52750
2018
2018
eng
2288
2292
5
23
59
article
Elsevier
Oxford
1
2018-05-03
2018-05-03
--
Ring current and anisotropy effects on OH chemical shifts in resonance-assisted intramolecular H-bonds
Ring current effects on resonance-assisted and intramolecularly bridged hydrogen bond protons for 10-hydroxybenzo[h]quinoline 1 and a number of related compounds were calculated and the through-space NMR shieldings (TSNMRS) obtained hereby visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. These calculations revealed that this through-space effect is comparably large (up to 2 ppm) dependent on the position of the intramolecularly bridged OH proton, and therefore, contribute considerably to the chemical shift of the latter making it questionable to use delta(OH)/ppm in the estimation of intramolecular hydrogen bond strength without taking this into account. Furthermore, the anisotropy effects of additional groups on the aromatic moiety (e.g. the carbonyl group in salicylaldehyde or in o-hydroxyacetophenone of ca. 0.6 ppm deshielding) should also be considered. These through-space effects need to be taken into account when using OH chemical shifts to estimate hydrogen bond strength.
Tetrahedron letters
10.1016/j.tetlet.2018.05.006
0040-4039
wos:2018
WOS:000446641000018
Kleinpeter, E (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Golm, Germany., ekleinp@uni-potsdam.de
2021-11-19T13:07:26+00:00
sword
importub
filename=package.tar
8cde2b6a9e84f36b3bd8a1157353c6fb
false
true
Poul Erik Hansen
Andreas Koch
Erich Kleinpeter
eng
uncontrolled
RA-intramolecular hydrogen bond
eng
uncontrolled
Through-space NMR shieldings (TSNMRS)
eng
uncontrolled
Iso-chemical-shielding surfaces (ICSS)
eng
uncontrolled
Ring current effect
eng
uncontrolled
Anisotropy effect
Chemie und zugeordnete Wissenschaften
Institut für Chemie
Referiert
Import
58085
2021
2021
eng
8
80
article
Elsevier
Amsterdam
1
2020-10-25
2021-01-29
--
Dative or coordinative carbon-boron bond in boron trapped N-heterocyclic carbenes (NHCs)?
The spatial magnetic properties, through-space NMR shieldings (TSNMRS), of isolated as well as B-C bond length varied model compounds (BR3 trapped NHCs) have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept and the results visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. The TSNMRS values (actually the anisotropy effects measurable in H-1 NMR spectroscopy) are employed to qualify and quantify the present dative vs. coordinative bond character of the boron-carbon bond in the trapped NHCs. Results are confirmed by bond lengths and B-11/C-13 chemical shift variations in the BR3 trapped NHCs.
Tetrahedron : the international journal for the rapid publication of full original research papers and critical reviews in organic chemistry
an answer given on the magnetic criterion
10.1016/j.tet.2020.131787
0040-4020
1464-5416
outputup:dataSource:WoS:2021
131787
WOS:000609617500002
Kleinpeter, E (corresponding author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Golm, Germany., ekleinp@uni-potsdam.de
Kleinpeter, Erich
2023-02-20T12:12:58+00:00
sword
importub
filename=package.tar
5f1ffa17d989e7a342536da3dd53b11d
2007072-X
204285-X
false
true
Erich Kleinpeter
Andreas Koch
eng
uncontrolled
NHCs
eng
uncontrolled
Dative vs. coordinative NHC -> BR3 bond
eng
uncontrolled
Through-space NMR
eng
uncontrolled
shieldings (TSNMRS)
eng
uncontrolled
NICS
eng
uncontrolled
Anisotropy effect
Chemie und zugeordnete Wissenschaften
Institut für Chemie
Referiert
Import
39001
2015
2015
eng
2273
2279
7
15
71
article
Elsevier
Oxford
1
--
--
--
Are para-nitro-pyridine N-oxides quinonoid or benzenoid? An answer given by spatial NICS (TSNMRS)
The spatial magnetic properties (Through-Space NMR Shieldings-TSNMRS) of a number of substituted para-nitro-pyridine N-oxides have been computed, visualized as Iso-Chemical-Shielding-Surfaces (ICSS) of various size and direction, and were examined subject to the present quinonoid or benzenoid pi-relectron distribution of the six-membered ring. (C) 2015 Elsevier Ltd. All rights reserved.
