Neutral Pyrrole Nitrogen Atom as a π- and Mixed n,π-Donor in Hydrogen Bonding

2018 ◽  
Vol 84 (2) ◽  
pp. 726-737 ◽  
Author(s):  
Alexander F. Pozharskii ◽  
Valery A. Ozeryanskii ◽  
Ekaterina A. Filatova ◽  
Olga V. Dyablo ◽  
Olga G. Pogosova ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Pyrrole Nitrogen

A New Hydrogen-Bonding Motif with Constituents Bearing Donor and Acceptor Sites 7 Å Apart

2005 ◽  
Vol 60 (7) ◽  
pp. 758-762 ◽  
Author(s):  
Katja Heinze ◽  
Anja Reinhart
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Nitrogen Atom ◽  
Hydrogen Bonds ◽  
Hydrogen Donor ◽  
Para Position ◽  
Hydrogen Acceptor ◽  
Aryl Ring ◽  
Donor And Acceptor ◽  
Pyrrole Nitrogen

Aryl substituted dipyrromethanes [di(pyrrol-2-yl)-phenyl-methanes] with hydrogen acceptor substituents R in para position of the aryl ring [R = CO2Me, CO2H, CONH(iPr) and NH2] located 7 Å apart from the hydrogen donor pyrrole nitrogen atom are shown to self-assemble in the solid state via hydrogen bonds to form rings or chains.

scholarly journals Kinetics of Free Radical Polymerization of N-Substituted Amides and Their Structural Implications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Anca Aldea ◽  
Ana-Maria Albu ◽  
Alina Nicolescu ◽  
Victorita Tecuceanu
Keyword(s):  
Hydrogen Bonding ◽  
Free Radical ◽  
Nitrogen Atom ◽  
Steric Hindrance ◽  
Solvent Polarity ◽  
Hydrogen Bonding Interaction ◽  
H Nmr ◽  
Bonding Interaction ◽  
Kinetics Of ◽  
C Nmr

Two N-substituted amides (N-acryloyl morpholine and N-methyl-N-vinylacetamide) were polymerized in different solvents using radical initiator. The tacticity of obtained polymers was determined by 400 MHz1H-NMR and13C-NMR. At a given temperature, the syndiotacticity increased with increasing the solvent polarity. This solvent effect may be related to the hydrogen bonding interaction among solvent, monomer, and/or growing species. A peculiar aspect regards the steric hindrance at the nitrogen atom.

scholarly journals Isolation of two N-monosubstituted protoporphyrins, bearing either the whole drug or a methyl group on the pyrrole nitrogen atom, from liver of mice given griseofulvin

1991 ◽  
Vol 274 (3) ◽  
pp. 843-848 ◽  
Author(s):  
A E Holley ◽  
Y Frater ◽  
A H Gibbs ◽  
F De Matteis ◽  
J H Lamb ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Protoporphyrin Ix ◽  
Secondary Product ◽  
Structural Isomers ◽  
Green Pigment ◽  
Methyl Group ◽  
Group 4 ◽  
Pyrrole Nitrogen

1. A hepatic green pigment with inhibitory properties towards the enzyme ferrochelatase has been isolated from the liver of mice treated with griseofulvin and identified as N-methylprotoporphyrin. 2. All four structural isomers of N-methylprotoporphyrin have been demonstrated to be present, NA, where ring A of protoporphyrin IX is N-methylated, being the predominant isomer. 3. In addition to N-methylprotoporphyrin, a second green pigment, present in far greater amounts, was also isolated from the liver of griseofulvin-treated mice. This second green pigment is also an N-monosubstituted protoporphyrin, but in this case the substituent on the pyrrole nitrogen atom appears to be intact griseofulvin rather than a methyl group. 4. The fragmentation of this adduct in tandem m.s. studies suggests that griseofulvin is bound to the pyrrole nitrogen through one of its carbon atoms and further suggests that N-methylprotoporphyrin may arise as a secondary product from the major griseofulvin pigment.

