scholarly journals Isomorphous diethyl 1-(4-chlorobenzyl)-4-(4-chlorophenyl)-2,2-dioxo-3,4,6,7,8,8a-hexahydro-1H-pyrrolo[2,1-c][1,4]thiazine-1,3-dicarboxylate and its 1-(4-methylbenzyl)-4-(4-methylphenyl)-substituted analogue obeying the chloro–methyl exchange rule

2018 ◽  
Vol 74 (9) ◽  
pp. 1267-1271 ◽  
Author(s):  
R. Sribala ◽  
N. Srinivasan ◽  
S. Indumathi ◽  
R. V. Krishnakumar
Keyword(s):  
Crystal Structure ◽  
Structure Prediction ◽  
Crystal Packing ◽  
Molecular Aggregation ◽  
Crystal Structure Prediction ◽  
Chemical Modifications ◽  
Methyl Group ◽  
Hirshfeld Analysis ◽  
Exchange Rule ◽  
Cl Atom

Accurate studies on the effect of substituents on the crystal packing are essential for understanding the intermolecular interactions and thus paving the way to crystal structure prediction. The crystal structures of diethyl 1-(4-chlorobenzyl)-4-(4-chlorophenyl)-2,2-dioxo-3,4,6,7,8,8a-hexahydro-1H-pyrrolo[2,1-c][1,4]thiazine-1,3-dicarboxylate, C26H29Cl2NO6S, (I), and its isomorphous pair diethyl 1-(4-methylbenzyl)-4-(4-methylphenyl)-2,2-dioxo-3,4,6,7,8,8a-hexahydro-1H-pyrrolo[2,1-c][1,4]thiazine-1,3-dicarboxylate, C28H35NO6S, (II), are described. The molecular aggregation patterns appear to be strikingly similar despite changes in the substituents, with a Cl atom in (I) being replaced by a methyl group in (II). Inspite of the chemical modifications, the structures of (I) and (I) are isomorphous, isostructural and found to obey the chlorine–methyl exchange rule. Both the structures feature C—H...O hydrogen bonding. However, a distinguishing feature between (I) and (II) is observed in the conformation of the pyrrole rings where the twist occurs on different C—N bonds. Hirshfeld analysis of both structures is presented and discussed.

scholarly journals Insight from energy surfaces: structure prediction by lattice energy exploration

2014 ◽  
Vol 70 (a1) ◽  
pp. C28-C28
Author(s):  
Graeme Day
Keyword(s):  
Crystal Structure ◽  
Structure Prediction ◽  
Crystal Packing ◽  
Lattice Energy ◽  
Organic Crystals ◽  
Crystal Structure Prediction ◽  
Stability Order ◽  
The Stability ◽  
Solid Form ◽  
Energy Surfaces

A long-standing challenge for the application of computational chemistry in the field of crystallography is the prediction of crystal packing, given no more than the chemical bonding of the molecules being crystallised. Recent years have seen significant progress towards reliable crystal structure prediction methods, even for traditionally challenging systems involving flexible molecules and multi-component solids [1]. These methods are based on global searches of the lattice energy surface: a search is performed to locate all possible packing arrangements, and these structures are ranked by their calculated energy [2]. One aim of this lecture is to provide an overview of advances in methods for crystal structure prediction, focussing on molecular organic crystals, and highlighting strategies that are being explored to extend the reach of these methods to more complex systems. A second aim is to discuss the range applications of crystal structure prediction calculations, which have traditionally included solid form screening, particularly of pharmaceutically active molecules, and structure determination. As energy models become more reliable at correctly ranking the stability order of putative structures, and the timescale required for structure searching decreases, crystal structure prediction has the potential for the discovery of novel molecular materials with targeted properties. Prospects for computer-guided discovery of materials will be discussed.

scholarly journals From Concept to Crystals via Prediction: Multi-Component Organic Cage Pots by Social Self-Sorting

