Preparation and structural properties of dithia[3.3.1]- metacyclophanes

Various substituents have been introduced into the inner or the outer posit ion of the dithia[3.3.1]metacyclophanes (MCPs). Conformational properties o f these MCPs are evaluated by variable temperature H-1-NMR spectral measure ments, IR measurements, computer calculation and X-ray structural analyses. It has been found that the conformations of dithia[3.3.1]MCPs are affected by not only the steric effect of the inner or the outer substituent but al so by the electronic nature of the component aromatic ring. Furthermore, a weak interaction such as NH-pi interaction or hydrogen-bonding also regulat es their conformation.