DASH - Cambridge Structural Database · DASH is a program suitable for both inexperienced and expert users. • Simple structure solution setup:DASH [1] features an intuitive interface

Cambridge Crystallographic Data Centre

Easy to use and interactive, DASH is your indispensibletool for solving the structures of simple or complexcompounds from powder diffraction data.

DASH

An interactive and accurate package for structure solution from powder diffraction data

www.ccdc .cam.ac .uk

Integration and deployment

Make use of DASH’s external software links and distributed computing options toaccelerate the process from powder pattern to structure.

• Choose your preferred indexing program: DASH features convenient links to twoexternal indexing packages - DICVOL (04 and 91) and McMaille. Selected peakpositions can also be easily exported for use in other indexing packages.

• Use interfaces to popular Rietveld refinement packages: Rietveld refinement ofthe solved structure can be performed using DASH’s integrated rigid-bodyrefinement module. Alternatively, you can use one of the built-in interfaces to thepopular external refinement packages TOPAS, GSAS and RIETAN.

• Multiple options are available to reduce run times: Employ DASH on a singlecomputer, in batch mode, multi-core processor or on a GRID network. The ability torun DASH on a Grid MP network or multi-core processor can significantly reducetotal run times. Large-scale parallelisation using the Grid MP platform in particularcan achieve the solution of considerably more challenging structures within aworkable time frame.

Monitor your structure solution throughout the process.

Ease of use

DASH is a program suitable for both inexperienced and expert users.

• Simple structure solution setup: DASH [1] features an intuitive interface andhelpful wizard to guide you through the various steps of the structure solutionprocess. Automatically fit and subtract backgrounds with a Bayesian high-passfilter and perform flexible manual peak fitting with an asymmetry-corrected Voigtfunction. Extract integrated intensities and their correlations via a Pawleyrefinement and determine the space group via probabilistic analysis of extractedintensities. Using a global optimisation approach a highly efficient simulatedannealing algorithm adjusts the trial molecular structure within the indexed cellin order to maximise the agreement with the intensities extracted during theprofile fit.

• Speed up structure solution and increase success rates by exploitinginformation from the Cambridge Structural Database (CSD)*: Use Mogul [2],an extensive library of intramolecular geometries derived from the CSD, toassess and automatically bias conformational searching towards torsion angleranges commonly observed in crystal structures. Use of Mogul torsion anglerestraints has been shown to give, on average, a 40% reduction in the number ofmoves required to solve the structure compared to unconstrained runs(unpublished results). In addition to speeding up structure solution use oftorsional restraints can make challenging problems tractable, e.g. restraints wereessential for solving the structure of the β-form of Pigment Yellow 181, a highlyflexible molecule containing ten rotatable torsions [3].

• Compare and visualise your solutions: Rationalise solutions and compareresults from different runs using a specially tailored version of CCDC’s popularsmall-molecule visualiser, Mercury [4]. Visualise how the molecules in thestructure pack and examine the interactions and motifs within the extendedcrystal structure.

* Access to this functionality requires a Cambridge Structural Database System licence, for information contact [email protected]

The link from DASH to Mogul enables bounds to be applied to

the torsion angle space explored by DASH during structure

solution. This proved essential when solving the structure of the

β-form of Pigment Yellow 181 (pictured above) that contains

ten flexible torsions.

Case studies demonstrating DASH’s effectiveness in solving a range of problems areavailable from the CCDC website: www.ccdc.cam.ac.uk/case_studies/.

References[1] W. I. F. David, K. Shankland, J. van de Streek, E. Pidcock, W. D. S. Motherwell, J. C. Cole, J. Appl. Cryst., 39,

920-915, 2006

[2] I. J. Bruno, J. C. Cole, M. Kessler, Jie Luo,W. D. S. Motherwell, L. H. Purkis, B. R. Smith, R. Taylor, R. I. Cooper,S. E. Harris, A. G. Orpen, J. Chem. Inf. Comput. Sci., 44, 2133-2144, 2004

