scholarly journals Intramolecular hydrogen bonding in conformationally semi-rigid α-acylmethane derivatives: a theoretical NMR study

2017 ◽  
Vol 15 (36) ◽  
pp. 7572-7579 ◽  
Author(s):  
Antonio J. Mota ◽  
Jürgen Neuhold ◽  
Martina Drescher ◽  
Sébastien Lemouzy ◽  
Leticia González ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Hydrogen Bonding Interactions ◽  
Nmr Study ◽  
Intramolecular Hydrogen

Experimental and computational evidence for unusual intramolecular hydrogen-bonding interactions is presented and discussed.

Synthesis of a series of M(ii) (M = Mn, Fe, Co) chloride complexes with both inter- and intra-ligand hydrogen bonding interactions

2021 ◽  
Vol 50 (35) ◽  
pp. 12088-12092
Author(s):  
Clare A. Leahy ◽  
Michael J. Drummond ◽  
Josh Vura-Weis ◽  
Alison R. Fout
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Intramolecular Hydrogen Bonding ◽  
Metal Chloride ◽  
Chloride Complexes ◽  
Hydrogen Bonding Interactions ◽  
Transition Metal Chloride ◽  
Hydrogen Bonding Networks ◽  
Intramolecular Hydrogen

Hydrogen bonding networks are vital for metallo-enzymes to function; however, modeling these systems is non-trivial. The development of 1st-row transition metal chloride complexes with intramolecular hydrogen-bonding interactions are detailed herein.

Longipilin acetate

2006 ◽  
Vol 62 (4) ◽  
pp. o1330-o1332 ◽  
Author(s):  
Olga L. Ospina ◽  
Carlos A. Rojas ◽  
Daniel Vega
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Membered Ring ◽  
Native Plant ◽  
Hydrogen Bonding Interactions ◽  
Molecular Folding ◽  
Intramolecular Hydrogen

Longipilin acetate, C23H28O9, is a compound isolated from Espeletia killipii, a Colombian native plant. The molecule contains two non-planar rings, a ten-membered ring and a five-membered lactone. Various substituents around the ten-membered ring provide very weak intramolecular hydrogen-bonding interactions that determine the molecular folding.

THE EFFECT OF SUBSTITUTION ON STRUCTURE, INTRAMOLECULAR HYDROGEN BONDING STRENGTH, ELECTRON DENSITY AND RESONANCE IN 3-AMINO 2-IMINOMETHYL ACRYL ALDEHYDE

2012 ◽  
Vol 11 (05) ◽  
pp. 925-939 ◽  
Author(s):  
HEIDAR RAISSI ◽  
MAHDI YOOSEFIAN ◽  
FARIBA MOLLANIA ◽  
FARZANEH FARZAD
Keyword(s):  
Hydrogen Bonding ◽  
Electron Density ◽  
Population Analysis ◽  
Intramolecular Hydrogen Bonding ◽  
Analysis Data ◽  
Covalent Character ◽  
Hydrogen Bonding Interactions ◽  
Hydrogen Bond Strength ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonding Strength

B3LYP/6-311++G** calculations have been carried out to simulate the influence of substitutions in position R1 and R2 of 3-amino 2-iminomethyl acryl aldehyde on intramolecular hydrogen bond strength. The following substituents are taken into considerations: CN, NO2, Cl, F, CH3, CHO, NH2, C2H5, SH, SCH3, CF3 and CH3CO and their vibrational frequencies are calculated at the same level of theory. Quantum theory of "Atoms in Molecules" and Natural Bond Orbitals method were applied to analyzed H-bond interactions. The electron density (ρ) and Laplacian (∇2ρ) properties, estimated by AIM calculations, indicate that N⋯H bond possesses low ρ and positive ∇2ρ values which are in agreement with electrostatic character of the HBs, whereas N–H bonds have covalent character (∇2ρ < 0). Natural population analysis data, the electron density and Laplacian properties, as well as, ν (N-H) and γ (N-H) have been used to evaluate the hydrogen bonding interactions.

