Chiral recognition in the crystal structure of a dichiral mesogen with a unique isotropic mesophase: 2-{4-[(R)-2-fluorohexyloxy]phenyl}-5-{4-[(S)-2-fluoro-2-methyldecanoyloxy]phenyl}pyrimidine

The crystal structure of the title compound, which has an optically isotropic IsoX phase with an endothermic transition on cooling from an Sm*C phase, has been determined at 230 K. The crystal has a smectic-like layer structure composed of four crystallographically independent molecules. In the layer, one-dimensional chains of tightly fitted pyrimidine rings, with N... H distances shorter than the van der Waals radii, result in the large overlapping of core moieties and further induce close contacts and stereo-specific F-methyl interactions between the chiral groups; this is considered to be responsible for the uniquely organized IsoX phase.     

The crystal and molecular structure of bis{μ[(tri-fluoromethyl)selono]manganese tetracarbonyl}

The crystal structure of [(CF₃Se)Mn(CO)₄]₂ has been determined by single crystal X-ray diffraction. The crystals are monoclinic, P2₁/c, a = 6.32, b = 15.35, c = 9.75 Å, β = 108.9°, Z = 2. The molecule possesses a crystallographic centre of symmetry, and is based on a planr [MnSe]₂ unit with four almost equal MnSe bonds (2.50 Å). The principal bonds length and angles are MnMn 3.74, SeSe 3.31 Å ; SeMnSe 83.1°, MnSeMn 96.9°; MnC (mean) 1.83, CO (mean) 1.16, SeC 1.97, CF (mean) 1.31 Å     

{苯基-[(吡啶-4-羰基)-氨基]-甲基}-膦酸二烷基酯的合成与波谱表征

α-氨基膦酸及其衍生物作为天然氨基酸的含磷类似物, 具有多种生物活性, 它的合成与性质的研究引起人们的浓厚兴趣. 合成了一系列含磷化合物, 产物经元素分析、红外光谱、核磁共振、质谱鉴定, 并初步研究这些化合物的抗菌与抗肿瘤生物活性.     

新型水溶性聚[(3-辛酰基吡咯-2,5-二)对二甲氨基苯甲烯]的合成、表征及性能研究

合成一种新型含推-拉电子基团的大π共轭高分子聚[(3-辛酰基吡咯-2,5-二)对二甲氨基苯甲烯](POPDMABE).用氢核磁共振谱、傅里叶红外光谱、紫外-可见光谱等分析手段对聚合物POPDMABE进行了结构表征.该聚合物易溶于多种极性有机溶剂和酸性水溶液,易于加工.热重分析表明,POPDMABE可耐180℃的高温.通过X射线衍射和透射电镜研究表明,POPDMABE以晶态和无定形态共存.光致发光光谱表明,在360nm的紫外光激发下,POPDMABE能发出蓝色荧光.     

Femtosecond dynamics of photocyclization of 1-[(4-{5-[4-chloromethyl-2,5-dimethyl-3-thienyl]-2-oxo-1,3-dioxol-4-yl}-2,5-dimethyl-3-thienyl)methyl]pyridinium chloride

The photochromic ring closure in diarylethylene was studied by femtosecond laser spectroscopy. The absorption spectrum of the initial excited state under pulse excitation at 305 nm was observed. The kinetic scheme of transitions from the initial excited state to the closed-ring isomer as the final product is proposed.     

Electrochemical synthesis of metal complexes of schiff bases: The crystal structure of bis{2-[(4-methylphenyl)iminomethyl]pyrrolato}copper(II)

The electrochemical oxidation of anodic nickel, copper, zinc or cadmium in acetonitrile solutions of Schiff bases (HL) derived from H-pyrrole-2-carbaldehyde and substituted anilines gives compounds of general formula ML₂. The crystal structure of bis{2-[(4-methylphenyl)iminomethyl]pyrrolato}copper(II) has been determined by X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n with a = 9.356(2), b = 16.697(2), c = 14.145(2) Å and β = 108.47(2)°. The crystal structure consists of monomeric molecules in which the central CuN₄ unit has distorted square-planar geometry with a dihedral angle of 25.8(3)° between the coordination planes. The IR, ¹H NMR and UV-visible spectra of the complexes are discussed and related to the structure.     

