Description

• Title:
  Carbon-13 longitudinal relaxation time measurements and DFT-GIAO NMR computations for two ammonium ions of a tetraazamacrocyclic scorpiand system
• Creator:
  Nazarski, Ryszard Bolesław
• Contributor:
  University of Łódź, Faculty of Chemistry, Laboratory of Molecular Spectroscopy
• Description:
  Spin-lattice relaxation times, T1s, for 13C nuclei in two cations Hn1n+ (n = 1, 5)of N-(2-amino-ethyl)-cyclam (1, scorpiand) were determined by means of 13C{1H} NMR experiments in aqueous solution at pH 11.5 and 0.2. The theoretical study [modeling with OPLS-AA, B3LYP/6-31G(d) geometry optimizations, dispersion-corrected energies (DFT-D3), and DFT-GIAO predictions of the NMR chemical shifts (including an IEF-PCM simulation of hydration)] was also done for several conformers of the tautomer iso-H414+ not investigated before. The binding directions in protonated polyamino receptors necessary for efficient complexation of the nitrate anion(s) were briefly outlined, as well. All these results were discussed in terms of 'abnormal' 13C chemical shift changes found previously for the side-chain carbons of amine 1 in strongly acidic solution (HNO3). In conclusion, an earlier proposal of its association with NO3- at pH=1 was rejected. Instead, the participation of small amounts of a microspecies iso-H414+Dhydr under such conditions can be proposed.;
  Publikacja w ramach programu Springer Open Choice/Open Access finansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego i realizowanego w ramach umowy na narodową licencję akademicką na czasopisma Springer w latach 2010-2013.
• Object availability:
  free access
• Rights:
  Uznanie autorstwa 3.0 Polska;
  http://creativecommons.org/licenses/by/3.0/pl
• Date:
  2014.02.06;
  2013
• Type:
  Article
• Language:
  English
• Format:
  application/pdf
• Publisher:
  Springer Netherlands
• Relation:
  Journal of Inclusion Phenomena and Macrocyclic Chemistry;Volume 78, Issue 1-4
• Subject:
  ‘Wrong-way’ protonation shift;
  Amino-pendant cyclams;
  NMR pH-titration;
  Protonated polyamines;
  Nitrate receptors;
  Dipolar relaxation;
  OPLS-AA force field;
  DFT-D3 dispersion correction;
  Organic Chemistry;
  Food Science;
  Crystallography
• Identifier:
  1573-1111;
  DOI: 10.1007/s10847-013-0298-x ;http://hdl.handle.net/11089/3447
• Data provider:
  Repozytorium Uniwersytetu Łódzkiego
• Can I use it?:
  check license
• Type:
  image