Synthesis and properties of naphthalene trimers linked by 1,3,4-oxadiazole spacers

✍ Scribed by Katsuhiko Ono; Hiroki Ito; Akihiro Nakashima; Mariko Uemoto; Masaaki Tomura; Katsuhiro Saito

• Book ID: 104095664
• Publisher: Elsevier Science
• Year: 2008
• Tongue: French
• Weight: 527 KB
• Volume: 49
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2008.07.122

✦ Synopsis

Two types of naphthalene trimers linked by 1,3,4-oxadiazole spacers were synthesized and investigated for their physical and electronic properties. 2,6-and 2,7-isomers on central naphthalene moieties were obtained in the forms of pale yellow solids and colorless crystals, respectively. The melting point of the 2,6-isomer was higher than that of the 2,7-isomer. An X-ray crystallographic analysis revealed a pstacked column with a short intermolecular distance in the crystals of the 2,6-isomer. The absorption maximum of the 2,6-isomer was red-shifted as compared to that of the 2,7-isomer, indicating a p-conjugation between di-2-naphthyloxadiazole moieties in the 2,6-isomer. The quantum yields of the 2,6-and 2,7-isomers were measured to be 0.97 and 0.74, relative to that of 2,5-di-2-naphthyl-1,3,4-oxadiazole (0.85). Molecular orbital (MO) calculations demonstrated that the 2,6-isomer had a higher electron affinity than the 2,7-isomer. Thus, the crosslinking of building blocks is important for the design of functional materials.