Interplay between the crystal stability and the energy of the molecular conformation

CrystEngComm ◽  
2021 ◽  
Author(s):  
Konrad Dyk ◽  
Łukasz Piotr Baran ◽  
Wojciech Rżysko ◽  
Marek Stankevic ◽  
Daniel Michael Kamiński
Keyword(s):  
Torsion Angle ◽  
Molecular Conformation ◽  
Crystal Stability

The specially designed new compound of 5,5’-bis(4-hydroxyphenyl)-2,2’-dihydroxy-1,1’-biphenyl, can crystallize in different crystallographic systems. The molecule adopts the C–conformation for the torsion angle around 60o and the T–conformation for the angle...

scholarly journals Crystal structure of 2,4-dinitrophenyl 4-methylbenzenesulfonate: a new polymorph

2015 ◽  
Vol 71 (9) ◽  
pp. 1085-1088 ◽  
Author(s):  
Tyler A. Cooley ◽  
Sean Riley ◽  
Shannon M. Biros ◽  
Richard J. Staples ◽  
Felix N. Ngassa
Keyword(s):  
Crystal Structure ◽  
Nucleophilic Substitution ◽  
Torsion Angle ◽  
Title Compound ◽  
Substitution Reaction ◽  
Sulfonate Group ◽  
Acta Cryst ◽  
Crystal Stability ◽  
Compound C ◽  
Centroid Distance

The title compound, C13H10N2O7S, was synthesizedviaa nucleophilic substitution reaction between 2,4-dinitrophenol andp-toluenesulfonyl chloride. This crystal structure is a polymorph of CSD entry WUVYUH [Vembuet al.(2003).Acta Cryst, E59, o378–380]. The aromatic substituents on the sulfonate group are orientedgaucheto one another with a C—O—S—C torsion angle of −62.0 (3)°. The supramolecular features that contribute to the crystal stability are offset π–π [centroid–centroid distance = 3.729 (2) Å] and multiple C—H...O interactions.

scholarly journals A new monoclinic polymorph of 1,1′-bis(diphenylthiophosphoryl)ferrocene

2015 ◽  
Vol 71 (8) ◽  
pp. 886-889 ◽  
Author(s):  
Yee Seng Tan ◽  
Chien Ing Yeo ◽  
Edward R. T. Tiekink
Keyword(s):  
Torsion Angle ◽  
Title Compound ◽  
Molecular Conformation ◽  
Crystal Packing ◽  
Bond Lengths ◽  
Significant Difference ◽  
New Form ◽  
Supramolecular Chains

The title compound, [Fe(C17H14PS)2], is a second monoclinic polymorph (P21/c, withZ′ = 1) of the previously reported monoclinic (C2/c, withZ′ = 1/2) form [Fanget al.(1995).Polyhedron,14, 2403–2409]. In the new form, the S atoms lie to the same side of the molecule with the pseudo S—P...P—S torsion angle being −53.09 (3)°. By contrast to this almostsyndisposition, in theC2/cpolymorph, the Fe atom lies on a centre of inversion so that the S atoms are strictlyanti, with a pseudo-S—P...P—S torsion angle of 180°. The significant difference in molecular conformation between the two forms does not result in major perturbations in the P=S bond lengths nor in the distorted tetrahedral geometries about the P atoms. The crystal packing of the new monoclinic polymorph features weak Cp—C—H...π(phenyl) interactions consolidating linear supramolecular chains along theaaxis. These pack with no directional interactions between them.

Synthesis and crystallographic, spectroscopic and computational characterization of 3,3′,4,4′-substituted biphenyls: effects of OR substituents on the intra-ring torsion angle

2020 ◽  
Vol 76 (3) ◽  
pp. 366-377
Author(s):  
Nahir Vadra ◽  
Sebastian A. Suarez ◽  
Leonardo D. Slep ◽  
Veronica E. Manzano ◽  
Emilia B. Halac ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Torsion Angle ◽  
Liquid State ◽  
Molecular Conformation ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
Molecular Conformations ◽  
X Ray ◽  
Selection Of

Presented here are the synthesis, characterization and study (using single crystal X-ray diffraction, Raman scattering, quantum mechanics calculations) of the structures of a series of biphenyls substituted in positions 3, 3′, 4 and 4′ with a variety of R (R = methyl, acetyl, hexyl) groups connected to the biphenyl core through oxygen atoms. The molecular conformation, particularly the torsion angle between aromatic rings has been extensively studied both in the solid as well as in the liquid state. The results show that the compounds appearing as rigorously planar in the solid present instead a twisted conformation in the melt. The solid versus melt issue strongly suggests that the reasons for planarity are to be found in the packing restraints. A `rule of thumb' is suggested for the design of biphenyls with different molecular conformations, based on the selection of the OR substituent.

