顺式二氯二氨合铂与核苷作用的13C核磁共振研究

本文用¹³C NMR法系统研究了溶液中顺式二氯二氨合铂与胸苷、胞苷、鸟苷和5'-腺嘌呤单核苷酸的作用,确定了不同条件下形成配合物的组成及其分子申铂原子与配体的成键方式。在中性介质中顺铂分别与胸苷、胞苷作用,生成N₃配位的顺-[Pt(NH₃)₂(ThyH_-1)₂]和顺-[Pt(NH₃)₂(Cyt)₂]²⁺;与鸟苷随摩尔比不同相应生成顺-[Pt(NH₃)₂(N₂-Guo)₂]²⁺和[Pt(NH₃)₂(N₂,N₁-GuoH_-1)]_nⁿ⁺,当pH=3和摩尔比为1时,尚有微量[Pt(NH₃)₂(N₇,O(C₆)Guo)]²⁺生成;在中性介质中顺铂与5'-AMP亦随摩尔比不同,生成顺-[Pt(NH₃)₂(N₇-5'-AMP)₂]^2-或兼生成顺-[Pt(NH₃)₂(N₇,N₁-5'-AMP)]_n。根据所得结果讨论了顺铂抗癌作用机制,提出了顺铂可能与DNA同一链上相邻二个鸟嘌呤基上的N₇N₁键合形成链内交联的新机制。     

2-(Phenyltelluromethyl)tetrahydrofuran (L) and 2-(2-{4-methoxyphenyl}telluroethyl)-1,3- dioxolane (L) and their palladium(II) and platinum(II) complexes

The nucleophile [ArTe⁻] generated in situ borohydride solution of Ar₂Te₂, reacts with 2-(chloromethyl) tetrahydrofuran and 2-(2-bromoethyl)-1,3-dioxolane resulting in L¹ and L², respectively. The complexes of palladium(II) and platinum(II) with L¹/L² having stoichiometries [MCl₂·L₂], [ML₂](ClO₄)₂, [(DPPE)ML₂](ClO)₄)₂, [(PPh₃)₂ML₂](ClO₄)₂ and [(phen)ML₂](ClO₄)₂ (where L = L¹/L² DPPE = Ph₂PC H₂CH₂PPh₂, PHEN = 1,10-phenanthroline and M = Pd/Pt) have been synthesized. IR, ¹H, ¹²⁵Te{¹H} and ³¹P{¹H} NMR and UV-vis spectral data of these species in conjunction with their molar conductance and molecular weight data have been used to authenticate the new species. In all complexes (1–20) the ligands L¹ and L² are coordinated through tellurium and in the complexes of formula [ML₂](ClO₄)₂ (M = Pd, Pt) the ligand is bidentate with the oxygen atom used in complexation. In solution, complexes PtCl₂L₂ exist as a mixture of cis and trans isomers whereas only the trans isomer was observed for the palladium analogues. The [(phen)PdL₂](ClO₄)₂(Q) quenches ¹O₂ readily. The plot of log [Q] vs time is linear. Mechanism compatible with the experimental observations is proposed.     

螯合萃取体系萃取常数的计算

本文介绍了计算萃取常数的七种方法。     

d(GGTATACC)2与乙二胺四乙酸在溶液中的相互作用

空气的尘埃中含有一种核苷酸降解酶,这种酶很容易被溶液中痕量的Mg2+等金属离子激活,从而使溶液中的DNA或RNA解链或失活.因而用NMR方法研究核酸的溶液结构时,需要在磷酸缓冲溶液中加入乙二胺四乙酸(EDTA)或其钠盐,保持其浓度大于0.1mmol/L[1～3],利用EDTA与包括Mg2+在内的众多金属离子的强络合作用,解除Mg2+等金属离子对核苷酸降解酶的激活功能,达到保护核酸活性的目的.     

