Search results for "ONJ"
showing 10 items of 1458 documents
Topochemical Reactions of Monomers with Conjugated Triple-Bonds VII Mechanism of Transition from Monomer to Polymer Phase During Solid-State Polymeri…
1972
The lattice-controlled solid-state polymerisation of three different modifications of 2,4-hexadiin-1,6-diol-bis(phenylurethane) was investigated by X-ray and optical methods. The polymerisation is a homogeneous reaction. The polymer grows in the form of single chains within the crystal of the monomer. The chains extend along a definite crystallographic direction. Monomer and polymer are isomorphous and monomer-polymer single crystals of various compositions are obtained up to a quantitative conversion in the case of modification I or III. Phase separation into a mesomorphic polymer and oriented monomer phase was observed on annealing partially polymerised single-crystals of modification II …
Monodisperse Dialkoxy-Substituted Oligo(phenyleneethenylene)s
2006
Individual but connected synthetic routes for the preparation of the all-E-configured 2,5-dipropoxy-substituted oligo(1,4-phenyleneethenylene)s 1a–g were developed. An increasing number of conjugated stilbene units from n = 1 to n = 11 led to a convergent bathochromic shift (Δλ = λ∞ − λ1 = 127 nm) in the UV/Vis absorption. An exponential function for the convergence of the absorption energies (wavelengths) in conjugated systems is proposed. By a simple extrapolation of this function the effective chain length may be determined.
An Open-Shell Coronoid with Hybrid Chichibabin-Schlenk Conjugation.
2021
A hexaradicaloid molecule with alternating Kekule and non-Kekule connectivities between adjacent spin centers was obtained by fusing two conjugation motifs in Chichibabin and Schlenk hydrocarbons into a coronoid structure. 1 H NMR, ESR, and SQUID experiments and computational analyses show that the system has a singlet ground state with a significant hexaradicaloid character (γ0 =0.826, γ1 =γ2 =0.773). It has multiple thermally accessible high-spin states (up to the septet), with uniform energy gaps of ca 1.0 kcal mol-1 between consecutive multiplicities. In line with its open-shell character, the coronoid has a small electronic band gap (ca. 0.8 eV) and undergoes two consecutive one-electr…
Tetrahedra from Aryleneethenylenes – From small Molecules to Luminescent Glasses
2004
AbstractThe fourfold Horner olefination of tetraphenylmethane or –silane with fourp-methyl- phosphonate groups and a variety of aromatic aldehydes with donor groups or extended conjugated systems results in the formation of tetrahedra from four chromophores connected via a central atom. Electronic spectra in solution reveal an electronic interaction between the π-systems. In the solid state, the emission of compounds with a dense packing is nearly identical to the solution spectra, more open structures show significant red shifts. The emission of scaffolds with 1-styrylpyrene chromophores is nearly completely quenched. Most of these tetrahedra are thermally stable up to 420°C. Depending on …
Mesomorphic Donor-Acceptor-substituted 1,4-Distyrylbenzenes
2009
Conjugated oligomers with terminal donor-acceptor substitution attract increasing attention in organic chemistry because of their outstanding and not seldom unexpected properties in materials science [1 – 4]. Although a variety of oligo(1,4-phenylene-vinylene)s with terminal donor-acceptor substitution (DAOPVs 1, Scheme 1) are known [5 – 22], the number of thermotropic liquid crystals among them is very low and is confined to monomers (n = 1), that means to certain push-pull substituted (E)-stilbenes [23 – 31]. The behavior of conjugatedmolecules, which are highly polar and form mesophases by self-organization, is very interesting for various applications of liquid crystals [3]. A big disad…
2,5-Bis[(E)-2-phenylethenyl]-3,6-bis(pyridin-2-yl)pyrazine
2020
The molecule of the title compound, C30H22N4, exhibits inversion symmetry adopting the shape of a St Andrew's Cross. It shows dihedral angles between adjacent aryl units of around 50° whereas torsion angles of ca 10° are found along the arylene vinylene path.
Suspension des poursuites individuelles. Créancier hypothécaire d'un époux in bonis marié sous le régime de communauté légale, Liquidation judiciaire…
1995
International audience; (Cass. ass. plén. 23 déc. 1994, Leclerc ès qual. c/ Union de Crédit pour le Bâtiment et autres, D. 1995, Jur. p. 145, rapp. Chartier et note Derrida)
'The sisters did her every imaginable injury': Power and violence in Cinderella
2012
The main aim of this article is to discuss the results achieved after investigating the presence of violence in the Grimm brothers’ <em>Cinderella</em> with the intention of finding out what kind of processes predominate in this tale and whether they can be related to violent actions. The analysis involved firstly, a study of the frequency and concordances of some words belonging to the semantic field ‘violence’, surveying in detail the context in which they appear and secondly, the analysis of transitivity processes. The method proved to be a good strategy to check whether each character’s identity and social position (power) were somehow related to the infliction of violence w…
Photoinduced DNA damage efficiency and cytotoxicity of novel viologen linked pyrene conjugates.
2010
Novel viologen linked pyrene conjugates permeate cells efficiently and exhibit spacer length dependent DNA damage and cytotoxicity upon photoexcitation.
Direct conjugal transfers of Ti plasmid to soil microflora
2002
The bacterial species in soil that can receive a Ti plasmid by conjugation from Agrobacterium spp. were investigated. In order to have direct access to the potential reservoir of Ti plasmid amongst soil microflora, the conjugal system consisting of a multiply auxotrophic derivative of C58 (ST-96-4) and a derivative of pTiC58Delta(acc)R (pSTiEGK) containing a triple antibiotic-resistance cassette in traM was used to transfer the Ti plasmid in a complex soil microflora used as the recipient. Numerous transconjugants were obtained by this method but none was identified as Agrobacterium. This could be explained by the low density of Agrobacterium in the tested soil. As indicated by analysis of …