Incorporation of lateral methyl groups into liquid crystalline compounds: Effects of structural modifications on phase behavior

CHED 709

Martin C. Whittle1, Edward T. Samulski, et@unc.edu2, and Eric Scharrer, escharrer@ups.edu1. (1) Department of Chemistry, University of Puget Sound, 3337 Wheelock Student Center, Tacoma, WA 98416, (2) Department of Chemistry, University of North Carolina, CB# 3290, Chapel Hill, NC 27599-3290
The incorporation of lateral methyl groups into compounds with liquid crystalline properties is known to lower the onset temperatures of liquid crystal phases, which is desirable for most modern applications of liquid crystals. We are in the process of incorporating lateral methyl substituents into two classes of compounds. The first type of compound is an oxadiazole derivative; unsubstituted oxadiazole derivatives exhibit the elusive biaxial nematic phase at impractically high temperatures. Compounds of the second type contain an alkyne moiety, which we have used as a site for metal complexation in order to generate metallomesogens. It would be desirable to lower the onset temperature of the mesophase in this system as well. After preparation of the target compounds, the effects of methyl incorporation on phase behavior will be investigated. Synthetic details and liquid crystalline properties will be discussed.