Emergent Supramolecular Assembly Properties of Recognition-Encoded Oligoesters

2019 ◽  
Author(s):  
Filip Szczypiński ◽  
Luca Gabrielli ◽  
Christopher Hunter
Keyword(s):  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Supramolecular Assembly ◽  
Functional Materials ◽  
Intramolecular Hydrogen Bonding ◽  
Dimensional Structure ◽  
Stem Loop ◽  
Recognition Sites ◽  
Hydrogen Bonding Interactions ◽  
Intramolecular Hydrogen

The sequences of oligomeric molecules equipped with interacting side-chains encode the three-dimensional structure, the supramolecular assembly properties, and ultimately function. In an attempt to replicate the duplex forming properties of nucleic acids, an oligoester containing an alternating sequence of hydrogen bonding donor (<b>D</b>) and acceptor (<b>A</b>) residues was synthesised. Characterisation of assembly properties of the <b>ADAD</b> oligomer revealed a supramolecular architecture that resembles the kissing stem-loops motif found in folded RNA. NMR dilution and melting experiments in chloroform and 1,1,2,2-tetrachloroethane show that intramolecular hydrogen bonding interactions between the terminal phenol and phosphine oxide recognition sites in the <b>ADAD</b> 4-mer leads to 1,4-folding. This folded stem-loop structure can be denatured to give the single strand by heating. At higher concentrations or lower temperatures, the stem-loop dimerises via intermolecular hydrogen bonding interactions between the two inner recognition sites, leading to a kissing stem-loops structure. The results suggest a rich supramolecular chemistry for these recognition-encoded oligoesters and lay strong foundations for the future development of new functional materials based on synthetic information molecules.

A zirconium zwitterion containing a caged amine H atom

2003 ◽  
Vol 59 (11) ◽  
pp. m494-m496 ◽  
Author(s):  
Alastair J. Nielson ◽  
Chaohong Shen ◽  
Joyce M. Waters
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Octahedral Geometry ◽  
Distorted Octahedral Geometry ◽  
Charge Balance ◽  
Aromatic Rings ◽  
Hydrogen Bonding Interactions ◽  
Distorted Octahedral ◽  
Intramolecular Hydrogen

The crystallographically centrosymmetric zwitterion bis[tris(3,5-dimethyl-2-oxidobenzyl-κO)ammonium]zirconium(IV) crystallizes as the chloroform disolvate, [Zr(C27H31NO3)2]·2CHCl3, with the two molecules of chloroform closely associated with two of the aromatic rings. The Zr atom has a distorted octahedral geometry with three phenoxy O atoms from each of the two ligands coordinated to it. Charge balance is maintained by protonation of each N atom, which then forms intramolecular hydrogen-bonding interactions to all three adjacent O atoms.

Synthesis, molecular packing and anti-cholinesterase activity of some new C-2 N-substituted anthranilamide derivatives

2019 ◽  
Vol 234 (9) ◽  
pp. 605-611 ◽  
Author(s):  
Muhammad Sarfraz ◽  
Nargis Sultana ◽  
Muhammad Ilyas Tariq ◽  
Masood Parvez
Keyword(s):  
Hydrogen Bonding ◽  
Cholinesterase Activity ◽  
Intramolecular Hydrogen Bonding ◽  
Pharmacokinetic Profile ◽  
Intermolecular Hydrogen Bonds ◽  
Standard Drug ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Intramolecular Hydrogen

Abstract Synthesis of C-2 N-substituted anthranilamide derivatives was carried out in a straight forward manner, utilizing 2-aminobenzamide and benzyl chloride as starting materials. Their crystal structures have been established by single crystal X-ray crystallographic method. In the molecules of 2-benzylamino-benzamide (3a), intramolecular hydrogen bonding b/w O atom and proton of –NH and classical intermolecular hydrogen bonding of the type N–H · · · O forming eight membered rings in R42(8) pattern. In both molecules of 2-(dibenzylamino)benzamide (3b), unlike the molecule in 3a, each H atoms is pointed towards N atom causing intramolecular hydrogen bonding interactions, resulting in S(6) motifs. However, it is interesting to note that both molecules in 3b are lying about inversion centres and form dimers in R42(8) motifs; the two dimers are linked via non-classical intermolecular hydrogen bonds C–H · · · O resulting in clusters of four molecules in the structure. In vitro assay results revealed that molecule 3b with IC50 values of 3.8 ± 0.08 μM (AChE) and 17.6 ± 1.10 μM (BChE) possessed better cholinesterase (AChE and BChE) inhibition potential as compared to standard drug galantamine. Preliminary in silico studies showed that more biological active derivatives were also having good pharmacokinetic profile with no AMES toxicity and carcinogenicity.

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