Synthesis and crystal structures of two structurally related kryptoracemates

2017 ◽  
Vol 73 (7) ◽  
pp. 575-581 ◽  
Author(s):  
Philipp Kramer ◽  
Michael Bolte
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Symmetry Element ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
Chiral Molecules ◽  
Space Groups ◽  
Independent Molecules

Kryptoracemates are racemic compounds (pairs of enantiomers) that crystallize in Sohnke space groups (space groups that contain neither inversion centres nor mirror or glide planes nor rotoinversion axes). Thus, the two symmetry-independent molecules cannot be transformed into one another by any symmetry element present in the crystal structure. Usually, the conformation of the two enantiomers is rather similar if not identical. Sometimes, the two enantiomers are related by a pseudosymmetry element, which is often a pseudocentre of inversion, because inversion symmetry is thought to be favourable for crystal packing. We obtained crystals of two kryptoracemates of two very similar compounds differing in just one residue, namely rac-N-[(1S,2R,3S)-2-methyl-3-(5-methylfuran-2-yl)-1-phenyl-3-(pivalamido)propyl]benzamide, C27H32N2O3, (I), and rac-N-[(1S,2S,3R)-2-methyl-3-(5-methylfuran-2-yl)-1-phenyl-3-(propionamido)propyl]benzamide dichloromethane hemisolvate, C25H28N2O3·0.5CH2Cl2, (II). The crystals of both compounds contain both enantiomers of these chiral molecules. However, since the space groups [P212121 for (I) and P1 for (II)] contain neither inversion centres nor mirror or glide planes nor rotoinversion axes, there are both enantiomers in the asymmetric unit, which is a rather uncommon phenomenon. In addition, it is remarkable that (II) contains two pairs of enantiomers in the asymmetric unit. In the crystal, molecules are connected by intermolecular N—H...O hydrogen bonds to form chains or layered structures.

scholarly journals Crystal structures of (2E)-1-(3-bromothiophen-2-yl)-3-(2-methoxyphenyl)prop-2-en-1-one and (2E)-1-(3-bromothiophen-2-yl)-3-(3,4-dimethoxyphenyl)prop-2-en-1-one

2015 ◽  
Vol 71 (8) ◽  
pp. 965-971 ◽  
Author(s):  
Vasant S. Naik ◽  
Venkataraya Shettigar ◽  
Tyler S. Berglin ◽  
Jillian S. Coburn ◽  
Jerry P. Jasinski ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Intramolecular Interaction ◽  
Intramolecular Interactions ◽  
Inversion Symmetry ◽  
Stacking Interactions ◽  
Asymmetric Unit ◽  
Space Group ◽  
Independent Molecules

In the molecules of the title compounds, (2E)-1-(3-bromo-thiophen-2-yl)-3-(2-methoxyphenyl)prop-2-en-1-one, C14H11BrO2S, (I), which crystallizes in the space groupP-1 with four independent molecules in the asymmetric unit (Z′ = 8), and (2E)-1-(3-bromothiophen-2-yl)-3-(3,4-dimethoxyphenyl)prop-2-en-1-one, C15H13BrO3S, (II), which crystallizes withZ′ = 8 in the space groupI2/a, the non-H atoms are nearly coplanar. The molecules of (I) pack with inversion symmetry stacked diagonally along thea-axis direction. Weak C—H...Br intramolecular interactions in each of the four molecules in the asymmetric unit are observed. In (II), weak C—H...O, bifurcated three-center intermolecular interactions forming dimers along with weak C—H...π and π–π stacking interactions are observed, linking the molecules into sheets along [001]. A weak C—H...Br intramolecular interaction is also present. There are no classical hydrogen bonds present in either structure.

