Crystal structure determining of 7-ADCA based on X-ray powder diffraction

Abstract

Optimum resolution data of X-ray powder diffraction for 7-amino desacetoxy cephalosporanic acid(7-ADCA) were collected from an X ′ Pert Pro MPD diffractometer with the setup of 0.01°/s and 0.01° per step. Indexing to the crystal system and searching space group from the diffraction data were conducted by means of the computational crystallography method. The pilot crystal models of 7-ADCA were then refined by Rietveld method to obtain the exact three-dimensional structure. The results show that the crystal structure of 7-ADCA is monoclinic, space group P2 1 with unit cell dimensions a=13.50 Å, b=6.01 Å, c =5.91 Å, α= γ =90.00°, β =101.96°, Z=2and V =469.10 Å 3 . The fraction coordinate of each atom in the unit cell is well located and reported.

Comparative crystal structure determination of griseofulvin: Powder X-ray diffraction versus single-crystal X-ray diffraction

“…The fact that results by the two techniques are identical demonstrates that powder X-ray diffraction can be as accurate as single-crystal X-ray diffraction in order to determine the crystal structure of griseofulivin. In addition, investigators in our laboratory have successfully determined the crystal structure of 7-amino-3-desacetoxy cephalosporanic acid [10] and β-cyclodextrin-p-aminobenzoic acid inclusion complex [11] from powder X-ray diffraction data. Therefore we can further verify the accuracy of powder X-ray diffraction to determine the crystal structure of small organic molecules.…”

Crystal structure determination of Jatrorrhizine chloride

“…Pressed at a higher pressure of 16 MPa, the apparent density of Jat tablet is close to, but sightly less than Jat density measured/calculated from the X-ray diffraction. Therefore, the density-screening of the candidates [4] could eliminate a great number of crystal structure candidates whose densities are less than or far from the apparent density of 1.29 g·cm −3 , such as P1, P2 1 /c, etc. Based on the symmetry and cell volume, we choose monoclinic system with space group P2 1 /c as the only possible crystal structure candidate, that is, No.…”

“…It is crucial to investigate the methodology and applicability of computational crystallography techniques for crystal structure determination from conventional laboratory powder X-ray diffraction data. Based on the data of a laboratory powder X-ray diffractometer, our laboratory determined the pilot crystal structure of 7-amino-desacetoxy-cephalosporanic acid, which is a key intermediate for the derivation of Cephalosporin's compounds [4] .Both the molecular formula and crystal structure of Jatrorrhizine chloride (Jat) were determined from an SCXRD pattern with direct method [5] , with no chemical reference information available, by Wang et al in 1989 [6] , and Ghosh et al in 1993 [7] .The results of Jat crystal structure and methodology of structure determination from data of powder X-ray diffraction (PXRD) and computational crystallography …”

“…It is crucial to investigate the methodology and applicability of computational crystallography techniques for crystal structure determination from conventional laboratory powder X-ray diffraction data. Based on the data of a laboratory powder X-ray diffractometer, our laboratory determined the pilot crystal structure of 7-amino-desacetoxy-cephalosporanic acid, which is a key intermediate for the derivation of Cephalosporin's compounds [4] .…”

Crystal structure determination of three polycyclic compounds and comparative Rietveld refinement between MS and GSAS programs

“…Only some programs such as material studio (MS) can independently complete the whole process of structure determination. We previously successfully solved the crystal structures of 7-ADCA [3], jatrorrhizine chloride [4], -cyclodextrin-p-aminobenzoic acid inclusion complex [5], and others by XRPD in MS 4.0. Nevertheless, Rietveld refinement (RR) [6] using non-linear least-square fitting from Reflex Plus in MS 4.0 is a rather rough tool in refining all variables together.…”