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

By comparing the matrix infrared spectrum (Ar, 12. K) with theoretically calculated 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 structures. The previously assumed higher symmetrical D-4h structure was found to be the transition state of this conformational interconversion. The conformational process involves the correlated and simultaneous pincer-like movement of the four relatively rigid anthracene units. Two pincers are always closed and two are open. Changing the state of one of the pincers reverses the state of the other three pincers. Upon suitable substitution, the molecular framework meets the requirements to be used as a logic gate. (C) 2000 Elsevier Science B.V. All rights reserved.