2,2′-联吡啶与锌电极作用的表面增强拉曼光谱研究

利用表面增强拉曼光谱(SERS)对2,2′-联吡啶分子在锌电极表面的吸附进行了研究. 实验表明, 2,2′-联吡啶和锌电极有较强的相互作用, 2,2′-联吡啶和锌表面的氧物种存在竞争吸附, 起始电位较正时, 氧物种的吸附使2,2′-联吡啶吸附电位负移；起始电位较负时, 2,2′-联吡啶的吸附抑止氧物种的吸附, 使其吸附电位正移, 且相同电位下氧化种的吸附量大大减少. 同时当电极电位由正往负移时, 吸附在锌表面的2,2′-联吡啶会发生构型转化, 在－1.3 V下以顺式构型垂直吸附, 而当电位负移至－1.4 V时则以反式构型吸附；而电极电位由负往正移时, 在研究电位区间内2,2′-联吡啶都以反式构型吸附, 不存在构型的转化.     

3′-叠氮-3′-去氧胸苷的密度泛函理论计算

利用量子化学密度泛函理论B3LYP方法和3-21G基组对HIV-1 逆转录酶抑制剂3′-叠氮-3′-去氧胸苷(AZT)中围绕核苷键的内旋转进行了计算研究, 得到内旋势能曲线. 对势能曲线上各驻点, 又在B3LYP/6-31G*水平上进行构型全优化和频率分析计算. 在计算得到的势能曲线上有两个能量相近的极小点, 其中一个能量极小点对应的构型的三个重要参数(P, χ , 和γ )与在3′-叠氮-3′-去氧胸苷5′-三磷酸盐与HIV-1逆转录酶结合时的AZT活性构型相符.     

1,1′-联萘(1,1′-BIN)激发态的衰变函数关系与构型

本文测定了能够给出有关~1(1,1′-BIN)~*构型变化信息的1,1′-BIN和其他一些化合物在不同溶剂中的荧光寿命和发射光谱,并研究了1,1′-BIN激发电荷转移的性质。其结果表明,在激发的双萘分子中的两个萘基在流体溶剂中于室温时绕c—C连键的旋转是非常快的,即使在粘度很大的溶剂中在280PS之内都观测不到它的构型变化。其荧光发射谱带证明~1(1,1′-BIN)~*构型与“两个萘基”共平面的~1(DBF)~*和~1(BOHF)~*的构型不同。1,1′-BIN与N-丙基-2,5-二甲基吡咯(PDMP)之间形成了激发络合物。测得了~1(1,1′-BIN)~*的荧光衰变函数。     

用硅胶担载三氯化铁催化氧化偶联2-萘酚制备(±)2,2′-二羟基-1,1′-联萘

2,2′-二羟基 - 1 ,1′-联萘 ,由于存在受阻 C- C键轴 ,可通过拆分获得对映体纯手性双膦配体BINAP的前体 [1] ,或经不对称氧化转化成催化剂前体 [2 ] ,或用作手性试剂 ,近年来备受人们的重视 .其常用制备方法多以 Fe3 、 Mn3 及 Cu2 氧化 2 -萘酚 .尤以 Fe3 [3～ 5] 为氧化剂制备 (± ) 2 ,2′-二羟基 -1 ,1′-联萘最为经济 .传统上以甲醇 /水 ( 1 /1 ,体积比 )为介质 ,用 Fe Cl3 氧化 2 -萘酚制 (± ) 2 ,2′-二羟基 - 1 ,1′-联萘 ,产率不太高 [5] .近年来 ,Toda等 [5]利用固态反应及超声波制备此化合物 ,收率明显提高 ,但…     

5-甲氧基-6′-羟基-2,2′-[乙二氧双(氮次甲基)]二酚及其四核锌(Ⅱ)配合物的合成与晶体结构(英文)

合成了一种不对称Salamo型配体5-甲氧基-6′-羟基-2,2′-[乙二氧双(氮次甲基)]二酚(H3L)及其四核锌髤配合物[Zn4L2(CH3OH)2(OAc)2],并通过X-射线单晶衍射分析确定了其晶体结构。其中配体呈现一种"V"构型,两个苯环单元的二面角为85.71(3)°,可近似认为是垂直的;而在配合物晶体结构中,金属离子有两种配位构型方式:一种为三角双锥构型,另一种为四方锥构型。配合物通过分子间的氢键作用形成了一个无限延伸的二维结构。     

