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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Journal ArticleDOI
Mononuclear Titanium Complexes That Contain Aminopyridinato Ligands.
Rhett Kempe,Perdita Arndt +1 more
TL;DR: Variable-temperature NMR investigations of complex 2c are indicative of exchange processes which proceed most likely via tetrahedral transition states, and proved these compounds to be monomeric with a slightly distorted octahedral coordination geometry.
Journal ArticleDOI
Synthesis of a new class of compounds containing a Ln-O-Al arrangement and their reactions and catalytic properties.
Jianfang Chai,Vojtech Jancik,Sanjay Singh,Hongping Zhu,Cheng He,Herbert W. Roesky,Hans-Georg Schmidt,Mathias Noltemeyer,Narayan S. Hosmane +8 more
TL;DR: Synthesis of a new class of compounds containing a Ln-O-Al moiety has been accomplished by the reaction of LAlOH(Me) with a series of Cp(3)Ln compounds, and complexes 1, 3, 4, and 6 exhibit good catalytic activity for the polymerization of epsilon-caprolactone.
Journal ArticleDOI
A Dense and Efficient Clathrate Hydrate Structure with Unusual Cages
Journal ArticleDOI
Photoisomerization of ammonium α,β-unsaturated carboxylates in the solid state: effect of the hydrogen-bond network on the reactivity
Kazushi Kinbara,Akiyoshi Kai,Yasunari Maekawa,Yukihiko Hashimoto,Shoji Naruse,Masaki Hasegawa,Kazuhiko Saigo +6 more
TL;DR: In this paper, a detailed study concerning the crystal structures suggested that the characteristics of the hydrogen-bond network had a close correlation with the isomerizability, and both the bulkiness of the carboxylate and ammonium groups as well as their difference in molecular length were considered to be the most important factors influencing the isomersizability.
Journal ArticleDOI
Cyclometalated Compounds. XI.1 Single and Double Cyclometalations of Poly(pyrazolylmethyl)benzenes
TL;DR: In this paper, six ligands containing 1,3-bis(pyrazol-1-ylmethyl)benzene subunits are shown to readily undergo cyclometalation reactions.
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.