六氟磷酸二(2,2'-联吡啶)·(4,4'-二甲基-2,2'-联吡啶) 合钌(Ⅱ)的二维核磁共振谱分析

用一维NMR方法研究了电化学发光物质六氟磷酸二(2,2'-联吡啶)·(4,4'-二甲基-2,2'-联吡啶)合钌(Ⅱ)的立体结构,借助二维1H-1H COSY和1H-13C COSY实验技术对其氢谱和碳谱进行了完全的归属,并给出了其氢谱和碳谱的化学位移值.     

Atom transfer radical polymerization and copolymerization of isoprene catalyzed by copper bromide/2,2'-bipyridine

ATRP, as one of the most successful controlled/‘‘living' radical polymerization techniques, has been applied to a large variety of monomers including styrenes,(meth)acrylates,(meth)acrylamides,acrylonitrile, and vinyl acetate. However, ATRP of isoprene still remains a challenge due to poor solubility of copper catalysts in isoprene and low chain propagation rate constant of the monomer. In this work,Cu Br/2,2'-bipyridine was found to effectively mediate ATRP of isoprene at 100 °C, 130 °C, and 150 °C with ethyl 2-bromopropionate as an initiator. The polymerizations proceeded smoothly and reached 48.1%,53.3%, and 71.0% conversions, respectively, in 72 h, producing polyisoprenes with molecular weights close to theoretical values and relatively narrow distributions. A block copolymer of polystyrene-bpolyisoprene was prepared using Cu Br/2,2'-bipyridine as a catalyst and polystyrene as a macroinitiator.The ~1H NMR and ~(13)C NMR analysis of polyisoprene indicated that the polymer had 88.8% 1,4-addition structure and 63.9% of the polymer backbone units were in trans-configuration.     

Blue phosphorescent Zn(II) and orange phosphorescent Pt(II) complexes of 4,4'-diphenyl-6,6'-dimethyl-2,2'-bipyrimidine

To investigate the different phosphorescent promoting effects of organic emitters by various metal centers, a new ligand, 4,4'-diphenyl-6,6'-dimethyl-2,2'-bipyrimidine (pmbp), and its Zn(II), Hg(II), and Pt(II) complexes, [Zn(pmbp)(2)](ClO(4))(2)(1), Pt(pmbp)Ph(2)(2), Zn(pmbp)Cl(2)(3), and Hg(pmbp)Cl(2)(4) were synthesized. Their structures were determined by single crystal X-ray diffraction. The zinc complexes 1 and 3 exhibit blue luminescence in the solid state at ambient temperature, but the mercury complex 4 is not luminescent. At 77 K, both pmbp and complex have blue emissions in MeOH solutions, which were demonstrated to be phosphorescence by their long decay lifetime (micros). By comparing the luminescent properties of the free ligand and the complex, we concluded that the phosphorescence of originates from ligand centered pi --> pi* transitions. Complex 2 exhibits orange luminescence both in CH(2)Cl(2) solution at 77 K and in the solid state at ambient temperature, which was assigned to metal-to-ligand [d(M) --> pi*(pmbp)] charge transfer (MLCT). The different origin of luminescence is responsible for the different luminescent color of the Zn(II) and Pt(II) complexes.     

Crystal chemistry in the system MSbO3

Cubic, disordered phases of the compounds MSbO₃ (M = Li, Na, K, Rb, Tl, and Ag) have been investigated. KSbO₃ is readily synthesized in the disordered, cubic structure at high pressure, and the other isomorphic compounds were obtained by ion exchange. The structures of NaSbO₃ and AgSbO₃, which have space group Im3, were solved by X-ray single-crystal analysis. The structures contain an essentially rigid SbO₃ subarray consisting of pairs of edge-shared octahedra sharing common corners. Within this subarray, face-shared octahedra form 〈111〉 tunnels that intersect at the origin and body center of the unit cell, and the M⁺ ions are randomly distributed over two positions within these tunnels. Ordered, cubic phases have the primitive-cubic space group Pn3. The two M positions are different for Na⁺ and for Ag⁺ ions. At one of the Ag⁺-ion positions, the AgO bond length is only 2.26 Å, consistent with the gray-black color of AgSbO₃. Deformation of the 4d¹⁰ Ag⁺-ion core by 4d-5s hybridization appears to be induced by AgO covalent bonding. This conclusion is compatible with the observation that ion exchange is reversible for all compounds but AgSbO₃. Several properties of these compounds are compared with the super ionic conductors M₂O·11Al₂O₃ β-alumina.     

Mass-spectrometric distinction of linear and angular 2,2'-dimethyl-3'-oxo-dihydropyranocoumarins

Summary The mass spectra of linear and angular 2,2-dimethyl-3-oxodihydropyranocoumarins and their deuterium analogs have been studied. A basic mass-spectrometric difference between these substances has been found which consists in the greater stability of the fragment (M - CO)⁺. for the linear isomer than for the angular isomer. A hypothesis has been put forward on the most probable route for the formation of the ion (M - 2CO - H)⁺ in the mass spectra of the compounds mentioned.M. V. Lomonosov Moscow State University. Patrice Lumumba International Friendship University, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 664–668, September–October, 1977.     

