Bis(methylphosphonic Acid) Derivatives of 1,4,8,11-Tetraazacyclotetradecane (Cyclam). Synthesis, Crystal and Molecular Structures, and Solution Properties

2000 ◽  
Vol 65 (8) ◽  
pp. 1289-1316 ◽  
Author(s):  
Jan Kotek ◽  
Pavel Vojtíšek ◽  
Ivana Císařová ◽  
Petr Hermann ◽  
Petr Jurečka ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Phosphonic Acid ◽  
Activation Parameters ◽  
Molecular Structures ◽  
Methylphosphonic Acid ◽  
Diethyl Phosphite ◽  
Temperature Dependent ◽  
Acid Moiety ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Cyclam derivatives with methylphosphonic acid arms in position 1,8 and substituent R = H, Me, CH2Ph in positions 4 and 11 are synthesised by Mannich reaction of an appropriate cyclam derivative, formaldehyde and phosphonic acid/diethyl phosphite followed by removal of protecting benzyl groups from nitrogen atoms. Mono(methylphosphonic acid) derivative of cyclam can be obtained by a similar route. Crystal structures of four phosphonic acid derivatives show the same ring conformation and orientation pendants due to strong intramolecular hydrogen bonds between phosphonate oxygen atoms and protonated nitrogen atoms adjacent over ethylene chains. The hydrogen bonds are stable even in aqueous solution. Activation parameters for destabilisation of the conformation are estimated from temperature-dependent NMR measurement. The protonation constants determined confirm the expected high basicity of the compounds and its dependence on the nitrogen atom substituents. The enhanced basicity of the nitrogen atoms non-bonded to methylenephosphonic acid moiety, is explained by the presence of the strong hydrogen bonds.

Hydrogen bonds in derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea

1991 ◽  
Vol 56 (4) ◽  
pp. 880-885 ◽  
Author(s):  
Oľga Hritzová ◽  
Dušan Koščík
Keyword(s):  
Hydrogen Bonds ◽  
Spectral Studies ◽  
Intramolecular Hydrogen Bonds ◽  
Tautomeric Forms ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Intramolecular hydrogen bonds of the N-H···O=C type have been detected in the derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea on the basis of IR spectral studies. The title compounds can exist in two tautomeric forms.

Intramolecular hydrogen bonds in the sulfonamide derivatives of oxamide, dithiooxamide, and biuret. FT-IR and DFT study, AIM and NBO analysis

Tetrahedron ◽  
2010 ◽  
Vol 66 (44) ◽  
pp. 8551-8556 ◽  
Author(s):  
B.A. Shainyan ◽  
N.N. Chipanina ◽  
T.N. Aksamentova ◽  
L.P. Oznobikhina ◽  
G.N. Rosentsveig ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Nbo Analysis ◽  
Dft Study ◽  
Intramolecular Hydrogen Bonds ◽  
Ft Ir ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Aim And Nbo

Intramolecular hydrogen bonds involving organic fluorine in the derivatives of hydrazides: an NMR investigation substantiated by DFT based theoretical calculations

2015 ◽  
Vol 17 (23) ◽  
pp. 15226-15235 ◽  
Author(s):  
Sandeep Kumar Mishra ◽  
N. Suryaprakash
Keyword(s):  
Hydrogen Bonds ◽  
Theoretical Calculations ◽  
Two Dimensional ◽  
Dimensional Solution ◽  
Intramolecular Hydrogen Bonds ◽  
Solution State ◽  
Nmr Techniques ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Organic Fluorine

The rare examples of intramolecular hydrogen bonds (HB) of the type the N–H⋯F–C, detected in a low polarity solvent in the derivatives of hydrazides, by utilizing one and two-dimensional solution state multinuclear NMR techniques, are reported.

scholarly journals Correlation Effects in Trimeric Acylphloroglucinols

Computation ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 121
Author(s):  
Liliana Mammino
Keyword(s):  
Hydrogen Bonds ◽  
Biological Activities ◽  
Correlation Effects ◽  
Comprehensive Overview ◽  
Conformational Preferences ◽  
B3lyp Calculations ◽  
Electron Correlation Effects ◽  
The Individual ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Trimeric acylphloroglucinols (T-ACPLs) are a subclass of the large class of acylphloroglucinols—derivatives of 1,3,5-trihydroxybenzene containing an R–C=O group. T-ACPL molecules contain three acylphloroglucinol moieties linked by methylene bridges. Many of them are present in natural sources and exhibit biological activities, often better than the corresponding activities of monomeric acylphloroglucinols. All the stable conformers of T-ACPLs contain seven intramolecular hydrogen bonds, which constitute the dominant stabilising factors. A total of 38 different T-ACPLs, including both naturally occurring and model molecules, have been calculated at the HF and DFT/B3LYP levels. The DFT/B3LYP calculations were carried out both without and with Grimme’s dispersion correction, to highlight the dispersion (and, therefore, also electron correlation) effects for these molecules. The roles of dispersion are evaluated considering the effects of Grimme’s correction on the estimation of the conformers’ energies, the description of the characteristics of the individual hydrogen bonds, the conformers’ geometries and other molecular properties. Overall, the results offer a comprehensive overview of the conformational preferences of T-ACPL molecules, their intramolecular hydrogen bond patterns, and the correlation effects on their properties.

scholarly journals Intramolecular hydrogen bond directed distribution of conformational populations in the derivatives of N′-benzylidenebenzohydrazide

2019 ◽  
Vol 43 (33) ◽  
pp. 13134-13142 ◽  
Author(s):  
Neeru Arya ◽  
Sandeep Kumar Mishra ◽  
N. Suryaprakash
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

The extensive NMR investigations reveal the presence of E-isomers in the derivative of N′-benzylidenebenzohydrazide. The different conformer populations are controlled by the strength of intramolecular hydrogen bonds.

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