Search results for "Benzene"

An improved molecular design of obtaining NLO active molecular glasses using triphenyl moieties as amorphous phase formation enhancers

2012

New molecular design of obtaining molecular glasses has been developed by linking triphenylmethyl moieties to chromophore core by flexible C-C bridge. Compounds capable of forming stable amorphous phase with good optical quality have been acquired with increased chemical and thermal sustainability compared to the previously reported design. NLO activity of compounds has been measured after corona discharge polling. Compared to previously synthesized trityloxy fragment containing compounds increase of d 33 coefficient by up to 17 times was achieved for the same chromophore core containing compounds.

ChemInform Abstract: Cyclic Esters of Aliphatic Diacids with Pyrocatechol and Hydroquinone.

1986

Cyclic esters of adipic acid, suberic acid and sebacic acid were prepared by reaction of the acid dichlorides and pyrocatechol or hydroquinone in benzene under high dilution conditions. While only the cyclic dimers could be obtained from hydroquinone, pyrocatechol formed cyclic monomers as well as cyclic dimers (and also a cyclic dimer with succinic acid). The structure of all compounds was confirmed by1H-NMR- and mass spectra. The crystal structures of the pyrocatechol esters were determined by single crystal X-ray analysis.

White Phosphorus Is Air-Stable Within a Self-Assembled Tetrahedral Capsule

2009

Molecular Fire Quencher Cage-shaped molecular assemblies can regulate the reactivity of smaller molecules trapped within them. Mal et al. (p. 1697 ) extend this approach to enable the protection of elemental white phosphorus (P 4 ), a substance that rapidly ignites on contact with oxygen. The tetrahedral cages self-assemble in aqueous solution through coordination of six ligands to four iron ions, and efficiently capture phosphorus from a suspension. The water-soluble host-guest constructs were stable in air for at least 4 months, but released intact P 4 rapidly on displacement by added benzene.

Crystal structure and reactivity of 2-chloro-3,5-dinitrothiophene and of 2-phenylsulphonyl-3,5-dinitrothiophene with nucleophiles

1988

The geometry obtained by a crystal structure determination of the title compounds, as compared with that of the analogous benzene derivatives, along with results of ab initio calculations, is used to interpret the different SNAr reactivities in some thiophene and benzene compounds. The smaller rotation of the nitro groups with respect to the aromatic rings observed in thiophene derivatives should be considered a relevant factor in the higher reactivity in the thiophene series.

Multi-Arm 1,2,3-Thiadiazole Systems

1997

Benzene derivatives 2a–c with 6, 4, and 3 side chains bearing terminal 1,2,3-thiadiazole rings, respectively, have been prepared. Alkaline cleavage of 2a–c led to the corresponding alkynethiolates 6a–c, which were trapped by electrophiles such as benzyl bromide or iodomethane. The method provides an alternative to the thermal or photochemical cleavage of 1,2,3-thiadiazoles to thioketenes, which react further with nucleophiles.

Light Induced Modifications of Langmuir-Blodgett-Multilayer Assemblies Containing Amphotropic Azocopolymer

1994

Abstract Photochromic LB-multilayers of amphotropic copolymers having rod-like azobenzene moieties as side groups which exhibit thermotropic liquid crystalline behaviour in the bulk have been characterized by UV-VIS spectroscopy as well as by angular dependent and energy dispersive SAXS. Upon irradiation with UV-light the initial optical in-plane anisotropy and the vertical layered structure of LB-films can be destroyed. A new layered structure can be rebuilt on irradiation with visible light or by annealing. Using linearly polarized light for the irradiation an optical anisotropy (POA) has been induced or reversibly modified by a photoselection process.

1980

ChemInform Abstract: Anionic-Anionic Asymmetric Tandem Reactions: One-Pot Synthesis of Optically Pure Fluorinated Indolines from 2-p-Tolylsulfinyl Al…

2009

ChemInform Abstract: 1,4-Regioselective Iodofunctionalizations of 1,3-Butadiene.

1989

1,3-Butadiene (I) is treated with a iodonium tetrafluoroborate in the presence of HBF4 and aqueous acetonitrile (II) or benzene (IV), yielding the 1,4-adducts (III) or (V).

Bestimmung der molekularen konstanten von naturkautschuk III. Molekulargewicht trägheitsradius und thermodynamische eigenschaften von cyclohexan-kaut…

1960

Lichtstreuungsmessungen an Crepekautschuk in Cyclohexan ergeben Mw = 1,85·106. In Verbindung mit Diffusions- und Sedimentationsmessungen ergibt sich als wahrscheinlichster Wert Mw = 1,7·10−6. Unter Verwendung der Messungen von CARTER, SCOTT und MAGAT wird als Molekulargewichts-Viskositatsbeziehung die Gleichung fur Losungen von Naturkautschuk in Cyclohexan vorgeschlagen. Der 2. Virialkoeffizient und der STAUDINGER-Index nehmen in der Reihenfolge Benzol, Cyclohexen, Cyclohexan zu. Die beiden ersten Losungsmittel sind endotherm, Cyclohexan ist exotherm. Der Tragheitsradius der Molekulknael nach Lichtstreuungsmessungen ist etwa Rw = 1000 A. Der wahrscheinlichste Wert unter Mitberucksichtigung …