LYOTROPIC PHASE-BEHAVIOR OF DISC-SHAPED TETRA-PALLADIUM ORGANYLS IN APOLAR ORGANIC-SOLVENTS .1.

The lyomesomorphic behaviour in apolar organic solvents of members of two series 1 and 2 of disc-shaped palladium organyls-the syntheses of four of them are new (1d, f and 2a, e) and are described here-each car rying twelve long lipophilic chains have been studied. Their lyomesomo rphism appeared to be complex and has been observed here for the first time with metal organyls. As can be seen by polarizing microscopy, mo st of the binary mixtures investigated here exhibit nematic properties . For two members of series 1-the chloro-bridged lb and its bromo-anal ogue lc-there is even evidence for the existence of two different nema tic lyomesophases side by side showing reversible transitions between them. In ternary systems, i.e. after the addition of 2,4,7-trinitroflu orenone (TNF, a strong electron acceptor), the nematic phases are stab ilized, suggesting that their mesophase structures are made up by colu mns with intercalated TNF molecules (charge transfer complex formation ). Influences of structural features of the pallado-mesogens on the on e hand and of the type of solvent on the other on the molecular self-a ggregation in the observed types of lyotropic mesophase formed are dis cussed in detail.