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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Alkaloids from Kopsia dasyrachis
TL;DR: A total of 32 alkaloids were obtained from the stem extract of Kopsia dasyrachis, of which ten were new, viz., kopsiflorine N (4)-oxide, 11-methoxykopsilongine N 4 -oxide,kopsifine, decarbomethoxy kopsifier, kopsinarine, 11,12-methylenedioxykopsine, dasyrusachine, rhazinicine, (+)-19 (R)-hydroxyeburnamine and (−)-19(R)-
Journal ArticleDOI
A structural, magnetic and mössbauer spectroscopic study of an unusual angular Jahn-Teller distortion in a series of high-spin iron(II) complexes
TL;DR: In this article, single crystal X-ray structures and susceptibility data are described for six homoleptic iron(II) complex salts, of 2,6-di(pyrazol-1-yl)pyridine or a 3,3″-disubstituted derivative of it.
Journal ArticleDOI
The influence of ligand conformation on the thermal spin transitions in iron(III) saltrien complexes
TL;DR: Six new salts of the iron(III) complexes of four hexadentate Schiff bases of the saltrien-type derived from 1,8-diamino-3,6-diazaoctane and 2 equiv.
Journal ArticleDOI
Bis-acetonitrile(dibromo)dioxomolybdenum(VI) and derivatives: synthesis, reactivity, structures and catalytic applications
Fritz E. Kühn,Eberhardt Herdtweck,Joachim J. Haider,Wolfgang A. Herrmann,Isabel S. Gonçalves,Isabel S. Gonçalves,André D. Lopes,Carlos C. Romão +7 more
TL;DR: In this article, the preparation and spectroscopic properties of complexes of the general formula MoBr2O2Ln with L=NCCH3 (n=2), NCC(CH3)3 (NCC6H5)
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Synthesis and Structure–Activity Correlation Studies of Secondary‐ and Tertiary‐Amine‐Based Glutathione Peroxidase Mimics
TL;DR: This study reveals that replacement of the tert-amino groups in benzylamine-based diselenides by sec-aminos moieties drastically enhances the catalytic activities in both the aromatic thiol (PhSH) and GSH assay systems.
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.