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Phase annealing in SHELX-90: direct methods for larger structures
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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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Dramatic Modifications of Magnetic Properties through Dehydration−Rehydration Processes of the Molecular Magnetic Sponges CoCu(obbz)(H2O)4·2H2O and CoCu(obze)(H2O)4·2H2O, with obbz = N,N‘-Bis(2-carboxyphenyl)oxamido and obze = N-(2-Carboxyphenyl)-N‘-(carboxymethyl)oxamido
Joulia Larionova,Suvarna A. Chavan,J. V. Yakhmi,Anne Gulbrandsen Frøystein,Jorunn Sletten,Claude Sourisseau,Olivier Kahn +6 more
TL;DR: In this article, the two compounds CoCu(obbz)4·2H2O (I) and Co2+Cu2+ pairs (in which the metal ions are bridged by an oxamide group) and noncoordinated water molecules were synthesized and their crystal structures were determined at room temperature.
Journal ArticleDOI
Facile Si–H bond activation and hydrosilylation catalysis mediated by a nickel–borane complex
TL;DR: In this paper, diphosphine-borane nickel complexes are described that activate Si-H bonds and catalyze the hydrosilylation of aldehydes, which is consistent with the intermediacy of a borohydrido-Ni-siloxyalkyl species.
Journal ArticleDOI
Preparation and Study of New Poly‐8‐Hydroxyquinoline Chelators for an anti‐Alzheimer Strategy
Céline Deraeve,Christophe Boldron,Alexandrine Maraval,Honoré Mazarguil,Heinz Gornitzka,Laure Vendier,Marguerite Pitié,Bernard Meunier +7 more
TL;DR: X-ray analyses of single-crystals of Cu II, Zn II or Ni II complexes of 2,2'-(2,2-propanediyl)-bis(8-hydroxyquinoline), including a one-atom linker, showed that all heteroatoms of the bis-8- hydroxyquinoline ligand chelate the same metal ion in a distorted square-planar geometry.
Journal ArticleDOI
Noncovalent assembly of functional groups on calix[4]arene molecular boxes
Peter Timmerman,Remko H. Vreekamp,Ron Hulst,Willem Verboom,David N. Reinhoudt,Kari Rissanen,Konstantin A. Udachin,John A. Ripmeester +7 more
TL;DR: In this paper, the first X-ray crystal structure and the MALDI TOF mass spectra together with the complete 1H NMR spectroscopic characterization of these hydrogen-bonded assemblies were reported.
Journal ArticleDOI
The formation and polymerization behavior of Ni(II) α-diimine complexes using various aluminum activators
TL;DR: Several Ni(II) α-diimine complexes have been synthesized and examined for ethylene and propylene polymerization in combination with different aluminum co-catalysts 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.