Crystal and solution structure of a pendant-armed macrocyclic complex of palladium(II)

1994 ◽  
Vol 72 (6) ◽  
pp. 1525-1532 ◽  
Author(s):  
B. Chak ◽  
A. McAuley ◽  
T.W. Whitcombe
Keyword(s):  
Crystal Structure ◽  
Solution Structure ◽  
Structural Features ◽  
Macrocyclic Complex ◽  
Chelating Ligands ◽  
Sulphur Atom ◽  
Positive Interaction ◽  
Range Interaction ◽  
X Ray ◽  
Long Range Interaction

The synthesis and X-ray crystal structure of [Pd)py2[9]aneN2S)](BF4)2 (py2[9]aneN2S = 1-thia-4,7-bis(pyridylmethyl)diaza-cyclononane) (P21/n,a = 10.233(4) Å, b = 11.484(5) Å, c = 19.913(6) Å, β = 94.03(4)°, V = 2334(2) Å3, R = 0.0705, Rw = 0.0759 ) are presented. The crystal structure indicates a long range interaction (2.92 Å) between the planar palladium and the apical sulphur atom. Although this distance is longer than the value for a Pd—S bond observed normally there is evidence for a net positive interaction provided by the solution structure as determined by NMR spectroscopy. Comparative analysis of the structural features exhibited by this complex with similar nine-membered chelating ligands emphasizes the presence of an axial Pd—S bond.

New Ternary Phosphide La7Pd17P12: Preparation and Crystal Structure

2002 ◽  
Vol 57 (12) ◽  
pp. 1409-1413 ◽  
Author(s):  
S. Budnyk ◽  
Yu. Prots ◽  
Yu. Kuz’ma ◽  
Yu. Grin
Keyword(s):  
Crystal Structure ◽  
Temperature Region ◽  
Large Family ◽  
Structural Features ◽  
Structural Motif ◽  
Crystal Data ◽  
Monoclinic Structure ◽  
X Ray ◽  
Data Space ◽  
Metal Ratio

The title compound was prepared from elements by sintering in the temperature region between 1073 and 1473 K. The monoclinic structure of La7Pd17P12 was solved and refined from X-ray single crystal data: space group C2/m, a = 24.519(1), b = 4.0859(5), c = 13.6106(8)Å , β = 112.129(3)°, Z = 2, RF = 0.025 for 1065 unique of 4877 measured reflections and 112 refined parameters. Main structural motif of the new phosphide are condensed blocks of trigonal prisms around phosphorus atoms connected to infinite chains via lanthanum atoms. The structural features of La7Pd17P12 are discussed in comparison with some representatives of a large family of structures with metal / non-metal ratio close to 2 : 1.

The Transition Metal-rich Orthophosphate Arrojadite with Special Structural Features

2010 ◽  
Vol 65 (12) ◽  
pp. 1427-1433 ◽  
Author(s):  
Christoph Kallfaß ◽  
Constantin Hoch ◽  
Hermann Schier ◽  
Arndt Simon ◽  
Helmut Schuber
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Single Crystal ◽  
Structural Features ◽  
Nickel Plate ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Different Types ◽  
New Feature

The crystal structure of the transition metal-rich orthophosphate mineral arrojadite was reexamined, and the disorder phenomena were analyzed applying modern X-ray single-crystal diffraction and refinement methods on samples from Nickel Plate (USA) and Hagendorf (Germany). As a new feature of the arrojadite structure, two different types of channels oriented along [010] are described. The occupancy of the atomic positions inside these channels have been elucidated.

