IR and Raman studies of 3,7-diazabicyclo(3.3.1)nonane-9-spiro-5′-hydantoins

The IR and Raman spectra of 3-methyl-7-alkyl-3,7-diazabicyclo(3.3.1)nonane-9-spiro-5′-hydantoi ns have been studied in the solid state and in deuterium oxide solution. The crystalline spirohydantoins are of three types: (1) those containing strong N3′H⋯N bonds and N1H⋯O=C2 bonds between pairs of molecules; (2) those of predominantly zwitterionic structure in the solid state and (3)_those of predominantly hydrated zwitterionic structure in the solid state. All the compounds exists as zwitterions in aqueous solution. © 1983.