scholarly journals Hydrophobic dipeptides: the final piece in the puzzle

2018 ◽  
Vol 74 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Carl Henrik Görbitz
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Hydrogen Bonding ◽  
Crystal Packing ◽  
Peptide Conformations ◽  
Bonding Patterns

The crystal structure of L-valyl-L-leucine acetonitrile solvate presented here adds to 24 previously reported structures of dipeptides constructed from the five nonpolar amino acids L-alanine, L-valine, L-isoleucine, L-leucine and L-phenylalanine. It thus constitutes the final piece in the 5 × 5 puzzle of hydrophobic dipeptide structures. This opportunity is taken to review the crystal packing arrangements and hydrogen-bonding preferences of a rather unique group of substances, with updated information on the various hydrogen-bonding patterns and the associated peptide conformations.

scholarly journals Crystal structure of 2-(2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-ylidene)acetonitrile

2015 ◽  
Vol 71 (10) ◽  
pp. o792-o793
Author(s):  
K. Priya ◽  
K. Saravanan ◽  
S. Kabilan ◽  
S. Selvanayagam
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Crystal Packing ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Chair Conformation ◽  
Equatorial Orientation ◽  
Amino Group ◽  
Phenyl Rings

In the title 3-azabicyclononane derivative, C22H22N2, both the fused piperidine and cyclohexane rings adopt a chair conformation. The phenyl rings attached to the central azabicylononane fragment in an equatorial orientation are inclined to each other at 23.7 (1)°. The amino group is not involved in any hydrogen bonding, so the crystal packing is stabilized only by van der Waals forces.

scholarly journals Crystal structure of 2-hydroxy-2-phenylacetophenone oxime

2021 ◽  
Vol 77 (1) ◽  
pp. 66-69
Author(s):  
Nurcan Akduran
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Phenyl Ring ◽  
Crystal Packing ◽  
Hirshfeld Surface ◽  
Oxime Group ◽  
Phenyl Rings ◽  
Ring Interaction ◽  
Van Der Waals Contacts

The title compound [systematic name: 2-(N-hydroxyimino)-1,2-diphenylethanol], C14H13NO2, consists of hydroxy phenylacetophenone and oxime units, in which the phenyl rings are oriented at a dihedral angle of 80.54 (7)°. In the crystal, intermolecular O—HOxm...NOxm, O—HHydr...OHydr, O—H′Hydr...OHydr and O—HOxm...OHydr hydrogen bonds link the molecules into infinite chains along the c-axis direction. π–π contacts between inversion-related of the phenyl ring adjacent to the oxime group have a centroid–centroid separation of 3.904 (3) Å and a weak C—H...π(ring) interaction is also observed. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (58.4%) and H...C/C...H (26.4%) contacts. Hydrogen bonding and van der Waals contacts are the dominant interactions in the crystal packing.

Study on Novel Structure of Praseodymium Complex, C5H13O11Pr

2013 ◽  
Vol 834-836 ◽  
pp. 515-518
Author(s):  
Hai Xing Liu ◽  
Qing Liu ◽  
Ting Ting Huang ◽  
Yang Xu ◽  
Lin Tong Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Crystal ◽  
Hydrothermal Reaction ◽  
Crystal Packing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Novel Structure ◽  
Praseodymium Complex

A novel praseodymium complex C5H13O11Pr has been synthesized from hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Pr1 atom is nine coordinated by nine O atoms. The crystal packing is stabilized by O-H...O hydrogen bonding interactions.

scholarly journals Crystal structure and Hirshfeld surface analysis of 1-(4-chlorophenyl)-2-{[5-(4-chlorophenyl)-1,3,4-oxadiazol-2-yl]sulfanyl}ethanone

2017 ◽  
Vol 73 (4) ◽  
pp. 524-527
Author(s):  
Rajesh Kumar ◽  
Shafqat Hussain ◽  
Khalid M. Khan ◽  
Shahnaz Perveen ◽  
Sammer Yousuf
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Surface Analysis ◽  
Title Compound ◽  
Crystal Packing ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Dihedral Angles ◽  
Compound C ◽  
Benzene Rings

In the title compound, C16H10Cl2N2O2S, the dihedral angles formed by the chloro-substituted benzene rings with the central oxadiazole ring are 6.54 (9) and 6.94 (8)°. In the crystal, C—H...N hydrogen bonding links the molecules into undulating ribbons running parallel to thebaxis. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are the H...C (18%), H...H (17%), H...Cl (16.6%), H...O (10.4%), H...N (8.9%) and H...S (5.9%) interactions.

scholarly journals Crystal structure of di-μ-hydroxido-κ4O:O-bis[bis(acetylacetonato-κ2O,O′)cobalt(III)]

2015 ◽  
Vol 71 (8) ◽  
pp. 983-985 ◽  
Author(s):  
Casseday P. Richers ◽  
Jeffery A. Bertke ◽  
Thomas B. Rauchfuss
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Transition Metal ◽  
Crystal Packing ◽  
Title Complex ◽  
Asymmetric Unit

The dinuclear title complex, [Co2(C5H7O2)4(μ-OH)2] or [Co(acac)2(μ-OH)]2, where acac is acetylacetonate, is centrosymmetric with half of the molecule per asymmetric unit. The molecular structure is a dimer of octahedrally coordinated CoIIIatoms with four O atoms from two chelating acac ligands and two O atoms from bridging hydroxide ligands. The crystal packing features weak C—H...O interactions between neighboring molecules, leading to the formation of chains normal to theacplane. The hydroxide H atoms are not involved in hydrogen bonding because of the bulky acac ligands. This is the first crystal structure reported of a dimeric transition metal bis-acac complex with OH−as the bridging group.

