@article{HansenKochKleinpeter2018,
  author    = {Hansen, Poul Erik and Koch, Andreas and Kleinpeter, Erich},
  title     = {Ring current and anisotropy effects on OH chemical shifts in resonance-assisted intramolecular H-bonds},
  series = {Tetrahedron letters},
  volume    = {59},
  journal   = {Tetrahedron letters},
  number    = {23},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0040-4039},
  doi       = {10.1016/j.tetlet.2018.05.006},
  pages     = {2288 -- 2292},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{KleinpeterKoch2021,
  author    = {Kleinpeter, Erich and Koch, Andreas},
  title     = {Dative or coordinative carbon-boron bond in boron trapped N-heterocyclic carbenes (NHCs)?},
  series = {Tetrahedron : the international journal for the rapid publication of full original research papers and critical reviews in organic chemistry},
  volume    = {80},
  journal   = {Tetrahedron : the international journal for the rapid publication of full original research papers and critical reviews in organic chemistry},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2020.131787},
  pages     = {8},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{KleinpeterMichaelisKoch2015,
  author    = {Kleinpeter, Erich and Michaelis, Marcus and Koch, Andreas},
  title     = {Are para-nitro-pyridine N-oxides quinonoid or benzenoid? An answer given by spatial NICS (TSNMRS)},
  series = {Tetrahedron},
  volume    = {71},
  journal   = {Tetrahedron},
  number    = {15},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2015.02.043},
  pages     = {2273 -- 2279},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@article{KleinpeterKoch2015,
  author    = {Kleinpeter, Erich and Koch, Andreas},
  title     = {Characterization and quantification of quasi-aromaticity by spatial magnetic properties (TSNMRS)},
  series = {Tetrahedron},
  volume    = {71},
  journal   = {Tetrahedron},
  number    = {33},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2015.06.019},
  pages     = {5275 -- 5284},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@article{KleinpeterKochSchulzetal.2014,
  author    = {Kleinpeter, Erich and Koch, Andreas and Schulz, Stefanie and Wacker, Philipp},
  title     = {Interplay of para- and diatropic ring currents [(anti)aromaticity] of macrocyclic rings subject to conformational influences, further annelation and hydrogenation of aromatic ring moieties},
  series = {Tetrahedron},
  volume    = {70},
  journal   = {Tetrahedron},
  number    = {48},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2014.10.018},
  pages     = {9230 -- 9239},
  year      = {2014},
  abstract  = {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.},
  language  = {en}
}