Density functional calculations of nuclear magnetic shieldings using the zeroth-order regular approximation (ZORA) for relativistic effects: ZORA nuclear magnetic resonance

Citation
Sk. Wolff et al., Density functional calculations of nuclear magnetic shieldings using the zeroth-order regular approximation (ZORA) for relativistic effects: ZORA nuclear magnetic resonance, J CHEM PHYS, 110(16), 1999, pp. 7689-7698
Citations number
54
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF CHEMICAL PHYSICS
ISSN journal
00219606 → ACNP
Volume
110
Issue
16
Year of publication
1999
Pages
7689 - 7698
Database
ISI
SICI code
0021-9606(19990422)110:16<7689:DFCONM>2.0.ZU;2-9
Abstract
We present a new relativistic formulation for the calculation of nuclear ma gnetic resonance (NMR) shielding tensors. The formulation makes use of gaug e-including atomic orbitals and is based on density functional theory. The relativistic effects are included by making use of the zeroth-order regular approximation. This formulation has been implemented and the Hg-199 NMR sh ifts of HgMe2, HgMeCN, Hg(CN)(2), HgMeCl, HgMeBr, HgMeI, HgCl2, HgBr2, and HgI2 have been calculated using both experimental and optimized geometries. For experimental geometries, good qualitative agreement with experiment is obtained. Quantitatively, the calculated results deviate from experiment o n average by 163 ppm, which is approximately 3% of the range of Hg-199 NMR. The experimental effects of an electron donating solvent on the mercury sh ifts have been reproduced with calculations on HgCl2(NH3)(2), HgBr2(NH3)(2) , and HgI2(NH3)(2). In addition, it is shown that the mercury NMR shielding s are sensitive to geometry with changes for HgCl2 of approximately 50 ppm for each 0.01 Angstrom change in bond length, and 100 ppm for each 10 degre es change in bond angle. (C) 1999 American Institute of Physics. [S0021-960 6(99)30313-5].