Hydrogen-Bonding Schemes of Galactonic Acid Hydrazide and its Hemihydrate

1997 ◽  
Vol 53 (3) ◽  
pp. 490-497 ◽  
Author(s):  
C. André ◽  
P. Luger ◽  
J.-H. Fuhrhop ◽  
F. Hahn
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Packing ◽  
Scintillation Counter ◽  
Acid Hydrazide ◽  
Coordination Shell ◽  
Hydroxyl Group ◽  
Free Sugar ◽  
Imaging Plate

The crystal structure of L-galactonic acid hemihydrate was determined using data obtained from an imaging plate detector (Stoe IPDS), whereas a conventional scintillation counter was used for the elucidation of the crystal structure of anhydrous D-galactonic acid. The H atom of the terminal hydroxyl group of the water-free sugar participates only in an intramolecular hydrogen bond with the preterminal O atom. This hydrogen bond is part of an antidromic hydrogen-bonding cycle. The hydrogen-bonding scheme of the hemihydrate is very intricate due to the occurrence of two independent molecules and the incorporated water, whose coordination shell can be described by a distorted tetrahedron. One of the hydrogen-bond chains observed in the structure of the hemihydrate is infinite, forming a spiral running in the a direction. The crystal packing of both compounds displays a herringbone arrangement. However, the tilt angle between molecules in different herringbone halves is by far smaller in the structure of the hydrated sugar than in the water-free compound (~ 60 versus 96°).

scholarly journals Synthesis, Crystal Structure, and DFT Calculations of 1,3-Diisobutyl Thiourea

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Ataf A. Altaf ◽  
Adnan Shahzad ◽  
Zarif Gul ◽  
Sher A. Khan ◽  
Amin Badshah ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Dft Calculations ◽  
Single Crystal ◽  
Crystal Packing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Model Support

1,3-Diisobutyl thiourea was synthesized and characterized by single crystal X-ray diffraction. It gives a monoclinic (α=γ= 90 andβ  ≠90) structure with the space group P21/c. The unit cell dimensions area= 11.5131 (4) Å,b= 9.2355 (3) Å,c= 11.3093 (5) Å,α= 90°,β= 99.569° (2),γ= 90°,V= 1185.78 (8) Å3, andZ= 4. The crystal packing is stabilized by intermolecular (N–H⋯S) hydrogen bonding in the molecules. The optimized geometry and Mullikan's charges of the said molecule calculated with the help of DFT using B3LYP-6-311G model support the crystal structure.

Crystal structure and hydrogen bonding in the hydrated cocrystalline salt tryptaminium–3,5-dinitrobenzoate–quinoline–water (3/3/2/2)

2016 ◽  
Vol 72 (10) ◽  
pp. 738-742 ◽  
Author(s):  
Daniel E. Lynch ◽  
Graham Smith ◽  
Tony D. Keene ◽  
Peter N. Horton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Crystal Packing ◽  
Ternary Systems ◽  
Causative Factor ◽  
Asymmetric Unit ◽  
One Dimensional ◽  
Solvent Molecules ◽  
Ring Centroid ◽  
Low Symmetry

The study of ternary systems is interesting because it introduces the concept of molecular preference/competition into the system where one molecule may be displaced because the association between the other two is significantly stronger. Current definitions of a tertiary system indicate that solvent molecules are excluded from the molecule count of the system and some of the latest definitions state that any molecule that is not a solid in the parent form at room temperature should also be excluded from the molecule count. In the structure of the quinoline adduct hydrate of tryptaminium 3,5-dinitrobenzoate, 3C10H13N2+·3C7H3N2O6−·2C9H7N·2H2O, the asymmetric unit comprises multiple cation and anion species which are conformationally similar among each type set. In the crystal, a one-dimensional hydrogen-bonded supramolecular structure is generated through extensive intra- and inter-unit aminium N—H...O and N—H...N, and water O—H...O hydrogen bonds. Within the central-core hydrogen-bonding associations, conjoined cyclicR44(10),R53(10) andR44(12) motifs are generated. The unit is expanded into a one-dimensional column-like polymer extending along [010]. Present also in the crystal packing of the structure are a total of 19 π–π interactions involving both cation, anion and quinoline species [ring-centroid separation range = 3.395 (3)–3.797 (3) Å], as well as a number of weak C—H...O hydrogen-bonding associations. The presence of the two water molecules in the crystal structure is considered to be the principal causative factor in the low symmetry of the asymmetric unit.

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