scholarly journals Crystal structure ofN-(tert-butoxycarbonyl)phenylalanyldehydroalanine isopropyl ester (Boc–Phe–ΔAla–OiPr)

2014 ◽  
Vol 70 (12) ◽  
pp. 599-602 ◽  
Author(s):  
Paweł Lenartowicz ◽  
Maciej Makowski ◽  
Bartosz Zarychta ◽  
Krzysztof Ejsmont
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Steric Hindrance ◽  
Main Chain ◽  
Peptide Bond ◽  
Intramolecular Interactions ◽  
Isopropyl Ester ◽  
Isopropyl Group ◽  
Packing Arrangement

In the title compound, the dehydrodipeptide (Boc–Phe–ΔAla–OiPr, C20H28N2O5), the molecule has atransconformation of theN-methylamide group. The geometry of the dehydroalanine moiety is to some extent different from those usually found in simple peptides, indicating conjugation between the H2C=C group and the peptide bond. The bond angles around dehydroalanine have unusually high values due to the steric hindrance, the same interaction influencing the slight distortion from planarity of the dehydroalanine. The molecule is stabilized by intramolecular interactions between the isopropyl group and the N atoms of the peptide main chain. In the crystal, an N—H...O hydrogen bond links the molecules into ribbons, giving a herringbone head-to-head packing arrangement extending along the [100] direction. In the stacks, the molecules are linked by weak C—H...O hydrogen-bonding associations.

scholarly journals Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

2013 ◽  
Vol 9 ◽  
pp. 1127-1134 ◽  
Author(s):  
Josué M Silla ◽  
Rodrigo A Cormanich ◽  
Roberto Rittner ◽  
Matheus P Freitas
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Conformational Equilibrium ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Interactions ◽  
Coupling Constant ◽  
Intramolecular Hydrogen ◽  
Phenylboronic Acids ◽  
Electron Donation

A 1 TS J F,H(O) coupling pathway, dictated by a hydrogen bond, in some 2-fluorobenzoic acids has been observed, while such an interaction does not occur in 2-fluorophenol. Thus, this work reports the conformational analysis of 2-fluorophenylboronic acid (1), in order to evaluate a possible intramolecular OH∙∙∙F hydrogen bond in comparison to an nF→pB interaction, which mimics the quantum nF→σ*OH hydrogen bond that would be expected in 2-fluorophenol. 2-Fluorophenylborane (3), which does not experience hydrogen bonding, was used to verify whether nF→pB interaction governs the conformational equilibrium in 1 due to a predominant OH∙∙∙F hydrogen bond or to other effects. A series of 2-X-phenylboranes (X = Cl, Br, NH2, PH2, OH and SH) were further computationally analyzed to search for electron donors to boron, capable of influencing the conformational equilibrium. Overall, the intramolecular OH∙∙∙F hydrogen bond in 1 is quite stabilizing and dictates the 1 h J F,H(O) coupling constant. Moreover, electron donation to the empty p orbital of boron (for noncoplanar BH2 moiety relative to the phenyl ring) is also significantly stabilizing for the NH2 and PH2 derivatives, but not enough to make the corresponding conformers appreciably populated, because of steric effects and the loss of πCC→pB resonance. Thus, the results found earlier for 2-fluorophenol about the lack of intramolecular hydrogen bonding are now corroborated.

scholarly journals Crystal structure and hydrogen bonding in the water-stabilized proton-transfer salt brucinium 4-aminophenylarsonate tetrahydrate

2016 ◽  
Vol 72 (5) ◽  
pp. 751-755 ◽  
Author(s):  
Graham Smith ◽  
Urs D. Wermuth
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Network Structure ◽  
Three Dimensional ◽  
Water Molecules ◽  
Arsanilic Acid ◽  
Dimensional Network

In the structure of the brucinium salt of 4-aminophenylarsonic acid (p-arsanilic acid), systematically 2,3-dimethoxy-10-oxostrychnidinium 4-aminophenylarsonate tetrahydrate, (C23H27N2O4)[As(C6H7N)O2(OH)]·4H2O, the brucinium cations form the characteristic undulating and overlapping head-to-tail layered brucine substructures packed along [010]. The arsanilate anions and the water molecules of solvation are accommodated between the layers and are linked to them through a primary cation N—H...O(anion) hydrogen bond, as well as through water O—H...O hydrogen bonds to brucinium and arsanilate ions as well as bridging water O-atom acceptors, giving an overall three-dimensional network structure.

