A Single-Crystal X-Ray Analysis of a Novel Intramolecular Hydrogen-Bonded Biphenyl Phosphorane

1990 ◽  
Vol 43 (4) ◽  
pp. 765 ◽  
Author(s):  
AD Abell ◽  
KB Morris ◽  
V Mckee

An X-ray crystal structure and 1H n.m.r. analysis of the biphenyl phosphorane (4a) has revealed the presence of an intramolecular hydrogen bond resulting in an unusual biphenyl with a bridge forming a nine- membered ring. The related biphenyl phosphorane (4b) exists as two diastereoisomers.

2006 ◽  
Vol 62 (5) ◽  
pp. o1679-o1681
Author(s):  
Jun-Fei Li ◽  
Hai-Bin Song ◽  
You-Quan Zhu ◽  
Hua-Zheng Yang

The title molecule, C17H25N5O3S2, belongs to the family of bis-heterocycles. In the crystal structure, there are one intra- and two intermolecular hydrogen bonds. One of the two pyrazole rings and the six-membered ring formed by the intramolecular hydrogen bond are approximately coplanar.


2016 ◽  
Vol 72 (9) ◽  
pp. 1239-1241 ◽  
Author(s):  
Galal H. Elgemeie ◽  
Peter G. Jones

In the title compound, C11H13N3O, the seven-membered ring adopts a conformation such that the three atoms not involved in the aromatic plane lie on the same side of that plane. One hydrazinic H atom forms an intramolecular hydrogen bond to the O atom; the other forms a classical intermolecular hydrogen bond N—H...O, which combines with a `weak' Har...O interaction to build up double layers of molecules parallel to thebcplane.


2002 ◽  
Vol 2 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Karna Wijaya ◽  
Iqmal Tahir ◽  
Armand Blaschette ◽  
Oliver Mours ◽  
Peter G Jones

The compound was prepared by dissolving 2-(phenylamino)pyridine (0.52 g ; 3.0 mmol) and di(methanesulfonyl)amine (0.51 g; 3.0 mmol) in 5 mL methanol. Slow partial evaporation of the solvent at low tempertaure (-30 oC) gave a yield of 0.66 g (64%) and crystals suitable for X-ray study (m.p. 150-152 oC). The single crystal X-ray result showed that the crystal system was trikline with space group P. The crystal structure of the title compound 2-(phenylamino)pyridinium-di(methane-sulfonyl)amidate forms a robust antidromic ring motif type. The structure testifies to the persistence of the  in question, which was previously detected as a robust supramolecular synthon in 2-aminopyridinium di(benzenesulfonyl)amidate and in a series of onium di(methane-sulfonyl)amidates.   Keywords: supramolecule, hydrogen-bond


Author(s):  
Kate J. Akerman ◽  
Orde Q. Munro

The Schiff base enaminones (3Z)-4-(5-ethylsulfonyl-2-hydroxyanilino)pent-3-en-2-one, C13H17NO4S, (I), and (3Z)-4-(5-tert-butyl-2-hydroxyanilino)pent-3-en-2-one, C15H21NO2, (II), were studied by X-ray crystallography and density functional theory (DFT). Although the keto tautomer of these compounds is dominant, the O=C—C=C—N bond lengths are consistent with some electron delocalization and partial enol character. Both (I) and (II) are nonplanar, with the amino–phenol group canted relative to the rest of the molecule; the twist about the N(enamine)—C(aryl) bond leads to dihedral angles of 40.5 (2) and −116.7 (1)° for (I) and (II), respectively. Compound (I) has a bifurcated intramolecular hydrogen bond between the N—H group and the flanking carbonyl and hydroxy O atoms, as well as an intermolecular hydrogen bond, leading to an infinite one-dimensional hydrogen-bonded chain. Compound (II) has one intramolecular hydrogen bond and one intermolecular C=O...H—O hydrogen bond, and consequently also forms a one-dimensional hydrogen-bonded chain. The DFT-calculated structures [in vacuo, B3LYP/6-311G(d,p) level] for the keto tautomers compare favourably with the X-ray crystal structures of (I) and (II), confirming the dominance of the keto tautomer. The simulations indicate that the keto tautomers are 20.55 and 18.86 kJ mol−1lower in energy than the enol tautomers for (I) and (II), respectively.


