冠醚配合物热力学性质的研究 Ⅹ.用NMR研究15-冠-5衍生物与钠离子的配位反应

用~(23)Na NMR研究了15-冠-5(15C5),2,3-苯并-15-冠-5(B-15C5),2,3-苯并-6-甲基-15冠-5(BC1-15C5),2,3-苯并-8,12-二甲基-15-冠-5(BC2-15C5)在丙酮中与Na~+的配位反应,由此探索甲基的影响。实验结果表明,当在金属盐溶液中加入冠醚,配体为15C5时,体系表观化学位移移至低场,配体为B-15C5,BC1-15C5,BC2-15C5时,体系的表现化学位移移至高场。后者与苯并-18-冠-6及其甲基衍生物不同,这是由于苯环在空间排布不同所致,用Newton-Raphson法和描坑法(Pit-mapping)拟合实验数据,发现BC1-15C5和BC2-15C5除形成NaL~+和NaL_2~+外还有不稳定的Na_3L_2~(3+)形成。本文对形成过程和生成NaL~+反应的平衡常数lgK_(11)与甲基数的关系亦作了讨论,lgK_(11)与甲基数目n近似成直线关系,可用下式表示:lgK_(11)=3.50-0.480n,n=0,1,2。     

稀土冠醚配合物的研究 Ⅸ.苯并-15-冠-5及4′-硝基苯并-15-冠-5对稀土离子的配合作用

冠醚稀土固体配合物的研究已有些报道,我们亦曾合成了苯并-15-冠-5的衍生物的稀土盐固体配合物,而关于冠醚对于稀土离子在溶液中的配合反应的研究尚较少.本工作采用离子选择性电极测定冠醚配合物稳定常数的方法,研究了苯并-15-冠_5(L_1)及4’-硝基苯并-15-冠-5(L_2)在甲醇溶液中对十种稀土离子的配合反应,按形成1∶1配合物计算了它们的稳定常数,并就与稀土离子半径相近的钙离子、钠离子在相同的实验条件下的竞争配合能力进行了讨论.     

锕系元素冠醚配合物研究(Ⅲ)——二水合硝酸铀酰苯并-15-冠-5配合物的晶体结构

锕系元素冠醚配合物中,研究得最多的是铀酰与冠醚形成的配合物,以往的工作主要集中在配合物的合成及性质研究方面,而对其结构很少研究。迄今为止,只测定过硝酸铀酰与18-冠-6配合物的晶体结构,铀酰与其它种类冠醚形成的配合物的结构文献中还未见报道。我们在乙腈溶液中培养出硝酸铀酰与苯并-15-冠-5的配合物[UO_2(NO_3)_2(H_2O)_2]·(B15C5)单晶,并研究该配合物的晶体及分子结构。     

冠醚配合物热力学性质的研究 X: 用NMR研究15-冠-5-衍生物与钠离子的配位反应

用^2^3Na NMR研究了15-冠-5(15C5), 2,3-苯并-15-冠-5(B-15C5), 2,3-苯并-6-甲基-15-冠-5(BCl-15C5), 2,3-苯并-8,12-二甲基-15-冠-5(BC2-15C5)在丙酮中与Na^+的配位反应, 由此探索甲基的影响, 实验结果表明, 当在金属盐溶液中加入冠醚, 配体为15C5时, 体系表观化学位移移至低场, 配体为B-15C5, BC1-15C5, BC2-15C5时, 体系在表观化学位移移至高场, 后者与苯并-18-冠-6及其甲基衍生物不同, 这是由于苯环在空间排布不同所致, 用Newton-Raphson法和描坑法(Pit-mapping)拟合实验数据, 发现BC1-15C5和BC2-15C5除形成NaL^+和NaL2^+外还有不稳定的Na3L2^3^+形成。本文对形成过程和生成NaL^+反应的平衡常数lgK11与甲基数的关系亦作了讨论, lgK11与甲基数目n近似成直线关系, 可用下式表示: lgK11=3.50-0.80n, n=0,1,2。     