Synthesis and X-ray diffraction analysis of the tetrazole peptide analogue Pro-LeuΨ[CN4]Gly-NH2

1988 ◽  
Vol 53 (11) ◽  
pp. 2863-2876 ◽  
Author(s):  
Giovanni Valle ◽  
Marco Crisma ◽  
Kuo-Long Yu ◽  
Claudio Toniolo ◽  
Ram K. Mishra ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Diffraction Analysis ◽  
Dopamine Receptor ◽  
Torsion Angle ◽  
Peptide Bond ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conformationally Restricted ◽  
Bond Characteristic

The synthesis of an analogue of the neuropharmacologically active peptide Pro-Leu-Gly-NH2 in which the Leu-Gly peptide bond has been replaced with a tetrazole moiety was carried out. The molecular and crystal structure of the tetrazole analogue Pro-Leuψ[CN4]Gly-NH2 was determined by X-ray diffraction and a comparison was made with the published X-ray structure of Pro-Leu-Gly-NH2. The tetrazole annular system turns out to be a good conformationally-restricted replacement for the cis-peptide bond in terms of bond lengths, bond angles and the ω torsion angle. The molecule was found to be folded at the -Leuψ[CN4]Gly- sequence, but it did not form the intramolecular N-H···O=C hydrogen bond characteristic of the type Vla β-bend conformation. In contrast to Pro-Leu-Gly-NH2, Pro-Leuψ[CN4]Gly-NH2 was found to be unable to enhance the binding of dopamine receptor agonists to the dopamine receptor.

3-(4-Oxocyclohexyl)propionic acid monohydrate: hydrogen bonding in the hydrate of a ζ-keto acid

2007 ◽  
Vol 63 (3) ◽  
pp. o1173-o1175
Author(s):  
Stephanie M. Witko ◽  
Mark Davison ◽  
Hugh W. Thompson ◽  
Roger A. Lalancette
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Carboxyl Group ◽  
Keto Acid ◽  
Carbonyl Groups ◽  
O 178 ◽  
Network Of Hydrogen Bonds

In the title crystal structure, C9H14O3·H2O, the water molecule accepts a hydrogen bond from the carboxyl group [O...O = 2.6004 (13) Å and O—H...O = 163°], while donating hydrogen bonds to the ketone [O...O = 2.8193 (14) Å and O—H...O = 178 (2)°] and the acid carbonyl groups [O...O = 2.8010 (14) Å and O—H...O = 174 (2)°]. This creates a network of hydrogen bonds confined within a continuous flat ribbon two molecules in width and extending in the [101] direction.

Phosphinsubstituierte Chelatliganden, XIV [1]. Wasserstoff-Brückenbindung in THF-Addukten von Tetracarbonylchrom-und -molybdänkomplexen mit P,S-koordinierten Phosphinothioformamid-Liganden. Kristallstruktur von [(CO)4Cr(PPh2C(S)NHMe)] · THF Phosphine-Substituted Chelate Ligands, XIV [1]. Hydrogen Bonding in THF-Adducts of Tetracarbonylchromium and -molybdenum Complexes with P,S-Coordinated Phosphinothioformamide Ligands. Crystal Structure of [(CO)4Cr(PPh2C(S)NHMe)] · THF