叔丁基｛1-[(对苯乙酰基)苯基]环丁基｝氨基甲酸酯的合成

叔丁基[1-(对溴苯基)环丁基]氨基甲酸酯与N-甲基-N-甲氧基-苄酰胺在正丁基锂的作用下,经Weinreb酮合成法合成了抗癌药物二氮杂萘衍生物的关键中间体——叔丁基{1-[(对苯乙酰基)苯基]环丁基}氨基甲酸酯,收率33%,其结构经1H NMR确证。     

Poly[(N-Acetylimino)ethylene] Macromonomers with Maleic Moieties in the Dispersion Copolymerization with Styrene

Three different poly(N-acetyliminoethylene) (PNAI) macromonomers containing maleic acid moieties were tested as stabilizers for the preparation of polymer microparticles by dispersion polymerization in a polar media (alcohol/water). A comparative study on the effect of various factors, such as initiator nature and solvency of the reaction medium, on system stability and particle characteristics was performed. Styrene was used as the main monomer and ethanol, isopropanol and 2-butanol as organic solvents. Chemical and photochemical techniques were applied as initiation routes. The photoinitiators allow the synthesis of microparticles with low diameters and narrow size polydispersity in a high yield. The polymerization duration was significantly improved as compared to the methods available in the literature.     

Poly[(3-hydroxypropyl) oxirane] and poly[(4-hydroxybutyl)oxirane]: New hydrophilic polyether elastomers

Preparations of poly[(3-hydroxypropyl)oxirane] and poly[(4-hydroxybutyl)oxirane] are described. Three routes to poly[(3-hydroxypropyl)oxirane] are discussed, each of which involves the methanolysis of a polymeric ester. (3-Acetoxypropyl)oxirane, [3-(m-chlorobenzoyloxy)propyl]oxirane, and (3-chloropropyl)oxirane were polymerized using the AIEt₃/H₂O/AcAc initiator system. Poly[(3-acetoxypropyl)oxirane] and poly{[3-(m-chlorobenzoyloxy)propyl]oxirane} were converted directly to poly[(3-hydroxypropyl)oxirane] by methanolysis, the former under either acidic or basic conditions only. Poly[(3-chloropropyl)oxirane] was first converted to poly[(3-benzoyloxypropyl)oxirane] by treatment with tetrabutylammonium benzoate; subsequent basic methanolysis then afforded poly[(3-hydroxypropyl)oxirane]. Poly[(3-hydroxypropyl)oxirane] is a colorless elastomer which can be cast into tough, clear films from water or methanol. Poly[(4-hydroxybutyl)oxirane] was prepared from poly[(4-chlorobutyl)oxirane] by benzoyloxylation and subsequent methanolysis. Poly[(4-hydroxybutyl)oxirane] is insoluble in water, but is hydrophilic and can be cast into tough films from methanol or dimethylsulfoxide.     

Azo polymers for reversible optical storage: 12. Poly{1-acryloyl-4-[4-(4-nitrophenylazo)phenyl] piperazine}

Two azo-containing vinyl monomers, 1-acryloyl-4-[4-(4-nitrophenylazo)phenyl]piperazine (ANPP) and 1-methacryloyl-4-[4-(4-nitrophenylazo)phenyl]piperazine (MNPP), were synthesized. MNPP did not polymerize in a few solvents, with a few free radical initiators and at a few temperatures. pANPP is amorphous with a T_g of 156 °C and decomposes above 230 °C. Birefringence can be induced by a polarized laser (514 nm) on a pANPP film to a level of 0.1 and is very stable. Comparison is made with poly{4′-[(2-(acryloyloxy)ethyl)ethylamino]-4-nitroazobenzene} (pDRIA). Biexponential curve fitting shows a lower writing rate for pANPP. Both the slow response to the laser and the higher stability of the photoinduced birefringence are due to the ‘rigid’ piperazine linkage between azobenzene groups and backbone which prevents the azo groups from rotating freely. pANPP decomposes under long term exposure to the laser.     

Synthesis of a novel liquid crystal rod–coil star block copolymer consisting of poly(methyl methacrylate) and poly{2,5‐bis[(4‐methoxy‐phenyl)oxycarbonyl] styrene} via atom transfer radical polymerization

A bromine capped star‐shaped poly(methyl methacrylate) (S‐PMMA‐Br) was synthesized with CuBr/sparteine/PT‐Br as a catalyst and initiator to polymerize methyl methacrylate (MMA) according to atom transfer radical polymerization (ATRP). Then, with S‐PMMA‐Br as a macroinitiator, a series of new liquid crystal rod–coil star block copolymers with different molecular weights and low polydispersity were obtained by this method. The block architecture {coil‐conformation of the MMA segment and rigid‐rod conformation of 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl] styrene segment} of the four‐armed rod–coil star block copolymers were characterized by ¹H NMR. The liquid‐crystalline behavior of these copolymers was studied by differential scanning calorimetry and polarized optical microscopy. We found that the liquid‐crystalline behavior depends on the molecular weight of the rigid segment; only the four‐armed rod–coil star block copolymers with each arm's M_n,_GPC of the rigid block beyond 0.91 × 10⁴ g/mol could form liquid‐crystalline phases above the glass‐transition temperature of the rigid block. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 733–741, 2005     

瓜环与4,4'-二氨基二苯甲烷衍生物的相互作用

合成了三种长链多芳环多胺基客体,它们分别由三种醛基吡啶异构体与4,4'-二氨基二苯甲烷形成的Schiff碱还原而成,并得到1H NMR以及质谱分析方法表征证实.以核磁共振技术、紫外吸收光谱分析方法以及滴定1H NMR方法为研究手段,对瓜环(cucurbit[n]urils,n=6～8)分别与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用进行了考察.实验结果表明,六元瓜环与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用均形成物质的量之比为2∶1的哑铃型包结配合物;八元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用形成以类轮烷结构为主的包结配合物;七元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用存在多种模式的竞争.     

