Reactions ofn-Bu2SnO and (n-Bu3Sn)2O with 1,1,2,3,3-Pentamethyltrimethylene Phosphinic Acid:  Synthesis and X-ray Crystal Structures of a Novel Spirocyclic Coordination Polymer and a 16-Membered Inorganic Macrocycle

2004 ◽  
Vol 23 (6) ◽  
pp. 1390-1395 ◽  
Author(s):  
Vadapalli Chandrasekhar ◽  
Viswanathan Baskar ◽  
Alexander Steiner ◽  
Stefano Zacchini
2008 ◽  
Vol 63 (3) ◽  
pp. 285-288 ◽  
Author(s):  
Karl E. Bessler ◽  
Claudia C. Gatto ◽  
Lincoln L. Romualdo ◽  
Javier A. Ellena ◽  
Maria J. de A. Sales

The alkaline earth tricyanomethanides Mg(tcm)2 · 2H2O, Ca(tcm)2, Sr(tcm)2 ・H2O and Ba(tcm)2 · 2H2O were prepared from aqueous solutions of the respective chlorides and silver tricyanomethanide. Their IR spectra and thermal behavior are described. The crystal structures of Ca(tcm)2 and Ba(tcm)2 · 2H2O were determined by single crystal X-ray diffraction. The structure of Ca(tcm)2 is of the type found for several transition metal tricyanomethanides [1], containing two independent interpenetrating networks. Ba(tcm)2 · 2H2O has a unique crystal structure corresponding to a three-dimensional coordination polymer with nine fold coordinated Ba atoms connected by water molecules and tricyanomethanide anions.


2018 ◽  
Vol 74 (12) ◽  
pp. 1576-1580 ◽  
Author(s):  
Ning-Ning Chen ◽  
Jian-Ning Ni ◽  
Jun Wang

A novel two-dimensional CdII coordination framework, poly[[[μ-1,3-bis(2-methyl-1H-imidazol-1-yl)benzene-κ2 N:N′](μ-1,3-phenylenediacetato-κ4 O,O′:O′′,O′′′)cadmium(II)] dihydrate], {[Cd(C10H8O4)(C14H14N4)]·2H2O} n or {[Cd(PDA)(1,3-BMIB)]·2H2O} n [1,3-BMIB is 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene and H2PDA is 1,3-phenylenediacetic acid], has been prepared and characterized using IR, elemental analysis, thermal analysis and single-crystal X-ray diffraction, the latter revealing that the compound is a (4,4) grid coordination polymer with layers oriented parallel to the bc crystal planes. In the crystal, adjacent layers are further connected by O—H...O and C—H...O hydrogen bonds, forming a three-dimensional structure in the solid state. In addition, the compound exhibits strong fluorescence emissions and shows photocatalytic activity for the degradation of methylene blue in the solid state at room temperature.


2007 ◽  
Vol 10 (10) ◽  
pp. 1149-1153 ◽  
Author(s):  
Robert Curran ◽  
Joanne Lenehan ◽  
Malachy McCann ◽  
Kevin Kavanagh ◽  
Michael Devereux ◽  
...  

Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.


1999 ◽  
Vol 82 (08) ◽  
pp. 271-276 ◽  
Author(s):  
Glen Spraggon ◽  
Stephen Everse ◽  
Russell Doolittle

IntroductionAfter a long period of anticipation,1 the last two years have witnessed the first high-resolution x-ray structures of fragments from fibrinogen and fibrin.2-7 The results confirmed many aspects of fibrinogen structure and function that had previously been inferred from electron microscopy and biochemistry and revealed some unexpected features. Several matters have remained stubbornly unsettled, however, and much more work remains to be done. Here, we review several of the most significant findings that have accompanied the new x-ray structures and discuss some of the problems of the fibrinogen-fibrin conversion that remain unresolved. * Abbreviations: GPR—Gly-Pro-Arg-derivatives; GPRPam—Gly-Pro-Arg-Pro-amide; GHRPam—Gly-His-Arg-Pro-amide


2019 ◽  
Author(s):  
Yunyang Zhang ◽  
Janice Mui ◽  
Thimali Arumaperuma ◽  
James P. Lingford ◽  
ETHAN GODDARD-BORGER ◽  
...  

<p>The sulfolipid sulfoquinovosyl diacylglycerol (SQDG) and its headgroup, the sulfosugar sulfoquinovose (SQ), are estimated to harbour up to half of all organosulfur in the biosphere. SQ is liberated from SQDG and related glycosides by the action of sulfoquinovosidases (SQases). We report a 10-step synthesis of SQDG that we apply to the preparation of saturated and unsaturated lipoforms. We also report an expeditious synthesis of SQ and (<sup>13</sup>C<sub>6</sub>)SQ, and X-ray crystal structures of sodium and potassium salts of SQ. Finally, we report the synthesis of a fluorogenic SQase substrate, methylumbelliferyl a-D-sulfoquinovoside, and examination of its cleavage kinetics by two recombinant SQases.</p>


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