Crystal structure of (1S,4S)-2,5-diazo­niabi­cyclo[2.2.1]heptane dibromide

The cage of 2,5-di­aza­bicyclo­[2.2.1]heptane is frequently employed in synthetic chemistry as a rigid bicyclic counterpart of the piperazine ring. The 2,5-di­azabicyclo­[2.2.1]heptane scaffold is incorporated into a variety of compounds having pharmacological and catalytic applications. The unsubstituted parent ring of the system, 2,5-di­aza­bicyclo­[2.2.1]heptane itself, has not been structurally characterized. We herein report on the mol­ecular structure of the parent ring in (1S,4S)-2,5-diazo­niabi­cyclo­[2.2.1]heptane dibromide, C(5)H(12)N(2) (2+)·2Br(−). The asymmetric unit contains two crystallographically independent cages of 2,5-di­aza­bicyclo­[2.2.1]heptane. Each cage is protonated at the two nitro­gen sites. The overall charge balance is maintained by four crystallographically independent bromide ions. In the crystal, the components of the structure are linked via a complex three-dimensional network of N—H⋯Br hydrogen bonds.