The structure of racemic (RS)-trichlormethiazide [systematic name: (RS)-6-chloro-3-(dichloromethyl)-1,1-dioxo-3,4-dihydro-2H-1λ⁶,2,4-benzothiadiazine-7-sulfonamide], C₈H₈Cl₃N₃O₄S₂ (RS-TCMZ), a diuretic drug used in the treatment of oedema and hypertension, was determined from laboratory X-ray powder diffraction data using DASH [David et al. (2006). J. Appl. Cryst. 39, 910–915.], refined by the Rietveld method with TOPAS-Academic [Coelho (2018). J. Appl. Cryst. 51, 210–218], and optimized using DFT-D calculations. The extended structure consists of head-to-tail dimers connected by π–π interactions which, in turn, are connected by C—Cl...π interactions. They form chains propagating along [101], further connected by N—H...O hydrogen bonds to produce layers parallel to the ac plane that stack along the b-axis direction, connected by additional N—H...O hydrogen bonds. The Hirshfeld surface analysis indicates a major contribution of H...O and H...Cl interactions (32.2 and 21.7%, respectively). Energy framework calculations confirm the major contribution of electrostatic interactions (E _elec) to the total energy (E _tot). A comparison with the structure of S-TCMZ is also presented.

The previously unreported crystal structure of ( S )-Dapoxetine hydrochloride (DAPHCl), the only active pharmaceutical ingredient specially developed for the treatment of premature ejaculation in men, has been determined from laboratory X-ray powder diffraction data with DASH and refined by the Rietveld method with TOPAS-Academic. The structure was evaluated and optimized by dispersion-corrected DFT calculations. This compound crystallizes in an orthorhombic cell, space group P 2 ₁ 2 ₁ 2 ₁ , with unit-cell parameters a = 6.3208(3) Å, b = 10.6681(5) Å, c = 28.1754(10) Å, V = 1899.89(14) Å ³ , Z = 4. The refinement converged to R _p = 0.0442, R _wp = 0.0577, and GoF = 2.440. The crystal structure is a complex 3D arrangement of DAPHCl moieties held together by hydrogen bonds, π⋯π, and C–H⋯π interactions. The chloride ions form layers parallel to the ab plane and are connected by dapoxetinium moieties through N–H⋯Cl and C–H⋯Cl hydrogen bonds. These layers stack along the c -axis, which are connected by C–H⋯π interactions. Hirshfeld surface analysis and fingerprint plot calculations have been performed.

Several benzothiophene-based compounds, including 1-benzothiophene-2-carboxylic acid, exhibit a wide variety of pharmacological activities. They have been extensively used to treat various types of diseases with high therapeutic effectiveness. In this contribution, the crystal structure of a new polymorph of 1-benzothiophene-2-carboxylic acid (BTCA) was determined from laboratory X-ray powder diffraction data with DASH, refined by the Rietveld method with TOPAS-Academic, and optimized using DFT-D calculations. The new form of 1-benzothiophene-2-carboxylic acid crystallizes in space group C 2/ c (No. 15) with a = 14.635(4), b = 5.8543(9), c = 19.347(3) Å, β = 103.95(1)°, V = 1608.8(6) Å ³ , and Z = 8. The structure is a complex 3D arrangement which can be described in terms of hydrogen-bonded dimers of BTCA molecules, joined by the acid–acid homosynthon, which interact through C–H⋯O hydrogen bonds to produce tapes further connected through head-to-tail π⋯π and edge-to-face C–H⋯π interactions. A comparison with a previously reported triclinic polymorph and with the related 1-benzofuran-2-carboxylic acid (BFCA) is also presented.