Electronic-Structure Relationship of Spin-Orbit-Induced Heavy Atom on the Light NMR Chemical Shifts Across the Periodic Table

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

Electronic-Structure Relationship of Spin-Orbit-Induced Heavy Atom on the Light NMR Chemical Shifts Across the Periodic Table

Original language description

Analysis of 1H NMR chemical shift trends of the 6th-period hydrides (Cs-At) led to discovery of general electronic-structure principles and mechanisms that dictate the size and sign of the Spin-Orbit-Induced Heavy Atom on the Light Atom (SO-HALA) NMR chemical shifts. Using third order perturbation theory (PT3) analysis we have identified and explained two general mechanisms responsible for SO-HALA shielding and deshielding and their relation to the presence/absence of occupied lone pairs of electron (LP) at HA. In short, when LP are present in HA valence shell, relativistic shielding at the light atom (LA) nuclei is induced by magnetic coupling of LP with HA-LA antibonding molecular orbital, as is the case of 5d2-5d8 and 6p2 and 6p4 HA hydrides. Absence of LP at HA than lead to the dominance of coupling from HA-LA antibonding molecular orbitals, which results in relativistic deshielding found in 4f0, 5d0, 6s0, 6p0 HA hydrides. Introduced principles have a general validity across the periodic table and explain the LA NMR chemical shift trends also for non-hydride ligands. The SO-HALA effect was further linked to the depletion/concentration of the electron density at LA nuclei caused by spin-orbit coupling at HA in the presence of magnetic field. These findings are believed to further increase the already rising interest in linking NMR parameters with the structure/chemical properties of heavy-element compounds.

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

2018

Confidentiality

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