The synthesis of polyenes with 3 or 5 conjugated double bonds bearing alkylanthryl and alkylpyridinium terminal groups is described. Alkyl chains of suitable length were introduced in both the anthracene and/or pyridine moiety to reduce the solubility in water thus improving the ability to form Langmuir-Blodgett films.
A series of 2,6-bis(arylethynyl)anthraquinones was prepared via double Sonogashira
coupling to 2,6-diiodoanthraquinone, and characterized with regard to their optical and electronic
properties. Substitution with a derivatized phenylethynyl group produced a λonset of 366 nm (Eg = 3.4
eV), but the more highly conjugated 2,6-bis(9’-anthracylethynyl)anthraquinones exhibited a λonset of
approximately 540 nm (Eg = 2.3 eV). Poor solubility in the unsubstituted 9’-anthracylethynyl system
hampered complete characterization or purification, but the 10’-hexanoylanthrac-9’-ylethynyl analog
exhibited significantly better solubility. The preparation of several other functionalized derivatives
was also explored, and key synthetic findings are reported.