1985 ◽  
Vol 40 (4) ◽  
pp. 512-517 ◽  
Author(s):  
Udo Kunze ◽  
Hussain Jawad ◽  
Wolfgang Hiller ◽  
Regina Naumer
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Nmr Spectra ◽  
Chelate Complexes ◽  
Triclinic Space Group ◽  
Lattice Constants ◽  
H Nmr ◽  
Contact Distance ◽  
Metal Hexacarbonyls

The tetracarbonyl chromium and molybdenum P,S-chelate complexes 1a, b and 2a, b are obtained by low-temperature photolysis of the metal hexacarbonyls with the neutral phosphinothioformamide ligands, Ph2PC(S)NHR (R = Me (a). Ph (b)), as stoichiometric 1/1 IHF adducts. A weak N-H···O(THF) hydrogen bond is deduced from the 1H NMR spectra which show a collapse of the N-methyl doublet in la (Tc -18 °C) but not in 2a. Unusually small P-C(S) couplings are observed in the 13C{1H} NMR spectra. The N-methyl chromium complex la crystal­lizes in the triclinic space group P1 (Z = 2) with the lattice constants a = 1076.6(3), b = 1235.8(3), c = 915.1(3) pm, α = 97.99(4)°, β = 92.73(5)°, γ = 87.63(5)°. The planar thioamide unit adopts the Z configuration and is linked to the tetrahydrofuran molecule by a hydrogen bond (N-H1-O31 164°) with an O···H contact distance of 191 pm.

scholarly journals Hydrogen bonding in the crystal structure of the molecular salt of pyrazole–pyrazolium picrate

2016 ◽  
Vol 72 (6) ◽  
pp. 861-863 ◽  
Author(s):  
Ping Su ◽  
Xue-gang Song ◽  
Ren-qiang Sun ◽  
Xing-man Xu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Organic Salt ◽  
Asymmetric Unit ◽  
Molecular Salt ◽  
Hydrogen Bonded

The asymmetric unit of the title organic salt [systematic name: 1H-pyrazol-2-ium 2,4,6-trinitrophenolate–1H-pyrazole (1/1)], H(C3H4N2)2+·C6H2N3O7−, consists of one picrate anion and one hydrogen-bonded dimer of a pyrazolium monocation. The H atom involved in the dimer N—H...N hydrogen bond is disordered over both symmetry-unique pyrazole molecules with occupancies of 0.52 (5) and 0.48 (5). In the crystal, the component ions are linked into chains along [100] by two different bifurcated N—H...(O,O) hydrogen bonds. In addition, weak C—H...O hydrogen bonds link inversion-related chains, forming columns along [100].

Inclusion compounds of thiourea and peralkylated ammonium salts. III. Hydrogen-bonded host lattices built of thiourea and nitrate ions

1996 ◽  
Vol 52 (6) ◽  
pp. 989-998 ◽  
Author(s):  
Q. Li ◽  
T. C. W. Mak
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Channel System ◽  
Nitrate Ion ◽  
Space Group ◽  
One Dimensional ◽  
X Ray Crystallography ◽  
Packing Arrangement ◽  
Host Lattices ◽  
Hydrogen Bonded

