X-ray, conformation and electronic structures of 1-nitropyrrolidine

• In the solid-state, the asymmetric part of the unit cell is composed of one quartermolecule.
• XRD and DFT studies reveal geometries that suggest slight pirymidisation of amine nitrogen atom.
• To compensate for spherical tension the ring adopts an asymmetric envelope conformation.
• A strong influence of the nitroamine group on the conformation of the pyrrolidine ring is observed.

The chemistry of pyrrolidine compounds has drawn much attention because of their biological activities. The crystal and molecular structure of 1-nitropyrrolidine (C4H8NNO2) at 150K, along with calculated structures (DFT and MP2), are reported herein. In the solid-state, the asymmetric part of the unit cell is composed of one quartermolecule at the position of two perpendicular mirror planes and the five-membered ring is disordered over a mirror plane, revealing the twisted conformation. Both geometries suggest slight sp3 hybridization of the amine nitrogen atom. The non-planar geometry suggests the lack of conjugation of the amine nitrogen lone pair with the nitro group, however the N–N bond distance indicates oppositely.

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