CH₂COO)₃=氨三乙酸根]. 通过单晶X射线衍射确定了其晶体结构. 在室温下测定了其红外光谱、 紫外-可见-近红外光谱以及在近红外区和可见区的发射光谱. 结果表明, 4种配合物在近红外区或可见区均出现Sm³⁺离子的特征发射. 这是形成配合物后, Zn-配体部分和配体对Sm³⁺离子发光的敏化作用所致. 此外, 讨论了不同有机配体或d过渡金属离子对Sm³⁺离子发光的影响, 并分析了配合物中Sm³⁺离子的近红外发射带位移、 劈裂和加宽的原因.