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71.
A new organic photochromic compound containing pyrazolone-ring photochromic functional unit: 1-phenyl-3-methyl-4-benzyl-5-one pyrazole S-methyl thiosemicarbazone (PMBP-smtsc) was synthesized. The photochromic properties and photochemical kinetics of PMBP-smtsc have been studied by UV reflectance spectra under irradiation of 365 nm light. The crystal structure analyses of photocolored product show the photochromism is due to the photoisomerization from enol form to keto form through an intermolecular proton transfer.  相似文献   
72.
The electrochemical stability of 10 organic cations, which can be used in ionic liquids (IL), was investigated as solutes in acetonitrile (ACN). The stability of three of the salts, BenMe2EtNCl (salt III), 1-butyl-2-methyl pyrrolidium chloride (salt VI), and its structural isomer, BuMe2ProNCl (salt VII), were also compared in chloroaluminate ILs. The chloroaluminate ILs of salts VI and VII are investigated for the first time. The NaCl-neutralized ILs of salts VI and VII have melting points of 43.2 and 3.7 degrees C, respectively. The benzyl-substituted cation, salt III, was more easily reduced in ACN or as the neutral chloroaluminate IL than the alkyl-substituted cation, salt VII, due to the better leaving ability of the benzyl group. Mass spectroscopy measurements before and after electrolysis on the benzyl-substituted solutions confirmed that reduction involves the loss of an alkyl group. In ACN, salt VI was found to be the most difficult to reduce (1 mA/cm2 at -2.09 V) due to its cyclic structure. However, in the chloroaluminate IL, the pyrrolidinium cation was more easily reduced than salt III or its isomer, salt VII, resulting in an insoluble black deposit. This is consistent with the mass spectrometry data, which do not show formation of low-molecular-weight products, as in the reduction of salts III and VII. The IL of salt VII was the most stable in the presence of sodium. Sodium ions could be reduced and reoxidized with a maximum Coulombic efficiency of 94.1% versus 87.2% for salt VI. Reduction of the pyrrolidinium cation produces insoluble products, most likely through opening of the cyclic ring, and an inferior medium for sodium ion reduction compared to the benzyl- and butyl-substituted cations, even though reduction of the cation occurs at a more negative potential in acetonitrile.  相似文献   
73.
Acid-catalyzed isomerization of the petrosterol side chain (1) proceeds stereospecifically to yield the naturally occurring 26-dehydro-25-epiaplysterol side chain (2); in addition, a 1.5-hydride shift leading to 22-dehydro-25-epiaplysteryl acetate (3) has also been observed.  相似文献   
74.
The complex [{(TMS)2N}4(mu4-Cl)Sm4(mu-SPh)4(mu3-Cl)Li(THF)] has been formed by protonolysis of [(Me3Si)2N]3Sm(mu-Cl)Li(THF)3 with 1 equiv of HSPh, which contains a square array of Sm(III) ions connected by a central mu4-Cl ligand. The edges of the square Sm4 array are bridged by four mu3-Cl and four mu-SPh ligands. The four Sm atoms and Li atom are connected by four mu3-Cl ligands.  相似文献   
75.
The synthesis and characterization of the anionic mononuclear and homobinuclear osmium complexes [AsPh4][OsCl5L].xEtOH [L = H2O, x = 2 (9); L = EtOH, x = 1 (10a); L = py, x = 0 (10b)] and [AsPh4]2[Cl5Os(pyz)OsCl5] (12) (pyz = pyrazine) are described. Upon reduction in a chloride-containing medium, OsO4 (1) affords the osmium(IV) species [OsCl5(H2O)]- (2), which could be isolated by extraction with n-tributyl phosphate (TBP). Complex 9 is the first fully characterized chloroaquo complex of Os(IV). This complex is an effective starting material for the preparation of novel species, such as 10a, 10b, and 12. The X-ray structures of 9 and 10a were determined. Both compounds crystallize in the monoclinic space group P2(1)/n. 9: C28H34AsCl5O3Os, a = 10.910(4) A, b = 17.127(5) A, c = 17.555(7) A, beta = 103.77(2) degrees, V = 3186(2) A3, and Z = 4. 10a: C28H32AsCl5O2Os, a = 10.7762(2) A, b = 17.3939(1) A, c = 17.1477(3) A, beta = 103.645(1) degrees, V = 3123.45(8) A, and Z = 4. Complexes 9 and 10a crystallize with two and one molecule of EtOH and are bonded via hydrogen bridges to the H2O and EtOH ligand in 9 and 10a, respectively.  相似文献   
76.