冠醚配合物热力学性质的研究 X: 用NMR研究15-冠-5-衍生物与钠离子的配位反应

用^2^3Na NMR研究了15-冠-5(15C5), 2,3-苯并-15-冠-5(B-15C5), 2,3-苯并-6-甲基-15-冠-5(BCl-15C5), 2,3-苯并-8,12-二甲基-15-冠-5(BC2-15C5)在丙酮中与Na^+的配位反应, 由此探索甲基的影响, 实验结果表明, 当在金属盐溶液中加入冠醚, 配体为15C5时, 体系表观化学位移移至低场, 配体为B-15C5, BC1-15C5, BC2-15C5时, 体系在表观化学位移移至高场, 后者与苯并-18-冠-6及其甲基衍生物不同, 这是由于苯环在空间排布不同所致, 用Newton-Raphson法和描坑法(Pit-mapping)拟合实验数据, 发现BC1-15C5和BC2-15C5除形成NaL^+和NaL2^+外还有不稳定的Na3L2^3^+形成。本文对形成过程和生成NaL^+反应的平衡常数lgK11与甲基数的关系亦作了讨论, lgK11与甲基数目n近似成直线关系, 可用下式表示: lgK11=3.50-0.80n, n=0,1,2。     

铜（Ⅱ）（溴代苯并—15—冠—5）配合物的研究

苯并冠醚对碱金属、碱土金属及稀土金属离子具有特殊的配位能力,但它们与溶剂化能量较大的“软酸”过渡金属离子配位较难。通过在冠醚苯环上引入吸电子取代基团减弱冠醚的碱性,是这类过渡金属大环配合物研究的一个重要方面。从模拟金属蛋白中铜(Ⅱ)离子的位置看,铜(Ⅱ)离子冠醚配合物的研究具有一定的意义。本文在过去工作的基础上,合成了高氯酸铜与4′-溴苯并-15-冠-5(L_A)及4′,5′-二溴苯并-15-冠-5(L_R)两种新配合物,并研究了它们的有关物理、化学性质。     

稀土硝酸盐15—冠—5络合物的一些性质

稀土冠醚络合物的组成和稳定性不但与稀土离子直径和冠醚孔径是否匹配,而且也和阴离子及合成用的溶剂有关.因15-冠-5(简写15C5)的孔径(2.2?)和大部分稀土离子直径相近.因此它们的络合物是研究孔径匹配关系的理想模型. Bunzli在乙腈中合成了大部分镧系硝酸盐15C5络合物,轻镧系(La-Gd)生成1:1无水络合物,重镧系(Tb-Lu)为含1—3分子水的1:1络合物.我们在无水丙酮中制备     

稀土硝酸盐冠醚配合物(Ⅺ)——Y(NO_3)_3·3H_2O-B15C5-C_2H_5OH三元体系18℃时溶解度的研究

我们曾用自己设计的半微量相平衡方法,研究了Y(NO_3)_5·3H_2O与冠醚B15C5分别在乙腈和丙酮中的溶解度。本文进一步研究了Y(NO_3)_3·3H_2O与冠醚B15C5在乙醇中的配合行为,以观察溶剂对所形成配合物组成的影响。图1是Y(NO_3)_3·3H_2O-B15C5-C_2H_5OH三元体系在18℃时的溶解度结果。     

冠醚过渡金属配合物的制备

碱金属、碱土金属、希土元素、锕系元素的阳离子与冠醚形成配合物的报导已有许多,但过渡金属Mn、Co、Ni、Cu的二价阳离子与冠醚形成配合物的报导却很少,而且不成系统,还未见到Fe~(3+)、Cr~(8+)与冠醚形成配合物的报导。我们以12-冠-4(Ⅰ)、15-冠-5(Ⅱ)、18-冠-6(Ⅲ)为配体,制备了Fe~(3+)、Cr~(3+)、Mn~(2+)、Co~(2+)、Ni~(2+)Cu~(2+)的硝酸盐和氯化物两系列配合物。     

