Layered Compounds. XXXVI. Structure and Properties of Triple-layered Metaparacyclophanes

• Published in: Bulletin of the Chemical Society of Japan Vol. 49; no. 11; pp. 3203 - 3207
• Main Authors: Kannen, Naoki, Otsubo, Tetsuo, Sakata, Yoshiteru, Misumi, Soichi
• Format: Journal Article
• Language: English
• Published: The Chemical Society of Japan 01.11.1976
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.49.3203

The geometrical structures of triple-layered metaparacyclophanes are discussed on the basis of the chemical shifts of the NMR spectra and their temperature dependence. [2.2]Metacyclo(4,7)[2.2]paracyclophane 1 and [2.2]metacyclo(12,15)[2.2]metaparacyclophane 2 proved to be mixtures of conformational isomers due to arrangement of meta-substituted ring. [2.2]Paracyclo(4,6)[2.2]metaparacyclophane 3 was confirmed to be a staircase-shape (anti-form), in contrast to a platform-shape (syn-form) of [2.2]metacyclo(4,6)[2.2]metaparacyclophane 5. In their electronic spectra, 1 and 2 exhibit a transannular electronic interaction between the benzene rings similar to that of multilayered [2.2]paracyclophanes; 3 and 5 show one similar to that of multilayered [2.2]metacyclo-phanes. The difference between the former and the latter groups seems to arise from the substitution modes of methylene bridges attached to the inside benzene of triple-layered metaparacyclophanes.