TY - JOUR

T1 - Outer Electronic Shell Visualization by NMR Chemical Shift Laplacian of a Helium Probe

AU - Tolstoy, Peter M.

AU - Денисов, Глеб Семенович

AU - Тупикина, Елена Юрьевна

AU - Ефимова, Александра Александровна

N1 - Funding Information: [a] E. Yu. Tupikina, A. A. Efimova, G. S. Denisov Department of Physics, St. Petersburg State University, Uljanovskaja 1, St. Petersburg 198504, Russia [b] P. M. Tolstoy Center for Magnetic Resonance, St. Petersburg State University, Universitetsky pr. 26, 198504, Russia E-mail: peter.tolstoy@spbu.ru Contract Grant sponsor: Russian Foundation for Basic Research; Contract Grant number: 17-03-00497

PY - 2018/11/5

Y1 - 2018/11/5

N2 - A new method of visualization of lone pairs is proposed using fluorine atoms in fluoroacetylene, trifluoroethylene, and fluoroform (sp, sp 2, and sp 3 hybridized carbons) as an example. The space around fluorines was probed by a helium atom and at each point 3He NMR chemical shift δ He and its Laplacian ∇ 2δ He were calculated. The ∇ 2δ He isosurfaces have symmetrical toroidal shapes along CF axes; the maximum values of ∇ 2δ He are reached at about 1.5 Å from fluorine atom center in the direction roughly coinciding with the lone pair localization. The absolute values of the ∇ 2δ He could be used to quantify the electron-rich regions of lone pairs. The results are compared with more common visualization methods—3D maps of the molecular electrostatic potential and the electron localization function. We show that a helium atom could be used for evaluation of fine features of molecular electronic shell, since 3He NMR spectral characteristics remain sensitive at relatively large distances.

AB - A new method of visualization of lone pairs is proposed using fluorine atoms in fluoroacetylene, trifluoroethylene, and fluoroform (sp, sp 2, and sp 3 hybridized carbons) as an example. The space around fluorines was probed by a helium atom and at each point 3He NMR chemical shift δ He and its Laplacian ∇ 2δ He were calculated. The ∇ 2δ He isosurfaces have symmetrical toroidal shapes along CF axes; the maximum values of ∇ 2δ He are reached at about 1.5 Å from fluorine atom center in the direction roughly coinciding with the lone pair localization. The absolute values of the ∇ 2δ He could be used to quantify the electron-rich regions of lone pairs. The results are compared with more common visualization methods—3D maps of the molecular electrostatic potential and the electron localization function. We show that a helium atom could be used for evaluation of fine features of molecular electronic shell, since 3He NMR spectral characteristics remain sensitive at relatively large distances.

KW - He NMR

KW - electronic structure

KW - lone pairs

KW - HYDROGEN

KW - LOCALIZATION

KW - He-3 NMR

KW - FULLERENE

KW - COMPLEXES

KW - SYSTEMS

KW - AROMATICITY PROBE

KW - LONE-PAIR

KW - HE-3 NMR

UR - http://www.scopus.com/inward/record.url?scp=85056477691&partnerID=8YFLogxK

UR - http://doi.wiley.com/10.1002/jcc.25585

UR - http://www.mendeley.com/research/outer-electronic-shell-visualization-nmr-chemical-shift-laplacian-helium-probe

U2 - 10.1002/jcc.25585

DO - 10.1002/jcc.25585

M3 - Article

VL - 39

SP - 2459

EP - 2462

JO - Journal of Computational Chemistry

JF - Journal of Computational Chemistry

SN - 0192-8651

IS - 29

ER -