scholarly journals Aliphatic–aromatic stacking interactions in cyclohexane–benzene are stronger than aromatic–aromatic interaction in the benzene dimer

2016 ◽  
Vol 18 (37) ◽  
pp. 25791-25795 ◽  
Author(s):  
D. B. Ninković ◽  
D. Z. Vojislavljević-Vasilev ◽  
V. B. Medaković ◽  
M. B. Hall ◽  
E. N. Brothers ◽  
...  

Stacking interactions between cyclohexane and benzene were studied in crystal structures from the Cambridge Structural Database and by ab initio calculations.

2020 ◽  
Vol 22 (24) ◽  
pp. 13721-13728 ◽  
Author(s):  
Jelena P. Blagojević Filipović ◽  
Michael B. Hall ◽  
Snežana D. Zarić

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.


2016 ◽  
Vol 70 (6) ◽  
pp. 649-659 ◽  
Author(s):  
Dusan Malenov ◽  
Snezana Zaric

Parallel interactions of aromatic and heteroaromatic molecules are very important in chemistry and biology. In this review, recent findings on preferred geometries and interaction energies of these molecules are presented. Benzene and pyridine were used as model systems for studying aromatic and heteroaromatic molecules, respectively. Searches of Cambridge Structural Database show that both aromatic and heteroaromatic molecules prefer interacting at large horizontal displacements, even though previous calculations showed that stacking interactions (with offsets of about 1.5 ?) are the strongest. Calculations of interaction energies at large horizontal displacements revealed that the large portion of interaction energy is preserved even when two molecules do not overlap. These substantial energies, as well as the possibility of forming larger supramolecular structures, make parallel interactions at large horizontal displacements more frequent in crystal structures than stacking interactions.


Author(s):  
Ivana S. Antonijević ◽  
Dušan P. Malenov ◽  
Michael B. Hall ◽  
Snežana D. Zarić

Tetrathiafulvalene (TTF) and its derivatives are very well known as electron donors with widespread use in the field of organic conductors and superconductors. Stacking interactions between two neutral TTF fragments were studied by analysing data from Cambridge Structural Database crystal structures and by quantum chemical calculations. Analysis of the contacts found in crystal structures shows high occurrence of parallel displaced orientations of TTF molecules. In the majority of the contacts, two TTF molecules are displaced along their longer C 2 axis. The most frequent geometry has the strongest TTF–TTF stacking interaction, with CCSD(T)/CBS energy of −9.96 kcal mol−1. All the other frequent geometries in crystal structures are similar to geometries of the minima on the calculated potential energy surface.


2005 ◽  
Vol 38 (4) ◽  
pp. 694-696 ◽  
Author(s):  
Jacco van de Streek ◽  
Sam Motherwell

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.


2017 ◽  
Vol 73 (3) ◽  
pp. 240-245 ◽  
Author(s):  
Colin R. Groom ◽  
Jason C. Cole

Many ligand-discovery stories tell of the use of structures of protein–ligand complexes, but the contribution of structural chemistry is such a core part of finding and improving ligands that it is often overlooked. More than 800 000 crystal structures are available to the community through the Cambridge Structural Database (CSD). Individually, these structures can be of tremendous value and the collection of crystal structures is even more helpful. This article provides examples of how small-molecule crystal structures have been used to complement those of protein–ligand complexes to address challenges ranging from affinity, selectivity and bioavailability though to solubility.


2015 ◽  
Vol 71 (10) ◽  
pp. 921-928 ◽  
Author(s):  
Kulsoom Kamal ◽  
Hardesh K. Maurya ◽  
Atul Gupta ◽  
Prema G. Vasudev

The revived interest in halogen bonding as a tool in pharmaceutical cocrystals and drug design has indicated that cyano–halogen interactions could play an important role. The crystal structures of four closely related δ-keto esters, which differ only in the substitution at a single C atom (by H, OMe, Cl and Br), are compared, namely ethyl 2-cyano-5-oxo-5-phenyl-3-(piperidin-1-yl)pent-2-enoate, C19H22N2O3, (1), ethyl 2-cyano-5-(4-methoxyphenyl)-5-oxo-3-(piperidin-1-yl)pent-2-enoate, C20H24N2O4, (2), ethyl 5-(4-chlorophenyl)-2-cyano-5-oxo-3-(piperidin-1-yl)pent-2-enoate, C19H21ClN2O3, (3), and the previously published ethyl 5-(4-bromophenyl)-2-cyano-5-oxo-3-(piperidin-1-yl)pent-2-enoate, C19H21BrN2O3, (4) [Maurya, Vasudev & Gupta (2013).RSC Adv.3, 12955–12962]. The molecular conformations are very similar, while there are differences in the molecular assemblies. Intermolecular C—H...O hydrogen bonds are found to be the primary interactions in the crystal packing and are present in all four structures. The halogenated derivatives have additional aromatic–aromatic interactions and cyano–halogen interactions, further stabilizing the molecular packing. A database analysis of cyano–halogen interactions using the Cambridge Structural Database [CSD; Groom & Allen (2014).Angew. Chem. Int. Ed.53, 662–671] revealed that about 13% of the organic molecular crystals containing both cyano and halogen groups have cyano–halogen interactions in their packing. Three geometric parameters for the C—X...N[triple-bond]C interaction (X = F, Cl, Br or I),viz.the N...Xdistance and the C—X...N and C—N...Xangles, were analysed. The results indicate that all the short cyano–halogen contacts in the CSD can be classified as halogen bonds, which are directional noncovalent interactions.


Author(s):  
Dušan P. Malenov ◽  
Jelena P. Blagojević Filipović ◽  
Snežana D. Zarić

In the crystal structures of methylated cyclopentadienyl (Cp) complexes (MeCp, Me4Cp and Me5Cp) deposited in the Cambridge Structural Database, certain orientation types of stacked contacts can be noted as the most frequent. These orientation preferences can be well explained by the matching of oppositely charged regions of electrostatic potential. Parallel displaced stacking, large offset stacking and C—H...π interactions are the dominant interaction types that are responsible for the arrangement in the crystal structures of stacked methylated Cp complexes.


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