Pyramidalization of a carbonyl C atom in (2S)-N-(seleno­acet­yl)proline methyl ester

The title compound, C₈H₁₃NO₂Se, crystallizes as a non-merohedral twin with an approximate 9:1 component ratio with two symmetry-independent mol­ecules in the asymmetric unit. Our density-functional theory (DFT) computations indicate that the carb­oxy C atom is expected to be slightly pyramidal due to an n→ π* inter­action, wherein the lone pair (n) of the Se atom overlap with the anti­bonding orbital (π*) of the carbonyl group. Such pyramidalization is observed in one mol­ecule of the title compound but not the other.