New organogold(I) complexes: Synthesis, structure, and dynamic behavior of the polynuclear organogold diphenylmethane and diphenylethane derivatives

Two organogold derivatives of diphenylmethane and diphenylethane, Ph₃PAu(o-C₆H₄)CH₂(C₆H₄-o)AuPPh₃ (1) and Ph₃PAu(o-C₆H₄)(CH₂)₂(C₆H₄-o)AuPPh₃ (2), have been synthesized by the reaction of ClAuPPh₃ with Li(o-C₆H₄)CH₂(C₆H₄-o)Li and Li(o-C₆H₄)(CH₂)₂(C₆H₄-o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh₃ groups to give a macrocyclic compound (3) that includes an Au Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph₃PAu]BF₄ to form new types of cationic complex [CH₂(C₆H₄-o)₂(AuPPh₃)₃]BF₄ (4), [CH₂(C₆H₄-o)₂(AuPPh₃)₄](BF₄)₂ (5), and [(CH₂)₂(C₆H₄-o)₂(AuPPh₃)₄](BF₄)₂ (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by ¹H and ³¹P NMR spectroscopy. A complicated system of Au H-C agostic interactions, involving the bridging alkyl groups (—CH₂— and CH₂-CH₂—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6.     

Raman spectroscopic characterization of high temperature MGaCl8 (M = Nb, Ta) dinuclear molecular complexes in the liquid and gaseous state

Raman spectra were obtained at temperatures 375–650 K and pressures up to 4 atm from GaCl₃-NbCl₅ and GaCl₃-TaCl₅ binary mixtures in the liquid and vapour state. The data indicate formation of NbGaCl₈ and TaGaCl₈ liquid and vapour dinuclear addition complexes. The spectra were interpreted in terms of a C_2ν configuration for the MGaCl₈ (M = Nb, Ta) molecules consisting of a MCl₆ octahedron sharing an edge with a GaCl₄ tetrahedron. A comparison of the spectral features of 1 : 1 GaCl₃-NbCl₅ and GaCl₃-TaCl₅ molten mixtures with the spectra of the corresponding polycrystalline samples indicates that the proposed identity for the complexes is maintained in all three phases. The NbGaCl₈ and TaGaCl₈ complexes exist in the liquid state in a wide temperature range beyond their melting points (125 and 150°C, respectively) and are shown to undergo dissociation to their components [Nb₂Cl₁₀(1)/NbCl₅(1), Ga₂Cl₆(1) and Ta₂Cl₁₀(1)/TaCl₅(1)] with increasing temperature. Both complex molecules are identified in the gaseous state in low percentages among the vapours of their components and are almost totally decomposed at temperatures higher than ca 325°C. The enthalpy of the reaction TaCl₅(g) +1/2Ga₂Cl₆(g) TaGaCl₈(g) was determined from accurate relative Raman intensity measurements as ΔH⁰ = −38±2 kJ mol⁻¹.     

多碳醇类化合物的合成

本文由正-二十四烷酸与五氯化磷反应,得到的二十四烷酰氯在氯仿中和三乙胺存在下与1-吗啉-1-环己烯反应所得中间体,经酸性水解,碱性开环和酸化,得到7-氧代-三十烷酸,而据文献报导[7],正-二十四烷酞氯与1-吗啉-1-环己烯反应结果,得到的仍然是原料二十四烷酸。作者采用上述方法合成了五种新的7-氧代烷酸R-C(=O)-(CH²)⁵-COOH(R=n-C₁₄H₂₉,n-C₁₆H₃₃,n-C₁₈H₃₇,n-C₂₁H₄₃和n-C₂₃H₄₇)。所制得的7-氧代三十烷酸经黄鸣龙改良的开息纳尔-武尔夫还原,再经四氢锂铝还原,即得三十烷醇。     

激光拉曼光谱研究NiMoP浸渍液活性组分的结构 Ⅱ.不同有机添加剂的影响

采用激光拉曼光谱（LRS）技术对添加有乙二醇和柠檬酸的NiMoP浸渍液和用该浸渍液制备的NiMoP/Al₂O₃催化剂进行了表征,研究了乙二醇和柠檬酸含量对NiMoP浸渍液及浸渍过程中活性相组成、结构的影响。结果表明,乙二醇使NiMoP(0.063)浸渍液中H_{x\[PMo11O39\]⁽7-x)- 或Hx\[PMo9O31\]⁽3-x)-及Hx\[PMo12O40\]⁽3-x)- 杂多阴离子结构转化成Hx\[P2Mo5O23\]⁽6-x)- 结构,而柠檬酸能保持NiMoP(0.063)浸渍液中Hx\[P2Mo5O23\]⁽6-x)-、Hx\[PMo11O39\]⁽7-x)- 或Hx\[PMo9O31\]⁽3-x)-及Hx\[PMo12O40\]⁽3-x)-杂多阴离子结构共存,但导致Hx\[P2Mo5O23\]⁽6-x)-含量降低,Hx\[PMo12O40\]⁽3-x)-含量升高。相对乙二醇而言,柠檬酸有机添加剂能够更有效地阻止浸渍过程中各杂多阴离子结构在载体氧化铝孔道中的分解。}     