2019 ◽  
Author(s):  
Rebecca L. Greenaway ◽  
Valentina Santolini ◽  
Angeles Pulido ◽  
Marc A. Little ◽  
Ben M. Alston ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Prediction ◽  
Chiral Recognition ◽  
Crystal Packing ◽  
A Priori ◽  
Computational Prediction ◽  
Crystal Structure Prediction ◽  
Social Self ◽  
The Social ◽  
Experimental Crystal

<p>We describe the <i>a priori </i>computational prediction and realization of multi-component cage pots, starting with molecular predictions based on candidate precursors through to crystal structure prediction and synthesis using robotic screening. The molecules were formed by the social self-sorting of a tri-topic aldehyde with both a tri-topic amine and di-topic amine, without using orthogonal reactivity or precursors of the same topicity. Crystal structure prediction suggested a rich polymorphic landscape, where there was an overall preference for chiral recognition to form heterochiral rather than homochiral packings, with heterochiral pairs being more likely to pack window-to-window to form two-component capsules. These crystal packing preferences were then observed in experimental crystal structures. <br></p>

Effect of packing motifs on the energy ranking and electronic properties of putative crystal structures of tricyano-1,4-dithiino[c]-isothiazole

2016 ◽  
Vol 72 (4) ◽  
pp. 562-570 ◽  
Author(s):  
Farren Curtis ◽  
Xiaopeng Wang ◽  
Noa Marom
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Structure Prediction ◽  
Density Functional ◽  
Crystal Packing ◽  
Crystal Structure Prediction ◽  
Dispersion Interactions ◽  
Blind Test ◽  
Electronic And Optical Properties ◽  
Inclusive Density

We present an analysis of putative structures of tricyano-1,4-dithiino[c]-isothiazole (TCS3), generated within the sixth crystal structure prediction blind test. Typical packing motifs are identified and characterized in terms of distinct patterns of close contacts and regions of electrostatic and dispersion interactions. We find that different dispersion-inclusive density functional theory (DFT) methods systematically favor specific packing motifs, which may affect the outcome of crystal structure prediction efforts. The effect of crystal packing on the electronic and optical properties of TCS3 is investigated using many-body perturbation theory within theGWapproximation and the Bethe–Salpeter equation (BSE). We find that a structure withPna21symmetry and a bilayer packing motif exhibits intermolecular bonding patterns reminiscent of π–π stacking and has markedly different electronic and optical properties than the experimentally observedP21/nstructure with a cyclic dimer motif, including a narrower band gap, enhanced band dispersion and broader optical absorption. ThePna21bilayer structure is close in energy to the observed structure and may be feasible to grow.

Rules governing the crystal packing of mono- and dialcohols

2001 ◽  
Vol 57 (6) ◽  
pp. 815-827 ◽  
Author(s):  
Robin Taylor ◽  
Clare F. Macrae
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Prediction ◽  
Crystal Packing ◽  
Bond Formation ◽  
Steric Effects ◽  
Hydroxyl Groups ◽  
Strongly Correlated ◽  
Crystal Structure Prediction ◽  
Hydrogen Bond Formation

A new program, Mercury, has been used to survey 144 monoalcohol (C m H n OH) and 101 dialcohol [C m H n (OH)2] crystal structures. Results show that their hydrogen-bonding patterns are strongly correlated with steric effects. Primary monoalcohols have a strong preference to form infinite ...OH...OH... chains. Secondary monoalcohols form chains and rings of hydrogen bonds with about equal facility. Tertiary monoalcohols very often form isolated OH...O hydrogen bonds or structures containing no OH...O hydrogen bonds at all. In the latter case, however, the structures almost invariably contain CH...O and/or OH...π interactions. Substitution on the β-carbon(s) of monoalcohols has a profound effect on packing patterns, with increased substitution disfavouring chains and rings. Dialcohols show a much stronger preference for chains of hydrogen bonds, compared with monoalcohols. This is particularly so when at least one of the hydroxyl groups is primary, in which case chains are overwhelmingly preferred. Once again, substitution on the β-C atoms is influential, heavy substitution tending to lead to packing arrangements that involve isolated or intramolecular OH...O hydrogen bonds. Dialcohols almost never crystallize without at least some OH...O hydrogen-bond formation. In both monoalcohols and dialcohols, chains show a stronger preference to be helical (usually threefold helices) as steric hindrance increases. Hydrogen-bonded rings usually contain four OH...O hydrogen bonds. It is possible that empirical observations such as these may aid crystal-structure prediction.

