scholarly journals Experimental evidence of a 3-centre, 2-electron covalent bond character of the central O–H–O fragment on the Zundel cation in crystals of Zundel nitranilate tetrahydrate

CrystEngComm ◽  
2017 ◽  
Vol 19 (28) ◽  
pp. 3898-3901 ◽  
Author(s):  
Krešimir Molčanov ◽  
Christian Jelsch ◽  
Emmanuel Wenger ◽  
Jernej Stare ◽  
Anders Ø. Madsen ◽  
...  
Keyword(s):  
Solid State ◽  
Charge Density ◽  
Experimental Evidence ◽  
Covalent Bond ◽  
Covalent Nature ◽  
Bond Character

Charge density of the Zundel cation in the solid state reveals a covalent nature of its central O–H–O fragment.

Experimental evidence for ‘carbon bonding’ in the solid state from charge density analysis

2014 ◽  
Vol 50 (1) ◽  
pp. 49-51 ◽  
Author(s):  
Sajesh P. Thomas ◽  
Mysore S. Pavan ◽  
T. N. Guru Row
Keyword(s):  
Solid State ◽  
Charge Density ◽  
Experimental Evidence ◽  
Density Analysis ◽  
Carbon Bonding

Closer to the polydopamine structure: new insights from a combined 13C/1H/2H solid-state NMR study on deuterated samples

2018 ◽  
Vol 9 (24) ◽  
pp. 3379-3387 ◽  
Author(s):  
Monica Cîrcu ◽  
Claudiu Filip
Keyword(s):  
Solid State ◽  
Experimental Evidence ◽  
Solid State Nmr ◽  
Water Dynamics ◽  
Π Stacking ◽  
Nmr Study

13C/1H/2H ss-NMR on deuterated samples provide strong experimental evidence for the most probable monomer connectivity, π–π stacking, and the water dynamics in polydopamine.

Solid State NMR Analysis for Hide Powder Tanned by Aluminum, Silicon and Phosphorus Tanning Agents before and after Hydrothermal Denaturation

2021 ◽  
Vol 116 (10) ◽  
Author(s):  
Jun Liu ◽  
Da-hai He ◽  
Hua-lin Chen ◽  
Ke-yi Ding
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
High Field ◽  
Chemical Shifts ◽  
Covalent Bond ◽  
29Si Nmr ◽  
Before And After ◽  
Collagen Molecules ◽  
Field Area ◽  
Aluminum Silicon

In order to investigate the change of chemical bonds between tanning agents and collagen molecules directly, hide powder tanned by aluminum, silicon and phosphorus tanning agents were prepared. The chemical shifts of Al, Si and P in tanned hide powder were analyzed by solid-state 27Al NMR, 29Si NMR and 31P NMR. The results showed that, the chemical shift of Al in aluminum tanned hide powder which interacted with collagen molecules through coordination bond could be regarded as unchanging after hydrothermal denaturation (only slightly moved to high field area). The chemical shift of Si in silicon tanned hide powder which interacted with collagen molecules through hydrogen bond did not change after hydrothermal denaturation. The chemical shift of P in phosphorus tanned hide powder, which interacted with collagen molecules through covalent bond, was obviously shifted to the high field area after hydrothermal denaturation.

Radiation D am age to Polypeptides and Proteins in the Solid State, II* Radiolysis of Poly-ʟ-Glutamic Acid

1981 ◽  
Vol 36 (11-12) ◽  
pp. 1091-1092 ◽  
Author(s):  
T. Söylemez ◽  
W. Baumeister ◽  
L. M. Herbertz
Keyword(s):  
Solid State ◽  
Glutamic Acid ◽  
Experimental Evidence ◽  
Butyric Acid ◽  
Radical Anion ◽  
Amino Butyric Acid

Abstract For the transformation of glutamic acid into α-amino-butyric acid upon irradiation a decarboxylation mechanism involving the formation of CO2 has been proposed previously. Here we present further experimental evidence in favour of this mechanism. A dditionally the formation of CO as a decarboxylation product has been detected; a radical anion mechanism for its formation is proposed.

Experimental evidence that electrospray-produced sodiated lysophosphatidyl ester structures exist essentially as protonated salts

2019 ◽  
Vol 25 (3) ◽  
pp. 333-338 ◽  
Author(s):  
Benoit Colsch ◽  
Annelaure Damont ◽  
Christophe Junot ◽  
François Fenaille ◽  
Jean-Claude Tabet
Keyword(s):  
Experimental Evidence ◽  
Collision Energy ◽  
Bond Cleavage ◽  
Covalent Bond ◽  
Energy Conditions ◽  
Sodium Retention ◽  
Charge Remote Fragmentation ◽  
Product Ions ◽  
Main Representative ◽  
Proton Migration

Sodiated lysoglycerophosphatidylethanolamine (LGPE) and lysoglycerophosphatidylcholine (LGPC) species dissociate under low collision energy by covalent bond cleavage resulting in product ions with either sodium retention or without sodium retention. For explaining these fragmentations, sodium chelation by heteroatoms (as charge-solvated structures) is often considered, and consequently, under keV collision conditions, sodium is “spectator” of cleavages (charge remote fragmentation). However, cleavage of such charge-solvated forms under low-energy conditions should result in sodium desolvation rather than covalent bond cleavage. In the present study, protonated salts are proposed as the main representative structures of the sodiated LGPE and LGPC forms. These structures are generated from sodiation of zwitterionic and betaine forms of LGPE and LGPC molecules, respectively. Experimental evidence to determine which structure is involved in the dissociations is provided, especially by comparing the dissociation of LGPL sodiated forms with that of sodiated polyethylene glycols. Energy-resolved mass spectrometry breakdown experiments were performed on a quadrupole time-of-flight instrument to demonstrate that both LGPE and LGPC sodiated forms exist as protonated salt structures. From such structures, proton migration by prototropy can result in different bond cleavages whereas the salt moiety remains spectator of these processes.

scholarly journals Systematic experimental charge density analysis of anion receptor complexes

2014 ◽  
Vol 16 (22) ◽  
pp. 10943-10958 ◽  
Author(s):  
Isabelle L. Kirby ◽  
Mark Brightwell ◽  
Mateusz B. Pitak ◽  
Claire Wilson ◽  
Simon J. Coles ◽  
...  
Keyword(s):  
Solid State ◽  
Charge Density ◽  
Anion Receptor ◽  
Binding Strength ◽  
Receptor Complexes ◽  
Density Analysis ◽  
Basic Anion ◽  
Experimental Charge Density ◽  
Resolution Study

The first systematic electronic resolution study of a series of urea-based anion receptor complexes is presented and shows the binding strength to be greater for more basic anion–receptor pairs in the solid state.

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