Cooperative effects in binuclear zirconocenes: Their synthesis and use as catalyst in propene polymerization

The mono- and bis-cyclopentadienyl compounds 1-(Cp″)-4-(CH₃)C₆H₄ (1) and 1, 4-(Cp″)₂C₆H₄ (2) (Cp″ = 3,4-dimethylcyclopenta-1,3-diene-1-yl) have been synthesized. The reactions of the lithium salts of 1 and 2 with CpZrCl₃ · dme (dme = dimethoxyethane) and Cp*ZrCl₃(CP* = C₅(CH₃)₅) yielded the mono- and bi-nuclear bridged zirconocenes 1-(Cp″ZrCpCl₂)-4-(CH₃)C₆H₄ (3), 1,4-(Cp″ZrCpCl₂)₂C₆H₄ (4) and 1,4-(Cp″ZrCp*Cl₂)₂C₆H₄ (5). When activated with methylaluminoxane (MAO), the mono- and bi-nuclear zirconocenes 3 and 4 catalyse the polymerization of propene. The influence of the catalyst composition on the polymerization kinetics and molecular weight is discussed.     

Etude des reactions de srn1—partie 10 : Action de sulfanions sur les halogenures d''aryle fonctionnalises. synthese directe de benzothiophenes et thienopyridines

Functionalized aromatic halides Ar₁XY (Ar₁ = C₆H₄, Y = OCH₃, CONH₂, CN, COCH₃, CHO, COC₆H₅) undergo S_RN1 reactions with sulphur anions ^-SR, either simple (R=C₂H₅, CH₂C₆H₅) or functionalized (R = (CH₂)₂OH, (CH₂)₂CO₂Et, CH₂CO₂Et). Products Ar₁YS^- formed from the fragmentation of the radical anion Ar₁YSR^- are related to the redox potential of the aryl moiety Ar₁Y and with the energy of the bond S-R. In the heterocyclic series (Ar₂ = pyridine, Ar₃ = quinoline) a similar relationship appears but a competitive S_N(Ar) reaction occurs for pyridine substrates bearing an electron withdrawing group. A direct synthesis of benzothiophen via S_RN1 reaction and an improved synthesis of thienopyridines based on the S_N(Ar) reaction are reported.     

Reaktionen von (η-formaldehyd)zirconocen-dimer mit heterokumulenen

The (η²-formaldehyde)zirconocene dimer (Cp₂ H₂)₂ (7) inserts CO₂ into the zirconium to carbon bond of the metallaoxirane moiety to give [(Cp₂ H₂)(Cp₂ =O)] (8). Reaction with diphenylketene 7 gives the cyclodimeric 1 : 1 addition product (Cp₂ =CPh₂)₂ (10) via the mono-insertion product 9. Similarly, treatment of 7 with t-butylisocyanate yields the intermediate complex [(Cp₂ H₂)(Cp₂ =NCMe₃)] (11) which gives the final product (Cp₂ =NCMe₃)₂ (12). Here two five-membered metallacycles are joined together by oxygen bridges via a central four-membered Zr₂O₂ metallacycle. Complex 12 was characterized by X-ray diffraction. It crystallizes in space group P2₁/n with cell parameters a 10.142(1), b 17.949(2), c 12.001(1) Å, β = 114.27(1)°; Z = 2, R = 0.055, R_w = 0.054.     

The phenomenon of conglomerate crystallization: Part 52. Stereochemical control of the crystallization pathway by small alterations of ligands

The X-ray structure analysis of mer-trans-[Co(aepn)Cl₂(OH₂)](ClO₄)·H₂O (1) (aepn=N-(2-aminoethyl)-1,3-propanediamine) reveals that the compound crystallizes in an enantiomorphic space group P2₁2₁2₁ implying a spontaneous resolution of its racemic solution, known as conglomerate crystallization. Substitutions of the two chloride ligands with bromides result in the isostructural compound mer-trans-[Co(aepn)Br₂(OH₂)](ClO₄)·H₂O (2), which also crystallizes as a conglomerate in the space group P2₁2₁2₁. Meanwhile, a substitution of the coordinated OH₂ of 1 with NH₃ gives mer-trans-[Co(aepn)Cl₂(NH₃)](ClO₄) (3), which crystallizes as a simple racemate in P2₁/n space group. When N-(3-aminopropyl)-1,3-propanediamine (dpt) is used instead of aepn in the preparation of 1, it gives racemic crystals of mer-trans-[Co(dpt)Cl₂(OH₂)](ClO₄) (4) whose molecular packing pattern is identical to that of 3. In the conglomerate structures, the protons of coordinated water ligand are strongly hydrogen-bonded to the oxygen of a water of crystallization to form a spiral packing structures. In the packing structures of 3 and 4, two molecules of opposite chirality are brought together around a crystallographic center of inversion by hydrogen bonds of the protons of the corresponding tridentate amine ligand with oxygens of perchlorate anion.     

