Triafulvenes structure

Library of Congress Cataloging in Publication Data. Main entry under title Cyclic compounds. (Topics in current chemistry 57). Bibliography p. Includes index. CONTENTS Eicher, T. and Weber, J. L. Structure and reactivity of cyclopropenones and triafulvenes. — Sargent, M. V. and Cresp, T. M. The higher annulenones. 1. Cyclic compounds—Addresses, essays, lectures. I. Eicher, Theophil, 1932- II. Series. 

Structure and Reactivity of Cyclopropenones and Triafulvenes Theophil Eicher and Josef L. Weber 1... 

The molecular structures of diphenyl cyclopropenone (anhydrous148 and as hy-drate13s 149 diphenylcyclopropene thione1501, 1,2-diphenyl-13S and 1,2-dimethyl-lsu 4,4-dicyano triafulvene, l,2-di-(p-tolyl)-4,4-di-(trifluoromethyl) triafulvenelslb), 5,6-diphenyl-1 S2 and 5,6-di-n-propyl-153 1,2,3,4-tetrachlorocalicene and 8-cyano-8-(diphenylcyclopropenyl)-heptafulvenylium tetrafluoroborate111 have been determined by X-ray analysis15 4). 

The UV spectra of most of the triafulvenes hitherto known are rather complex in structure due to effects of either phenyl substitution or of conjugated chromophores at the exocyclic carbon, which obscure information on the cross-conjugated system itself. 

Triafulvenes of type 224 capable of cis-trans rotational isomerism in most cases occur as equilibrium mixtures of structures 224A and 224B their configura-... 

With 4,4-diacyl triafulvenes two principal fragmentation pathways have been observed5 s In 4-aroyl-4-acetyl triafulvenes 241 the molecular ion is followed by a fragment ion of probable structure 242 arising from primary loss of (CvI R), which surprisingly has incorporated a CH2 unit from the acetyl group and the exo-cyclic aryl residue. It is not unlikely that the (C7H6R)-residue corresponds to a substituted tropyl radical due to its well-known formation from electron-impact of benzylic precursors. 

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