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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Interaction of 1,3-Adamantanediacetic Acid (H2ADA) and Ditopic Pyridyl Subunits with Cobalt Nitrate under Hydrothermal Conditions: pH Influence, Crystal Structures, and Their Properties
Wei-Hong Zhang,Yao-Yu Wang,Elmira Kh. Lermontova,Guo-Ping Yang,Bin Liu,Jun-Cheng Jin,Zhe Dong,Qi-Zhen Shi +7 more
TL;DR: In this article, a systematic investigation of the pH influence on the interaction between 1,3-adamantanediacetic acid (H2ADA), 1, 3-bis(4-pyridyl)propane (bpp)/4, 4′-dipyridine (4,4′-bipy), and cobalt nitrate under hydrothermal conditions has resulted in a series of coordination polymers with different composition and dimensionality, namely [Co(HADA)2(bpp)]n (1), {[Co(ADA)(
Journal ArticleDOI
Design, Synthesis, and Evaluation in Vitro of Quinoline-8-carboxamides, a New Class of Poly(adenosine-diphosphate-ribose)polymerase-1 (PARP-1) Inhibitor
TL;DR: 3-substituted compounds for inhibition of human recombinant PARP-1 activity showed a requirement for a small narrow group, and substitutes in the 2-position increased potency.
Journal ArticleDOI
Structurally Novel Bioconversion Products of the Marine Natural Product Sarcophine Effectively Inhibit JB6 Cell Transformation.
Khalid A. El Sayed and,Mark T. Hamann,Christopher A. Waddling and,Craig Jensen,Sang Kook Lee,and Christina Andersson Dunstan,John M. Pezzuto +6 more
TL;DR: When evaluated for potential to inhibit TPA-induced JB6 cell transformation, several of the metabolites mediated inhibitory responses greater than sarcophytol A or sarcophine, most notably 7alpha-hydroxy-Delta(8(19))-deepoxysarcophine (6), which was comparable to 13-cis-retinoic acid.
Journal ArticleDOI
Five-Membered Zirconacycloallenoids : Synthesis and Characterization of Members of a Unique Class of Internally Metal-Stabilized Bent Allenoid Compounds
TL;DR: Treatment of the bis-acetylide zirconocene complexes (RCp)2Zr(C) with HB(C6F5)2 results in the formation of the five-membered organometallic zIRconacycloallenoid products (9a, 9b), characterized by X-ray diffraction, and the special bonding features of 9a were studied by DFT calculation.
Journal ArticleDOI
Carbonylation Reactions of Intramolecular Vicinal Frustrated Phosphane/Borane Lewis Pairs
Muhammad Sajid,Arunlibertsen Lawzer,Weishi Dong,Christoph Rosorius,Wolfram Sander,Birgitta Schirmer,Stefan Grimme,Constantin G. Daniliuc,Gerald Kehr,Gerhard Erker +9 more
TL;DR: A DFT study has shown that the phosphonium hydrido borate zwitterion 10 is formed exergonically in solution but tends to lose H2 when brought into the gas phase.
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.