Crystal Structure Prediction as a Tool for Identifying Components of Disordered Structures from Powder Diffraction: A Case Study of Benzamide II

2021 ◽  
Author(s):  
Eric J. Chan ◽  
Alexander G. Shtukenberg ◽  
Mark E. Tuckerman ◽  
Bart Kahr
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
Disordered Structures

scholarly journals ROY revisited, again: the eighth solved structure

2018 ◽  
Vol 211 ◽  
pp. 477-491 ◽  
Author(s):  
Melissa Tan ◽  
Alexander G. Shtukenberg ◽  
Shengcai Zhu ◽  
Wenqian Xu ◽  
Eric Dooryhee ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
X Ray ◽  
Prediction Algorithms

X-ray powder diffraction and crystal structure prediction algorithms are used in synergy to establish the crystal structure of the eighth polymorph of ROY, form R05.

scholarly journals Crystal structure prediction of organic pigments: quinacridone as an example

2007 ◽  
Vol 40 (1) ◽  
pp. 105-114 ◽  
Author(s):  
N. Panina ◽  
F. J. J. Leusen ◽  
F. F. B. J. Janssen ◽  
P. Verwer ◽  
H. Meekes ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Energy Minimization ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
X Ray ◽  
Organic Pigments ◽  
Structural Database ◽  
Diffraction Patterns ◽  
Experimental Structure

The structures of the α, β and γ polymorphs of quinacridone (Pigment Violet 19) were predicted usingPolymorph Predictorsoftware in combination with X-ray powder diffraction patterns of limited quality. After generation and energy minimization of the possible structures, their powder patterns were compared with the experimental ones. On this basis, candidate structures for the polymorphs were chosen from the list of all structures. Rietveld refinement was used to validate the choice of structures. The predicted structure of the γ polymorph is in accordance with the experimental structure published previously. Three possible structures for the β polymorph are proposed on the basis of X-ray powder patterns comparison. It is shown that the α structure in the Cambridge Structural Database is likely to be in error, and a new α structure is proposed. The present work demonstrates a method to obtain crystal structures of industrially important pigments when only a low-quality X-ray powder diffraction pattern is available.

scholarly journals Powder diffraction and crystal structure prediction identify four new coumarin polymorphs

2017 ◽  
Vol 8 (7) ◽  
pp. 4926-4940 ◽  
Author(s):  
Alexander G. Shtukenberg ◽  
Qiang Zhu ◽  
Damien J. Carter ◽  
Leslie Vogt ◽  
Johannes Hoja ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Structure Prediction ◽  
Prediction Method ◽  
Crystal Structure Prediction ◽  
Free Energies ◽  
Structure Prediction Method

Crystal structures of four new coumarin polymorphs were solved by crystal structure prediction method and their lattice and free energies were calculated by advanced techniques.

Ab-initio crystal structure prediction. A case study: NaBH4

2011 ◽  
Vol 184 (7) ◽  
pp. 1622-1630 ◽  
Author(s):  
Riccarda Caputo ◽  
Adem Tekin
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Structure Prediction ◽  
Crystal Structure Prediction

scholarly journals Graded IR Filters: Distinguishing Between Single and Multipoint NO2···I Halogen Bonded Supramolecular Synthons (P, Q, and R Synthons)

2014 ◽  
Vol 67 (12) ◽  
pp. 1840 ◽  
Author(s):  
Subhankar Saha ◽  
Somnath Ganguly ◽  
Gautam R. Desiraju
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
Supramolecular Synthon ◽  
High Throughput Analysis ◽  
Disordered Structures ◽  
Recognition Pattern ◽  
The Individual ◽  
Ir Spectroscopic

The NO2···I supramolecular synthon is a halogen bonded recognition pattern that is present in the crystal structures of many compounds that contain these functional groups. These synthons have been previously distinguished as P, Q, and R types using topological and geometrical criteria. A five step IR spectroscopic sequence is proposed here to distinguish between these synthon types in solid samples. Sets of known compounds that contain the P, Q, and R synthons are first taken to develop IR spectroscopic identifiers for them. The identifiers are then used to create graded IR filters that sieve the synthons. These filters contain signatures of the individual NO2···I synthons and may be applied to distinguish between P, Q, and R synthon varieties. They are also useful to identify synthons that are of a borderline character, synthons in disordered structures wherein the crystal structure in itself is not sufficient to distinguish synthon types, and in the identification of the NO2···I synthons in compounds with unknown crystal structures. This study establishes clear differences for the three different geometries P, Q, and R and in the chemical differences in the intermolecular interactions contained in the synthons. Our IR method can be conveniently employed when single crystals are not readily available also in high throughput analysis. It is possible that such identification may also be adopted as an input for crystal structure prediction analysis of compounds with unknown crystal structures.

Frontiers between crystal structure prediction and determination by powder diffractometry

2008 ◽  
Vol 23 (S1) ◽  
pp. S5-S12 ◽  
Author(s):  
Armel Le Bail
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Structure Determination ◽  
Structure Prediction ◽  
Water Molecules ◽  
Crystal Structure Prediction ◽  
Large Intensity ◽  
Cell Parameters ◽  
Structure Solution ◽  
Diffraction Patterns

The fuzzy frontiers between structure determination by powder diffractometry and crystal structure prediction are discussed. The application of a search-match program combined with a database of more than 60 000 predicted powder diffraction patterns is demonstrated. Immediate structure solution (before indexing) is shown to be possible by this method if the discrepancies between the predicted crystal structure cell parameters and the actual ones are <1%. Incomplete chemistry of the hypothetical models (missing interstitial cations, water molecules, etc.) is not necessarily a barrier to a successful identification (in spite of inducing large intensity errors), provided the search-match is made with chemical restrictions on the elements present in both the virtual and experimental compounds.

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