3-(1-Methyl-pyrrolidin-2-yl-idene)-3H-indole sesquihydrate.

The asymmetric unit of the title compound, C(13)H(14)N(2)·1.5H(2)O, contains two similar mol-ecules of 3-(1-methyl-pyrrolidin-2-yl-idene)-3H-indole, (I), and three water mol-ecules. (I) is the product of reacting indole with 1-methyl-pyrrolidin-2-one in the presence of phospho-rus oxychloride. Both organic molecules are almost completely planar; the maximum distances above and below the least-squares plane through all the atoms of mol-ecule 1 are 0.050 (8) and -0.045 (8) Å, respectively, and the deviations for mol-ecule 2 are 0.096 (8) and -0.059 (8) Å, respectively. In the crystal, the two crystallographically different mol-ecules alternate in π-stacked columns [centroid-centroid distances = 3.729 (5) and 3.858 (5) Å], which are linked by O-H⋯N hydrogen bonds to a network of hydrogen-bonded water mol-ecules. O-H⋯O inter-actions are also present.