The new inclusion complexes tetraethylammonium nitrate–thiourea (1:3), (C2H5)4N+.NO3 −. 3(NH2)2CS (1), tetra-n-propylammonium nitrate–thiourea–water (1:3:1), (n-C3H7)4N+.NO3 −.3(NH2)2CS.H2O (2), tetramethylammonium nitrate–thiourea (1:1), (CH3)4N+.NO3 −.(NH2)2CS (3), tetra-n-propylammonium nitrate–thiourea (1:1), (n-C3H7)4N+.NO3 −. (NH2)2CS (4), and tetra-n-butylammonium nitrate–thiourea (1:1), (n-C4H9)4N+.NO3 −.(NH2)2CS (5) have been prepared and characterized by X-ray crystallography. Crystal data, Mo Kα: (1), space group P{\bar 1}, a = 10.300 (2), b = 14.704 (3), c = 15.784 (4) Å, α = 75.30 (3), β = 86.98 (3), γ = 72.25 (3)°, Z = 4 and RF = 0.039 for 5034 observed data; (2), space group P21/n, a = 8.433 (2), b = 9.369 (2), c = 34.361 (7) Å, β = 91.01 (3)°, Z = 4 and RF = 0.050 for 2475 observed data; (3), space group Pnma, a = 15.720 (3), b = 8.218 (2), c = 8.709 (2) Å, Z = 4 and RF = 0.073 for 579 observed data; (4), space group P21/n, a = 8.784 (2), b = 14.421 (3), c = 15.078 (3) Å, β = 92.31 (3)°, Z = 4 and RF = 0.046 for 2507 observed data; (5), space group Pna21, a = 19.934 (3), b = 12.680 (2), c = 9.092 (3) Å, Z = 4 and RF = 0.047 for 1646 observed data. In the crystal structure of (1) infinite chains each composed of an alternate arrangement of a twisted thiourea trimer and a nitrate ion are cross-linked to form a puckered layer and further hydrogen bonding between such layers leads to a channel host framework for accommodation of the cationic guests. In the crystal structure of (2) two independent thiourea molecules are used to construct a hydrogen-bonded puckered layer normal to the c axis, whereas the remaining thiourea molecule, together with the nitrate ion and water molecule, generate another puckered layer that is parallel to the first. Hydrogen bonding between these two types of layers gives rise to a channel system running parallel to the [100] direction and the cations are stacked regularly within each column. Compounds (3), (4) and (5) have closely related crystal structures in which the cations are separated by one-dimensional, infinitely extended thiourea–nitrate composite ribbons in a sandwich-like packing arrangement.

scholarly journals Crystal structure of 2,5-dimethylanilinium hydrogen maleate

2014 ◽  
Vol 70 (11) ◽  
pp. o1183-o1184 ◽  
Author(s):  
Maha Mathlouthi ◽  
Daron E. Janzen ◽  
Mohamed Rzaigui ◽  
Wajda Smirani Sta
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Ammonium Group ◽  
Hydrogen Bonding Interactions ◽  
Graph Set

The crystal structure of the title salt, C8H12N+·C4H3O4−, consists of a 2,5-dimethylanilinium cation and an hydrogen maleate anion. In the anion, a strong intramolecular O—H...O hydrogen bond is observed, leading to anS(7) graph-set motif. In the crystal, the cations and anions pack in alternating layers parallel to (001). The ammonium group undergoes intermolecular N—H...O hydrogen-bonding interactions with the O atoms of three different hydrogen maleate anions. This results in the formation of ribbons extending parallel to [010] with hydrogen-bonding motifs of the typesR44(12) andR44(18).

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°).

A novel self-complementary three-dimensional inorganic network organized by H-bond dimers of inorganic chains — Synthesis and crystal structure of (C6H16N2)[Zn(HPO4)2]

2004 ◽  
Vol 82 (5) ◽  
pp. 616-621 ◽  
Author(s):  
Xian-Ming Zhang ◽  
Chan-Juan Bai ◽  
Yan-Li Zhang ◽  
Hai-Shun Wu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Crystal Structural ◽  
Inorganic Framework ◽  
Phosphate Groups ◽  
Inorganic Network

A novel organic-templated zincophosphate, namely (C6H16N2)[Zn(HPO4)2], was hydrothermally synthesized and X-ray single-crystal structural analysis reveals that the anions [Zn(HPO4)2]2–, which have square-twisted chains containing corner-sharing four-rings of alternating ZnO4 and PO4 tetrahedra, are assemblied via self-complementary strong and symmetrical hydrogen-bonding R22(8) synthons between the phosphate groups into three-dimensional hydrogen bond frameworks featuring three-dimensional intersecting pseudochannels. The doubly protonated 2,5-dimethylpiperazinium cations are attached to the three-dimensional inorganic framework via N-H···O hydrogen bonds to strengthen the 3-D network.

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