Journal ArticleDOI
Phase annealing in SHELX-90: direct methods for larger structures
Reads0
Chats0
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
More filters
Journal ArticleDOI
Syntheses, crystal structures and magnetic properties of copper(II) dicyanamide complexes; dinuclear, chain and ladder compounds
TL;DR: In this article, the preparation, crystal structures and magnetic properties of three heteroleptic copper(II) complexes with dicyanamide (dca) bridges, [Cu(bpca)(H2O)(dca)]2 (1) (bpca = bis(2-pyridylcarbonyl)amidate), [Cu[bpy)(dCA)2]n (2) (bpy = 2,2′-bipyridine),
Journal ArticleDOI
Catalytic Hydrodefluorination of Aromatic Fluorocarbons by Ruthenium N-Heterocyclic Carbene Complexes
TL;DR: The catalytic reactions reveal a novel selectivity for substitution at the 2-position in C(6)F(5)H and C(5), and a first-order dependence on [fluoroarene] and zero-order relationship with respect to [R(3)SiH].
Journal ArticleDOI
Ruthenium‐Based Four‐Coordinate Olefin Metathesis Catalysts
Journal ArticleDOI
A complex clathrate hydrate structure showing bimodal guest hydration
TL;DR: A new hydrate structure has a number of unusual features; in particular the choline guest exhibits both hydrophobic and hydrophilic modes of hydration, and might conceivably be found in those settings in which clathrate hydrates form naturally.
Journal ArticleDOI
Synthesis, Structure, and Properties of {(tBu2PC2H4PtBu2)Ni}2(μ-η2:η2-C6H6) and (tBu2PC2H4PtBu2)Ni(η2-C6F6)1
Ingrid Bach,Klaus-Richard Pörschke,Richard Goddard,Carsten Kopiske,Carl Krüger,and Anna Rufińska,Klaus Seevogel +6 more
TL;DR: In this paper, the X-ray structure analysis reveals an antifacial coordination of the [(tBu2PC2H4PtBu 2)Ni0] moieties to adjacent CC bonds of a formal cyclohexatriene ligand.
References
More filters
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.