A list of organometallic kryptoracemates

2015 ◽  
Vol 71 (3) ◽  
pp. 216-221 ◽  
Author(s):  
Ivan Bernal ◽  
Steven Watkins
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
Room Temperature ◽  
Cambridge Structural Database ◽  
Acta Cryst ◽  
Influence Of Temperature ◽  
Space Groups ◽  
Chiral Compounds ◽  
Structural Database ◽  
Racemic Crystals

The vast majority of racemic solutions of chiral compounds apparently crystallize at room temperature in non-Sohncke space groups as racemic crystals. However, kryptoracemic crystals composed of nearly enantiomeric pairs occasionally crystallize at room temperature, or appear as low-temperature phases, in Sohncke space groups. As a complement to the previously published catalog of organic kryptoracemates [Fábián & Brock (2010).Acta Cryst.B66, 94–103], 1412 chiral organometallic crystal structures have now been extracted from the Cambridge Structural Database and analyzed. 26 are listed herein as credible kryptoracemates. The possible influence of temperature is discussed, together with some problems in characterizing and classifying these structures.

Crystallization of chiral molecular compounds: what can be learned from the Cambridge Structural Database?

2020 ◽  
Vol 76 (3) ◽  
pp. 307-315 ◽  
Author(s):  
Toms Rekis
Keyword(s):  
Crystal Structures ◽  
Solid Solutions ◽  
Cambridge Structural Database ◽  
Frequency Of Occurrence ◽  
Chiral Compound ◽  
Chiral Compounds ◽  
Fundamental Phenomenon ◽  
Structural Database ◽  
Molecular Compounds

A detailed study on chiral compound structures found in the Cambridge Structural Database (CSD) is presented. Solvates, salts and co-crystals have intentionally been excluded, in order to focus on the most basic structures of single enantiomers, scalemates and racemates. Similarity between the latter and structures of achiral monomolecular compounds has been established and utilized to arrive at important conclusions about crystallization of chiral compounds. For example, the fundamental phenomenon of conglomerate formation and, in particular, their frequency of occurrence is addressed. In addition, rarely occurring kryptoracemates and scalemic compounds (anomalous racemates) are discussed. Finally, an extended search of enantiomer solid solutions in the CSD is performed to show that there are up to 1800 instances most probably hiding among the deposited crystal structures, while only a couple of dozen have been previously known and studied.

scholarly journals Some more space-group corrections

2014 ◽  
Vol 70 (9) ◽  
pp. 834-836 ◽  
Author(s):  
Lawrence M. Henling ◽  
Richard E. Marsh
Keyword(s):  
Crystal Structures ◽  
Cambridge Structural Database ◽  
Space Group ◽  
Space Groups ◽  
Structural Database

A survey of approximately 100 000 entries in recent releases of the Cambridge Structural Database (CSD) has uncovered 156 crystal structures that were apparently described in inappropriate space groups. We have revised these space groups and prepared CIFs containing the new coordinates and brief comments describing the revisions.

Frequency of Z′ values in organic and organometallic crystal structures

2000 ◽  
Vol 56 (4) ◽  
pp. 673-676 ◽  
Author(s):  
Thomas Steiner
Keyword(s):  
Crystal Structures ◽  
Cambridge Structural Database ◽  
Space Groups ◽  
Structural Database ◽  
The Absolute

The frequencies of Z′ values (formula units per asymmetric crystal unit) are documented for organic and organometallic crystal structures, using the Cambridge Structural Database. The absolute frequencies of all Z′ values reported, relative frequencies for certain substance classes, the seven crystal systems and the most abundant space groups are given. The three Z′ values ½, 1 and 2 make up 95.3% of all crystal structures. Structures with Z′ > 1 occur most frequently with nucleosides and nucleotides (20.8%), and with steroids (18.8%).

scholarly journals The development and use of a crystallographic database

2016 ◽  
Vol 72 (2) ◽  
pp. 167-168 ◽  
Author(s):  
Carl Henrik Görbitz
Keyword(s):  
Crystal Structures ◽  
Small Molecule ◽  
Organometallic Compounds ◽  
Cambridge Structural Database ◽  
Acta Cryst ◽  
Individual Crystal ◽  
Data Source ◽  
Structural Database

To scientists working with small-molecule or organometallic compounds, the Cambridge Structural Database constitutes an extremely important tool for reference to individual crystal structures and as a data source for statistical investigations. The article by Groomet al.[(2016),Acta Cryst.B72, 171–179] provides updated information on the use, development and future of this database.