Tetrahedron
10.1016/j.tet.2015.02.043
0040-4020
wos:2015
WOS:000351795100012
Kleinpeter, E (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Golm, Germany., ekleinp@uni-potsdam.de
Erich Kleinpeter
Marcus Michaelis
Andreas Koch
eng
uncontrolled
para-Nitro-pyridine N-oxides
eng
uncontrolled
Quinonoid structure
eng
uncontrolled
Benzenoid structure
eng
uncontrolled
Ring current effect
eng
uncontrolled
Anisotropy effect
eng
uncontrolled
Theoretical calculations
Institut für Chemie
Referiert
38677
2015
2015
eng
5275
5284
10
33
71
article
Elsevier
Oxford
1
--
--
--
Characterization and quantification of quasi-aromaticity by spatial magnetic properties (TSNMRS)
The spatial magnetic properties (Through Space NMR Shieldings-TSNMRS) of various types of structures with suggested quasi-aromaticity (a summaring topic: in detail push pull, captodative, chelate, supramolecular aromaticity, etc.) have been computed, are visualized as Isochemical Shielding Surfaces (ICSS) of various size/direction and examined subject to identify and quantify present (partial) aromaticity. While the TSNMRS approach proves really helpful [even in cases of (4n+2) pi-electron cyclic moieties formed via non-covalent polar interactions] quasi-aromaticity suggested for enol forms of 1,3-dicarbonyl compounds via resonance-assisted intramolecular and intermolecular hydrogen bonding cannot be confirmed. (C) 2015 Elsevier Ltd. All rights reserved.
Tetrahedron
10.1016/j.tet.2015.06.019
0040-4020
wos:2015
WOS:000358394100009
Kleinpeter, E (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Golm, Germany., ekleinp@uni-potsdam.de
Erich Kleinpeter
Andreas Koch
eng
uncontrolled
Quasi-aromaticity
eng
uncontrolled
Ring current effect
eng
uncontrolled
Anisotropy effect
eng
uncontrolled
Theoretical calculations
eng
uncontrolled
ICSS
eng
uncontrolled
TSNMRS
Institut für Chemie
Referiert
37309
2014
2014
eng
9230
9239
10
48
70
article
Elsevier
Oxford
1
--
--
--
Interplay of para- and diatropic ring currents [(anti)aromaticity] of macrocyclic rings subject to conformational influences, further annelation and hydrogenation of aromatic ring moieties
The spatial magnetic properties (Through Space NMR Shieldings-TSNMRS) of a variety of porphyrins, hemiporphyrazines and tetraoxo[8]circulenes have been computed, visualized as Iso-chemical Shielding Surfaces (ICSS) of various size and direction, and were examined subject to the interplay of present (para)-diatropic ring currents [(anti)aromaticity] and influences on the latter property originating from the macrocyclic ring conformation, further annelation and partial to complete hydrogenation of aromatic ring moieties. Caution seems to be indicated when concluding from a single NICS parameter to present (para)diatropic ring currents [(anti)aromaticity]. (C) 2014 Elsevier Ltd. All rights reserved.
Tetrahedron
10.1016/j.tet.2014.10.018
0040-4020
wos:2014
WOS:000345492200009
Kleinpeter, E (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Golm, Germany., ekleinp@uni-potsdam.de
Erich Kleinpeter
Andreas Koch
Stefanie Schulz
Philipp Wacker
eng
uncontrolled
Porphyrins
eng
uncontrolled
Hemiporphyrazines
eng
uncontrolled
Tetraoxo[8]circulenes
eng
uncontrolled
(Anti)aromaticity
eng
uncontrolled
Anisotropy effect
eng
uncontrolled
Theoretical calculations
Institut für Chemie
Referiert