[3] E. Pidcock, J. van de Streek, M. U. Schmidt, Z. Krist., 222, 713-717, 2007

[4] C. F. Macrae, I. J. Bruno, J. A. Chisholm, P. R. Edgington, P. McCabe, E. Pidcock, L. Rodriguez-Monge, R. Taylor, J.van de Streek, P. A. Wood, J. Appl. Cryst., 41, 466-470, 2008

[5] A. J. Florence, N. Shankland, K. Shankland,W. I. F. David, E. Pidcock, X. Xu, A. Johnston, A. R. Kennedy, P. J. Cox,J. S. O. Evans, G. Steele, S. D. Cosgrove, C. S. Frampton, J. Appl. Cryst., 38, 249-259, 2005

[6] K. Sugimoto, R. E. Dinnebier, M. Zakrzewski, J. Pharm. Sci., 96, 3316-3323, 2007

[7] A. Llinàs, L. Fábián, J. C. Burley, J. van de Streek, J. M. Goodman, Acta Cryst., E62, o4196-o4199, 2006

[8] P. Fernandes, K. Shankland, A. J. Florence, N. Shankland, A. Johnston, J. Pharm. Sci., 96, 1192-1202, 2007

[9] R. P. Pandian, M. Dolgos,V. Dang, J. Z. Sostaric, P. M. Woodward, P. Kuppusamy, Chem. Mater., 19, 3545-3552, 2007

[10] C. L. Schmidt, R. Dinnebier, U.Wedig, M. Jansen, Inorg. Chem., 46, 907-916, 2007

[11] R. E. Dinnebier, A. Kowalevsky, H. Reichert, M. Jansen, Z. Krist., 222, 420-426, 2007

[12] J. C. Burley, W. D. S. Motherwell, J. Maaranen, M. Ringwald, Acta Cryst., E63, m238-m240, 2007

Case Studies

www.ccdc .cam.ac .uk

Versatility

Widely applicable, DASH has been used to solve a diverse range of structure types.

• Powder diffraction data input: DASH accepts both synchrotron andmonochromatic laboratory X-ray powder diffraction data in a wide variety ofcommon formats including .raw (Bruker and STOE), .asc (Rigaku), .xye, .rd and.sd (Philips), as well as many others.

• Solve the structures of complex molecules: DASH has been successful insolving the structures of many systems of both academic and industrial interest[5]. At the upper level of complexity, DASH has solved structures for moleculescomprising up to 16 flexible torsion angles, more than 72 non-hydrogen atomsand up to six molecules in the asymmetric unit. A particularly challengingexample solved using DASH was Verapamil hydrochloride, a salt complex with13 torsional degrees of freedom [5]; read more in a case study provided on ourwebsite: www.ccdc.cam.ac.uk/case_studies/small_mol/Verapamil_DASH.pdf.

• Apply DASH to a wide range of applications: DASH has been successfully usedto solve a diverse array of structure types including pharmaceutical compounds(e.g. naltrexone hydrochloride [6]), salts (e.g. amodiaquinium dichloridedehydrate [7]), solvates (e.g. chlorothiazide N,N-dimethylformamide solvate[8]), semiconductors (e.g. lithium 1,8,15,22-tetraphenoxyphthalocyanine [9])and explosives (e.g. silver azide [10]). DASH can also be routinely applied to thesolution of organometallic crystal structures [11], and has been used to solveinorganic crystal structures [12].

Verapamil hydrochloride, a salt complex with 13 torsional

degrees of freedom, was a particularly challenging structure for

DASH to solve.

Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK

www.ccdc.cam.ac.uk • Email: [email protected] • Tel: +44 1223 336408

Registered in England No. 2155347 • Registered Charity No. 800579

Evaluations

To request an evaluation copy of DASH please contact [email protected]

Acknowledgements

DASH has been jointly developed by CCDC Software Ltd and the UK's Science andTechnology Facilities Council (STFC) and was initially written by Prof. Bill David(Rutherford Appleton Laboratory) and Dr. Kenneth Shankland (University of Reading).

Supported platforms

For a full list of supported platforms and operating systems please visit theCCDC website.

Related products

The Cambridge Structural Database System: The world’s repository ofexperimentally determined small molecule structures. Comprehensive of thepublished literature and fully curated, the CSD is an essential resource to scientistsaround the world.