Solid-state structures of sym -dibenzo-16-crown-5 and its derivatives

Solid-state structures of sym -dibenzo-16-crown-5 ( 1 ) and five derivatives with one or two substituents on the three-carbon bridge have been determined. The derivatives with three sp 3 -hybridized carbons include sym -(propyl)dibenzo-16-crown-5 ( 4 ), sym -(pentafluorophenoxy)-dibenzo-16-crown-5 ( 5 ), and sym -[di(methoxymethyl)]dibenzo-16-crown-5 ( 6 ). Structures of two derivatives with sp 2 -hybridization of the central carbon ( 7 and 8 ) were also determined. Twisting of the three-carbon bridge causes one of the terminal methylene groups to be oriented within the polyether cavity.