(Z)-Selective anti-Markovnikov or Markovnikov thiol–yne-click reactions of an internal alkyne by amide hydrogen bond control

2020 ◽  
Vol 56 (20) ◽  
pp. 2991-2994 ◽  
Author(s):  
Milan Pramanik ◽  
Khokan Choudhuri ◽  
Subhayan Chakraborty ◽  
Arindam Ghosh ◽  
Prasenjit Mal
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Amide Hydrogen ◽  
Click Reactions ◽  
Metal Free ◽  
Hydrogen Bonding Interactions ◽  
Internal Alkyne

Hydrogen bonding interactions like N–H⋯S, N–H⋯N and C–H⋯O helped to obtain either (Z)-selective anti-Markovnikov or Markovnikov Thiol–Yne-Click products exclusively with excellent yields from an internal alkyne under metal free conditions.

scholarly journals Pentaaqua(1H-benzimidazole-5,6-dicarboxylato-κN3)cobalt(II) pentahydrate

2009 ◽  
Vol 65 (6) ◽  
pp. m702-m702 ◽  
Author(s):  
Wen-Dong Song ◽  
Hao Wang ◽  
Shi-Jie Li ◽  
Pei-Wen Qin ◽  
Shi-Wei Hu
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Organic Ligand ◽  
Octahedral Geometry ◽  
Mononuclear Complex ◽  
Distorted Octahedral Geometry ◽  
Water Molecules ◽  
Supramolecular Network ◽  
Hydrogen Bonding Interactions ◽  
Distorted Octahedral

In the title mononuclear complex, [Co(C9H4N2O4)(H2O)5]·5H2O, the CoIIatom exhibits a distorted octahedral geometry involving an N atom of a 1H-benzimidazole-5,6-dicarboxylate ligand and five water O atoms. A supramolecular network is generated through intermolecular O—H...O hydrogen-bonding interactions involving the coordinated and uncoordinated water molecules and the carboxyl O atoms of the organic ligand. An intermolecular N—H...O hydrogen bond is also observed.

Sulfur as hydrogen-bond acceptor in cocrystals of 2-thio-modified thymine

2018 ◽  
Vol 74 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Wilhelm Maximilian Hützler ◽  
Michael Bolte
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Engineering ◽  
Rational Design ◽  
Three Dimensional ◽  
Good Reliability ◽  
Hydrogen Bond Acceptor ◽  
Hydrogen Bonding Interactions ◽  
Hydrogen Bonding Site ◽  
Hydrogen Bonded

Doubly and triply hydrogen-bonded supramolecular synthons are of particular interest for the rational design of crystal and cocrystal structures in crystal engineering since they show a high robustness due to their high stability and good reliability. The compound 5-methyl-2-thiouracil (2-thiothymine) contains an ADA hydrogen-bonding site (A = acceptor and D = donor) if the S atom is considered as an acceptor. We report herein the results of cocrystallization experiments with the coformers 2,4-diaminopyrimidine, 2,4-diamino-6-phenyl-1,3,5-triazine, 6-amino-3H-isocytosine and melamine, which contain complementary DAD hydrogen-bonding sites and, therefore, should be capable of forming a mixed ADA–DAD N—H...S/N—H...N/N—H...O synthon (denoted synthon 3s N·S;N·N;N·O), consisting of three different hydrogen bonds with 5-methyl-2-thiouracil. The experiments yielded one cocrystal and five solvated cocrystals, namely 5-methyl-2-thiouracil–2,4-diaminopyrimidine (1/2), C5H6N2OS·2C4H6N4, (I), 5-methyl-2-thiouracil–2,4-diaminopyrimidine–N,N-dimethylformamide (2/2/1), 2C5H6N2OS·2C4H6N4·C3H7NO, (II), 5-methyl-2-thiouracil–2,4-diamino-6-phenyl-1,3,5-triazine–N,N-dimethylformamide (2/2/1), 2C5H6N2OS·2C9H9N5·C3H7NO, (III), 5-methyl-2-thiouracil–6-amino-3H-isocytosine–N,N-dimethylformamide (2/2/1), (IV), 2C5H6N2OS·2C4H6N4O·C3H7NO, (IV), 5-methyl-2-thiouracil–6-amino-3H-isocytosine–N,N-dimethylacetamide (2/2/1), 2C5H6N2OS·2C4H6N4O·C4H9NO, (V), and 5-methyl-2-thiouracil–melamine (3/2), 3C5H6N2OS·2C3H6N6, (VI). Synthon 3s N·S;N·N;N·O was formed in three structures in which two-dimensional hydrogen-bonded networks are observed, while doubly hydrogen-bonded interactions were formed instead in the remaining three cocrystals whereby three-dimensional networks are preferred. As desired, the S atoms are involved in hydrogen-bonding interactions in all six structures, thus illustrating the ability of sulfur to act as a hydrogen-bond acceptor and, therefore, its value for application in crystal engineering.

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).

