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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Nonaqueous Synthesis and Characterization of a New 2-Dimensional Layered Aluminophosphate [Al3P4O16]3−· 3[CH3CH2NH3]+
Qiuming Gao,Baozong Li,Jie-Sheng Chen,Shougui Li,Ruren Xu,Ian D. Williams,Jiaqi Zheng,David J. Barber +7 more
TL;DR: In this paper, a 4×6×8 network with a cavity size of 3.8×6.0A and anAAAAstacking sequence was constructed for the compound [Al3P4O16]3−·3[CH3CH2NH3]+.
Journal ArticleDOI
Synthesis, structures, magnetism and electrochemical properties of triruthenium–acetylide complexes
Ching-Kuo Kuo,Jung-Che Chang,Chen-Yu Yeh,Gene-Hsiang Lee,Chih-Chieh Wang,Shie-Ming Peng,Shie-Ming Peng +6 more
TL;DR: Compounds 2-6 display three triruthenium-based reversible one-electron redox couples, two oxidations and one reduction, and the electrode potentials shift upon varying the substituents, and a linear relationship is observed when the Hammett constants are plotted against the redox potentials.
Journal ArticleDOI
Detection of explosives via photolytic cleavage of nitroesters and nitramines.
TL;DR: In this article, a series of 9,9-disubstituted 9,10-dihydroacridines (DHAs) are synthesized from either Nphenylanthranilic acid methyl ester or a diphenylamine derivative and are similarly shown to be rapidly nitrated by the photofragmentation products of RDX and PETN.
Journal ArticleDOI
Four novel nanometer-sized cobalt azametallacrown complexes
Shen Lin,Shen Lin,Shi-Xiong Liu,Shi-Xiong Liu,Jian-Quan Huang,Jian-Quan Huang,Chi-Chang Lin,Chi-Chang Lin +7 more
TL;DR: In this article, four nanometer-sized cobalt azametallacrowns were synthesized by self-assembly reaction of cobalt ions with N-substituted salicylhydrazide ligands.
Journal ArticleDOI
Substituent and temperature controlled tautomerism: multinuclear magnetic resonance, X-ray, and theoretical studies on 2-phenacylquinolines
Erkki Kolehmainen,Borys Ośmiałowski,Tadeusz M. Krygowski,Reijo Kauppinen,Maija Nissinen,Ryszard Gawinecki +5 more
TL;DR: In this article, proton transfer equilibria in chloroform solution of twelve 2-phenacylquinolines were studied by 1H, 13C and 15N NMR spectroscopies.
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.