Periodic Trends of Spin-Orbit Heavy Atom on the Light Atom Effect to NMR Chemical Shifts Rationalized

Result code in IS VaVaI

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Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Periodic Trends of Spin-Orbit Heavy Atom on the Light Atom Effect to NMR Chemical Shifts Rationalized

Original language description

The importance ofrelativistic effccts 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. However, generally valid correlation between the electronicstructure of heavy element complexes and S O-HALA effect ha ve been missing. By analyzing 1H NMR chemical shifts of the 6th-period hydrides (Cs-At) we uncovered the basic 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. The LA nucleus thus became relativistically shielded in 5d2-5d8 and 6p4 HA hydrides and deshielded in 4í°, 5d0 , 6s0 , 6p0 HA hydrides. The introduced principles have a general validity across the periodic table and can be extended to non-hydride LAs as well. Moreover, the connection between the SO-HALA NMR chemical shifts and Spin-Orbit-induced Electron Deformation Density (SO-EDD) is derived. SO-EDD provides an intuitive understanding of the SO-HALA effect in tenns of the depletion/concentration of the electron density at LA nuclei caused by spin-orbit coupling dueto HA in the presence of magnetic field. Using an analogy between SO-EDD concept and arguments from classic NMR theory, the complex question of the SO-HALA NMR chemical shifts becomes easily understancbble for a wide chemical audience.

Czech name

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Czech description

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Type

O - Miscellaneous

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

2019

Confidentiality

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