Vibrational spectra, hydrogen bonding interactions and chemical reactivity analysis of nicotinamide–citric acid cocrystals by an experimental and theoretical approach

2019 ◽  
Vol 43 (40) ◽  
pp. 15956-15967 ◽  
Author(s):  
Priya Verma ◽  
Anubha Srivastava ◽  
Anuradha Shukla ◽  
Poonam Tandon ◽  
Manishkumar R. Shimpi
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Citric Acid ◽  
Physicochemical Properties ◽  
Vibrational Spectra ◽  
Theoretical Approach ◽  
Chemical Reactivity ◽  
Hydrogen Bond Interactions ◽  
Hydrogen Bonding Interactions

The hydrogen bond interactions in the cocrystal lead to spatial arrangements enhancing the physicochemical properties.

Correspondence: Hydrogen Bond to Gold? 1H NMR is Not a Proof of Hydrogen Bonds in Transition Metal Complexes

2018 ◽  
Author(s):  
Jan Vícha ◽  
Cina Foroutan-Nejad ◽  
Michal Straka
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Chemical Shifts ◽  
X Ray ◽  
Structure And Dynamics ◽  
Hydrogen Bonding Interactions ◽  
Overall Stability ◽  
Gold Compounds ◽  
C Nmr

Illusive Au<sup>I/III</sup>···H hydrogen bonds and their effect on structure and dynamics of molecules have been a matter of debate. While a number of X-ray studies reported gold compounds with short Au<sup>I/III</sup>···H contacts, a solid spectroscopic evidence for Au<sup>I/III</sup>···H bonding has been missing. Recently<a></a><a>, Bakar <i>et al.</i></a> (NATURE COMMUNICATIONS 8:576) reported compound with four short Au···H contacts (2.61­–2.66 Å; X-ray determined). Assuming the central cluster be [Au<sub>6</sub>]<sup>2+</sup>and observing the <sup>1</sup>H (<sup>13</sup>C) NMR resonances at relevant H(C) nuclei deshielded with respect to precursor compound, the authors concluded with reservations that <i>“the present Au···H–C interaction is a kind of “hydrogen bond”, where the [Au<sub>6</sub>]<sup>2+</sup>serves as an acceptor”</i>. Here, we show that the Au<sub>6</sub>cluster in their compound bears negative charge and the Au···H contacts lead to a weak (~1 kcal/mol) auride···hydrogen bonding interactions, though unimportant for the overall stability of<b></b>the molecule. Additionally, computational analysis of NMR chemical shifts reveals that the deshielding effects at respective hydrogen nuclei are not directly related to Au···H–C hydrogen bonding .

Amide hydrogen bonding in organic medium

1980 ◽  
Vol 58 (13) ◽  
pp. 1372-1375 ◽  
Author(s):  
J. N. Spencer ◽  
Robert C. Garrett ◽  
Fred J. Mayer ◽  
Johanna E. Merkle ◽  
Carla R. Powell ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Proton Donor ◽  
Organic Medium ◽  
Association Constants ◽  
The Self ◽  
Amide Hydrogen ◽  
Theoretical Predictions ◽  
Self Association

Thermodynamic parameters for the self-association of N-methylformamide and N-methylacetamide in CCl4 solvent have been determined by infrared spectroscopy. The pure base calorimetric method was used to determine the enthalpy of hydrogen bond complex formation of N-methylformamide and N-methylacetamide with N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and dioxane. Comparison of the calorimetric and spectroscopic results show that the dimers of N-methylformamide and N-methylacetamide are linear with hydrogen bond enthalpies of −2.9 and −3.9 kcal mol−1 respectively. The carbonyl group of N-methylacetamide was found to be a better proton accepter than the carbonyl of N-methylformamide in agreement with theoretical predictions. N-methylacetamide was found to be a better proton donor than N-methylformamide in disagreement with theoretical predictions. The dimer self-association constants appear to be larger than previously reported.

scholarly journals Hydrogen-Bond-Promoted Metal-Free Hydroamination of Alkynes

Synlett ◽  
2019 ◽  
Vol 30 (18) ◽  
pp. 2086-2090
Author(s):  
Janet Bahri ◽  
Nour Tanbouza ◽  
Thierry Ollevier ◽  
Marc Taillefer ◽  
Florian Monnier
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Ethylene Glycol ◽  
Proton Exchange ◽  
Secondary Amines ◽  
Metal Free ◽  
Original Metal

An original metal-free regio- and stereoselective intermolecular hydroamination of alkynes is described. Various (E)-enamines were obtained from arylacetylenes and aliphatic secondary amines in the presence of ethylene glycol as a solvent. The latter is assumed to play a major role in the mechanism through hydrogen bonding and proton exchange.

Halogen-bond and hydrogen-bond interactions between three benzene derivatives and dimethyl sulphoxide

2014 ◽  
Vol 16 (15) ◽  
pp. 6946-6956 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Nan-Nan Wang ◽  
Yu Zhou ◽  
Zhi-Wu Yu
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Computational Methods ◽  
Halogen Bond ◽  
Dimethyl Sulphoxide ◽  
Benzene Derivatives ◽  
Hydrogen Bond Interactions ◽  
Hydrogen Bonding Interactions

We examine and compare the halogen- and hydrogen-bonding interactions between benzene derivatives and DMSO by experimental and computational methods.

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