scholarly journals Using more than 801 296 small-molecule crystal structures to aid in protein structure refinement and analysis. Addendum

2017 ◽  
Vol 73 (12) ◽  
pp. 1029-1029
Author(s):  
Jason C. Cole ◽  
Ilenia Giangreco ◽  
Colin R. Groom
Keyword(s):  
Protein Structure ◽  
Crystal Structures ◽  
Small Molecule ◽  
Structure Refinement ◽  
Cambridge Structural Database ◽  
Acta Cryst ◽  
Protein Structure Refinement ◽  
Structure Solution ◽  
Structural Database

An addendum to theIntroductionof Coleet al.[(2017),Acta Cryst.D73, 234–239] is made to recognize the work of Bricogne, Smart and others in the development of methods to make use of Cambridge Structural Database data in protein structure solution.

Three new phosphoric triamides with a [C(O)NH]P(O)[N(C)(C)]2skeleton: a database analysis of C—N—C and P—N—C bond angles

2014 ◽  
Vol 70 (10) ◽  
pp. 998-1002 ◽  
Author(s):  
Mehrdad Pourayoubi ◽  
Atekeh Tarahhomi ◽  
Arnold L. Rheingold ◽  
James A. Golen
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
The Other ◽  
Database Analysis ◽  
Acta Cryst ◽  
Bond Angles ◽  
Cyclic Amide ◽  
Phosphoric Triamide ◽  
Structural Database ◽  
Phosphoric Triamides

InN,N,N′,N′-tetraethyl-N′′-(4-fluorobenzoyl)phosphoric triamide, C15H25FN3O2P, (I), andN-(2,6-difluorobenzoyl)-N′,N′′-bis(4-methylpiperidin-1-yl)phosphoric triamide, C19H28F2N3O2P, (II), the C—N—C angle at each tertiary N atom is significantly smaller than the two P—N—C angles. For the other new structure,N,N′-dicyclohexyl-N′′-(2-fluorobenzoyl)-N,N′-dimethylphosphoric triamide, C21H33FN3O2P, (III), one C—N—C angle [117.08 (12)°] has a greater value than the related P—N—C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]2skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002).Acta Cryst.B58, 380–388], the C—N—C angle is significantly smaller than the two P—N—C angles; exceptions were found for four structures with theN-methylcyclohexylamide substituent, similar to (III), one structure with the seven-membered cyclic amide azepan-1-yl substituent and one structure with anN-methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linkedviapairs of N—H...O=P hydrogen bonds to form dimers.

Stacking interactions of resonance-assisted hydrogen-bridged rings and C6-aromatic rings

2020 ◽  
Vol 22 (24) ◽  
pp. 13721-13728 ◽  
Author(s):  
Jelena P. Blagojević Filipović ◽  
Michael B. Hall ◽  
Snežana D. Zarić
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Cambridge Structural Database ◽  
Stacking Interactions ◽  
Aromatic Rings ◽  
Structural Database

Stacking interactions between six-membered resonance-assisted hydrogen-bridged (RAHB) rings and C6-aromatic rings have been studied by analyzing crystal structures in the Cambridge Structural Database and performing quantum chemical calculations.

GRX: a program to search the CSD for functional group exchanges

2005 ◽  
Vol 38 (4) ◽  
pp. 694-696 ◽  
Author(s):  
Jacco van de Streek ◽  
Sam Motherwell
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Functional Group ◽  
Cambridge Structural Database ◽  
Structural Database

In order to establish the effect of exchanging one functional group by another on the crystal structure, one would like to be able to search the Cambridge Structural Database for all pairs of crystal structures where this substitution has been made. A program calledGRX(group exchange) was written for that purpose.

Temperature dependence of the AV3O7 (A = Ca, Sr) structure

2007 ◽  
Vol 63 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Single Crystal ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Temperature Ranges ◽  
First Time

The V4+ (spin ½) oxovanadates AV3O7 (A = Ca, Sr) were synthesized and studied by means of single-crystal X-ray diffraction. The room-temperature structures of both compounds are orthorhombic and their respective space groups are Pnma and Pmmn. The previously assumed structure of SrV3O7 has been revised and the temperature dependence of both crystal structures in the temperature ranges 297–100 K and 315–100 K, respectively, is discussed for the first time.

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

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