scholarly journals The Use of Punched Cards in Molecular Structure Determinations I. Crystal Structure Calculations

1946 ◽  
Vol 14 (11) ◽  
pp. 648-658 ◽  
Author(s):  
P. A. Shaffer ◽  
Verner Schomaker ◽  
Linus Pauling
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Structure Determinations ◽  
Structure Calculations ◽  
Crystal Structure Calculations

Crystal-structure calculations with distorted ions

1993 ◽  
Vol 48 (5) ◽  
pp. 2889-2908 ◽  
Author(s):  
Daniel J. Lacks ◽  
Roy G. Gordon
Keyword(s):  
Crystal Structure ◽  
Structure Calculations ◽  
Crystal Structure Calculations

Vibrational properties of nanoparticles iron oxide by Raman spectroscopy

2020 ◽  
pp. 2150125
Author(s):  
T. A. Darziyeva ◽  
E. Sh. Alekperov ◽  
S. H. Jabarov ◽  
M. N. Mirzayev
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Iron Oxide ◽  
Gaussian Function ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Cubic Crystal ◽  
Cubic Symmetry ◽  
Structure Calculations ◽  
Crystal Structure Calculations

The crystal structure and atomic dynamics of Fe3O4 nanoparticles have been studied. The crystal structure of iron oxide nanoparticles was determined by X-ray diffraction. The analysis showed that the crystal structure of [Formula: see text] 50–100 nm dimensional iron oxide corresponds to a high symmetry cubic crystal structure. Calculations have shown that there are four infrared active, five Raman active and seven hyper-Raman active modes in the space group Fd-3m with cubic symmetry. Four of these modes have been observed using Raman spectroscopy: 213, 271, 380 and 591 cm[Formula: see text]. The vibrational modes are interpreted by Gaussian function. It was found that these vibration modes correspond to the vibration of O–Fe–O bonds and iron-oxygen polyhedra.

scholarly journals The crystal structure of di- n -propylmonocyanogold

1939 ◽  
Vol 173 (953) ◽  
pp. 147-159 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Molecular Weight ◽  
Dipole Moment ◽  
Nitrogen Atom ◽  
Gold Atom ◽  
Ring Structure ◽  
Structure Determinations ◽  
Tetrameric Form

Recent chemical investigations (Gibson 1938) have led to the view that gold in its auric compounds is always 4-covalent, and crystal structure determinations (Cox and Webster 1937; Burawoy and others 1937) have shown that the arrangement of the four valencies is a planar one as predicted by Pauling (1931). The compound diethylmonobromogold achieves these two conditions by dimerization with formation of the ring structure (I). Et Br Et ⭩ / Au Au (I) / ⭧ Et Br Et It is of particular interest to examine a corresponding cyanogold compound, since it is impossible in this case for the square containing two gold atoms to be formed. The co-ordinate link from the nitrogen atom to the next gold atom must be collinear with the Au—C≡N links, and the simplest structure in which this principle of the 4-covalency of auric gold is adhered to is by the arrangement of four molecules as in (II). Et Et I I Et—A vk-N = C —Au—Et I t C N I I I III (II) N C i | Et—Au—C=N-*Au—Et Et Et This structure was suggested by Gibson and co-workers (Burawoy, Gibson and Holt 1935) and is supported by molecular weight evidence. This compound is, however, unstable, and the corresponding methyl compound has not yet been prepared. The next homologue, di- n -propylmonocyanogold, is comparatively stable, and its crystal structure determination was therefore undertaken. Previous observations on this compound make a determination of its molecular structure desirable, since, although the molecular weight is in agreement with the tetrameric form, it has a small dipole moment, 1.47 D.

scholarly journals NMR Crystallography at Fast Magic-Angle Spinning Frequencies: Application of Novel Recoupling Methods

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 231 ◽  
Author(s):  
Mukul G. Jain ◽  
Kaustubh R. Mote ◽  
Perunthiruthy K. Madhu
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Nmr Crystallography ◽  
Angle Spinning ◽  
Fast Magic Angle Spinning ◽  
Structure Calculations ◽  
Crystal Structure Calculations

Chemical characterisation of active pharmaceutical compounds can be challenging, especially when these molecules exhibit tautomeric or desmotropic behaviour. The complexity can increase manyfold if these molecules are not susceptible to crystallisation. Solid-state NMR has been employed effectively for characterising such molecules. However, characterisation of a molecule is just a first step in identifying the differences in the crystalline structure. 1 H solid-state Nuclear Magnetic Resonance (ssNMR) studies on these molecules at fast magic-angle-spinning frequencies can provide a wealth of information and may be used along with ab initio calculations to predict the crystal structure in the absence of X-ray crystallographic studies. In this work, we attempted to use solid-state NMR to measure 1 H - 1 H distances that can be used as restraints for crystal structure calculations. We performed studies on the desmotropic forms of albendazole.

