Arylethynyl Groups That Modulate Anion-Binding and Assembling Modes of Rod- and Fan-Shaped π-Electronic Systems.

The introduction of arylethynyl moieties at the pyrrole α- and ß-positions of dipyrrolyldiketone BF2 complexes as anion-responsive π-electronic molecules was investigated. The arylethynyl-substituted derivatives formed a variety of anion complexes with planar [1+1]- and interlocked [2+1]-type structures in solution and in the solid state. The derivatives with long alkyl chains in the introduced arylethynyl groups also formed mesophases in the form of ion pairs of the anion complexes and a counter cation. The geometries of the constituent anion complexes affected the packing modes of the dimension-controlled assemblies.

Cyclic Anion-Responsive π-Electronic Molecules That Overcome Energy Losses Induced by Conformation Changes.

Preorganized structures suitable for anion binding were prepared by introducing dipyrrolyldiketone BF2 complexes as acyclic anion-responsive π-electronic molecules into macrocycles. Pyrrole-inverted conformations, which typically present low stability in the case of acyclic derivatives, were obtained by covalent linkages through ring-closing olefin metathesis, exhibiting extremely high affinity for different anions.