8-(Dimethylamino)naphthylcopper(I), a novel stable organocopper compound with unusual structural features. Its synthesis, crystal structure (X-ray), and reactivity

1987 ◽  
Vol 325 (1-2) ◽  
pp. 293-309 ◽  
Author(s):  
Erik Wehman ◽  
Gerard van Koten ◽  
Martin Knotter ◽  
Hans Spelten ◽  
Dick Heijdenrijk ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structural Features ◽  
X Ray

Structure of 5,5-dimethyl-2-phenylimino-Δ3-1,3,4-thiadiazoline from oxidative cyclization of a thiosemicarbazone

1987 ◽  
Vol 65 (6) ◽  
pp. 1154-1157 ◽  
Author(s):  
R. Faggiani ◽  
M. Kaminski ◽  
C. J. L. Lock ◽  
J. Warkentin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Atom ◽  
Phenyl Ring ◽  
Direct Methods ◽  
Oxidative Cyclization ◽  
Repulsive Interaction ◽  
Sulphur Atom ◽  
Normal Range ◽  
X Ray ◽  
Bond Lengths

The X-ray crystal structure of 5,5-dimethyl-2-phenylimino-Δ3-1,3,4-thiadiazoline, C10H11N3S, has been determined. The compound is monoclinic, P21/c (No. 14), with a = 13.200(5), b = 6.340(4), and c = 13.823(4) Å, β = 113.50(4)°, and Z = 4. The structure was determined by direct methods and refined to R = 0.061, Rw = 0.067 for 1277 unique reflections. The molecule has the Z configuration. The thiadiazoline ring is planar. C—N and N=N bond lengths are within the normal range. The C—S bond lengths are similar to those we have observed previously in thiazolidines. Angles differ markedly from an expected average 108°. The small C—S—C angle (90.6(2)°) is accompanied by larger C—N=N angles (114.9(3), 117.8(3)°). The phenyl ring is not coplanar with the thiadiazoline ring (dihedral angle 38.6(4)°) because of repulsive interaction of the phenyl o-hydrogen atom with the sulphur atom.

scholarly journals Crystal structure solution of an elusive polymorph of Dibenzylsquaramide

2013 ◽  
Vol 28 (S2) ◽  
pp. S470-S480 ◽  
Author(s):  
Anna Portell ◽  
Xavier Alcobé ◽  
Latévi M. Lawson Daku ◽  
Radovan Černý ◽  
Rafel Prohens
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Structural Features ◽  
Powder Diffraction Data ◽  
Asymmetric Unit ◽  
X Ray ◽  
The Third ◽  
Group Assignment ◽  
Structure Solution

The crystal structure of the third polymorph of dibenzylsquaramide (Portell, A. et al., 2009), (fig. 1) has been determined from laboratory X-ray powder diffraction data by means of direct space methods using the computing program FOX. (Favre-Nicolin and Černý, 2002) The structure resolution has not been straightforward due to several difficulties on the indexing process and in the space group assignment. The asymmetric unit contains two different conformers, which has implied an additional difficulty during the Rietveld (Rietveld, 1969) refinement. All these issues together with particular structural features of disquaramides are discussed.

scholarly journals Structural basis for the binding of SNAREs to the multisubunit tethering complex Dsl1

2020 ◽  
Author(s):  
Sophie M. Travis ◽  
Kevin DAmico ◽  
I-Mei Yu ◽  
Safraz Hamid ◽  
Gabriel Ramirez-Arellano ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Relative Orientation ◽  
Snare Complex ◽  
Structural Basis ◽  
Binding Modes ◽  
Range Interaction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Long Range Interaction ◽  
Target Membrane

AbstractMultisubunit tethering complexes (MTCs) are large (250 to >750 kDa), conserved macromolecular machines that are essential for SNARE-mediated membrane fusion in all eukaryotes. MTCs are thought to function as organizers of membrane trafficking, mediating the initial, long-range interaction between a vesicle and its target membrane and promoting the formation of membrane-bridging SNARE complexes. Previously, we reported the structure of the Dsl1 complex, the simplest known MTC, which is essential for COPI-mediated transport from the Golgi to the endoplasmic reticulum (ER). This structure suggested how the Dsl1 complex might function to tether a vesicle to its target membrane by binding at one end to the COPI coat and at the other end to ER SNAREs. Here, we use x-ray crystallography to investigate these Dsl1-SNARE interactions in greater detail. The Dsl1 complex comprises three subunits that together form a two-legged structure with a central hinge. Our results show that distal regions of each leg bind N-terminal Habc domains of the ER SNAREs Sec20 (a Qb-SNARE) and Use1 (a Qc-SNARE). The observed binding modes appear to anchor the Dsl1 complex to the ER target membrane while simultaneously ensuring that both SNAREs are in open conformations with their SNARE motifs available for assembly. The proximity of the two SNARE motifs, and therefore their ability to enter the same SNARE complex, depends on the relative orientation of the two Dsl1 legs.

