Direct Detection of <sup>17</sup>O in [Gd(DOTA)]<sup>−</sup> by NMR Spectroscopy

Fusaro, Luca; Casella, Girolamo; Bagno, Alessandro

doi:10.1002/chem.201405092

Cited by 11 publications

(14 citation statements)

References 46 publications

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“…The spin magnetization polarization introduced at the RAS [12,100] level causes m ∥ S (r) to be negative around the oxygen atoms roughly along the O eq −Pu direction while at the same time the positive spin magnetization increases around the carbon atoms. This finding is consistent with the increase of the positive FC contribution to the carbon pNMR shifts when going from CAS (24) to RAS [12,100] (Table 4). To access the quality of the spin polarization with RAS [12,100], the spin density of the SR state corresponding to the 3 H term of the plutonyl ion was also calculated using KS theory; the result is shown in Figure S10.…”

Section: −supporting

confidence: 87%

“…For metal complexes with relatively pure spin multiplets, KS methods have been shown useful for calculating and rationalizing pNMR shifts. ,,,− Recently, a mixed WFT/KS approach was put forward for the calculation of pNMR shifts in selected, more difficult, transition metal complexes. , The EPR parameters ( g -factors and ZFS tensors) were calculated with WFT, whereas the HyF coupling tensors were obtained from KS calculations. The approach was then improved by taking into account contributions from excited electronic states based on recent theoretical developments by Soncini and Van den Heuvel (SvH). , However, for most lanthanide or actinide complexes as well as transition metal systems with orbitally degenerate states, KS theory with available approximate functionals has well-known serious difficulties in describing the complexity of the electronic structure, which in turn may limit the accuracy at which the HyF interactions entering the pNMR shift expression are described.…”

Section: Introductionmentioning

confidence: 99%

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Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f¹ vs 5f² Actinides

Gendron

Autschbach

2016

J. Chem. Theory Comput.

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Ligand paramagnetic NMR (pNMR) chemical shifts of the 5f complexes UO(CO) and NpO(CO), and of the 5f complexes PuO(CO) and (CH)UCH are investigated by wave function theory calculations, using a recently developed sum-over-states approach within complete active space and restricted active space paradigm including spin-orbit (SO) coupling [J. Phys. Chem. Lett. 2015, 20, 2183-2188]. The experimental C pNMR shifts of the actinyl tris-carbonate complexes are well reproduced by the calculations. The results are rationalized by visualizing natural spin orbitals (NSOs) and spin-magnetizations generated from the SO wave functions, in comparison with scalar relativistic spin densities. The analysis reveals a complex balance between spin-polarization, spin and orbital magnetization delocalization, and spin-compensation effects due to SO coupling. This balance creates the magnetization due to the electron paramagnetism around the nucleusof interest, and therefore the pNMR effects. The calculated proton pNMR shifts of the (CH)UCH complex are also in good agreement with experimental data. Because of the nonmagnetic ground state of (CH)UCH, the H pNMR shifts arise mainly from the magnetic coupling contributions between the ground state and low-energy excited states belonging to the 5f manifold, along with the thermal population of degenerate excited states at ambient temperatures.

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Section: −supporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f¹ vs 5f² Actinides

Gendron

Autschbach

2016

J. Chem. Theory Comput.

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“…In the case of Gd 3+ complexes, the paramagnetic effects of Gd on DOTA nuclear spins prevent the characterization by 1 H or 13 C NMR. For those complexes, only the signal from the noncoordinated oxygen atoms may be detected by 17 O NMR, and it is not possible to distinguish between the SAP and TSAP geometries. ,, These isomers constitute two diastereoisomeric pairs of enantiomers, where the macrocyclic ring and the acetate arms have the opposite and the same helicity, respectively . The SAP conformation is the most stable for [Gd(DOTA)] − in solution, representing around 80% of the population at 298 K .…”

Section: Introductionmentioning

confidence: 99%

Modeling Gd³⁺ Complexes for Molecular Dynamics Simulations: Toward a Rational Optimization of MRI Contrast Agents

et al. 2022

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The correct parametrization of lanthanide complexes is of the utmost importance for their characterization using computational tools such as molecular dynamics simulations. This allows the optimization of their properties for a wide range of applications, including medical imaging. Here we present a systematic study to establish the best strategies for the correct parametrization of lanthanide complexes using [Gd(DOTA)]− as a reference, which is used as a contrast agent in MRI. We chose the bonded model to parametrize the lanthanide complexes, which is especially important when considering the study of the complex as a whole (e.g., for the study of the dynamics of its interaction with proteins or membranes). We followed two strategies: a so-called heuristic approach employing strategies already published by other authors and another based on the more recent MCPB.py tool. Adjustment of the Lennard-Jones parameters of the metal was required. The final topologies obtained with both strategies were able to reproduce the experimental ion to oxygen distance, vibrational frequencies, and other structural properties. We report a new strategy to adjust the Lennard-Jones parameters of the metal ion in order to capture dynamic properties such as the residence time of the capping water (τm). For the first time, the correct assessment of the τm value for Gd-based complexes was possible by recording the dissociative events over up to 10 μs all-atom simulations. The MCPB.py tool allowed the accurate parametrization of [Gd(DOTA)]− in a simpler procedure, and in this case, the dynamics of the water molecules in the outer hydration sphere was also characterized. This sphere was divided into the first hydration layer, an intermediate region, and an outer hydration layer, with a residence time of 18, 10 and 19 ps, respectively, independent of the nonbonded parameters chosen for Gd3+. The Lennard-Jones parameters of Gd3+ obtained here for [Gd(DOTA)]− may be used with similarly structured gadolinium MRI contrast agents. This allows the use of molecular dynamics simulations to characterize and optimize the contrast agent properties. The characterization of their interaction with membranes and proteins will permit the design of new targeted contrast agents with improved pharmacokinetics.