2016 ◽  
Vol 40 (12) ◽  
pp. 753-757
Author(s):  
Shagufta Perveen ◽  
Jeremy D. Kilburn ◽  
Areej M. Al-Taweel ◽  
Mark E. Light

A novel pyridyl urea based macrocycle has been synthesised and fully characterised including a single crystal X-ray structure determination. The synthetic approach first involves the reaction of benzyloxycarbonylaminopropyl-3-isocyanate with t-butyl 2-[(2-aminopyridin-3-yl)oxy]acetate resulting in a coupling product. After deprotection of the amine and acid moieties and coupling subsequent coupling in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), a macrocycle is formed. The structures of the compounds were confirmed by mass spectrometry and NMR spectroscopy. The X-ray crystal structure of the macrocycle reveals as expected a non-binding conformation with an intramolecular hydrogen bond between the urea NH and the pyridyl nitrogen.


2019 ◽  
Vol 41 (3) ◽  
pp. 452-452
Author(s):  
Juan Liu Juan Liu ◽  
Wen Zhi Wang Wen Zhi Wang ◽  
Jia Zhen Wang Jia Zhen Wang ◽  
Gui Ge Hou Gui Ge Hou ◽  
Qing Guo Meng Qing Guo Meng

(20R,24R)-epoxy-dammar-3β,6α,12β,25-tetraol (1) and (20R,24S)-epoxy- dammar-3β, 6α,12β,25-tetraol (2) have been synthesized from 20(R)-protopanaxatriol with same polarity. In order to obtain optically pure 1 and 2, (20R,24R)-3,6-diacetyl- 20,24-epoxydammar-3β,6α,12β,25-tetraol (3) and (20R,24S)-3,6-diacetyl-20,24- epoxydammar-3β,6α,12β,25-tetraol (4) were designed and prepared to enhance the polarity difference of C24 epimers. Two suitable crystals of 3 and 4 were obtained and their structures were determined by 1H NMR, 13C NMR, HR-MS and X-ray single-crystal diffraction. The results indicated that the C-24 configuration of 3 and 4 are R-form and S-form, respectively. 3 has two intramolecular hydrogen bond. While there is only one in 4 and the crystal stacking displays that it generates a right-handed helically chiral channel viewing from the crystallographic b axis via classical O–H•••O intermolecular hydrogen bond.


2005 ◽  
Vol 60 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Pritha Talukder ◽  
Amitabha Datta ◽  
Samiran Mitra ◽  
Georgina Rosair

A new one-dimensional coordination polymer [Co(CCl3COO)2(CH3OH)2(μ-4,4’-bipy)]n (1), has been synthesised and its crystal structure determined by single-crystal X-ray diffraction. The structure consists of a one-dimensional linear chain of cobalt(II) centres linked by bridging 4,4’-bipyridine units. The Co(II) ion lies at an inversion centre forming an elongated octahedral coordination sphere. There is an intramolecular hydrogen bond [2.02(5) Å ] between a trichloroacetate oxygen and a methanolic hydrogen forming a planar six-membered ring.


1984 ◽  
Vol 39 (7-8) ◽  
pp. 720-724 ◽  
Author(s):  
Bogdan Lesyng ◽  
Christian Marck ◽  
Wolfram Saenger

Abstract From an equimolar dipeptide/xanthosine mixture in water/methanol, only the nucleoside crystallized in anhydrous form, space group P212121 with a = 17.406 (5) Å, b = 12.378 (4), c = 5.350 (2) Å, Z = 4, C10H12O6N4, FW = 284.26, Dx = 1.639 g · cm-3. The structure was determined by direct methods on the basis of 984 X-ray data and refined to an agreement index of R = 3.9%. Xanthosine occurs in the syn conformation with χ = -132.7° which is stabilized by an intramolecular hydrogen bond N (3) - H ... O(5′). The pseudorotation parameters for sugar puckering are P = 156° and τm = 38.7° corresponding to C(2′)-endo form. The crystal packing of xanthosine in anhydrous and dihydrate modifications are very different, yet the molecular conformations are similar. In the anhydrous form, an unusual intramolecular hydrogen bond O (2′) - H ... O(3′) is observed.


2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  

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.


Sign in / Sign up

Export Citation Format

Share Document