Fixation o f Neutral Molecules in the Binding Cavity of Nonplanar Porphyrins - A Third Dodecaphenylporphyrin Modification with NH -Solvent Hydrogen Bonding

1999 ◽  
Vol 54 (6) ◽  
pp. 821 ◽  
Author(s):  
Mathias O. Senge
Keyword(s):  
Hydrogen Bonding ◽  
Crystalline Modification ◽  
Free Base ◽  
Binding Cavity ◽  
Pyrrole Nitrogen ◽  
Hydrogen Bonded

A third crystalline modification of dodecaphenylporphyrin is described in which the pyrrole nitrogen atoms are hydrogen-bonded to two ethanol molecules. This is the first crystallographic proof for the accessibility of nitrogen atoms in saddle-distorted free base porphyrins for hydrogen bonding. No such coordination is possible in either planar or ruffled porphyrins. Thus, the possibility exists to utilize conformationally distorted porphyrins for the binding of neutral m olecules

The structure of dichloro(L-histidine)copper(II)

1982 ◽  
Vol 35 (8) ◽  
pp. 1581 ◽  
Author(s):  
K Colyvas ◽  
HR Tietze ◽  
SKJ Egri
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Oxygen Atom ◽  
Least Squares ◽  
Copper Atom ◽  
Title Compound ◽  
Amino Nitrogen ◽  
Chlorine Atoms ◽  
X Ray ◽  
X Ray Crystallography

The structure of the orthorhombic form of the title compound has been determined by X-ray crystallography. The space group was found to be P212121 (No.19,D24 = V4) with a 10.01(5), b 5.944(6), c 17.5469(7) � and Z 4. The structure was refined by least squares to R 0.0614. It consists of chains of molecules with the carboxy oxygen atom, the amino nitrogen atom and the two chlorine atoms forming an approximate square plane about the copper atom, with two bridging chlorine atoms from two adjacent molecules completing a distorted octahedron. Extensive hydrogen bonding links the chains together.

Basicité de liaison hydrogène de formamidines substituées sur l'azote imino

1992 ◽  
Vol 70 (8) ◽  
pp. 2203-2208 ◽  
Author(s):  
Ewa D. Raczyńska ◽  
Christian Laurence ◽  
Michel Berthelot
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Hydrogen Bonds ◽  
Frequency Shift ◽  
Field Effect ◽  
Formation Constant ◽  
Steric Effect ◽  
Imino Nitrogen ◽  
Alkyl Groups ◽  
Electron Withdrawing Substituents

The basicity of the hydrogen bonds of formamidines 1–19 was measured by means of the formation constant KHB of their complexes with p-fluorophenol and the frequency shift Δν(OH) of methanol hydrogen-bonded to 1–19. The study of the ν(C=N) band shows that hydrogen bonding takes place with the imino nitrogen atom. On the hydrogen-bonding basicity scale, the formamidines appear to be more basic than the corresponding amides and pyridines, and as basic as the imidazoles. The field effect of electron-withdrawing substituents and the steric effect of bulky alkyl groups on the imino nitrogen atom markedly decrease the hydrogen-bonding basicity.

Intramolecular hydrogen bonding with the participation of the nitrogen atom of five- and six-membered heterocycles

1971 ◽  
Vol 7 (2) ◽  
pp. 220-225
Author(s):  
M. V. Gorelik ◽  
T. Kh. Gladysheva ◽  
N. N. Shapet'ko ◽  
B. E. Zaitsev ◽  
L. N. Kurkovskaya ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen

Structures of the adducts urea:pyrazine (1:1), thiourea:pyrazine (2:1) and thiourea:piperazine (2:1)

2017 ◽  
Vol 72 (6) ◽  
pp. 441-445 ◽  
Author(s):  
Cindy Döring ◽  
Julian F.D. Lueck ◽  
Peter G. Jones
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Hydrogen Bonds ◽  
Layer Structure ◽  
Three Dimensional ◽  
Graph Set

AbstractThe adducts urea:pyrazine (1:1) (1), thiourea:pyrazine (2:1) (2), and thiourea:piperazine (2:1) (3) were prepared and their structures determined. Adduct 1 forms a layer structure, in which urea chains of graph set C(4)[${\rm{R}}_{\rm{2}}^{\rm{1}}$(6)] run parallel to the b axis and are crosslinked by N–H···N hydrogen bonding to the pyrazine residues. Adduct 2 is a variant of the well-known ${\rm{R}}_{\rm{2}}^{\rm{2}}$(8) ribbon substructure for urea/thiourea adducts, with the pyrazine molecules attached to the remaining thiourea NH groups via bifurcated hydrogen bonds (N–H···)2S; the more distant end of the pyrazine molecules is crosslinked to another symmetry-equivalent but perpendicular ribbon system, thus creating a three-dimensional packing. The packing of adduct 3 involves thiourea layers parallel to the ab plane; the piperazine molecules occupy the regions between these layers and are linked to the thiourea molecules by two hydrogen bonds (one as donor, one as acceptor) at each piperazine nitrogen atom.

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