However, the crystal structure determined by XRPD closely resembled that determined by SCXRD, only when the correct conformation of the neotame molecule had been chosen before detailed analysis of the XRPD pattern. Diffraction patterns can be obtained from a randomly oriented crystalline powder composed of crystallites (crystalline regions within a particle) (USP ) or crystal fragments of finite size. However, with 13 rigid bodies defined, Cerius2 gives a conformation of the neotame molecule, which is different from that determined by SCXRD.įor neotame anhydrate polymorph G, the unit cell dimensions calculated from XRPD were almost identical to those determined by SCXRD. Every crystalline phase of a given substance produces a characteristic X-ray diffraction pattern. CCT Macromedia Director Shockwave Cast(Adobe Systems Incorporated) CCV Crystal Vision Report(CTMS) CCX CorelDraw File CCX Corel Compressed Exchange File CCX. The program has three main windows, the Main Screen where molecules are displayed, the Text Port where messages appear, and the Controls, which give you access to a wide range of menus and control panels. The XRPD pattern of polymorph G, analyzed by Cerius2 software, led to the same P2(1)2(1)2(1) space group and almost identical unit cell dimensions. Cerius2 is a product of Molecular Simulations Incorporated (MSI). The crystal structure of polymorph G was determined by single crystal X-ray crystallography (SCXRD) and also from the X-ray powder diffraction (XRPD) pattern using molecular modeling (Cerius2, Powder Solve module).įrom SCXRD, polymorph G crystals are orthorhombic with space group of P2(1)2(1)2(1) with Z = 4, unit cell constants: a = 5.5999(4), b = 11.8921(8), c = 30.917(2) A, and one neotame molecule per asymmetric unit.
To determine the crystal structure of the neotame anhydrate polymorph G and to evaluate X-ray powder diffractometry (XRPD) with molecular modeling as an alternative method for determining the crystal structure of this conformationally flexible dipeptide.
0 kommentar(er)