Low-temperature heat capacity and thermodynamic properties of crystalline [Re2(Ala)4(H2O)8](ClO4)6 (Re = Eu, Er; Ala = alanine)

[Re₂(Ala)₄(H₂O)₈](ClO₄)₆ (Re=Eu, Er; Ala=alanine) were synthesized, and the low-temperature heat capacities of the two complexes were measured with a high-precision adiabatic calorimeter over the temperature range from 80 to 370 K. For [Eu₂(Ala)₄(H₂O)₈](ClO₄)₆, two solid–solid phase transitions were found, one in the temperature range from 234.403 to 249.960 K, with peak temperature 243.050 K, the other in the range from 249.960 to 278.881 K, with peak temperature 270.155 K. For [Er₂(Ala)₄(H₂O)₈](ClO₄)₆, one solid–solid phase transition was observed in the range from 270.696 to 282.156 K, with peak temperature 278.970 K. The molar enthalpy increments, ΔH_m, and entropy increments,ΔS_m, of these phase transitions, were determined to be 455.6 J mol⁻¹, 1.87 J K⁻¹ mol⁻¹ at 243.050 K; 2277 J mol⁻¹, 8.43 J K⁻¹ mol⁻¹ at 270.155 K for [Eu₂(Ala)₄(H₂O)₈](ClO₄)₆; and 4442 J mol⁻¹, 15.92 J K⁻¹ mol⁻¹ at 278.970 K for [Er₂(Ala)₄(H₂O)₈](ClO₄)₆. Thermal decompositions of the two complexes were investigated by use of the thermogravimetric (TG) analysis. A possible mechanism for the thermal decomposition is suggested.     

Gas-phase stability of cluster ions SF m + (SF6) n with m = 0–5 and n = 1–3

The gas-phase stabilities of cluster ions SF⁺_m (SF₆)_n with m = 0−5 were determined by using a high pressure mass spectrometer. The bond energies of SF⁺_m (SF₆)₁ were found to be less than 10 kcal/mol and to decrease with m = 0 → 5. There appear to be rather large gaps in the bond energies between n = 1 and 2 for the clusters SF⁺_m (SF₆)_n with m = 0−4. The structures of SF⁺₅, SF⁺ (SF₆)₁, SF⁺₃ (SF₆)₁, and SF⁺₅ (SF₆)₁ were investigated by ab initio molecular orbital calculations. For SF⁺₅, the D_3h geometry is found to be most stable andC_4v is a transition state of the Berry pseudorotation. For the ion-molecule complexes, the “on-top hat” models were found to be the most stable structures.     

Ab initio study of the electronic spectrum of dichlorocarbene CCl2

The equilibrium geometries, excitation energies, force constants and vibrational frequencies for seven low-lying electronic states X ¹A₁, ¹B₁, ³B₁, ¹A₂, ³A₂, ¹B₂ and ³B₂ of dichlorocarbene CCl₂ have been calculated at the MRSDCI level with a double-zeta plus polarization basis set. Our calculated equilibrium geometry for the X ¹A₁ state, excitation energy for X ¹A₁ → ¹B₁ and vibrational frequencies for the X ¹A₁ and ¹B₁ states are in good agreement with experimental data. The electronic transition dipole moments, oscillator strengths for the ¹B₁ → X ¹A₁ and ¹B₂ → X ¹A₁ transitions, radiative lifetimes for the ¹B₁ and ¹B₁ states are calculated using MRSDCI wavefunctions, predicting results in reasonable agreement with experiment.     

