SYNTHESIS OF FERROCENE DERIVATIVES WITH PI-EXTENDED CONJUGATION

Synthesis of (E)-1-ferrocenyl-2-(p-iodophenyl)ethene was carried out b y means of the Wittig reaction between the p-iodobenzyl triphenylphosp honium ylid and the ferrocene carboxaldehyde, satisfactory as a mixtur e of E/Z isomers. Isomerization Z --> E was induced by iodine-NBS in q uantitative yield. The X-ray molecular structure of this (E)-isomer in dicates that the molecules are linked by charge transfer complexation between the iodine atom and the cyclopentadiene ring. The conjugation of the molecule of 1-ferrocenyl-2-(p-iodophenyl)ethene was expanded to the (Z,Z)- and(E, E)-1,4-di[1-ferrocenyl-2- (p-iodophenyl)ethenyl]bip henyl and to the (Z,Z)- and di(1-ferrocenyl-2-(p-phenylethenyl)-1,3-bu tadiyne, both as centrosymmetric structures.