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

scholarly journals Crystal structure of ethyl 2-[(4-bromophenyl)amino]-3,4-dimethylpent-3-enoate

2014 ◽  
Vol 70 (10) ◽  
pp. o1122-o1123
Author(s):  
Julio Zukerman-Schpector ◽  
I. Caracelli ◽  
Hélio A. Stefani ◽  
Amna N. Khan ◽  
Edward R. T. Tiekink
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Crystal Packing ◽  
Dihedral Angles ◽  
Methyl Groups ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules

In the title compound, C15H20BrNO2, there are two independent molecules (AandB) comprising the asymmetric unit and these adopt very similar conformations. InA, the dihedral angle between the CO2and MeC=CMe2groups is 80.7 (3)°, and these make dihedral angles of 3.5 (3) and 84.09 (16)°, respectively, with the bromobenzene ring. The equivalent dihedral angles for moleculeBare 78.4 (3), 2.1 (3) and 78.37 (12)°, respectively. The most prominent interactions in the crystal packing are amine-N—H...O(carbonyl) hydrogen bonds between the two independent molecules, resulting in non-centrosymmetric ten-membered {...OC2NH}2synthons. Statistical disorder is noted for each of the terminal methyl groups of the ethyl residues.

scholarly journals Crystal structures of two (±)-exo-N-isobornylacetamides

2015 ◽  
Vol 71 (10) ◽  
pp. 1117-1120 ◽  
Author(s):  
Dmitrijs Stepanovs ◽  
Daniels Posevins ◽  
Maris Turks
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Asymmetric Unit ◽  
Double Chain ◽  
Space Group ◽  
Axis Direction ◽  
Independent Molecules

The title compounds consist of a bornane skeleton with attached acetamide, C12H21NO (±)-(1) {systematic name: (±)-N-[(1RS,2RS,4RS)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl]acetamide}, and chloroacetamide, C12H20ClNO (±)-(2) {systematic name: (±)-2-chloro-N-[(1RS,2RS,4RS)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl]acetamide}, functionalities to the 2-exo-position. The crystal structure of the first monoclinic polymorph of (±)-(1) has been reported previously [Unget al.(2014).Monatsh. Chem.145, 983–992]. Compound (±)-(1) crystallizes in the space groupP21/nwith two independent molecules in the asymmetric unit, in contrast to the above-mentioned polymorph which crystallized in the space groupC2/cwith one molecule in the asymmetric unit. In the title compounds, the bicyclic bornane moieties have normal geometries. In the crystals of both compounds, molecules are linked by N—H...O hydrogen bonds, reinforced by C—H...O contacts, formingtrans-amide chains propagating along thea-axis direction. In the case of compound (±)-(1), neighbouring chains are linked by further C—H...O contacts, forming double-chain ribbons along [100].

scholarly journals Crystal structure of poly[diaqua(μ2-benzene-1,4-dicarboxylato-κ2O1:O4)(μ2-benzene-1,4-dicarboxylato-κ4O1,O1′:O4,O4′)bis(μ2-3,3′,5,5′-tetramethyl-4,4′-bipyrazole-κ2N:N′)dinickel(II)]

2015 ◽  
Vol 71 (6) ◽  
pp. m127-m128
Author(s):  
Chao Wu ◽  
Peng Cao
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Crystal Packing ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
Dimensional Network

The asymmetric unit of the polymeric title compound, [Ni(C8H4O4)(C10H14N4)(H2O)]n, contains one Ni2+cation, one coordinating water molecule, one 3,3′,5,5′-tetramethyl-4,4′-bipyrazole ligand and half each of two benzene-1,4-dicarboxylate anions, the other halves being generated by inversion symmetry. The Ni2+cation exhibits an octahedral N2O4coordination sphere defined by the O atoms of the water molecule and two different anions and the N atoms of two symmetry-relatedN-heterocycles. TheN-heterocycles and both anions bridge adjacent Ni2+cations into a three-dimensional network structure, with one of the anions in a bis-bidentate and the other in a bis-monodentate bridging mode. N—H...O and O—H...O hydrogen bonds between the N-heterocycles and water molecules as donor groups and the carboxylate O atoms as acceptor groups consolidate the crystal packing.

scholarly journals Synthesis and X-Ray Crystal Structure of Two Acridinedione Derivatives

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Dalbir Kour ◽  
D. R. Patil ◽  
M. B. Deshmukh ◽  
Vivek K. Gupta ◽  
Rajni Kant
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Direct Methods ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
X Ray ◽  
Independent Molecules

