SYNTHESIS AND PHASE BEHAVIOR OF LIQUID CRYSTALLINE DIPHENYLACETYLENE DERIVATIVES POSSESSING HIGH CLEARING TEMPERATURES

A series of diphenylacetylene derivatives were synthesized to serve as ligands for metal alkyne complexes. The target compounds, alkyl 4′-(4-phenylethynylbenzoyloxy)-biphenyl-4-carboxylates, were prepared using a three-step synthetic procedure. Both the diphenylacetylene derivatives as well as their immediate precursors, alkyl 4′-(4-iodobenzoyloxy)-biphenyl-4-carboxylates, exhibit liquid crystalline behavior. The diphenylacetylene derivatives possess large liquid crystalline phase ranges and high clearing temperatures. Synthetic details and the phase behavior of these compounds are discussed.