ChemInform Abstract: Activation of a Vinyl Carbon-Hydrogen Bond in a Tris(pyrazolyl)boratoiridium Complex. The X-Ray Crystal Structure of (IrH(HB(pz)3)(σ-C8H13)(η2-C8H14)).

ChemInform ◽  
1990 ◽  
Vol 21 (4) ◽  
Author(s):  
M. J. FERNANDEZ ◽  
M. J. RODRIGUEZ ◽  
L. A. ORO ◽  
F. J. LAHOZ
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Vinyl Carbon ◽  
X Ray

Crystal structure of ziprasidone hydrochloride monohydrate, C21H22Cl2N4OS(H2O)

2015 ◽  
Vol 30 (3) ◽  
pp. 192-198
Author(s):  
James A. Kaduk ◽  
Kai Zhong ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Powder Diffraction ◽  
Density Functional ◽  
Minimum Energy ◽  
Strong Hydrogen Bond ◽  
Powder Diffraction File ◽  
X Ray ◽  
Hydrochloride Monohydrate ◽  
Positively Charged

The crystal structure of ziprasidone hydrochloride monohydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Ziprasidone hydrochloride monohydrate crystallizes in space group P-1 (#2) with a = 7.250 10(3), b = 10.986 66(8), c = 14.071 87(14) Å, α = 83.4310(4), β = 80.5931(6), γ = 87.1437(6)°, V = 1098.00(1) Å3, and Z = 2. The ziprasidone conformation in the solid state is very close to the minimum energy conformation. The positively-charged nitrogen in the ziprasidone makes a strong hydrogen bond with the chloride anion. The water molecule makes two weaker bonds to the chloride, and acts as an acceptor in an N–H⋯O hydrogen bond. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1492.

The crystal structure of ethyl-Z-3-amino-2-benzoyl-2-butenoate and measurement of the barrier to E,Z-isomerization

1980 ◽  
Vol 58 (17) ◽  
pp. 1821-1828 ◽  
Author(s):  
Gary D. Fallon ◽  
Bryan M. Gatehouse ◽  
Allan Pring ◽  
Ian D. Rae ◽  
Josephine A. Weigold
Keyword(s):  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bond ◽  
Free Energy ◽  
Magnetic Resonance ◽  
Energy Of Activation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Free Energy Of Activation ◽  
Nuclear Magnetic

Ethyl-3-amino-2-benzoyl-2-butenoate crystallizes from pentane as either the E (mp 82–84 °C) or the Z-isomer (mp 95.5–96.5 °C). The E isomer is less stable, and changes spontaneously into the Z, which bas been identified by X-ray crystallography. The structure is characterised by an N–H/ester CO hydrogen bond and a very long C2—C3 bond (1.39 Å). Nuclear magnetic resonance methods have been used to measure the rate of [Formula: see text] isomerization at several temperatures, leading to the estimate that the free energy of activation at 268 K is 56 ± 8 kJ.

scholarly journals Synthesis and Complexation Properties of 2-Hydroxy-5-methoxyphenylphosphonic Acid (H3L1). Crystal Structure of the [Cu(H2L1)2(Н2О)2] Complex

2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Methoxy Group ◽  
Protonation Constants ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability ◽  
Intramolecular Hydrogen ◽  
Oxygen Atoms

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.

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.

Crystal structure of methylprednisolone acetate form II, C24H32O6

2018 ◽  
Vol 33 (1) ◽  
pp. 44-48
Author(s):  
Austin M. Wheatley ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Powder Diffraction ◽  
Density Functional ◽  
Hydroxyl Groups ◽  
Methylprednisolone Acetate ◽  
Powder Diffraction File ◽  
X Ray ◽  
Bond Network ◽  
Acetate Form

The crystal structure of methylprednisolone acetate form II, C24H32O6, has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Methylprednisolone acetate crystallizes in space group P212121 (#19) with a = 8.17608(2), b = 9.67944(3), c = 26.35176(6) Å, V = 2085.474(6) Å3, and Z = 4. Both hydroxyl groups act as hydrogen bond donors, resulting in a two-dimensional hydrogen bond network in the ab plane. C–H⋯O hydrogen bonds also contribute to the crystal energy. The powder pattern is included in the Powder Diffraction File™ as entry 00-065-1412.