螺旋共轭分子2,2′-螺二茚-1,1′, 3,3′-四酮及其衍生物的二阶非线性光学性质与分子结构关系的研究

采用AM1和ZINDO系列方法研究了螺旋共轭分子2,2′-螺二茚-1,1′, 3,3′-四酮及其含氮衍生物的几何构型和各分子的稳定构型, 并以稳定构型为基础, 计算了这些分子的电子光谱、二阶非线性光学系数βμ, β0及电荷转移, 考察了取代基变化对βμ的影响. 计算结果表明, 所设计分子兼具较大的二阶非线性光学系数和较高的透过率, 有希望成为一类新型的二阶非线性光学材料.     

对苯二胺类与2,2′-二噻吩共轭共聚物的金属催化法合成与表征

以1,3-二(二苯基膦)丙烷二氯化镍(Ⅱ)作为催化剂,分别合成了2,2′-二噻吩与N,N′-二氯对苯醌二亚胺和2,5-二甲基-N,N′-二氯对苯醌二亚胺的共轭交替共聚物:聚(N,N′-对苯醌二亚胺-2,2′-二噻吩)和聚(2,5-二甲基-N,N′-对苯醌二亚胺-2,2′-二噻吩)。利用红外光谱、紫外可见光谱、循环伏安等测试方法对这2种共聚物进行了表征和性能研究。结果表明:这2种共聚物分别在263、315、410、261、3214、03 nm处出现了紫外吸收峰,对苯二胺上的甲基对共聚物电化学活性具有一定的影响。     

2，2′-联喹啉-4，4′-二羧酸构筑的一维钴(Ⅱ)配位聚合物

利用2,2′-联喹啉-4,4′-二羧酸钠(Na2bqdc),2,2-联吡啶与硫酸钴在溶剂热作用下合成了1个一维配位聚合物[Co(bqdc)(bipy)(H2O)]n(1)。通过元素分析、粉末衍射、红外、紫外光谱对配合物进行了表征,利用X射线单晶衍射仪测定了其晶体结构。中心CoⅡ离子分别与2个来自2,2-联喹啉-4,4-二羧酸钠配体的双齿羧基氧原子和1个来自配体的单齿羧基氧原子、辅助配体2,2-联吡啶上的2个N原子和1个水分子的氧原子配位,形成了1个稍微扭曲的八面体配位构型。紫外光谱实验表明,相对2,2′-联喹啉-4,4′-二羧酸钠配体,配合物的紫外光谱发生了少量的蓝移。对该配合物多晶样品的差热分析(TGA)表明该化合物在217℃后开始分解。     

六氟磷酸二(2,2′-联吡啶)(2,2′-联吡啶-4,4′-二羧酸)合钌(Ⅱ)的二维核磁共振谱分析

利用核磁共振氢谱和碳谱研究了电化学探针六氟磷酸二(2,2′-联吡啶)(2,2′-联吡啶-4,4'-二羧酸)合钌(Ⅱ)的立体结构,并通过二维1H-1H同核相关及1H-13C异核相关技术对其氢谱和碳谱进行了归属.     

5,5′-二(对-取代苯基)-2,2′-联噁唑的合成及其光性能研究

合成了8种5,5′-二(对-取代苯基)-2,2′-联噁唑,其中6种是未见报道的新化合物。讨论了它们的结构与光性能间的关系,并比较了它们和5,5′-二(对-取代苯基)-2,2′-联-1,3,4-噁二唑的光性能。     

Platinum complex-catalyzed hydrosilylation and isomerization of methylenecyclopropane derivatives. Effect of structures of the substrate and catalyst