Über die Reaktion von SbPh3 mit S3N2Cl2 Kristallstrukturen von [xxx] und [(Ph3SbCl2)2·S4N4]/ On the Reaction of SbPh3 with S3N2Cl2. Crystal Structures of [xxx] and [(Ph3SbCl2)2· S4N4]

1997 ◽  
Vol 52 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Frank Kunkel ◽  
Klaus Harms ◽  
Hak-Chul Kang ◽  
Werner Massa ◽  
Kurt Dehnicke
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Phenyl Group ◽  
Dichloromethane Solution ◽  
Space Group ◽  
Trigonal Bipyramidal ◽  
Structure Determinations ◽  
Molecular Compounds ◽  
Van Der Waals Contacts ◽  
Distorted Trigonal Bipyramidal

Abstract Triphenylantimony reacts with S3N2Cl2 in dichloromethane solution to give yellow crystals of the cyclostibathiazene derivative [xxx], As a by-product orange single crystals of [(Ph3SbCl2)2·S4N4] were isolated, in which the molecular compounds Ph3SbCl2 and S4N4 only form van der Waals contacts with one another. Both compounds are characterized by crystal structure determinations. [xxx]: Space group P21/n, Z = 4; lattice dimensions at -80°C: a = 759.4(1), b = 1448.5(3); c = 1557.6(2) pm; β = 91.09(1)°, R = 0.026. The complex has a molecular structure in which the Sb atom is coordinate in a distorted trigonal-bipyramidal fashion with one phenyl group and one of the nitrogen atoms of the planar [xxx] ring in the apical positions.[(Ph3SbCL)2·S4N4]: Space group C2/c, Z = 8 ; lattice dimensions at -60°C: a = 1549.3(1), b = 1017.7(1), c = 2623.9(1) pm, β = 105.56(2)°, R = 0.050.

scholarly journals N-Iod-triphenylphosphanimin. Synthese und Kristallstrukturen von [Me3SiNPPh3· ICl] und Ph3PNI / N -Iodo-triphenylphosphaneimine. Synthesis and Crystal Structures of [Me3SiNPPh3 · ICl] and Ph3PNI

1996 ◽  
Vol 51 (12) ◽  
pp. 1739-1743 ◽  
Author(s):  
Jutta Grebe ◽  
Frank Weller ◽  
Kurt Dehnicke
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Iodine Atom ◽  
Bond Angle ◽  
Potassium Fluoride ◽  
Linear Arrangement ◽  
Space Group ◽  
Bond Lengths ◽  
Structure Determinations ◽  
Donor Acceptor

N-Iodo-triphenylphosphaneimine, Ph3PNI, has been prepared by thermolysis of the donor acceptor complex [Me3SiNPPh3·ICl] in boiling acetonitrile in the presence of potassium fluoride. Both compounds have been characterized by IR spectroscopy and by crystal structure determinations. [Me3SiNPPh3 · ICl]: Space group P1̄, Z = 2, a = 888.3(1), b = 1070.7( 1), c = 1310.2( 1) pm, α = 95.15( 1)°, β = 108.67( 1)°, γ = 97.78( 1)° at 20°C. The complex has a molecular structure in which the N atom of the phosphaneimine is connected with the iodine atom of the ICI molecule in a linear arrangement N-I-Cl with bond lengths N-I = 232.7 pm, I-Cl = 255.37 pm. \Ph3PNI: Space group P21/n, Z = 4, a = 952.8(1), b = 1800.8(2), c = 1003.6(1) pm, β = 110.25(1)° at -50°C. The compound forms monomeric molecules with bond lengths PN = 159.1 pm, I-N = 205.6 pm and an INP bond angle of 113.3°.

Synthesis, Conformational Analysis and Crystal Structure of New Thioxo, Oxo, Seleno Diastereomeric Cyclophosphamides Containing 1,3,2-dioxaphosphorinane

2019 ◽  
Vol 23 (2) ◽  
pp. 205-213
Author(s):  
Dorra Kanzari-Mnallah ◽  
Med L. Efrit ◽  
Jiří Pavlíček ◽  
Frédéric Vellieux ◽  
Habib Boughzala ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Density Functional ◽  
Chemical Shifts ◽  
Structural Determination ◽  
Conformational Study ◽  
Functional Theory ◽  
One Step ◽  
High Resolution Mass Spectroscopy ◽  
Resolution Mass

Thioxo, Oxo and Seleno diastereomeric cyclophosphamides containing 1,3,2- dioxaphosphorinane are prepared by a one-step chemical reaction. Their structural determination is carried out by means of Nuclear Magnetic Resonance NMR (31P, 1 H, 13C) and High-Resolution Mass Spectroscopy (HRMS). The conformational study of diastereomeric products is described. Density Functional Theory (DFT) calculations allowed the identification of preferred conformations. Experimental and calculated 31P, 13C, 1H NMR chemical shifts are compared. The molecular structure of the 2-Benzylamino-5-methyl-5- propyl-2-oxo-1,3,2-dioxaphosphorinane (3d) has been determined by means of crystal Xray diffraction methods.

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