The crystal and molecular structure of a polymorph and a pseudo-polymorph of droperidol

Crystals of two crystal modifications of droperidol: a hemihydrate (1) and the z polymorph (2), have been isolated and their structure determined using X-ray diffraction methods. Droperidol hemihydrate crystallized in the triclinic space group P - 1, with unit cell parameters a = 6.2842(15), b = 10.1473(8), c = 16.1850(2) Å; α = 102.554(9); β = 91.917(14); γ = 99.316(12)°; V = 991.6(3) ų, and Z = 2. The droperidol z polymorph crystallized in the monoclinic space group P2₁/c, with unit cell parameters a = 20.0406(8), b = 7.4955(4), c = 12.9733(5) Å; β = 98.089(2)°; V = 1929.39(15) ų, and Z = 4. In 1 and 2 two molecules of droperidol are joined by two N-H⋯O hydrogen bonds. The structure of 1 shows a possible additional hydrogen bond linking the two droperidol molecules via the water molecule.