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
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β-Octamolybdate as a Building Block. Synthesis and Structural Characterization of Rare Earth−Molybdate Adducts
TL;DR: In this paper, the reaction of tetra-n-butylammonium (n-C4H9)4N]4[Mo8O26]4] with nitrate salts of rare earth metals yields two different series of new compounds [Ln(Mo 8O26)2]5- and [{Ln (NO3)3}2(Mo8 O26)]4- (Ln = Y, La, Ce, Pr, Nd, Gd, Yb) as tetra nbutylmonium
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New weakly coordinating counter anions for high activity polymerisation catalysts: [(C6F5)3B–CN–B(C6F5)3]– and [Ni{CNB(C6F5)3}4]2–
TL;DR: The new borate [CPh3]+[CN{B(C6F5)3}2] and the anionic isocyanoborate complex [Ni{CNB(C 6F5)-4]2] are readily accessible in one-pot reactions and act as highly efficient activators for metallocene polymerisation catalysts; turnover numbers of up to 53 000 s−1 appear to be the highest reported so far for ethene polymerization catalysts as discussed by the authors.
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Synthesis, structure and solution chemistry of mixed-ligand oxovanadium(IV) and oxovanadium(V) complexes incorporating tridentate ONO donor hydrazone ligands
TL;DR: In this article, the ONO donor ligands are the acetylhydrazones of salicylaidehyde (H2L1) and 2-hydroxyacetophenone (H 2L2) (general abbreviation, H2L2).
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Synthesis, characterization, and anticancer activity of a series of ketone-N(4)-substituted thiosemicarbazones and their ruthenium(II) arene complexes.
TL;DR: A series of ketone-N(4)-substituted thiosemicarbazone compounds (L1-L9) and their corresponding [(η(6)-p-cymene)Ru(II)(TSC)Cl](+/0) complexes (1-9) were synthesized and characterized by NMR, IR, elemental analysis, and HR-ESI-mass spectrometry.
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Hybrid Framework Iron(II) Phosphate-Oxalates
TL;DR: Two inorganic-organic hybrid framework iron phosphate-oxalates, I, [N2C4H12] and II, [Fe-2(OH2)PO4(C2O4)(0.5)] have been synthesized by hydrothermal means and the structures determined by X-ray crystallography as discussed by the authors.
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.