1,1′-Di(tert-butyl)metallocenium Cations. The X-Ray Crystal Structures of [M(C5H4tBu)2]PF6 (M = Fe, Co) and [Co (C5H4t Bu)2]2CoCl4

2000 ◽  
Vol 55 (9) ◽  
pp. 814-820 ◽  
Author(s):  
Max Herberhold ◽  
Yan-Xiang Cheng ◽  
Guo-Xin Jin ◽  
Wolfgang Milius
Keyword(s):  
Crystal Structures ◽  
X Ray ◽  
Tert Butyl ◽  
Transoid Conformation

The hexafluorophosphate salts [Fe(C5H4tBu)2]PF6 (1) and [Co(C5 H4 tBu)2]PF6 (2) crystallize in isotypic structures with centrosymmetric cations which have a staggered (transoid) conformation of the exactly parallel ring ligands (conformational angle τ = 180°). The tetrachlorocobaltate salt, [Co(C5H4tBu)2 ]2 CoCl4 (3), contains one almost eclipsed (τ = 140.4°) and one almost staggered (τ = 101.4°) cobaltocenium cation; in both cases, the cyclopentadienyl ring planes are slightly inclined (by α = 5.4° and 4.1°, respectively) to give more room to the tert-butyl substituents which are bent away from the metal in all three complexes 1 - 3

scholarly journals Azo-linked corner porphyrin systems: synthesis, crystal structures and spectroscopic investigation

2010 ◽  
Vol 14 (06) ◽  
pp. 481-493 ◽  
Author(s):  
Bruno Bašić ◽  
John C. McMurtrie ◽  
Dennis P. Arnold
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Spectroscopic Investigation ◽  
The Other ◽  
X Ray ◽  
Tert Butyl ◽  
Dinitro Derivative

1,2-bis[10,15-di(3,5-di-tert-butyl)phenylporphyrinatonickel(II)-5-yl]diazene was synthesised via copper-catalyzed coupling of aminated nickel(II) 5,10-diarylporphyrin ("corner porphyrin") and its X-ray crystal structure was determined. Two different crystals yielded different structures, one with the free meso-positions in a trans-like orientation, and the other with a cis-like disposition. The free meso-positions of the obtained dimer have been further functionalized while the synthesis of a zinc analog has so far been unsuccessful. The X-ray crystal structure of the dinitro derivative of the dinickel(II) azoporphyrin was determined, and the structure showed a cis-like disposition of the nitro groups.

scholarly journals Kristallstrukturen komplexer Metalate mit dem sterisch anspruchsvollen 1,3,5-Tri(tert-butyl)tropylium-Kation / X-Ray Crystal Structures of Complex Metallates Containing the Sterically Demanding 1,3,5-Tri(tert-butyl)tropylium Cation

2006 ◽  
Vol 61 (10) ◽  
pp. 1189-1197 ◽  
Author(s):  
Matthias Tamm ◽  
Thomas Bannenberg ◽  
Victoria Urban ◽  
Tania Pape ◽  
Olga Kataeva
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Transition Metal Complexes ◽  
Crystal Packing ◽  
Proton Donor ◽  
Close Inspection ◽  
X Ray ◽  
Tert Butyl ◽  
Sterically Demanding ◽  
Anions And Cations

The X-ray crystal structures of anionic transition metal complexes containing the sterically demanding 1,3,5-tri-tert-butyltropylium cation, [1,3,5-C7H4tBu3]+, as the compensating ion are presented. Bis(1,3,5-tri-tert-butyltropylium) hexachlorodiferrate(II), [1,3,5-C7H4tBu3]2[Fe2Cl6] (4), was obtained from the reaction of the 1,3,5-tri-tert-butyltropylium hydrogendichloride, [1,3,5- C7H4tBu3][HCl2] (3), with FeCl2, whereas the 1,3,5-tri-tert-butyltropylium tetrabromooxomolybdate( V) [1,3,5-C7H4tBu3][trans-Mo(O)Br4(CH3CN)] (7) was isolated from the reaction of the cycloheptatrienyl complex [(η7-1,3,5-C7H4tBu3)Mo(CO)2Br] (6) with elemental bromine. The crystal structures of 3, 4, 7 and 7 · CH3CN show in each case well separated anions and cations and the absence of any covalent anion-cation interactions. However, close inspection of the crystal packing reveals that the 1,3,5-tri-tert-butyltropylium cation can act as a CH-proton donor towards the counterion leading to the formation of weak C-H· · ·Cl-M and C-H· · ·O=M hydrogen bonds in 4 and in 7 and 7 ·CH3CN, respectively.

scholarly journals Synthesis, Crystal Structures, Characterization and Catalytic Property of Copper(II) Complexes Derived from Hydrazone Ligands

2021 ◽  
Vol 68 (1) ◽  
pp. 44-50
Author(s):  
Yao Tan ◽  
Yan Lei
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Catalytic Property ◽  
Octahedral Coordination ◽  
Chemical Methods ◽  
X Ray ◽  
Tert Butyl ◽  
Physico Chemical ◽  
Hydrazone Ligands

A new bromido-coordinated mononuclear copper(II) complex [Cu(HL1)Br2] (1), and a new mononuclear copper(II) complex [CuL2(HL2)]ClO4 · 0.5H2O (2), with the hydrazone ligands 4-tert-butyl-N’-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL1) and 4-bromo-N’-(pyridin-2-ylmethylene)benzohydrazide (HL2), have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the Cu atom in complex 1 is in distorted square pyramidal coordination, and that in complex 2 is in octahedral coordination. The catalytic property for epoxidation of styrene by the complexes was evaluated.

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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