NMR Spectroscopy in Transition Metal Complexes

A special issue of Magnetochemistry (ISSN 2312-7481). This special issue belongs to the section "Magnetic Resonances".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 4812

Special Issue Editors

Multidisciplinary Institute of Chemistry, Multidisciplinary Center UFRJ-Macaé, Federal University of Rio de Janeiro, Macaé, Rio de Janeiro, Brazil
Interests: quantum chemistry; relativistic quantum chemistry; computa-tional chemistry; DFT; basis sets; heavy nuclei; transition metal complexes; NMR; nonlinear optics
Department of Chemistry, Federal University of Juiz de Fora, Juiz de Fora, Minas Ge-rais, Brazil
Interests: molecular dynamics; quantum mechanics; docking; carbon materials; medicinal chemistry; metallodrugs

Special Issue Information

Dear Colleagues,

Transition metal complexes are of great interest in chemistry due to its variety of applications, including catalysis, advanced materials and medicinal chemistry. Considering the constant interest in the understanding of the structure and properties of transition metal complexes, Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful and versatile technique used in the characterization of the reaction mechanism and properties of these compounds. Although most studies using NMR are focused on the light nuclei of the ligands coordinated to the metallic center, there is a wide range of metallic nuclei that also have advantageous properties for their use in NMR.

This Special Issue aims to publish a collection of experimental and/or computational papers covering solution or solid-state NMR spectroscopy applied to transition metal complexes. Research articles, short communications and reviews are welcome. This Special Issue in the Open Access journal Magnetochemistry aims to expand the journal on the topic of Magnetic Resonance in Chemistry.

Prof. Dr. Diego Paschoal
Prof. Dr. Hélio Dos Santos
Guest Editors

Manuscript Submission Information

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Keywords

  • nuclear magnetic resonance (NMR) spectroscopy
  • solution-state NMR
  • solid-state NMR
  • transition metal complexes
  • heavy nuclei
  • structure
  • advanced NMR techniques
  • theoretical models and calculations

Published Papers (4 papers)

