Crystal structure solution

Once a structure of the desired protein has been solved, it is a very rapid process to produce subsequent high-quality structures and, in fact, some groups have even linked various scripts together, or modified software tools to provide much more automated software aids to repeated crystal structure solution, such as when solving multiple ligand complexes of the same protein [7]. 

On the crystal structure solution and characterization of ECS-2, a novel microporous hybrid organic-inorganic material... 

Reeves, Z. R. Mann, K. L. V. Jeffery, J. C. McCleverty, J. A. Ward, M. D. Barigelletti, F. Armaroli, N. Lanthanide complexes of a new sterically hindered potentially hexadentate podand ligand based on a tris(pyrazolyl)borate core crystal structures, solution structures and luminescence properties. J. Chem. Soc., Dalton Trans. 1999, 349-355. 

Sheldrick, G. M. SHELXTL-PLUS Program for Crystal Structure Solution and Refinement University of Gottingen Gottingen, Germany, 1997. 

The Electron Density Function and the "Phase Problem." The electron density function p x, y, z) at the general point (x, y, z) in the crystal is the goal of every crystal structure solution formally, it is the Fourier transform of the stucture factors ... 

Crystal Structure Solution from Powder Diffraction Data Using ... 

As already described, the GA approach has proven very successful as a tool for direct-space crystal structure solution from powder diffraction data. However, there remain many opportunities for optimizing GA methodologies. In this section, we discuss one approach for increasing the power and scope of GA methodologies which takes advantage of modern computational techniques. 

Sheldrick G. M., SHELXS 97, Program for Crystal Structure Solution, University of Gottingen, 1997. 

MacLean et al. (2000) have recently smdied the dimorphic behaviour of the pigment precursor ( latent pigment) derivative of 8-VI (R = COOr-but, R = H) (abbreviated DPP-Boc). The latency is due to the thermal decomposition reaction of both polymorphs resulting in the commercially important pigment DPP. The a form of DPP-Boc contains three half molecules in the asymmetric unit (see also Ellern et al. 1994) while the form contains one half molecule per asymmetric unit. Hence, they are easily distinguishable by solid state NMR as well as by X-ray powder diffraction. The crystal structure solution from powder data and Rietveld refinement of both polymorphs is an exemplary smdy demonstrating the potential of these methods in determining the detailed crystal structure of these compounds which are often difficult to crystallize. 

Engel, G.E., S. Wilke, O. Konig, K.D.M. Harris, and F.J.J. Leussen, Powder Solve—A Complete Package for Crystal Structure Solution from Powder Diffraction Patterns, J. Applied Crystallogr. 32 1169-1179 (1999). 

Figure 4.1. The flowchart illustrating common steps employed in a structural characterization of materials by using the powder diffraction method. It always begins with the sample preparation as a starting point, followed by a properly executed experiment both are considered in Chapter 3. Preliminary data processing and profile fitting are discussed in this chapter in addition to common issues related to phase identification and analysis. Unit cell determination, crystal structure solution and refinement are the subjects of Chapters 5,6, and 7, respectively. The flowchart shows the most typical applications for the three types of experiments, although any or all of the data processing steps may be applied to fast, overnight and weekend experiments when justified by their quality and characterization goals.

A crystal structure solution does not end with the development of a plausible model after the model has been built completely, multiple structural and profile parameters should be refined to achieve the best... 

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