3-Oxoandrosta-4,6-dien-17β-yl 2-methyl-1H-imidazole-1-carboxylate and 3-oxo-5α-androst-17β-yl 2-methyl-1H-imidazole-1-carboxylate: C—H...π and π–π intermolecular interactions

2009 ◽  
Vol 65 (3) ◽  
pp. o88-o91
Author(s):  
Manuela Ramos Silva ◽  
Vânia M. Moreira ◽  
Cláudia Cardoso ◽  
Ana Matos Beja ◽  
Jorge A. R. Salvador
Keyword(s):  
Solid State ◽  
Ab Initio ◽  
Torsion Angle ◽  
Molecular Conformation ◽  
Asymmetric Unit ◽  
Compound I ◽  
The Mean ◽  
Independent Molecules ◽  
Compound Ii ◽  
Supramolecular Aggregation

The title compounds, C24H30N2O3, (I), and C24H34N2O3, (II), both contain an androstane backbone and a 2-methylimidazole-1-carboxylate moiety at the 17-position. Compound (I) contains two symmetry-independent molecules (denoted 1 and 2), while compound (II) contains just one molecule in the asymmetric unit. The C—C—O—C torsion angle that reflects the twisting of the 2-methylimidazole-1-carboxylate moiety from the mean steroid plane is 143.1 (2)° for molecule 1 of (I), 73.1 (3)° for molecule 2 of (I) and 86.63 (17)° for (II). The significance of this study lies in its observation of significant differences in both molecular conformation and supramolecular aggregation between the molecules of the title compounds. The solid-state conformations compared with those obtained theoretically fromab initiomethods for the isolated molecules show large differences, especially in the orientation of the methylimidazole substituent.

scholarly journals Ethyl 5-(4-methylphenyl)-2,4,5,7-tetraazatricyclo[6.4.0.02,6]dodeca-1(8),3,6,9,11-pentaene-3-carboxylate

IUCrData ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Ahmed Moussaif ◽  
Youssef Ramli ◽  
Lhoussaine El Ghayati ◽  
El Mokhtar Essassi ◽  
Joel T. Mague
Keyword(s):  
Hydrogen Bonds ◽  
Ethyl Ester ◽  
Benzene Ring ◽  
Dihedral Angle ◽  
Torsion Angle ◽  
Title Compound ◽  
Molecular Conformation ◽  
Ring System ◽  
Compound C ◽  
Π Stacking

In the title compound, C18H16N4O2, the dihedral angle between the fused tricyclic ring system and the pendant benzene ring is 11.03 (4)°. The C—O—C—C torsion angle in the ethyl ester is 102.97 (12)°. The molecular conformation is supported by intramolecular C—H...N and C—H...O hydrogen bonds, which close S(6) and S(7) rings, respectively. Aromatic π–π stacking is observed in the crystal [shortest centroid–centroid separation = 3.5274 (7) Å].

The interplay of solvation, molecular conformation and supramolecular assembly in 1,1′-({[(ethane-1,2-diyl)dioxy](1,2-phenylene)}bis(methanylylidene))bis(thiosemicarbazide) and itsN,N-dimethylformamide disolvate

2015 ◽  
Vol 71 (11) ◽  
pp. 959-964
Author(s):  
Shaaban K. Mohamed ◽  
Sabry H. H. Younes ◽  
Eman M. M. Abdel-Raheem ◽  
Joel T. Mague ◽  
Mehmet Akkurt ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Torsion Angle ◽  
Molecular Conformation ◽  
Supramolecular Assembly ◽  
Antitubercular Agents ◽  
Site Specific ◽  
Rotation Axes ◽  
Solvent Molecules ◽  
Molecular Components ◽  
Related Compounds

The wide diversity of applications of thiosemicarbazones and bis(thiosemicarbazones) has seen them used as anticancer and antitubercular agents, and as ligands in metal complexes designed to act as site-specific radiopharmaceuticals. Molecules of 1,1′-({[(ethane-1,2-diyl)dioxy](1,2-phenylene)}bis(methanylylidene))bis(thiosemicarbazide) {alternative name: 2,2′-[ethane-1,2-diylbis(oxy)]dibenzaldehyde bis(thiosemicarbazide)}, C18H20N6O2S2, (I), lie across twofold rotation axes in the space groupC2/c, with an O—C—C—O torsion angle of −59.62 (13)° and atrans-planar arrangement of the thiosemicarbazide fragments relative to the adjacent aryl rings. The molecules of (I) are linked by N—H...S hydrogen bonds to form sheets containingR24(38) rings and two types ofR22(8) ring. In theN,N-dimethylformamide disolvate, C18H20N6O2S2·2C3H7NO, (II), the independent molecular components all lie in general positions, but one of the solvent molecules is disordered over two sets of atomic sites having occupancies of 0.839 (3) and 0.161 (3). The O—C—C—O torsion angle in the ArOCH2CH2OAr component is −75.91 (14)° and the independent thiosemicarbazide fragments both adopt acis-planar arrangement relative to the adjacent aryl rings. The ArOCH2CH2OAr components in (II) are linked by N—H...S hydrogen bonds to form deeply puckered sheets containingR22(8),R24(8) and two types ofR22(38) rings, and which contain cavities which accommodate all of the solvent molecules in the interior of the sheets. Comparisons are made with some related compounds.

