Crystal structure determination of a series of small organic compounds from powder data

Abstract

Abstract The crystal structures of 2,4-di-bromo-aniline (A; C6H5NBr2 ), 4-iodo-anisole (B; C7H7OI), 2-iodo-benzenemethanol (C; C7H7OI), 2-amino-benzothiazole (D; C7H6N2S) and 2-amino, 5-bromo-pyridine (E; C5H5N2Br) have been determined from X-ray powder diffraction data. Grid search and Rietveld refinement have been used to determine the structures. The crystals of (A) and (B) are orthorhombic, the crystals of (C), (D) and (E) are monoclinic. (A): Space group P212121, Z=4 with cell parameters a = 11.18(1), b = 16.17(1), c = 4.110(3)Å; (B): Space group Pca21, Z = 4, a = 6.288(4), b = 7.361(4), c = 16.93(1)Å; (C): Space group P21/n, Z = 4, a = 13.23(1), b = 4.652(3), c = 12.82(1)Å, β = 109.69(4)°; (D): Space group P21/c, Z = 4, a = 14.58(2), b = 4.094(4), c = 11.62(1)Å, β = 94.12(6)°; (E): Space group P21/c, Z = 4, a = 13.80(1), b = 5.839(5), c = 7.687(7)Å, β = 106.04(5)°. Chemical diagrams of all five compounds are depicted in Fig. 1. Soft constraints have been applied to the molecules during Rietveld refinement. The final R p values obtained were 7.3 (A), 2.9 (B), 11.1 (C), 16.4 (D) and 7.9% (E) respectively. All compounds were measured on a Guinier camera. In addition, the structure of compound (A) was confirmed by single-crystal structure determination.