Glycoluril derivatives form hydrogen bonded tapes rather than cucurbit[n]uril congeners

The synthesis and X-ray crystallographic characterization of diphenylglycoluril derivatives () that possess one or two alkyl groups on their N- or O-atoms is reported. Compounds preferentially form linear hydrogen bonded tapes in the crystal by heterochiral recognition processes. We do not observe cyclic hydrogen bonded cucurbit[n]uril congeners that would result from homochiral recognition processes. The high propensity of alkylated derivatives of diphenylglycoluril to form hydrogen bonded tapes stands in stark contrast to the reported X-ray crystal structures of other known alkylated derivatives of glycoluril. We attribute this high propensity to form tapes to the phenyl and alkyl substituents that impart good solubility in non-polar aprotic solvents which do not compete for H-bonds. These results suggest that suitably functionalized glycoluril derivatives have untapped potential in studies of crystal engineering.