Relativistic Spin-Orbit Heavy Atom on the Light Atom NMR Chemical Shifts: General Trends Across the Periodic Table Explained

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28610%2F18%3A63518939" target="_blank" >RIV/70883521:28610/18:63518939 - isvavai.cz</a>

Alternative codes found

RIV/61388963:_____/18:00491253 RIV/00216224:14740/18:00100905

Result on the web

<a href="http://dx.doi.org/10.1021/acs.jctc.8b00144" target="_blank" >http://dx.doi.org/10.1021/acs.jctc.8b00144</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jctc.8b00144" target="_blank" >10.1021/acs.jctc.8b00144</a>

Result language

angličtina

Original language name

Relativistic Spin-Orbit Heavy Atom on the Light Atom NMR Chemical Shifts: General Trends Across the Periodic Table Explained

Original language description

The importance of relativistic effects on the NMR parameters in heavy-atom (HA) compounds, particularly the SO-HALA (Spin-Orbit Heavy Atom on the Light Atom) effect on NMR chemical shifts, has been known for about 40 years. Yet, a general correlation between the electronic structure and SO-HALA effect has been missing. By analyzing 1H NMR chemical shifts of the sixth-period hydrides (Cs-At), we discovered general electronic-structure principles and mechanisms that dictate the size and sign of the SO-HALA NMR chemical shifts. In brief, partially occupied HA valence shells induce relativistic shielding at the light atom (LA) nuclei, while empty HA valence shells induce relativistic deshielding. In particular, the LA nucleus is relativistically shielded in 5d2-5d8 and 6p4 HA hydrides and deshielded in 4f0, 5d0, 6s0, and 6p0 HA hydrides. This general and intuitive concept explains periodic trends in the 1H NMR chemical shifts along the sixth-period hydrides (Cs-At) studied in this work. We present substantial evidence that the introduced principles have a general validity across the periodic table and can be extended to nonhydride LAs. The decades-old question of why compounds with occupied frontier π molecular orbitals (MOs) cause SO-HALA shielding at the LA nuclei, while the frontier σ MOs cause deshielding is answered. We further derive connection between the SO-HALA NMR chemical shifts and Spin-Orbit-induced Electron Deformation Density (SO-EDD), a property that can be obtained easily from differential electron densities and can be represented graphically. SO-EDD provides an intuitive understanding of the SO-HALA effect in terms of the depletion/concentration of the electron density at LA nuclei caused by spin-orbit coupling due to HA in the presence of a magnetic field. Using an analogy between the SO-EDD concept and arguments from classic NMR theory, the complex question of the SO-HALA NMR chemical shifts becomes easily understandable for a wide chemical audience.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10403 - Physical chemistry

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Chemical Theory and Computation

ISSN

1549-9618

e-ISSN

—

Volume of the periodical

14

Issue of the periodical within the volume

6

Country of publishing house

US - UNITED STATES

Number of pages

15

Pages from-to

3025-3039

UT code for WoS article

000435416200019

EID of the result in the Scopus database

2-s2.0-85046296572