Calculations of the EPR <b>g</b>-tensor using unrestricted two- and four-component relativistic approaches within the HF and DFT frameworks

Cherry, Peter J.; Komorovský, Stanislav; Malkin, Vladimir G.; Malkina, Olga L.

doi:10.1080/00268976.2016.1191688

Cited by 15 publications

(12 citation statements)

References 29 publications

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“…The superscript J v indicates that the molecular orbitals depend on the chosen direction of magnetization, v , as described in refs. and . In ref.…”

Section: A Short Review Of the Theoretical Backgroundmentioning

confidence: 70%

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Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF₆]²⁻ and [IrF₆]²⁻

Haase

Repiský

Komorovský

et al. 2017

Chemistry A European J

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The performance of relativistic density functional theory (DFT) methods has been investigated for the calculation of the recently measured hyperfine coupling constants of hexafluorido complexes [ReF6]2− and [IrF6]2−. Three relativistic methods were employed at the DFT level of theory: the 2‐component zeroth‐order regular approximation (ZORA) method, in which the spin–orbit coupling was treated either variationally (EV ZORA) or as a perturbation (LR ZORA), and the 4‐component Dirac–Kohn–Sham (DKS) method. The dependence of the results on the basis set and the choice of exchange‐correlation functional was studied. Furthermore, the effect of varying the amount of Hartree–Fock exchange in the hybrid functionals was investigated. The LR ZORA and DKS methods combined with DFT led to very similar deviations (about 20 %) from the experimental values for the coupling constant of complex [ReF6]2− by using hybrid functionals. However, none of the methods were able to reproduce the large anisotropy of the hyperfine coupling tensor of complex [ReF6]2−. For [IrF6]2−, the EV ZORA and DKS methods reproduced the experimental tensor components with deviations of ≈10 and ≈5 % for the hybrid functionals, whereas the LR ZORA method predicted the coupling constant to be around one order of magnitude too large owing to the combination of large spin–orbit coupling and very low excitation energies.

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“…The superscript J v indicates that the molecular orbitals depend on the chosen direction of magnetization, v , as described in refs. and . In ref.…”

Section: A Short Review Of the Theoretical Backgroundmentioning

confidence: 70%

“…The superscript J v indicates that the molecular orbitals depend on the chosen directiono fm agnetization, v,a sd escribed in refs. [21] and [22].I nr ef. [6],t he use of ar estricted kinetically balanced basis set is described, which leads to the following final expression [Eq.…”

Section: -Component Dirac-kohn-sham Methodsmentioning

confidence: 99%

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF₆]²⁻ and [IrF₆]²⁻

Haase

Repiský

Komorovský

et al. 2017

Chemistry A European J

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“…While in the case of compounds containing 3d transition metal complexes it is sufficient to treat the relativistic SOC effects in the evaluation of the g-tensor as a perturbation of the non-relativistic wavefunction, 44 in the case of 4d- and 5d- transition metal compounds the explicit inclusion of both scalar and SOC relativistic effects 82 appears neccessary. 51, 52, 53, 54, 55 Herein, we wish to compare the performance of the g-tensor evaluation of 2 [1] − using a perturbative inclusion of SOC in the scalar relativistic ZORA wavefunction using either DFT or CASSCF levels of theory 44 with the rigorous treatment of relativistic effects and g-tensor evaluation at the DKS level. 51, 52, 53, 54, 55 Furthermore, the solvent polarization effects will be considered for further consistency via the COSMO approach.…”

Section: Resultsmentioning

confidence: 99%

“…52, 53, 54 The non-collinear Kramers unrestricted formalism was used as the best currently available method for description of spin polarization at the relativistic DFT level of theory. 51, 54, 55 The recent implementation of solvent models in the ReSpect program 51 allowed us to take into account effects of the environment (Me 2 SO) in the framework of COSMO model.…”