[Hg(sulfamethoxazolato)2]·2DMSO ( 1 ) and [Cu2(CH3COO)4(sulfa‐methoxazole)2] ( 2 ) can be obtained by the reaction of sulfamethoxazole with mercury acetate or copper acetate in methanol. The structures of the two complexes were characterized by single crystal X—ray diffractometry. Compound 1 consists of sulfamethoxazolato ligands bridging the metal ions building an unidimensional chain. Two solvent dimethylsulfoxide molecules are involved via N‐H···O hydrogen bridges. The mercury atom shows a linear primary coordination arrangement formed by two trans deprotonated sulfonamidic nitrogen atoms. The overall coordination around the metal atom may be regarded as a strongly distorted octahedron when the interactions of mercury with four sulfonamidic oxygen atoms [bond distances of 2.761(4) Å—2.971(4) Å] are also considered to build an equatorial plane and the N1 and N1′ atoms [bond distance of 2.037(5) Å] occupy the apical positions. Compound 2 is a dinuclear complex in which the copper ions are bridged by four syn‐syn acetate ligands which are related by a symmetry centre located in the centre of the complex. Each copper atom presents a nearly octahedral coordination where the equatorial plane is formed by four oxygen atoms and an isoxazolic nitrogen atom and the second copper atom occupy the apical positions.  相似文献   
77.
钴(II)-联吡啶-α-氨基酸的热力学和动力学研究   总被引:3,自引:0,他引:3  
关于联吡啶为第一配体的二元、三元配合物的热力学和动力学性质的研究,以铜(Ⅱ)作为中心离子最为多见,而以钴(Ⅱ)作为中心离子的报导较少.实验表明,过渡金属钻(Ⅱ)能与大多数的生物配体、大π共轭体系形成相当稳定的二元、三元配合物,是生物功能模拟的一个具有应用价值的中心离子·钴(Ⅱ)卟啉可以代替铁(Ⅱ)卟啉,模拟血红蛋白、肌红蛋白[1],在生物体内起到输送氧的作用.为了充分了解钴(Ⅱ)与生物配体的配伍能力、配位方式以及其配位过程的动态行为,为推动钴(Ⅱ)配合物及其生物功能的模拟研究,本文分别采用PH电位法…  相似文献   
78.
An on-line two-stage column chromatographic technique is described which combines reversed-phase and anion-exchange chromatography for the separation of purine nucleic acid components. The elution program applied, consisting of two gradient programmes, provides a separation of bases and nucleosides on the octadecyl silica column and a separation of the nucleotides on the anion-exchange column to which they have been switched at the beginning of the elution. This method is easy to modify for special problems and can be used when establishing a complete profile of purines.  相似文献   
79.
The reaction of tellurium(IV) tetrahalides with hydrochloric and hydrobromic acid leads to the formation of (H3O)2[TeX6], which reacts subsequently with (2‐Br‐C5NH5)+X to afford (2‐Br‐C5NH5)2[TeCl6] ( 1 ) and (2‐Br‐C5NH5)2[TeBr6] ( 2 ). The structure of the complex salts were analysed by X‐ray diffractometry affording the centrosymmetric space groups P21/n (monoclinic, 1 ) and P1¯ (triclinic, 2 ). Interionic hydrogen bondings hold their lattices in bidimensional supramolecular arrays not yet described in the literature. The lone electron pair of the AX6E‐system of the hexahalotellurates [TeX6]2‐ (X = Cl, Br) seems to be fully delocalized since only small octahedral deviations were observed for the anionic species. The structures of the title compounds were refined with the Te atoms occupying sites with full point symmetry, approximately m3¯m. In both cases the Te atoms enclose centers of inversion and the octahedrally dynamic structures are enforced and stabilized along the supramolecular lattices by the crystal field of the 2‐Br‐pyridinium cations.  相似文献   
80.
Two copper complexes [Cu(TTA)2(4,4′‐azpy)] (1) and [Cu‐(TTA)2(3,3′‐azpy)] (2) (HTTA = 1,1,1‐trifluoro‐3‐(2‐thenoyl)‐acetone, 4,4′‐azpy = 4,4′‐azobispyridine, 3,3′‐azpy = 3,3′‐azobispyridine) were synthesized and characterized. The crystal structures were determined by X‐ray diffraction analysis. The crystal 1 belongs to triclinic with space group P1 , a = 0.8515(2) nm, b = 0.9259(2) nm, c = 0.9468(2) nm, a = 66.126(9)°, β = 79.667(9)°, γ = 90.13(1)°, Z = 1, V = 0.6692(2) nm3, Dc = 3.425 g/cm3, γ = 2.113 mm?1, F(000) = 694, R1 = 0.0594, wR2 = 0.1499. The crystal 2 belongs to monoclinic with space group P21/c, a = 1.0661(2) nm, b = 1.4296(3) ran, c = 1.0041(3) nm, β = 114.50(3)°, V = 1.3926(5) nm3, Z = 2, Dc = 1.646 g/ cm3, μ = 1.015 mm?1, F(000) = 694, R1, = 0.0535, wR2 = 0.1113. In the crystals of complexes 1 and 2, the copper atoms have distorted octahedral symmetry. The two compounds possess very similar one‐dimensional linear chains linked through the rodlike 4,4′‐azpy ligands or 3,3′‐azpy ligands.  相似文献   
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