Amphotropic Properties of Multi-Palladium and -Platinum Liquid Crystals [1]

Abstract

Tetrametallomesogens containing palladium ( 2 , 3 a 4 or platinum (4, Sa<) macroheterocyclic central cores show wide ranging liquid crystalline properties, both thermotropic and lyotropic in apolar organic solvents. Here, we present an overview of recent work from our laboratory concerning these novel metallomesogens and related bis-metal analogues 6 and 7. We also propose new nomenclature to satisfy the growing range of liquid crystalline mesophases exhibited by these materials.

Thermotropic Liquid-Crystalline Materials Based on Supramolecular Coordination Complexes

“…In the case of the chloro-and bromobridged metalla-cycles (Figure 1), the nematic phase was stabilized upon addition of 2,4,7trinitrofluorenone (TNF), suggesting intercalation of TNF between the disk-shaped columnar stacks. Following this initial study, analogous systems built from either palladium or platinum metal centers were prepared and their liquid-crystalline properties examined [21][22][23][24][25], showing similar organization in the lyotropic mesophases. Later on, analogous platinum Schiff base pyridyl type metalla-cycles were synthesized by MacLachlan and his coworkers [26].…”