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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N‐Heterocyclic Carbenes and Imidazole‐2‐thiones as Ligands for the Gold(I)‐Catalysed Hydroamination of Phenylacetylene
TL;DR: The gold complexes in the hydroamination of phenylacetylene with substituted anilines was tested and compared to control catalyst systems, and the best catalytic performance was obtained with [(C^Imine(tBu))AuCl], with the exclusive formation of the Markovnikov addition product in excellent yield regardless of the substituents on aniline.
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Cooperative Jahn-Teller induced phase transition of TbVO4: single crystal structure analyses of the tetragonal high temperature phase and the twinned orthorhombic phase below 33 K
TL;DR: The rare earth vanadate TbVO4 undergoes a crystallographic phase transition below 33 K induced by a cooperative Jahn-Teller effect as mentioned in this paper, resulting in a domain structure.
Journal ArticleDOI
Stepwise Spin Transition in a Mononuclear Iron(II) Complex with Unusually Wide Plateau
TL;DR: In this article, an octahedral iron(II) complex with the formula FeL(CNpy)2·0.25CNpy (1) was investigated using temperature-dependent susceptibility measurements (SQUID) and Mossbauer spectroscopy.
Journal ArticleDOI
Structure, characterization and photoreactivity of monomeric dioxovanadium(v) schiff-base complexes of trigonal-bipyramidal geometry
TL;DR: In this paper, five mononuclear cis-dioxovanadium(V) complexes of tridentate Schiff bases derived from salicylaldehyde and its derivatives and 8-aminoquinoline have been synthesized and characterized.
Journal ArticleDOI
Goldilocks Effect of a Distal Substituent on Living Ziegler−Natta Polymerization Activity and Stereoselectivity within a Class of Zirconium Amidinate-Based Initiators
TL;DR: In this article, a series of cationic zirconium amidinates was synthesized and their ability to function as initiators for the stereoselective living Ziegler−Natta polymerization of 1-hexene was evaluated.
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.