The two acridinedione derivatives 1 [3,3,6,6-tetramethyl-9-(4-methoxyphenyl)-3,4,6,7,9,10-hexahydro-2H,5H-acridine-1,8-dione (C24H29NO3)] and 2 [3,3,6,6-tetramethyl-9-(4-methylphenyl)-3,4,6,7,9,10-hexa-hydro-2H,5H-acridine-1,8-dione (C24H29NO2)] were synthesized and their crystal structures were determined by direct methods. The asymmetric unit of compound 1 contains two independent molecules. The 1,4-dihydropyridine (DHP) ring adopts boat conformation in both 1 and 2. In 1 the dione rings exist in sofa conformation (for both the crystallographically independent molecules) while the corresponding rings in 2 adopt half chair and sofa conformations, respectively. The crystal packing is stabilized by intermolecular N–H⋯O and C–H⋯O interactions in compound 1 and N–H⋯O interactions in compound 2.

scholarly journals Crystal structure and Hirshfeld surface analysis of (E)-N′-[4-(piperidin-1-yl)benzylidene]arylsulfonohydrazides

2018 ◽  
Vol 74 (12) ◽  
pp. 1826-1832
Author(s):  
Nikhila Pai ◽  
Sabine Foro ◽  
B. Thimme Gowda
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structural Parameters ◽  
Hirshfeld Surface ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Monoclinic Crystal ◽  
Space Groups ◽  
Unit Cells ◽  
Independent Molecules

The crystal structures and Hirshfeld surface analyses of three Schiff bases, namely (E)-N′-[4-(piperidin-1-yl)benzylidene]benzenesulfonohydrazide, C18H21N3O2S, (I), (E)-4-methyl-N′-[4-(piperidin-1-yl)benzylidene]benzenesulfonohydrazide, C19H23N3O2S, (II), and (E)-4-chloro-N′-[4-(piperidin-1-yl)benzylidene]benzenesulfonohydrazide, C18H20ClN3O2S, (III), derived from arylsulfonohydrazides and 4-(piperidin-4-yl)benzaldehyde have been analysed to investigate the effect of substituents on the structural parameters. All three structures crystallize in monoclinic crystal systems, in the space groups P21/c for (I) and (II), and C2/c for (III). Compound (III) contains two independent molecules in the asymmetric unit and sixteen molecules per unit cell, while (I) and (II) both have one and four molecules, respectively, in their asymmetric units and unit cells. In all cases, the central part of the molecule is twisted at the S atom. In the crystals, the molecules are linked via N—H...O hydrogen bonds, forming chains. Two-dimensional fingerprint plots of various interatomic contacts show that the major contributions are from H...H interactions.

scholarly journals Crystal structure and Hirshfeld surface analysis of (4Z)-1-butyl-4-(2-oxopropylidene)-2,3,4,5-tetrahydro-1H-1,5-benzodiazepin-2-one

2018 ◽  
Vol 74 (11) ◽  
pp. 1669-1673 ◽  
Author(s):  
Karim Chkirate ◽  
Nada Kheira Sebbar ◽  
Tuncer Hökelek ◽  
Damodaran Krishnan ◽  
Joel T. Mague ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Surface Analysis ◽  
Crystal Packing ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Asymmetric Unit ◽  
Compound C ◽  
Benzene Rings ◽  
Independent Molecules

The asymmetric unit of the title compound, C16H20N2O2, consists of two independent molecules differing slightly in the conformations of the seven-membered rings and the butyl substituents, where the benzene rings are oriented at a dihedral angle of 34.56 (3)°. In the crystal, pairwise intermolecular C—H...O and complementary intramolecular C—H...O hydrogen bonds form twisted strips extending parallel to (012). These strips are connected into layers parallel to (111) by additional intermolecular C—H...O hydrogen bonds. The layers are further joined by C—H...π interactions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (65.5%), H...C/C...H (16.0%) and H...O/O...H (15.8%) interactions.

scholarly journals Crystal structures of three (trichloromethyl)(carbamoyl)disulfanes