Cu(Ⅱ)—苯并-15-冠-5在溶液中的磁共振研究

本文利用ESR和NMR谱对配合物Cu(II)—苯并-15-冠-5丙酮溶液的磁共振性质进行了研究.{[Cu(II)(C_(14)O_5H_(20))(H_2O)_2](ClO_4)_2}·3H_2O在丙酮中解离形成[Cu(II)(C_(14)O_5H_(20))(H_2O)_2]~(2+)和[Cu(H_2O)_6]~(2+)两种配位离子.其自旋哈密顿参量分别为g_∥=1.9887,g_⊥=2.3179,A_∥=0.0133cm~(-1),|A_⊥|<0.0032cm~(-1);(g')_∥=2.4143,(g')_⊥=2.0768,(A')_∥=0.0137cm~(-1),|(A')_⊥|<0.0016cm~(-1).基于ESR谱中g_∥相似文献   

Stabilities and Transfer Activity Coefficients from Water to Polar Nonaqueous Solvents of Benzo-15-Crown-5- and 15-Crown-5-Alkali Metal Ion Complexes

Stability constants (K_ML) of 1 : 1 benzo-15-crown-5 (B15C5) complexes with alkali metal ions were conductometrically measured in water at 25°C. Transfer activity coefficients of B15C5 and 15-crown-5 (15C5) from water to polar nonaqueous solvents were determined at 25°C. By using these data and the literature values, transfer activity coefficients of the B15C5 and 15C5 complexes with alkali metal ions from water to the polar nonaqueous solvents were calculated to study the solute-solvent interaction of the crown ether complexes. The stability of the B15C5 complex is lower in water than in any other nonaqueous solvent. The K_ML value for B15C5 is always smaller than the corresponding K ML value for 15C5. The interaction of the B15C5 or the 15C5 complex with the solvents depends on the alkali metal ion in the crown cavity. All the B15C5 and 15C5 complexes undergo hydrophobic hydration, which is particularly stronger for the B15C5 complexes with Na⁺ and K⁺. The unexpectedly lowest stability of the B15C5- or the 15C5-alkali metal ion complex in water among all the solvents is caused by the hydrogen bonding between ether oxygen atoms of uncomplexed B15C5 or 15C5 and water.     

Complexes of Lanthanoid Nitrates with 15-Crown-5 and 18-Crown-6 Ethers

Complexes between the heavier lanthanoid nitrates Ln(NO₃)₃ and 15-crown-5 ( 1 ) and 18-crown-6 ( 2 ) ethers were isolated and characterized. Both 1:1 and 4:3 complexes are formed with each Ln(III) ion, except in the case of Gd and 2 . The thermal transformation of the 1:1 complexes into the corresponding 4:3 complexes was studied by thermogravimetry and by DSC, X-ray and vibrational data provide information about the structure of these complexes. The interaction between Ln(III) ions and ligands 1 and 2 in non-aqueous solutions is discussed on the basis of conductometric, fluorescence, UV./VIS. and ¹H-NMR. data. Only 1:1 complexes of 2 formed in solution and their formation constants range from logK_f = 4.4 (Ln = La) to 2.4 (Ln = Yb); for Eu, K_f of the 15-crown-5 and 18-crown-6 ether complexes are of the same order of magnitude. For La, Pr, Nd, Eu, Yb, a variable temperature NMR. study gave some indications about the chemical exchanges in solution. The factors which determine the stoichiometry of the complexes are discussed.     

Effects of Side-Chain Substituents in Benzo-15-Crown-5 on Lithium Extraction

Chloroform–water extraction systems have been studied using crown-ethers as extracting agents, namely: benzo-15-crown-5 (B15C5), 2,3-naphtho-15-crown-5 (N15C5), 4′-nitro-benzo-15-crown-5 (NO₂B15C5), 4′-tert-butyl-benzo-15-crown-5 (TBB15C5), and 4′-acetyl-benzo-15-crown-5 (AcB15C5). Extraction isotherms of these systems have been obtained, and an attempt made to elucidate the effect of the structure of extracting agent on extraction characteristics. IR-spectroscopic studies have been performed for selected crown-ethers and their complexes in crystalline form and in chloroform solutions, namely, for N15C5, NO₂B15C5, AcB15C5, and B15C5. The complexes LiN15C5H₂OClO₄ (1), LiN15C5H₂OI (2), LiNO₂B15C5H₂OI (3), LiAcB15C5H₂OI (4), and LiTBB15C5H₂OI (5) have been isolated for the first time and characterized by IR spectroscopy. Single-crystal X-ray data have been obtained for complexes 1–3.     

