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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Preparation of New Monoanionic “Scorpionate” Ligands: Synthesis and Structural Characterization of Titanium(IV) Complexes Bearing This Class of Ligand
Antonio Otero,Juan Fernández-Baeza,Antonio Antiñolo,Fernando Carrillo-Hermosilla,Juan Tejeda,Agustín Lara-Sánchez,Luis F. Sánchez-Barba,M. Fernandez-Lopez,and Ana M. Rodríguez,Isabel López-Solera +9 more
TL;DR: The preparation of new "scorpionate" ligands in the form of the lithium derivatives has been carried out and the X-ray crystal structures of 3, 7, 10, and 11 were also established.
Journal ArticleDOI
Radical-type reactivity of the 1,3-dibora-2,4-diphosphoniocyclobutane-1,3-diyl.
TL;DR: Despite through-space and through-bond B-B interactions, the stable 1,3-bora-2,4-diphosphoniocyclobutane-1, 3-diyl displays some radical-type behavior, as illustrated by the spontaneous formation of the trans 1,2-adduct with trimethyltin hydride and a B-spiro derivative with bromotrichloromethane.
Journal ArticleDOI
Synthesis of cyclopentadienyl-, indenyl-, and fluorenylbis(pentafluorophenyl)boranes as ligands in titanium and zirconium half-sandwich complexes. The crystal structures of C13H9B(C6F5)(2)center dot t-BuNH2,C13H8SiMe3B(C6F5)(2), and {eta(5)-C5H4B(C6F5)(2)}TiCl3
TL;DR: In this paper, the boron-C6F5 substituent was replaced by NMe2 substituents, resulting in the trichlorides 1- and 2-{C9H6B(C6Fs5)(NMe2)}ZrCl3.
Journal ArticleDOI
Lanthanide-Based Molecular Materials: Gel Medium Induced Polymorphism
Carole Daiguebonne,André Deluzet,Magatte Camara,Kamal Boubekeur,Nathalie Audebrand,Yves Gérault,Christophe Baux,Olivier Guillou +7 more
TL;DR: In this article, a new Er3+ 1,2,4,5-benzenetetetracarboxylate based coordination polymer was synthesized and its crystal structure was reported.
Journal ArticleDOI
Amino-aryl-carbenes: alternative ligands for transition metals?
TL;DR: Despite the presence of a single amino substituent, an amino-anthryl-carbene was found to behave as a strong sigma-donor weak pi-acceptor ligand toward rhodium(I) fragments.
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.