2015 ◽  
Vol 71 (10) ◽  
pp. 1169-1173 ◽  
Author(s):  
Barbara L. Goldenberg ◽  
Victor G. Young Jr ◽  
George Barany
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Molecular Structures ◽  
Protecting Groups ◽  
Asymmetric Unit ◽  
Bond Lengths ◽  
Independent Molecules ◽  
Related Compounds

The present paper reports crystallographic studies on three related compounds that were of interest as precursors for synthetic and mechanistic work in organosulfur chemistry, as well as to model nitrogen-protecting groups: (N-methylcarbamoyl)(trichloromethyl)disulfane, C3H4Cl3NOS2, (1), (N-benzylcarbamoyl)(trichloromethyl)disulfane, C9H8Cl3NOS2, (2), and (N-methyl-N-phenylcarbamoyl)(trichloromethyl)disulfane, C9H8Cl3NOS2, (3). Their molecular structures, with similar bond lengths and angles for the CCl3SS(C=O)N moieties, are confirmed. Compounds (1) and (3) both crystallized with two independent molecules in the asymmetric unit. Classical hydrogen bonding, as well as chlorine-dense regions, are evident in the crystal packing for (1) and (2). In the crystal of (1), molecules are linkedviaN—H...O hydrogen bonds forming chains along [110], which are linked by short Cl...Cl and S...O contacts forming sheets parallel to (001). In the crystal of (2), molecules are linkedviaN—H...O hydrogen bonds forming chains along [001], which in turn are linked by pairs of short O...Cl contacts forming ribbons along thec-axis direction. In the crystal of (3), there are no classical hydrogen bonds present and the chlorine-dense regions observed in (1) and (2) are lacking.

scholarly journals Crystal structures of threeN-(arylsulfonyl)-4-fluorobenzamides

2016 ◽  
Vol 72 (4) ◽  
pp. 575-582 ◽  
Author(s):  
P. A. Suchetan ◽  
S. Naveen ◽  
N. K. Lokanath ◽  
K. S. Srivishnu ◽  
G. M. Supriya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Crystal Structures ◽  
Dihedral Angle ◽  
Three Dimensional ◽  
Asymmetric Unit ◽  
Solvent Water ◽  
Benzene Rings ◽  
Independent Molecules

The crystal structures of threeN-arylsulfonyl-4-fluorobenzamides, namely 4-fluoro-N-(2-methylphenylsulfonyl)benzamide, C14H12FNO3S, (I),N-(2-chlorophenylsulfonyl)-4-fluorobenzamide, C13H9ClFNO3S, (II), andN-(4-chlorophenylsulfonyl)-4-fluorobenzamide monohydrate, C13H9ClFNO3S·H2O, (III), are described and compared with related structures. The asymmetric unit of (I) contains two independent molecules (AandB), while that of (II) contains just one molecule, and that of (III) contains a molecule of water in addition to one main molecule. The dihedral angle between the benzene rings is 82.83 (11)° in moleculeAand 85.01 (10)° in moleculeBof (I), compared to 89.91 (10)° in (II) and 81.82 (11)° in (III). The crystal structure of (I) features strong N—H...O hydrogen bonds between theAandBmolecules, resulting in anR44(16) tetrameric unit. These tetrameric units are connected into sheets in thebcplane by various C—H...O interactions, and adjacent sheets are further interlinkedviaC—H...πarylinteractions, forming a three-dimensional architecture. The crystal structure is further stabilized by πaryl–πaryland S=O...πarylinteractions. In the crystal of (II), molecules are connected intoR22(8) andR22(14) dimersviaN—H...O hydrogen bonds and C—H...O interactions, respectively; the dimers are further interconnectedviaa weak C=O...πarylinteraction, leading to the formation of chains along [1-10]. In the crystal of (III), N—H...O and O—H...O hydrogen bonds involving both the main molecule and the solvent water molecule results in the formation of sheets parallel to thebcplane. The sheets are further connected by C—H...O interactions and weak C—Cl...πaryl, C—F...πaryland S=O...πarylinteractions, forming a three-dimensional architecture.

Sign in / Sign up

Export Citation Format

Share Document