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organic compounds
The title compounds, C7H9N2O+.ClO4-, (1), and C13H15N3O2+.2ClO4-.H2O, (2), have been synthesized and their crystal structures determined. The C-N(carbamoyl) bond in each compound has some double-bond character [bond lengths 1.319 (5) for (1) and 1.325 (7) Å for (2)], indicating that the sp2 hybridization is delocalized over the O-C-N(carbamoyl) unit. The carbamoylmethyl plane is canted with respect to the attached pyridinium plane at an angle of 63.5 (2) for (1) and 79.1 (2)° for (2). Two major conformers have been found in the molecular mechanics calculations performed on the N-carbamoylmethylpyridinium cation.