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“…in which β e , g N , β N , and k B represent the Bohr magneton, the nuclear g ‐factor, the nuclear magneton, and the Boltzmann constant, respectively, corresponds to the Zeeman coupling matrix and is calculated either by using wave‐function theory or by using KS‐DFT, and is the hyperfine coupling matrix and is obtained from KS‐DFT calculations (see the Computational Details). Such a computational strategy has already been applied successfully to a large panel of transition‐metal complexes . To assemble the Zeeman g ‐tensors, the hyperfine coupling matrices, and the orbital shielding, we have used the pNMRShift program developed by the Autschbach's group .…”

Section: Methodsmentioning

confidence: 99%

“…[89][90][91][92][93][94][95][96][97][98][99] To assemble the Zeeman g-tensors, the hyperfine coupling matrices, and the orbital shielding, we have used the pNMRShift program developed by the Autschbach's group. Such acomputational strategy has already been applied successfully to al arge panel of transition-metal complexes.…”

Section: Ab-initio Paramagnetic Nmr Calculationsmentioning

confidence: 99%

Probing the Local Magnetic Structure of the [Fe^III(Tp)(CN)₃]⁻ Building Block Via Solid‐State NMR Spectroscopy, Polarized Neutron Diffraction, and First‐Principle Calculations

Flambard

Garnier

et al. 2019

Chemistry A European J

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The local magnetic structure in the [Fe III (Tp)(CN) 3 ] À building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutrond iffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanidol igands: Spin-polarization on the carbon atomsa nd spin-delocalization on the nitrogen atoms.T he resultso fo ur combined density functional theory (DFT) and multireference calculations were found in good agreementw ith the PND results and the experimen-tal NMR chemical shifts. Moreover,t he ab-initio calculations allowedu st oc onnectt he experimental spin-density map characterized by PNDa nd the suggested distribution of the spin-density on the ligandso bserved by NMR spectroscopy. Interestingly,s ignificant differences were observed between the pseudo-contact contributions of the chemical shifts obtained by theoretical calculations and the values derived from NMR spectroscopy using as imple point-dipole model. These discrepancies underline the limitation of the pointdipole model and the need for more elaborate approaches to break down the experimental pNMR chemical shifts into contacta nd pseudo-contact contributions.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.org/10.1002/chem.201902239.A dditional data regarding the experimental and computational details,experimental NMR data for the diamagnetic reference and the paramagnetic complex, crystal structure data for the diamagnetic reference and the magnetization characterization:DFT spin-densities, NLMOs, g-factors, and HyFCCs for [Fe III (Tp)(CN) 3 ] À .Additional calculated NMR shielding constants and chemical shifts.

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Direct Detection of ¹⁷O in [Gd(DOTA)]⁻ by NMR Spectroscopy

Cited by 11 publications

References 46 publications

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f¹ vs 5f² Actinides

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f¹ vs 5f² Actinides

Modeling Gd³⁺ Complexes for Molecular Dynamics Simulations: Toward a Rational Optimization of MRI Contrast Agents

Probing the Local Magnetic Structure of the [Fe^III(Tp)(CN)₃]⁻ Building Block Via Solid‐State NMR Spectroscopy, Polarized Neutron Diffraction, and First‐Principle Calculations

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Direct Detection of 17O in [Gd(DOTA)]− by NMR Spectroscopy

Cited by 11 publications

References 46 publications

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f1 vs 5f2 Actinides

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f1 vs 5f2 Actinides

Modeling Gd3+ Complexes for Molecular Dynamics Simulations: Toward a Rational Optimization of MRI Contrast Agents

Probing the Local Magnetic Structure of the [FeIII(Tp)(CN)3]− Building Block Via Solid‐State NMR Spectroscopy, Polarized Neutron Diffraction, and First‐Principle Calculations

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Direct Detection of ¹⁷O in [Gd(DOTA)]⁻ by NMR Spectroscopy

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f¹ vs 5f² Actinides

Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f¹ vs 5f² Actinides

Modeling Gd³⁺ Complexes for Molecular Dynamics Simulations: Toward a Rational Optimization of MRI Contrast Agents

Probing the Local Magnetic Structure of the [Fe^III(Tp)(CN)₃]⁻ Building Block Via Solid‐State NMR Spectroscopy, Polarized Neutron Diffraction, and First‐Principle Calculations