Mass-spectrometric distinction of linear and angular 2,2'-dimethyl-3'-oxo-dihydropyranocoumarins

Summary A chromatospectrophotometric method for determining ferutinin and teferin + ferutin in a preparation has been developed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 616–618, September–October, 1976.     

Isolation and Crystal Structure of Trans-2,2'''',4,4''''-tetramethyl-6,6''''-dinitro Azobenzene

1 INTRODUCTION The aconitum plants produce various diterpene and norditerpene alkaloids[1, 2]. Up to now more than 450 diterpenoid and norditerpenoid alkaloids have been isolated from the roots of this genus[3]. Sub- sequent studies on the flower of the same subspecies were directed to the other secondary metabolites such as flavonoids[4, 5]. The flavonoidic composi- tions of several oriental species of A. plants have been reported[6～8]. A. sungpanense hand. Mazz., a very highly poi- s…     

In situ atom transfer radical polymerization of styrene with a tetraethylthiuram disulfide/copper bromide/2,2′‐bipyridine initiating system

The living radical polymerization of styrene in bulk was successfully performed with a tetraethylthiuram disulfide/copper bromide/2,2′‐bipyridine (bpy) initiating system. The initiator Et₂NCS₂Br and the catalyst cuprous bromide (CuBr) were produced from the reactants in the system through in situ atom transfer radical polymerization (ATRP). A plot of natural logarithm of the ratio of original monomer concentration to monomer concentration at present, ln([M]₀/[M]) versus time gave a straight line, indicating that the kinetics was first‐order. The number‐average molecular weight from gel permeation chromatography (GPC) of obtained polystyrenes did not agree well with the calculated number‐average molecular weight but did correspond to a 0.5 initiator efficiency. The polydispersity index (i.e., the weight‐average molecular weight divided by the number‐average molecular weight) of obtained polymers was as low as 1.30. The resulting polystyrene with α‐diethyldithiocarbamate and ω‐Br end groups could initiate methyl methacrylate polymerization in the presence of CuBr/bpy or cuprous chloride/bpy complex catalyst through a conventional ATRP process. The block polymer was characterized with GPC, ¹H NMR, and differential scanning calorimetry. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4001–4008, 2001     

Synthesis of novel nematic liquid crystals containing 3,3'-dimethyl-2,2'-bipyridyl

Liquid-crystalline 3,3′-dimethyl-2,2′-bipyridyl derivatives with long 4-(alkoxyphenyl)ethynyl (-C≡C-C₆H₄-OR) groups in the 5,5′-positions were synthesized by palladium-catalysed crosscoupling reactions. The compounds exhibit exclusively nematic behaviour; for example, the hexyl derivative showed a nematic phase over the temperature range 145.2–205.0°C. On increasing the length of the terminal chain, the transition temperatures were lowered; for example, the hexadecyl derivative was nematic in the range 117.0–126.8°C.     

Synthesis of novel nematic liquid crystals containing 3,3'-dimethyl-2,2'-bipyridyl

Liquid-crystalline 3,3'-dimethyl-2,2'-bipyridyl derivatives with long 4-(alkoxyphenyl)ethynyl (-C=C-C₆H₄-OR) groups in the 5,5'-positions were synthesized by palladium-catalysed crosscoupling reactions. The compounds exhibit exclusively nematic behaviour; for example, the hexyl derivative showed a nematic phase over the temperature range 145.2-205.0°C. On increasing the length of the terminal chain, the transition temperatures were lowered; for example, the hexadecyl derivative was nematic in the range 117.0-126.8°C.     

(2,2''''-联苯酸)(4,4''''-联苯胺)合镍微晶粉体的水热合成及表征

以2,2'-联苯酸(diphenic acid)和联苯胺(Benzidine)为配体,通过水热法制备了2,2'-联苯酸·4,4'-联苯胺合镍[Ni(Dipha)(Benzidine)]微晶粉体(dipha=diphenic acid).通过元素分析、IR、热重分析等手段对配合物进行了表征.     

钯碳催化法合成4,4'-二甲基-2,2'-联吡啶

以4-甲基吡啶为原料, 钯碳催化合成了4,4'-二甲基-2,2'-联吡啶. 通过¹H NMR, GC-MS, 元素分析对产物进行了表征, 对催化反应进行了分析, 并且讨论了钯碳催化反应的机理.     

Experimental and computational studies of nuclear substituted 1,1'-dimethyl-2,2'-bipyridinium tetrafluoroborates

The synthesis and spectral properties of a new 2,2'-bipyridinium ion, 1,1'-dimethyl-4,4'-(dimethylamino)-2,2'-bipyridinium bis(tetrafluoroborate) are reported. Rotation of the dimethylamino group is slow at room temperature on the 400 MHz 1H and 100 MHz 13C NMR time scales. Complete line shape fit of the dynamically broadened NMR spectra was used to determine the activation barriers for this process. The first complete set of UV-vis spectra for a 2,2'-bipyridinium dication and its one- and two-electron reduced products was reported. TD-DFT calculations were used to help assign the origin of the long wavelength absorptions in these species. The effect of substituents on the energies and conformational potential energy surfaces of all three species were also examined using the B3LYP/6-31G(d) computational method.