PtI(2)(PPh(3))(2) catalyzes hydrosilylation of 2,2-diphenyl-1-methylenecyclopropane with HSiEt(3), HSiPh(3), HSiEt(2)Ph, HSiPhCl(2), and HSiCl(3) under solvent-free conditions at 140 degrees C to produce the silyl compounds with a (2,2-diphenylcyclopropyl)methyl substituent in moderate to high yields without ring-opening of the substrate. PtI(2)(PPh(3))(2) is converted by the reaction into PtH(I)(PPh(3))(2), which also catalyzes the hydrosilylation of the methylenecyclopropanes. The reaction of 2-phenyl-1-methylenecyclopropane, 2-methyl-2-phenyl-1-methylenecyclopropane, 2,2-diphenethyl-1-methylenecyclopropane, and alkylidenecyclopropanes with HSiEt(3) catalyzed by PtI(2)(PPh(3))(2) causes addition of hydrosilane to the substrate accompanied by ring-opening. 2,2-Diphenyl-1-methylenecyclopropane undergoes ring-opening isomerization in the presence of HSi(OEt)Me(2) and Pt(PEt(3))(3) catalyst to give 1,1-diphenyl-1,3-butadiene. The pathways for the hydrosilylation and the isomerization are discussed.     

光诱导有机化合物异构化反应的研究——Ⅹ. 吲哚啉螺吡喃瞬态吸收光谱的研究

研究了1-正-辛基-3,3-二甲基-吲哚啉-2,2′-螺-5′,6′-(2-溴-4-硝基-苯并)吡喃, 1-正-辛基-3,3-二甲基-吲哚啉-2,2′-螺-5′,6′-(4-硝基-苯并)吡喃, 1-正-辛基-3,3-二甲基-吲哚啉-2,2′-螺-5′,6′-(2,4-二硝基-苯并)吡喃及1-正-辛基-3,3-二甲基-吲哚啉-2,2′螺-5′6′-(2-氯-4-硝基-苯并)吡喃在环已烷和甲苯溶液中光致开环过程的瞬态吸收光谱。观察到具有较长寿命的中间体及聚集体的存在。初步提出异构化反应过程的机制中既包含有三重态过程, 也有单重态参与。     

Semiconductor-catalyzed photocycloreversion,valence isomerization and [1,3]-sigmatropic rearrangement

The semiconductor-catalyzed photochemical [2+2]cycloreversion of n-methylquinolone dimer, valence isomerization of hexamethyl(Dewar)benzene, and [1,3]-sigmatropic rearrangement of 2,2-bis(4-methoxyphenyl)-1-dideuteriomethylenecyclopropane gave N-methylquinolone, hexamethylbenzene, and 2,2-bis(4- methoxyphenyl)-3,3-dideuterio-1-methylenecyclopropane, respectively.     

Isomerization of n-Hexane Over Platinum Ion-Exchanged Zeolite Beta

Zeolite Beta was synthesized from appropriate gels and crystallized under the controlled temperature and pressurized conditions. For isomerization of n-hexane, platinum ion-exchanged zeolite Beta exhibited high activity and selectivity for 2,2-dimethylbutane (2,2-DMB), 2,3-dimethylbutane (2,3-DMB), 2-methylpentane (2-MP) and 3-methylpentane (3-MP). As high as 72% of n-hexane conversion and 98% of product selectivity were obtained at 250°C, 1600 h^–1 for 20 min on stream. The influences of reaction temperature and space velocity were also studied. Pt/H-Beta zeolite was recommended as one of the promising catalyst for n-hexane isomerization due to its high activity and stability. The combined effect of the stronger acidity possessed by H-Beta and the dehydrogenation role played by Pt was believed to be responsible for the good catalytic performance of Pt/H-Beta.     

Efficient Isomerization for Preparing thans-2,2-Dimethyl-3-(2,2-dichloroethenyl) cyclopropanecarbonyl Chloride

2,2-Dimethyl-3-(2,2-dichloroethecyclopropanecarbonylchloride(hereafterreferredtoaspermethricacidchloride)isausefulintermediateforthepreparationofsomesyntheticpyrethroids,suchaspermethrinandcypermethrin.Permethricacidchloridehasageometricalisomericpair,oiLyandtrans,owingtoitscyclopropanering.Itisknownthat,ingeneral,theestersderivedfromtheirans-isomerarelesstoxictomammalsthanthosederivedfromtheets-isomerl--3.Thepermethricacidproducedindustriallyisalwaysinformsofmixturesoftrans-andets-isomers.Ac…     

Reaction of aziridines with acetylenic γ-hydroxy aldehydes

The corresponding acetylenic aziridino hydroxy carbinols were obtained by the reaction of aziridine, 2,2-dimethylaziridine, and methyl aziridine-2-carboxylate with 4-hydroxy-4-methylpent-2-yn-1-al and 3-(1-hydroxycyclohexyl)prop-2-yn-1-al. It is shown that the latter at room temperature undergo isomerization with time to 2-hydroxy-4-aziridino-5,5-dialkylduiydrofurans. The isomerization of acetylenic aziridinocarbinols, which includes an intermediate step involving retrodecomposition of the aziridino (hydroxy) carbinols to the starting aldehydes and aziridines, was investigated by dynamic NMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 334–337, March, 1979.     