scholarly journals Ethyl 2-(5-bromo-2-iodoanilino)cyclopent-1-ene-1-carboxylate

IUCrData ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Paul Barnes ◽  
John M. D. Storey ◽  
William T. A. Harrison
Keyword(s):  
Hydrogen Bond ◽  
Torsion Angle ◽  
Title Compound ◽  
Molecular Conformation ◽  
Bond Angle ◽  
Compound C

In the title compound, C14H15BrINO2, the conformation of the C—O—CH2—CH3grouping isanti[torsion angle = 173.8 (6)°] and the bond-angle sum at the N atom bridging the two rings is 360°. An unusual intramolecular bifurcated N—H...(O,I) hydrogen bond helps to establish the molecular conformation, in which the I atom and the C=O grouping aresyn. In the crystal, inversion dimers created by pairs of short intermolecular C—I...O interactions [C—I = 2.080 (7) Å; I...O = 3.211 (5) Å; C—I...O = 152.4 (2)°] occur.

scholarly journals cis,trans,cis-1,2,3,4-Tetrakis[2-(ethylsulfanyl)phenyl]cyclobutane

IUCrData ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Barbara Sohr ◽  
Florian Glöcklhofer ◽  
Berthold Stöger ◽  
Matthias Weil ◽  
Johannes Fröhlich
Keyword(s):  
Hydrogen Bonding ◽  
Intermolecular Interactions ◽  
Torsion Angle ◽  
Molecular Conformation ◽  
The Other ◽  
Hydrogen Bonding Interaction ◽  
Asymmetric Unit ◽  
Bonding Interaction ◽  
Cyclobutane Ring ◽  
Cyclobutane Derivative

The title cyclobutane derivative, C36H40S4, formed serendipitously through a photochemically initiated [2 + 2] cycloaddition. The asymmetric unit contains half a molecule with the 2-(ethylsulfanyl)phenyl substituents in acisconfiguration, the other half of the molecule being generated by the application of a twofold rotation operation. The substituents in both halves of the molecules are in atransarrangement relative to each other. The cyclobutane ring shows angular and torsional strains, with C—C—C bond angles of 89.80 (8) and 88.40 (8)°, and an average absolute torsion angle of 14.28 (10)°. The angle of pucker in the ring is 20.27 (12)°. The Ccb—Ccb—Cbangles between the cyclobutane (cb) ring atoms and the attached benzene (b) ring atoms are widened and range from 115.19 (10) to 121.66 (10)°. A weak intramolecular C—H...S hydrogen-bonding interaction between one of the cyclobutane ring H atoms and the S atom may help to establish the molecular conformation. No specific intermolecular interactions are found.

Homologation: A Versatile Molecular Modification Strategy to Drug Discovery

2019 ◽  
Vol 19 (19) ◽  
pp. 1734-1750 ◽  
Author(s):  
Lídia M. Lima ◽  
Marina A. Alves ◽  
Daniel N. do Amaral
Keyword(s):  
Protein Structure ◽  
Homologous Series ◽  
Molecular Conformation ◽  
Chemical Properties ◽  
Lead Optimization ◽  
Pharmacokinetic Property ◽  
Molecular Modification ◽  
Physico Chemical ◽  
Pharmacokinetic Properties ◽  
Lead Identification

Homologation is a concept introduced by Gerhard in 1853 to describe a homologous series in organic chemistry. Since then, the concept has been adapted and used in medicinal chemistry as one of the most important strategies for molecular modification. The homologation types, their influence on physico-chemical properties and molecular conformation are presented and discussed. Its application in lead-identification and lead optimization steps, as well as its impact on pharmacodynamics/pharmacokinetic properties and on protein structure is highlighted from selected examples. <p> • Homologation: definition and types <p> • Homologous series in nature <p> • Comparative physico-chemical and conformational properties <p> • Application in lead-identification and lead-optimization <p> • Impact on pharmacodynamic property <p> • Impact on pharmacokinetic property <p> • Impact on protein structure <p> • Concluding remarks <p> • Acknowledgment <p> • References

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