A highly correlated conformational motion of a tube-like fully conjugated hydrocarbon

By comparing the matrix infrared spectrum (Ar, 12. K) with theoretically ca lculated spectra (B3LYP/6-31G*), the structure of the tube-like hydrocarbon I has been determined to he a fast equilibrium of two D-2d symmetrical str uctures. The previously assumed higher symmetrical D-4h structure was found to be the transition state of this conformational interconversion. The con formational process involves the correlated and simultaneous pincer-like mo vement of the four relatively rigid anthracene units. Two pincers are alway s closed and two are open. Changing the state of one of the pincers reverse s the state of the other three pincers. Upon suitable substitution, the mol ecular framework meets the requirements to be used as a logic gate. (C) 200 0 Elsevier Science B.V. All rights reserved.