Synthesis and spectral properties of [MI2(CO)(NCMe)(.eta.2-RC2R')2] and [Mo(.mu.-I)I(CO)(.eta.2-MeC2Me)2]2 bis(alkyne) complexes. X-ray crystal structures of [WI2(CO)(NCMe)(.eta.2-MeC2Me)2] and [WI2(CO)(NCMe)(.eta.2-PhC2Ph)2]

1988 ◽  
Vol 7 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Elaine M. Armstrong ◽  
Paul K. Baker ◽  
Michael G. B. Drew
Keyword(s):  
Crystal Structures ◽  
Spectral Properties ◽  
X Ray ◽  
Alkyne Complexes

Bis(1-phenyl-1-propyne) complexes of tungsten(II): crystal structures of [WI2(CO)(NCR)(η2-MeC2Ph)2] (R = Me, Et, or Ph)

2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans
Keyword(s):  
Carbon Monoxide ◽  
Solid State ◽  
Crystal Structures ◽  
Octahedral Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alkyne Complexes ◽  
First Time

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.

gem-Dibromovinyl boron dipyrrins: synthesis, spectral properties and crystal structures

2019 ◽  
Vol 48 (30) ◽  
pp. 11492-11507
Author(s):  
Hasrat Ali ◽  
Brigitte Guérin ◽  
Johan E. van Lier
Keyword(s):  
Crystal Structures ◽  
Surface Analysis ◽  
Spectral Properties ◽  
Hirshfeld Surface ◽  
Molecular Structures ◽  
Hirshfeld Surface Analysis ◽  
X Ray ◽  
X Ray Crystallography

New asymmetric/symmetric BODIPY derivatives, bearing gem-dibromovinyl substituents were synthesized and studied for their absorption, fluorescence, solvatochromism, X-ray crystallography and Hirshfeld surface analysis to determine molecular structures.

Crystal structures of aminophenalenones with relation to their spectral properties

1998 ◽  
Vol 213 (9) ◽  
Author(s):  
A. V. Yatsenko ◽  
V. A. Tafeenko ◽  
K. A. Paseshnichenko ◽  
T. V. Stalnaya ◽  
S. L. Solodar
Keyword(s):  
Crystal Structures ◽  
Spectral Properties ◽  
Structural Investigations ◽  
X Ray

AbstractX-ray structural investigations of 9-amino-1

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

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.

Crystal Structures of Fragments D and Double-D from Fibrinogen and Fibrin

1999 ◽  
Vol 82 (08) ◽  
pp. 271-276 ◽  
Author(s):  
Glen Spraggon ◽  
Stephen Everse ◽  
Russell Doolittle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Crystal Structures ◽  
Structure And Function ◽  
X Ray ◽  
Long Period ◽  
And Function

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

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