Journal ArticleDOI
Phase annealing in SHELX-90: direct methods for larger structures
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TLDR
In this article, a phase annealing method, related to the simulated-annealing approach in other optimization problems, is proposed and it is shown that it can result in an improvement of up to an order of magnitude in the chances of solving large structures at atomic resolution.Abstract:
A number of extensions to the multisolution approach to the crystallographic phase problem are discussed in which the negative quartet relations play an important role. A phase annealing method, related to the simulated annealing approach in other optimization problems, is proposed and it is shown that it can result in an improvement of up to an order of magnitude in the chances of solving large structures at atomic resolution. The ideas presented here are incorporated in the program system SHELX-90; the philosophical and mathematical background to the direct-methods part (SHELXS) of this system is described.read more
Citations
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Synthetic, EPR spectroscopic, magnetic and x-ray crystallographic structural studies on copper(II) complexes of the tridentate N2S donor ligand formed from 6-methyl-2-formylpyridine and S-methyldithiocarbazate (Hmpsme)
Mohammad Ali,Aminul Huq Mirza,R J Fereday,Ray J. Butcher,Julie M. Fuller,Simon C. Drew,Lawrence R. Gahan,Graeme R. Hanson,Boujemaa Moubaraki,K. S. Murray +9 more
TL;DR: In this paper, the EPR spectra of the [Cu(mpsme)X] (X = Cl, N-3, NO3, NCS) complexes reveal a tetragonally distorted coordination sphere around the mononuclear Cu(II) centre.
Journal ArticleDOI
Alkaline earth metal nitride compounds with the composition M2NX (M=Ca, Sr, Ba; X=□, H, Cl or Br)
Olaf Reckeweg,Francis J. DiSalvo +1 more
TL;DR: In this article, an overview of M 2 NX and alkaline earth metal subnitride compounds is presented, where the reaction products obtained from the nominal starting compositions "Ca 2 NH x " (0⩽ x ⩽1) were also analyzed by X-ray powder diffraction.
Journal ArticleDOI
"Induced fit" in chiral recognition: epimerization upon dimerization in the hierarchical self-assembly of helicate-type titanium(IV) complexes.
Journal ArticleDOI
Synthesis, structural versatility, luminescent and magnetic properties of a series of coordination polymers constructed from biphenyl-2,4,4′-tricarboxylate and different N-donor ligands
TL;DR: In this paper, eight new coordination polymers were constructed from different metal(II) chlorides and biphenyl-2,4,4′-tricarboxylic acid (H3btc) as a main building block, and various aromatic N-donors (phen = 1,10-phenanthroline, 4,4-bpy = 4, 4′-bipyridine, 2,2-bupyridine), as supporting ligands.
Journal ArticleDOI
Self-assembling systems based on amphiphilic alkyltriphenylphosphonium bromides: Elucidation of the role of head group
G. A. Gainanova,Guzalia I. Vagapova,Victor V. Syakaev,A. R. Ibragimova,Farida G. Valeeva,Elena V. Tudriy,Irina V. Galkina,Olga N. Kataeva,Lucia Ya. Zakharova,Shamil K. Latypov,Alexander I. Konovalov +10 more
TL;DR: Differences in aggregation behavior between TPPB and TMAB series and between low and high homologs can be due to the specific structural character of the TPP(+) cation, which is supported by X-ray data.
References
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Book
Crystallographic Computing 3: Data Collection, Structure Determination, Proteins and Databases
TL;DR: The latest in a series on crystallographic computing, this collection of 33 papers covers the full spectrum of computer applications in crystallography, including the use of micro-, mini-, and mainframe computers.