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
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Reactions of 1,4- and 2,3-Diazadienes with Titanocene and Zirconocene Complexes of Bis(trimethylsilyl)acetylene: Acetylene Coupling or Substitution Including Subsequent C−H Activation, C−C Coupling, and N−N Cleavage to Heterobimetallic Complexes
TL;DR: In this article, the reaction of 1,4-diazadienes RNCHCHNR with the titanocene and zirconocene complexes of bis(trimethylsilyl)acetylene Cp2M(L)(η2-Me3SiC2SiMe3) (M = Ti, without L (1); M = Zr, L = THF (2), pyridine (3)) is a general and new method to obtain 1metalla-2,5diazacyclopent-3-ene complexes
Journal ArticleDOI
Inhibition of monoamine oxidase-B by condensed pyridazines and pyrimidines: Effects of lipophilicity and structure-activity relationships
Cosimo Altomare,Saverio Cellamare,Luciana Summo,Marco Catto,Angelo Carotti,Ulrike Thull,Pierre-Alain Carrupt,Bernard Testa,Helen Stoeckli-Evans +8 more
TL;DR: The pyrimidine derivatives proved to be reversible and selective MAO-A inhibitors, and structure-activity relations highlighted the main factors determining both selectivity and inhibitory potency.
Journal ArticleDOI
Solution and Solid-State Characteristics of Imine Adducts with Tris(pentafluorophenyl)borane
TL;DR: In this paper, the N-benzyl imines Ph(R)CNBn (R = Ph, CH3, H) and tBu(CH3), with the tris(pentafluorophenyl)borane, B(C6F5)3, were characterized in solution and in the solid state.
Journal ArticleDOI
Active-site architecture of endopolygalacturonase I from Stereum purpureum revealed by crystal structures in native and ligand-bound forms at atomic resolution.
TL;DR: In this article, the crystal structures of endopolygalacturonase from Stereum purpureum were solved in native and two galacturonic acid complex states at atomic resolution.
Journal ArticleDOI
Molecular Packing and Photoluminescence Efficiency in Odd-Membered Oligothiophene S,S-Dioxides
Luciano Antolini,Emilio Tedesco,G. Barbarella,Laura Favaretto,Giovanna Sotgiu,Massimo Zambianchi,Daniele Casarini,and Giuseppe Gigli,Roberto Cingolani +8 more
TL;DR: In this article, the single-crystal X-ray structures of three odd-membered thiophene oligomers bearing one central thienyl-S,S-dioxide moietytrimer, pentamer, and heptamer were reported.
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.