scholarly journals From Concept to Crystals via Prediction: Multi-Component Organic Cage Pots by Social Self-Sorting

2019 ◽  
Author(s):  
Rebecca L. Greenaway ◽  
Valentina Santolini ◽  
Angeles Pulido ◽  
Marc A. Little ◽  
Ben M. Alston ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Prediction ◽  
Chiral Recognition ◽  
Crystal Packing ◽  
A Priori ◽  
Computational Prediction ◽  
Crystal Structure Prediction ◽  
Social Self ◽  
The Social ◽  
Experimental Crystal

<p>We describe the <i>a priori </i>computational prediction and realization of multi-component cage pots, starting with molecular predictions based on candidate precursors through to crystal structure prediction and synthesis using robotic screening. The molecules were formed by the social self-sorting of a tri-topic aldehyde with both a tri-topic amine and di-topic amine, without using orthogonal reactivity or precursors of the same topicity. Crystal structure prediction suggested a rich polymorphic landscape, where there was an overall preference for chiral recognition to form heterochiral rather than homochiral packings, with heterochiral pairs being more likely to pack window-to-window to form two-component capsules. These crystal packing preferences were then observed in experimental crystal structures. <br></p>

Crystal Structure Prediction via Deep Learning

2018 ◽  
Vol 140 (32) ◽  
pp. 10158-10168 ◽  
Author(s):  
Kevin Ryan ◽  
Jeff Lengyel ◽  
Michael Shatruk
Keyword(s):  
Crystal Structure ◽  
Deep Learning ◽  
Structure Prediction ◽  
Crystal Structure Prediction

scholarly journals New high-pressure phases of Fe7N3 and Fe7C3 stable at Earth's core conditions: evidences for carbon–nitrogen isomorphism in Fe-compounds

RSC Advances ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 3577-3581 ◽  
Author(s):  
Nursultan Sagatov ◽  
Pavel N. Gavryushkin ◽  
Talgat M. Inerbaev ◽  
Konstantin D. Litasov
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Ab Initio ◽  
Structure Prediction ◽  
Harmonic Approximation ◽  
Crystal Structure Prediction ◽  
Earth’S Core ◽  
Earth's Core ◽  
Core Conditions

We carried out ab initio calculations on the crystal structure prediction and determination of P–T diagrams within the quasi-harmonic approximation for Fe7N3 and Fe7C3.

scholarly journals Contact map based crystal structure prediction using global optimization

CrystEngComm ◽  
2021 ◽  
Author(s):  
Jianjun Hu ◽  
Wenhui Yang ◽  
Rongzhi Dong ◽  
Yuxin Li ◽  
Xiang Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Global Optimization ◽  
Crystal Engineering ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
New Materials ◽  
Contact Map

Crystal structure prediction is now playing an increasingly important role in the discovery of new materials or crystal engineering.

Rational design and crystal structure prediction of ring-fused double-PDI compounds as n-channel organic semiconductors: a DFT study

2021 ◽  
Author(s):  
Suryakanti Debata ◽  
Smruti R. Sahoo ◽  
Rudranarayan Khatua ◽  
Sridhar Sahu
Keyword(s):  
Crystal Structure ◽  
Charge Transport ◽  
Organic Semiconductors ◽  
Structure Prediction ◽  
Rational Design ◽  
Molecular Design ◽  
Design Strategy ◽  
Dft Study ◽  
Crystal Structure Prediction ◽  
Model Compounds

In this study, we present an effective molecular design strategy to develop the n-type charge transport characteristics in organic semiconductors, using ring-fused double perylene diimides (DPDIs) as the model compounds.

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