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Research

19 pages, 13319 KiB  
Article
Assessment of a Computational Protocol for Predicting Co-59 NMR Chemical Shift
by Matheus G. R. Gomes, Andréa L. F. De Souza, Hélio F. Dos Santos, Wagner B. De Almeida and Diego F. S. Paschoal
Magnetochemistry 2023, 9(7), 172; https://doi.org/10.3390/magnetochemistry9070172 - 02 Jul 2023
Viewed by 1335
Abstract
In the present study, we benchmark computational protocols for predicting Co-59 NMR chemical shift. Quantum mechanical calculations based on density functional theory were used, in conjunction with our NMR-DKH basis sets for all atoms, including Co, which were developed in the present study. [...] Read more.
In the present study, we benchmark computational protocols for predicting Co-59 NMR chemical shift. Quantum mechanical calculations based on density functional theory were used, in conjunction with our NMR-DKH basis sets for all atoms, including Co, which were developed in the present study. The best protocol included the geometry optimization at BLYP/def2-SVP/def2-SVP/IEF-PCM(UFF) and shielding constant calculation at GIAO-LC-ωPBE/NMR-DKH/IEF-PCM(UFF). This computational scheme was applied to a set of 34 Co(III) complexes, in which, Co-59 NMR chemical shift ranges from +1162 ppm to +15,100 ppm, and these were obtained in distinct solvents (water and organic solvents). The resulting mean absolute deviation (MAD), mean relative deviation (MRD), and coefficient of determination (R2) were 158 ppm, 3.0%, and 0.9966, respectively, suggesting an excellent alternative for studying Co-59 NMR. Full article
(This article belongs to the Special Issue NMR Spectroscopy in Transition Metal Complexes)
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15 pages, 954 KiB  
Article
NMR Magnetic Shielding in Transition Metal Compounds Containing Cadmium, Platinum, and Mercury
by Andy D. Zapata-Escobar, Alejandro F. Maldonado, Jose L. Mendoza-Cortes and Gustavo A. Aucar
Magnetochemistry 2023, 9(7), 165; https://doi.org/10.3390/magnetochemistry9070165 - 27 Jun 2023
Cited by 1 | Viewed by 974
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 PtXn2 (X = F, Cl, Br, I; [...] Read more.
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 PtXn2 (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 PtX42 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 PtX62 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 phosphorus. The only discrepancy arises from the σSO(1) contribution, which changes sign between the two molecules due to the contribution of bond orbitals between the metal and tellurium atoms. Full article
(This article belongs to the Special Issue NMR Spectroscopy in Transition Metal Complexes)
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12 pages, 4311 KiB  
Article
Improving the Path to Obtain Spectroscopic Parameters for the PI3K—(Platinum Complex) System: Theoretical Evidences for Using 195Pt NMR as a Probe
by Taináh M. R. Santos, Gustavo A. Andolpho, Camila A. Tavares, Mateus A. Gonçalves and Teodorico C. Ramalho
Magnetochemistry 2023, 9(4), 89; https://doi.org/10.3390/magnetochemistry9040089 - 26 Mar 2023
Cited by 3 | Viewed by 1146
Abstract
The absence of adequate force field (FF) parameters to describe certain metallic complexes makes new and deeper analyses impossible. In this context, after a group of researchers developed and validated an AMBER FF for a platinum complex (PC) conjugated with AHBT, new possibilities [...] Read more.
The absence of adequate force field (FF) parameters to describe certain metallic complexes makes new and deeper analyses impossible. In this context, after a group of researchers developed and validated an AMBER FF for a platinum complex (PC) conjugated with AHBT, new possibilities emerged. Thus, in this work, we propose an improved path to obtain NMR spectroscopic parameters, starting from a specific FF for PC, allowing to obtain more reliable information and a longer simulation time. Initially, a docking study was carried out between a PC and PI3K enzyme, aiming to find the most favorable orientation and, from this pose, to carry out a simulation of classical molecular dynamics (MD) with an explicit solvent and simulation time of 50 ns. To explore a new PC environment, a second MD simulation was performed only between the complex and water molecules, under the same conditions as the first MD. After the results of the two MDs, we proposed strategies to select the best amino acid residues (first MD) and water molecules (second MD) through the analyses of hydrogen bonds and minimum distance distribution functions (MDDFs), respectively. In addition, we also selected the best frames from the two MDs through the OWSCA algorithm. From these resources, it was possible to reduce the amount and computational cost of subsequent quantum calculations. Thus, we performed NMR calculations in two chemical environments, enzymatic and aqueous, with theory level GIAO–PBEPBE/NMR-DKH. So, from a strategic path, we were able to obtain more reliable chemical shifts and, therefore, propose safer spectroscopic probes, showing a large difference between the values of chemical shifts in the enzymatic and aqueous environments. Full article
(This article belongs to the Special Issue NMR Spectroscopy in Transition Metal Complexes)
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14 pages, 3429 KiB  
Article
Four-Component Relativistic Calculations of NMR Shielding Constants of the Transition Metal Complexes—Part 3: Fe, Co, Ni, Pd, and Pt Glycinates
by Dmitry O. Samultsev, Valentin A. Semenov and Leonid B. Krivdin
Magnetochemistry 2023, 9(3), 83; https://doi.org/10.3390/magnetochemistry9030083 - 16 Mar 2023
Cited by 1 | Viewed by 880
Abstract
The relativistic effects of the values of the shielding constants of 1H, 13C, 15N, 57Fe, 59Co, 61Ni, 105Pd, and 195Pt nuclei were studied at the four-component relativistic level and were compared to the results of [...] Read more.
The relativistic effects of the values of the shielding constants of 1H, 13C, 15N, 57Fe, 59Co, 61Ni, 105Pd, and 195Pt nuclei were studied at the four-component relativistic level and were compared to the results of non-relativistic calculations perfomed on a series of biologically important Fe(II), Co(III), Ni, Pd, and Pt glycinates. The accuracy factors affecting the calculation of the chemical shifts of the title heavy nuclei were analyzed. First of all, the advantages and limitations of the different levels of theory used to take into account the electron correlation effects (namely HF, DFT, MP2, and CCSD) at the geometry optimization stage were thoroughly scrutinized. Among the employed DFT functionals, the behavior of 11 dedicated functionals of different types and hierarchies were analyzed. The contribution of the exact-exchange admixture was established both in the geometrical search and during the calculation of the shielding constants, which was exemplified with the PBE family of functionals. The main result of the performed study was that relativistic effects were of major importance to the theoretical calculations of the shielding constants and chemical shifts of the chelate complexes of the transition metals of the 8–10 groups. Thus, the relativistic effects of the values of the shielding constants of those metals, as well as those of the light nuclei located in the α-position to the latter, were found to reach as much as 35 ppm for nitrogen and up to an enormous 4300 ppm for platinum. Full article
(This article belongs to the Special Issue NMR Spectroscopy in Transition Metal Complexes)
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