X-ray Crystal Structure of a Metalled Double-Helix Generated by Infinite and Consecutive C*-AgI -C* (C*:N1 -Hexylcytosine) Base Pairs through Argentophilic and Hydrogen Bond Interactions

2017 ◽  
Vol 23 (9) ◽  
pp. 2103-2108 ◽  
Author(s):  
Angel Terrón ◽  
Blas Moreno-Vachiano ◽  
Antonio Bauzá ◽  
Angel García-Raso ◽  
Juan Jesús Fiol ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Double Helix ◽  
Base Pairs ◽  
X Ray ◽  
Hydrogen Bond Interactions

scholarly journals The caesium phosphates Cs3(H1.5PO4)2(H2O)2, Cs3(H1.5PO4)2, Cs4P2O7(H2O)4, and CsPO3

2020 ◽  
Vol 151 (9) ◽  
pp. 1317-1328
Author(s):  
Matthias Weil ◽  
Berthold Stöger
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Single Crystal ◽  
Diffraction Data ◽  
Room Temperature ◽  
Structure Type ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Hydrogen Phosphate ◽  
X Ray

Abstract The caesium phosphates Cs3(H1.5PO4)2(H2O)2 and Cs3(H1.5PO4)2 were obtained from aqueous solutions, and Cs4P2O7(H2O)4 and CsPO3 from solid state reactions, respectively. Cs3(H1.5PO4)2, Cs4P2O7(H2O)4, and CsPO3 were fully structurally characterized for the first time on basis of single-crystal X-ray diffraction data recorded at − 173 °C. Monoclinic Cs3(H1.5PO4)2 (Z = 2, C2/m) represents a new structure type and comprises hydrogen phosphate groups involved in the formation of a strong non-symmetrical hydrogen bond (accompanied by a disordered H atom over a twofold rotation axis) and a very strong symmetric hydrogen bond (with the H atom situated on an inversion centre) with symmetry-related neighbouring anions. Triclinic Cs4P2O7(H2O)4 (Z = 2, P$$\bar{1}$$ 1 ¯ ) crystallizes also in a new structure type and is represented by a diphosphate group with a P–O–P bridging angle of 128.5°. Although H atoms of the water molecules were not modelled, O···O distances point to hydrogen bonds of medium strengths in the crystal structure. CsPO3 is monoclinic (Z = 4, P21/n) and belongs to the family of catena-polyphosphates (MPO3)n with a repetition period of 2. It is isotypic with the room-temperature modification of RbPO3. The crystal structure of Cs3(H1.5PO4)2(H2O)2 was re-evaluated on the basis of single-crystal X-ray diffraction data at − 173 °C, revealing that two adjacent hydrogen phosphate anions are connected by a very strong and non-symmetrical hydrogen bond, in contrast to the previously described symmetrical bonding situation derived from room temperature X-ray diffraction data. In the four title crystal structures, coordination numbers of the caesium cations range from 7 to 12. Graphic abstract

Article

1998 ◽  
Vol 76 (3) ◽  
pp. 301-306
Author(s):  
Sengen Sun ◽  
James F Britten ◽  
Christopher N Cow ◽  
Chérif F Matta ◽  
Paul HM Harrison
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
The Other ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Form Part ◽  
Two Sides ◽  
Opposite Helicity

The crystal structure of 3,4,7,8-tetramethylglycoluril (5) was determined by X-ray diffraction. The structure reveals a hydrogen-bonding motif in the crystal lattice that differs from that present in related glycolurils. The two sides of each molecule form part of two independent, but parallel, infinite helical chains. These chains are formed by the NH donor and C==O acceptor on one side of a glycoluril molecule, forming H-bonds to two different molecules at adjacent positions within the helix. On the other side of the same molecule, a similar motif generates another helix of opposite helicity to the first. The molecule has a crystallographic plane of symmetry through the two bridgehead carbon atoms and the two bridgehead methyl groups, which are syn-periplanar. Thus, 5 is similar to 3,4-dimethylglycoluril (3), but differs from some glycolurils, where there is a significant dihedral angle between the two bridgehead-to-bridgehead substituent bonds. Bond lengths and angles in 5 resemble those reported for 3, but bond lengths around the bridgehead positions are slightly lengthened relative to 3.Key words: glycoluril, 1,2,5,8-tetramethyl-2,6,7,8-tetraazabicyclo[3.3.0]octane-3,7-dione, X-ray diffraction, crystal structure, hydrogen-bond array.

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