scholarly journals Structural Studies of Overlapping Dinucleosomes in Solution

2019 ◽  
Author(s):  
A. Matsumoto ◽  
M. Sugiyama ◽  
Z. Li ◽  
A. Martel ◽  
L. Porcar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Scattering ◽  
Small Angle ◽  
Solution Structure ◽  
Scattering Data ◽  
Mode Analysis ◽  
Conformational Ensemble ◽  
Histone Tails ◽  
Nucleosome Remodeling ◽  
X Ray

AbstractAn overlapping dinucleosome (OLDN) is a structure composed of one hexasome and one octasome and appears to be formed through nucleosome collision promoted by nucleosome remodeling factor(s). In the present study, the solution structure of the OLDN was investigated through integration of small-angle X-ray and neutron scattering (SAXS and SANS, respectively), computer modeling, and molecular dynamics simulations. Starting from the crystal structure, we generated a conformational ensemble based on normal mode analysis, and searched for the conformations that well reproduced the SAXS and SANS scattering curves. We found that inclusion of histone tails, which are not observed in the crystal structure, greatly improved model quality. The obtained structural models suggest that OLDNs adopt a variety of conformations stabilized by histone tails situated at the interface between the hexasome and octasome, simultaneously binding to both the hexasomal and octasomal DNA. In addition, our models define a possible direction for the conformational changes or dynamics, which may provide important information that furthers our understanding of the role of chromatin dynamics in gene regulation.Statement of SignificanceOverlapping dinucleosomes (OLDNs) are intermediate structures formed through nucleosome collision promoted by nucleosome remodeling factor(s). To study the solution structure of OLDNs, a structural library containing a wide variety of conformations was prepared though simulations, and the structures that well reproduced the small angle X-ray and neutron scattering data were selected from the library. Simultaneous evaluation of the conformational variation in the global OLDN structures and in the histone tails is difficult using conventional MD simulations. We overcame this problem by combining multiple simulation techniques, and showed the importance of the histone tails for stabilizing the structures of OLDNs in solution.

Crystal Structure Explains Crystal Habit for the Antiviral Drug Rimantadine Hydrochloride

2014 ◽  
Vol 69 (7) ◽  
pp. 823-828 ◽  
Author(s):  
Anatoly Mishnev ◽  
Dmitrijs Stepanovs
Keyword(s):  
Crystal Structure ◽  
Symmetry Axis ◽  
Antiviral Drug ◽  
Structural Features ◽  
Unit Cell ◽  
Crystal Habit ◽  
Maximal Dimension ◽  
X Ray ◽  
Rimantadine Hydrochloride ◽  
Inner Channel

The crystal structure of the antiviral drug rimantadine hydrochloride, C12H22N+ Cl−, has been elucidated by a single-crystal X-ray structure analysis. The structure consists of 1-(1- adamantyl)ethanamine (rimantadinium) cations and chloride anions. The Cl− anions link the rimantadinium cations via N-H...Cl hydrogen bonds into infinite rectangular chord-like structural units with charged groups in the inner channel and aliphatic groups on the surface, and oriented along the unit cell c axis. In contrast to strong electrostatic and hydrogen bonding inner interactions the chords in the crystal are held together by weak van der Waals forces only. A two-fold symmetry axis passes through the center of the chord. By indexing of the crystal faces it has been shown that the maximal dimension of the needle-like crystals coincides with the direction of the unit cell c axis. These structural features explain the crystal habit and the anisotropy of the mechanical properties of rimantadine hydrochloride crystals observed upon slicing and cleavage.

Sign in / Sign up

Export Citation Format

Share Document