Characterisation of uniformly 13C, 15N labelled bacteriochlorophyll a and bacteriopheophytin a in solution and in solid state: complete assignment of the 13C, 1H and 15N chemical shifts

In this investigation we report a complete assignment of (13)C, (1)H and (15)N solution and solid state chemical shifts of two bacterial photosynthetic pigments, bacteriochlorophyll (BChl) a and bacteriopheophytin (BPheo) a. Uniform stable-isotope labelling strategies were developed and applied to biosynthetic preparation of photosynthetic pigments, namely uniformly (13)C, (15)N labelled BChl a and BPheo a. Uniform stable-isotope labelling with (13)C, (15)N allowed performing the assignment of the (13)C, (15)N and (1)H resonances. The photosynthetic pigments were isolated from the biomass of photosynthetic bacteria Rhodopseudomonas palustris 17001 grown in uniformly (13)C (99%) and (15)N (98%) enriched medium. Both pigments were characterised by NMR in solution (acetone-d(6)) and by MAS NMR in solid state and their NMR resonances were recorded and assigned through standard liquid 2D (13)C-(13)C COSY, (1)H-(13)C HMQC, (1)H-(15)N HMBC and solid 2D (13)C-(13)C RFDR, (1)H-(13)C FSLG HETCOR and (1)H-(15)N HETCOR correlation techniques at 600 MHz and 750 MHz. The characterisation of pigments is of interest from biochemical to pharmaceutical industries, photosynthesis and food research.     

Cation-Coordinating Properties of Perfluoro-15-Crown-5

The coordinative properties of perfluoro-15-crown-5 with monocations were investigated using ¹⁹F NMR spectroscopy and ion-selective electrodes with perfluoro-15-crown-5 as the matrix of their sensor membranes and the fluorophilic tetrakis[3,5-bis(perfluorohexyl)phenyl]borate as ion exchanger site. The results show that perfluoro-15-crown-5 interacts weakly but significantly with Na⁺ and K⁺. Assuming 1:1 stoichiometry, the formal complexation constants were determined to be 5.5 and 1.7 M⁻¹, respectively. This weak binding is consistent with the strong electron withdrawing nature of the many fluorine atoms in the perfluorocrown ether. While perfluorinated crown ethers have been known to form host-guest complexes with the anions O₂⁻ and F⁻ in the gas-phase, this is the first study that quantitatively confirms cation binding to a perfluorocrown ether.     

A 1H, 13C and 15N NMR study in solution and in the solid state of six N-substituted pyrazoles and indazoles

Three N-substituted pyrazoles and three N-substituted indazoles [1-(4-nitrophenyl)-3,5-dimethylpyrazole (1), 1-(2,4-dinitrophenyl)-3,5-dimethylpyrazole (2), 1-tosyl-pyrazole (3), 1-p-chlorobenzoylindazole (4), 1-tosylinda-zole (5) and 2-(2-hydroxy-2-phenylethyl)-indazole (6)] have been studied by NMR spectroscopy in solution (1H, 13C, 15N) and in the solid state (13C, 15N). The chemical shifts have been compared with GIAO/DFT calculated absolute shieldings. Some discrepancies have been analyzed.     

锂盐阴离子和不同侧基的15-冠-5系冠醚对锂盐/冠醚固态配合物远红外位移的影响

按文献的方法研究了锂盐阴离子和不同侧基的15-冠-5系冠醚对四种锂盐/冠醚固态配合物远红外位移的影响.     