Formation of a THF adduct of the organometallic samarium oxide [(C5Me5) 2Sm]2(μ-O)

(C₅Me₅)₂Sm(THF)₂ reacts with 1,2-epoxybutane in toluene to form, in addition to the toluene soluble [(C₅ Me₅)₂Sm]₂(μ-O), 1, the hexane soluble [(C₅Me₅)₂Sm(THF)]₂(μ-O), 2. In hexane, 2 loses THF to form 1 as a precipitate, but 1 cannot be converted to 2 by addition of THF at room temperature. Compound 1 does convert to 2 in low yield in THF at reflux. The reaction of (C₅Me₅)₂SM(phthalan) with 1,2-epoxybutane generates 1 and a phthalan analog of 2, [(C₅Me₅)₂Sm(phthalan)]₂(μ,-O), 3. Compound 2 reacts with Me₃CCN to form [(C₅Me₅)₂Sm(NCCMe₃)]₂(μ-O), 4, by displacement of THF.     

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.     

2,4-二硫代尿嘧啶的紫外吸收光谱和共振拉曼光谱

硫代嘧啶碱基是光动力疗法潜在的重要光敏剂,其最低单重激发态的光物理研究已有广泛报道。然而,其较高激发态的跃迁性质和反应动力学研究较为稀少。因此,本文采用共振拉曼光谱和密度泛函理论计算方法研究2,4-二硫代尿嘧啶的紫外光谱和几个较高单重激发态的短时结构动力学。首先,基于共振拉曼光谱强度与电子吸收带振子强度f的关系,将紫外光谱去卷积成四个吸收带,分别为358 nm(f=0.0336)中等强度吸收带(A带),338 nm(f=0.1491)、301 nm(f=0.1795)和278 nm(f=0.3532)强而宽的吸收带(B、C和D带)。这一结果既吻合密度泛函理论计算结果,又符合共振拉曼光谱强度模式对紫外光谱带的预期。据此,去卷积得到的四个吸收带被分别指认为S0→S2跃迁、S0→S6跃迁、S0→S7跃迁和S_0→S_8跃迁。同时,分别对B,C和D带共振拉曼光谱进行了详细的指认,获得了短时动力学信息。结果表明,S_8态短时动力学的显著特征是在Franck-Condon区域或附近发生了S8(ππ~*)/S(nπ~*)势能面交叉引发的、伴随超快结构扭转的非绝热过程。S7和S6态短时动力学的主要特征是反应坐标的多维性,它们分别沿C_5C_6/C_2S_8/C_4S_(10)/N_2C_3+C_4N_3H_9/N_1C_2N_3/C_2N_1C_6/C_6N_1H_7/C_5C_6H_(12)和C_5C_6/N_3C_2/C_4S_(10)/C_2S_8+C_6N_1H_7/C_5C_6H_(12)/C_5C_6N_1/C_5C_6H_(12)/C_2N_1C_6/N_1C_2N_3/C_4N_3H_9/N_1C_2N_3等内坐标演化。     

A comparative electron correlation treatment in H(2)S-benzene dimer with DFT and wavefunction-based ab initio methods

The S₀ (X¹A′), T₁ (a³A″), S₁ (A¹A″), T₂ (b³A′), and S₂ (B¹A′) states of the (trans-)HONO molecule were studied by using the CASSCF and CASPT2 methods. The CASPT2(//CASPT2) adiabatic and vertical excitation energy values are in good agreement with available experimental data. The CASPT2//CASSCF potential energy curves (PECs) calculations indicate that: (i) all the five states correlate with the products of OH (X²Π) + NO (X²Π); (ii) along each of the T₁, S₁, and T₂ PECs there is a minimum followed by a transition state (barrier); and (iii) the repulsive S₂ PEC crosses the T₂, S₁, and T₁ PECs. The geometries and relative energies for the stationary points along these PECs were calculated at the CASPT2(//CASPT2) level, and the calculations predict that the barrier height value for S₁ is negligibly small (0.0018 eV).     

Transition metal sulfur dioxide hexafluoroarsenates and hexafluoroantimonates

The preparation and characterization by X-ray crystallography of transition metal sulfur dioxide hexafluoroarsenates of the general formula [M(SO₂)_x](AsF₆)₂ 1 (1a: M=Mn, x=2; 1c: M=Co, x=4; 1e: M=Cu, x=4) and the hexafluoroantimonate [Co(SO₂)₂](SbF₆)₂ 3 is reported. The structural features of the compounds mentioned are compared with those of [Fe(SO₂)₄](AsF₆)₂ (1b) and [Ni(SO₂)₆](AsF₆)₂ (1d), reported previously. The structural diversity of transition metal sulfur dioxide complexes is discussed.