Title: 

NMR Magnetic Shielding in Transition Metal Compounds Containing Cadmium, Platinum, and Mercury

Year of Publication:

2023

Authors:

Andy D Zapata-Escobar, Alejandro F Maldonado, Jose L Mendoza-Cortes, Gustavo A Aucar

Journal:

Magnetochemistry

Abstract:

In this article, we delve into the intricate behavior of electronic mechanisms underlying NMR magnetic shieldings σ in molecules containing heavy atoms, such as cadmium, platinum, and mercury. Specifically, we explore PtXn−2 (X = F, Cl, Br, I; n = 4, 6) and XCl2Te2Y2H6 (X = Cd, Hg; Y = N, P) molecular systems. It is known that the leading electronic mechanisms responsible for the relativistic effects on σ are well characterized by the linear response with elimination of small components model (LRESC). In this study, we present the results obtained from the innovative LRESC-Loc model, which offers the same outcomes as the LRESC model but employs localized molecular orbitals (LMOs) instead of canonical MOs. These LMOs provide a chemist’s representation of atomic core, lone pairs, and bonds. The whole set of electronic mechanisms responsible of the relativistic effects can be expressed in terms of both non-ligand-dependent and ligand-dependent contributions. We elucidate the electronic origins of trends and behaviors exhibited by these diverse mechanisms in the aforementioned molecular systems. In PtX4−2 molecules, the predominant relativistic mechanism is the well-established one-body spin–orbit (σSO(1)) mechanism, while the paramagnetic mass–velocity (σMv) and Darwin (σDw) contributing mechanisms also demand consideration. However, in PtX6−2 molecules, the σ(Mv/Dw) contribution surpasses that of the SO(1) mechanism, thus influencing the overall ligand-dependent contributions. As for complexes containing Cd and Hg, the ligand-dependent contributions exhibit similar magnitudes when nitrogen is substituted with …

URL:

https://www.mdpi.com/2312-7481/9/7/165