SYNTHESIS AND CHARACTERIZATION OF COPOLYMER OF 2,5-BIS[（4-METHOXYPHENYL）OXYCARBONYL]STYRENE AND STYRENE WITH HIGH MOLECULAR WEIGHT

The random copolymers of styrene and 2,5-bis[(4-methoxyphenyloxycarbonyl)styrene] (MPCS) with different copolymerization ratio were synthesized by conventional free radical polymerization. The copolymer having high molecular weight was experimentally elucidated using a combination of proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The liquid crystalline behavior of the copolymer was studied using differential scanning calorimetry, X-ray diffractometry and polarized optical microscopy. It was found that the liquid crystalline behavior was dependent on the content of styrene. Experimental results show that the copolymer could turn into a liquid crystalline phase at about 180℃ when the content of styrene was less than 20%. The mechanical properties of the copolymer were also studied. Preliminary results indicate that the tensile strength decreases while the tensile modulus increases as the content of MPCS is increased.     

Crystal structures of nitrato-{4-bromo-2-[(2-hydroxyethylimion)methyl]phenolo}-(3,5-Dibromopyridine)copper and nitrato-{2,4-dibromo-6-[(2-hydroxyethylimino)methyl]phenolo}-(3,5-dibromopyridine)copper

The crystal structures of nitrato-{4-bromo-2-[2-hydroxyethylimino)methyl]phenolo}-(3,5-dibromopyridine)copper (I) and nitrato-{2,4-dibromo-6-[(2-hydroxyethylimino)methyl]phenolo}-(3,5-dibromopyridine)copper (II) are determined. The crystals of compound I are orthorhombic: a = 14.157(3) Å, b = 15.420(3) Å, c = 17.494(4) Å, space group Pbca, Z = 8, R = 0.067. The crystals of compound II are monoclinic: a = 10.675 Å, b = 13.973 Å, c = 14.007 Å, β = 111.92°, space group P2₁/n, Z = 4, R = 0.0464. In the structures of compounds I and II, the copper atom coordinates, correspondingly, singly deprotonated 4-bromo-2-[(2-hydroxyethylimino)methyl]phenol and 2,4-dibromo-6-[(2-hydroxyethylimino)methyl]phenol molecules, and 3,5-dibromopyridine, and the nitrate ion. The coordination polyhedron of the copper ion in complexes I and II is a slightly distorted tetragonal pyramid. The bases of the pyramids are formed by the imine and pyridine nitrogen atoms and the phenolic and alcoholic oxygen atoms, and the axial vertices are occupied by the oxygen atoms of the monodentate nitrato groups. In the complexes under study, the six-membered metallocycles have asymmetric gauche conformation. In crystal, complexes I are united, due to the slip plane a, through bifurcate hydrogen bonds into infinite chains along the direction [100]. Complexes II in crystal form two-dimensional networks by means of hydrogen bonds.     

瓜环与4,4'-二氨基二苯甲烷衍生物的相互作用

合成了三种长链多芳环多胺基客体, 它们分别由三种醛基吡啶异构体与4,4'-二氨基二苯甲烷形成的Schiff碱还原而成, 并得到¹H NMR以及质谱分析方法表征证实. 以核磁共振技术、紫外吸收光谱分析方法以及滴定¹H NMR方法为研究手段, 对瓜环(cucurbit[n]urils, n＝6～8)分别与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用进行了考察. 实验结果表明, 六元瓜环与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用均形成物质的量之比为2∶1的哑铃型包结配合物; 八元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用形成以类轮烷结构为主的包结配合物; 七元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用存在多种模式的竞争.     

N-{3-氯4-[(3-氟苄基)氧基]苯基}-6-碘喹唑啉-4-胺的合成工艺改进

以2-胺基-5-碘苯甲酸为起始原料,经四步反应合成了新型喹唑啉类抗肿瘤药物拉帕替尼的关键中间体-N-{3-氯4-[(3-氟苄基)氧基]苯基}-6-碘喹唑啉-4-胺,总收率77.9%,其结构经1H NMR和ESI-MS确证.Williamson醚化反应的最佳条件为:4-(6-碘喹唑啉-4-基氨基)-2-氯苯酚(5)30.0 mmol,K2CO3 24.8 g,18-冠-6 0.79 g,KI 0.49 g,丙酮250 mL.于35℃反应12 h,收率90.1%.