Turning off phototriggered linkage isomerizations in ruthenium dimethyl sulfoxide complexes

We report on the spectroscopy, electrochemistry, and linkage isomerization in a family of [Ru(tpy)(L2)(dmso)](z)()(+) complexes (tpy is 2,2':6',2' '-terpyridine, dmso is dimethyl sulfoxide, and L2 is a variable ligand: 2,2'-bipyridine (bpy), 2-picolinate (pic), N,N,N',N'-tetramethylethylenediamine (tmen), acetylacetonate (acac), or malonate (mal)). The identity of this bidentate ligand serves to tune the absorption maxima (lambda(max) = 419-502 nm) and the reduction potential (E(1/2) = 1.67 to 0.82 V) of these complexes. Photochemical and electrochemical studies show that S-->O and O-->S linkage isomerization may be triggered through an electron transfer mechanism, resulting in dramatic shifts in both the absorption maxima and the reduction potential (for [Ru(tpy)(pic)(dmso)](+) S-bonded, 421 nm, 1.38 V vs Ag/AgCl; O-bonded, 527 nm, 1.38 V vs Ag/AgCl). Certain of these complexes [Ru(tpy)(acac)(dmso)](+) and [Ru(tpy)(mal)(dmso)] do not undergo isomerization. These results are discussed in the context of electron transfer triggered isomerization.     

Photocrosslinkable resins with benzylideneacetophenone (chalcone) structure in the repeat units

Syntheses, characterization and photoreactions of six diglycidyl ethers obtained by condensing 2,2′, 2′,4, and 4,4′-dihydroxychalcones with epichlorohydrin in two different molar proportions have been reported. It has been observed that the well known cyclodimerization and trans-cis isomerization of the chalcone moiety under photoirradiation could be significantly affected to the extent of completely supressing the isomerization in 2,2′, and 2′,4-chalconic resins by steric factors. Increase in molecular weight made the photodimerization difficult in the 2,2′, and 2′,4-chalocnic resins whereas the 4,4′-chalconic resin remained unaffected. It has been suggested that the chalconic resin could be used in photomechanical processes mixed with aryldiazonium fluoroborates. These additives are known to decompose under photoirradiation yielding BF₃ which is a crosslinking agent for the epoxide group.     

Reaction of difluorocarbene with 2H-azirines: generation and transformations of strained azomethine ylides -- aziriniodifluoromethanides

The reaction of difluorocarbene with azirines affords a new type of azomethine ylides, viz., strained aziriniodifluoromethanides. 1,3-Dipolar cycloadditions of ylides derived from 2-unsubstituted 3-arylazirines to dimethyl acetylenedicarboxylate and aldehydes give derivatives of 2,2-difluoro-1-azabicyclo[3.1.0]hex-3-ene-3,4-dicarboxylic acids and 1,4-oxazin-3(4H)-ones, respectively. Ylides derived from 2-mono- and 2,2-disubstituted azirines undergo isomerization to 2-aza-1,3-diene derivatives. 2,2-Difluoro-1-azabicyclo[3.1.0]hex-3-enes are transformed into 2-fluoropyridine derivatives in high yields and react with amines to give 2,4-diamino-1-azabicyclo[3.1.0]hex-2-ene derivatives.     

Prototropic Isomerization of Spiro[2,3]hexanes 1,1,5-Trisubstituted with Electron-acceptor Groups into 1,3-Disubstituted Bicyclo[1.1.0]butanes

1,1-Dicyano- and 1,1-dialkoxycarbonylspiro[2.3]hexane-1-carbonitriles treated with lithium diisopropylamide or potassium tert-butylate in THF undergo a prototropic isomerization into 3-(2,2-dicyanoethyl)- and 3-(2,2-dialkoxycarbonylethyl)bicyclo[1.1.0]butane-1-carbonitriles respectively.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 201–204.Original Russian Text Copyright © 2005 by Razin, Ulin.