0000000000161307
AUTHOR
Johann Lex
showing 9 related works from this author
An ionene with spirane structure (spiroionene)
1990
The secondary diamine 1,3,5,7-tetrahydro[1,2c:4,5c'] benzodipyrrole (3) and 1,2,4,5-tetrabromomethylbenzene (1) form a polymeric ionene with spirane structure through a repetitive alkylation reaction. The structure of the product could be proven by13C-NMR spectroscopy by comparison with suitable reference compounds. Solutions in aqueous methanol exhibit a typical polyelectrolyte effect. Variation of the counterions produces sufficient solubility in organic solvents. From the crystal structure of a similar model compound one can conclude that the synthesized polymer has a rod-like shape.
1,2,3,4,5‐[1′,8′] Anthra‐8,9;10,11‐dibenzo[13]annulene and 1,8‐Distyrylanthracene as Models for Phenylenevinylene Species. Syntheses, Structures, and…
1987
The synthesis of the title compound 4, formally a [13] perimeter, and of its acyclic model system, 1,8-distyrylanthracene (6) is described. The crystal structure of 4 reveals the configuration of the double bonds and the conformation of the macrocycle. Related findings come from the 1H-NMR spectroscopic characterization of 4 and 6 in solution. The spin density distribution of the radical anions 4−· and 6−· is interpretet in terms of the singly occupied molecular orbital and of the prevailing geometry. In contrast to 4, compund 6 proves to be an efficient electron acceptor since it can even be reduced to a tetraanion salt. The complete redox sequence is characterized by NMR and ESR spectrosc…
Structure and fluxional behaviour of heptaleneirontricarbonyl and heptalenebis (Irontricarbonyl)
1987
Abstract The synthesis of heptaleneirontricarbonyl ( 4 ) is described. The structures of 4 and of the closely related heptalenebis(irontricarbonyl) ( 3 ) are elucidated by NMR spectroscopy ( 1H and 13C) and by X-ray crystallography. Compounds 3 and 4 are shown by dynamic NMR to undergo an isodynamic 1 ,2-migration of the Fe(CO3)-groups as well as a carbonyl scrambling. The relevant kinetic data allow for a mechanistic discussion of the dynamics and a comparison with other irontricarbonyl complexes.
New Porphycene Ligands: Octaethyl- and Etioporphycene(OEPc and EtioPc)—Tetra- and Pentacoordinated Zinc Complexes of OEPc
1993
Influence of conformational factors on acid-catalyzed cyclizations of germacranolides: Molecular structure of the cyclization products of gallicin an…
1995
Acid-catalyzed cyclization of the natural germacranolide gallicin (8) yielded, among other products, the 1,4-epoxyeudes-manolide 9, which has a trans-fused decaline system. Under the same conditions the closely related germacranolide shonachalin A (8α-hydroxygallicin) (3) cyclized to the eudesmanolide 4 with a cis fused decaline system. The structures of these cyclization products were secured by means of chemical correlations and X-ray diffraction analyses.
Oxygenated germacranes from Santolina chamaecyparissus
1993
The polar fraction of an extract of Santolina chamaecyparissus ssp. squarrosa yielded six new germacrane derivatives and a novel seco-germacrane lactone. The structures have been derived from spectral data, X-ray diffraction and chemical correlations.
syn-1,6-imino-8,13-oxido[14]annulene
1990
Abstract syn -1,6-Imino-8,13-oxido[14]annulene (1) , an aromatic annulene featuring closely spaced NH and O-bridges, has been synthesized. Contrary to expectation, NH ⋯ O hydrogen bonding in I does not profit from the proximity of the functionalities noticeably.
New oxygenated eudesmanolides from artemisia herba-alba
1990
Abstract The aerial parts of Artemisia herba-alba Asso subsp.valentina Lam. (Asteraceae) yielded the new eudesmanolides 1-11 and the new sesquiterpene-monoterpene adducts 12-13. The absolute configuration of compound 6 was confirmed with the aid of X-ray diffraction analysis. Some aspects of the thermal and photochemical reactivity of 2,4-cyclohexadienones are discussed.