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
Effects of N7-methylation, N7-platination, and C8-hydroxylation of guanine on H-bond formation with cytosine: platinum coordination strengthens the Watson-Crick pair.
TL;DR: In this paper, the hydrogen bonding properties of 1-methylcytosine (1-MeC) with the following guanine base derivatives have been studied in DMSO-d 6, applying concentration-dependent 1H NMR spectroscopy.
Journal ArticleDOI
Versatility of Heterocyclic Thioamides in the Construction of a Trinuclear Cluster [Cu3I3(dppe)3(SC5H4NH)] and CuI Linear Polymers {Cu6(SC5H4NH)6I6}n·2nCH3CN and {CuI6(SC3H6N2)6X6}n (X = Br, I)
TL;DR: The (mu3-S) modes of bonding of neutral heterocyclic thioamides are first examples, as are trinuclear cluster and linear polymers rare examples in copper chemistry.
Journal ArticleDOI
Synthesis, characterization and crystal structures of some four coordinated nickel(II) complexes with tridentate Schiff base ligands
TL;DR: A number of Ni(II) complexes with tridentate Schiff base ligands with a N2O donor set and coordinating NNN− and SCN− anions have been synthesized and characterized by analytical, spectroscopic and electrochemical techniques.
Journal ArticleDOI
Coordination behaviour of sulfanilamide derivatives.
Angel García-Raso,Juan J. Fiol,Santiago Rigo,Antonio López-López,Elies Molins,Enrique Espinosa,Elisa Borrás,Gloria Alzuet,Joaquín Borrás,Alfonso Castiñeiras +9 more
TL;DR: In this paper, the X-ray crystal structures of [Hg(sulfamethoxypyridazinato)2] (2a), [Cd(Sulfadimitriou)2(H2O)] (4b) and [Zn(methoxazolato) 2(py)2.2(h2O)2 (6d) have been determined.
Journal ArticleDOI
Modification of estrone at the 6, 16, and 17 positions: novel potent inhibitors of 17beta-hydroxysteroid dehydrogenase type 1.
Gillian M. Allan,Harshani Rithma Ruchiranani Lawrence,Josephine Cornet,Christian Bubert,Delphine S. Fischer,Nigel Vicker,Andrew Smith,Helena J. Tutill,Atul Purohit,Joanna M. Day,Mary F. Mahon,Michael J. Reed,Barry V. L. Potter +12 more
TL;DR: The syntheses and biological evaluation of novel inhibitors based on the estrone or estradiol template are reported and three libraries of amides are reported that led to the identification of inhibitors 19e and 20a, which have IC50 values of 510 and 380 nM respectively, and 20 h which is the most potent inhibitor of 17beta-HSD1 reported to date.
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.