竹红菌乙素镁、锌配位聚合物的光物理和光生物性质

竹红菌乙素(HB)能与Mg2+和Zn2+形成重复单元数为5-20的配位聚合物(Mg2+-HB,Zn2+-HB),利用紫外-可见(UV-Vis)吸收光谱,傅里叶变换红外(FTIR)光谱,核磁共振氢谱(1H NMR)对其进行了表征.Mg2+-HB和Zn2+-HB的单重态氧量子产率分别为HB的1.2倍和0.42倍.瞬态吸收实验表明:氧气能够猝灭Mg2+-HB和Zn2+-HB的三重态,其效率可超过96％.系间窜越效率(φT)和将能量传递给氧气并能产生单重态氧的三重态光敏剂的比例(fT△)对HB及其金属配合物的单重态氧量子产率有较大影响.电子自旋共振(EPR)实验结果表明:Mg2+-HB和Zn2+-HB产生半醌负离子自由基的能力较弱,进而降低了Mg2+-HB和Zn2+-HB光敏产生超氧负离子自由基的能力.紫外-可见吸收光谱与小牛胸腺脱氧核糖核酸(CT DNA)熔链温度实验表明:Mg2+-HB和Zn2+-HB可通过静电作用与DNA结合.有氧条件下,Mg2+-HB,HB和Zn2+-HB对小牛胸腺DNA的光敏损伤效率分别为32％,25％和22％.活性氧猝灭实验表明Mg2+-HB主要通过单重态氧光敏损伤DNA.     

Synthesis and Crystal Structures of Group 10 Metal Bis(dithiolate) Complexes Constructed by 2,3-Naphtho-15-Crown-5 or 2,3-Naphtho-18-Crown-6

Five novel 2,3-naphtho crown ether group 10 metal bis(dithiolate) complexes, [Na(N15C5)₂]₂[Pd(mnt)₂] (1), [Na(N15C5)]₂[Pd(i-mnt)₂] (2) and [K(N18C6)]₂[M(i-mnt)₂] (3 5) (where mnt = 1,2-dicyanoethylene-1,2-dithiolate, i-mnt = 1,1-dicyanoethylene-2,2-dithiolate and M = Ni, Pd, Pt for complexes 3–5, respectively), have been synthesized and characterized by elemental analysis, FT-IR, UV–Visible spectra and single crystal X-ray diffraction. X-ray diffraction analyses reveal that complexes 1 and 2 have different structural features while complexes 3–5 are structurally isomorphous. Complex 1 consists of two [Na(N15C5)₂]⁺ sandwich complex cations and one [Pd(mnt)₂]²⁻ anion, affording a zero-dimensional structure. For 2, the [Na(N15C5)]⁺ mono-capped complex cations act as the bridges linking the [Pd(i-mnt)₂]²⁻ anions into a 1D infinite chain through Na–N interactions and SȮFC and SȮFπ interactions are observed in the resulting chain. Complexes 3–5 all consist of two [K(N18C6)]⁺ complex cations and one [M(i-mnt)₂]²⁻ (M = Ni, Pd or Pt) anion and the complex molecules are linked into␣1D␣chains by the bridging K–O(ether) interactions between the adjacent [K(N18C6)]⁺ units. What’s novel is that the resulting chains are assembled into novel 2D networks through interchain π–π stacking interactions between the neighboring naphthylene moieties of N18C6. The stack model of naphthylene group in complexes 3–5 is discussed.     

Partial Molar Volumes of 15-Crown-5 Ether in Mixtures of N,N-Dimethylformamide with Water

The density of 15-crown-5 ether (15C5) solutions in the mixtures of N,N-dimethylformamide (DMF) and water (H₂O) was measured within the temperature range 293.15–308.15 K using an Anton Paar oscillatory U-tube densimeter. The results were used to calculate the apparent molar volumes (V _Φ ) of 15C5 in the mixtures of DMF + H₂O over the whole concentration range. Using the apparent molar volumes and Redlich and Mayer equation, the standard partial molar volumes of 15-crown-5 were calculated at infinite dilution ( $ V_{\text{m}}^{^\circ } $ ). The limiting apparent molar expansibilities (α) were also calculated. The data are discussed from the point of view of the effect of concentration changes on interactions in solution.