Study on the orientation of benzodixanthene analogue having alkyl chain in Langmuir-Blodgett film

Xantheno[1',9':4,5,6]benzo[1,2,3-kl]N-(1-dodecyl-2-pyridynium)-acridine iodide (2a) was synthesized from 1,5-dichloroanthraquinone in six steps. The polarized UV-VIS spectra of the LB film of (2a) on CaF2 were compared with the transition moments of (2a) calculated by semi-empirical molecular orbital method to discuss the orientation of (2a) in the LB film. The plane of the skeleton structure of the polycondensed aromatic ring of (2a) on CaF2 in the LB film was rather oblique, nor parallel to the CaF2 surface.