Section: Methodsmentioning

confidence: 99%

cis-Tetrachlorido-bis(indazole)osmium(iv) and its osmium(iii) analogues: paving the way towards the cis-isomer of the ruthenium anticancer drugs KP1019 and/or NKP1339

et al. 2017

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The relationship between cis-trans isomerism and anticancer activity has been mainly addressed for square-planar metal complexes, in particular, for platinum(II), e.g., cis- and trans-[PtCl2(NH3)2], and a number of related compounds, of which, however, only cis-counterparts are in clinical use today. For octahedral metal complexes, this effect of geometrical isomerism on anticancer activity has not been investigated systematically, mainly because the relevant isomers are still unavailable. An example of such an octahedral complex is trans-[RuCl4(Hind)2]−, which is in clinical trials now as its indazolium (KP1019) or sodium salt (NKP1339), but the corresponding cis-isomers remain inaccessible. We report the synthesis of Na[cis-OsIIICl4(κN2-1H-ind)2] (Na[1]) to show that cis-isomer of NKP1339 can in principle be prepared as well. The procedure involves heating (H2ind)[OsIVCl5(κN1-2H-ind)] in a high boiling point organic solvent resulting in an Anderson rearrangement with formation of cis-[OsIVCl4(κN2-1H-ind)2] ([1]) in high yield. The transformation is accompanied by an indazole coordination mode switch from κN1 to κN2 and stabilization of the 1H-indazole tautomer. Fully reversible spectroelectrochemical reduction of [1] in acetonitrile at 0.46 V vs NHE is accompanied by a change in electronic absorption bands indicating formation of cis-[OsIIICl4(κN2-1H-ind)2]− ([1]−). Chemical reduction of [1] in methanol with NaBH4 followed by addition of nBu4NCl afforded the osmium(III) complex nBu4N[cis-OsIIICl4(κN2-1H-ind)2] (nBu4N[1]). Metathesis reaction of nBu4N[1] with an ion exchange resin led to isolation of the water-soluble salt Na[1]. The X-ray diffraction crystal structure of [1]·Me2CO was determined and compared with that of trans-[OsIVCl4(κN2-1H-ind)]·2Me2SO (2·2Me2SO), also prepared in this work. EPR spectroscopy was performed on the OsIII complexes and the results analyzed by ligand-field and quantum chemical theories. We furthermore assayed effects of [1] and Na[1] on cell viability and proliferation in comparison to trans-[OsIVCl4(κN1-2H-ind)] [3] and cisplatin and found a strong reduction of cell viability at concentrations between 30 and 300 µM in different cancer cell lines (HT29, H446, 4T1 and HEK293). HT-29 cells are less sensitive to cisplatin than 4T1 cells, but more sensitive to [1] and Na[1], as shown by decreased proliferation and viability as well as an increased late apoptotic/necrotic cell population.

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“…For a more detailed discussion of four-component g-tensor calculations and the di↵erences between Kramers restricted and unrestricted methods can be found in Refs. [35,97].…”

Section: Four-component Epr Theorymentioning

confidence: 99%

Four-component relativistic density functional theory with the polarisable continuum model: application to EPR parameters and paramagnetic NMR shifts

et al. 2016

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The description of chemical phenomena in solution is as challenging as it is important for the accurate calculation of molecular properties. Here, we present the implementation of the polarizable continuum model (PCM) in the four-component Dirac-Kohn-Sham density functional theory framework, o↵ering a cost-e↵ective way to concurrently model solvent and relativistic e↵ects. The implementation is based on the matrix representation of the Dirac-Coulomb Hamiltonian in the basis of restricted kinetically balanced Gaussian-type functions, exploiting a non-collinear Kramers unrestricted formalism implemented in the program ReSpect, and the integral equation formalism of the PCM (IEF-PCM) available through the standalone library PCMSolver. Calculations of EPR parameters (g-tensors and hyperfine coupling A-tensors), as well as of the temperature-dependent contribution to paramagnetic NMR (pNMR) shifts, are presented to validate the model and to demonstrate the importance of taking both relativistic and solvent e↵ects into account for magnetic properties. As shown for selected Ru and Os complexes, the solvent shifts may amount to as much as 25% of the gas-phase values for g-tensor components and even more for pNMR shifts in some extreme cases.

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Calculations of the EPR g-tensor using unrestricted two- and four-component relativistic approaches within the HF and DFT frameworks

Cited by 15 publications

References 29 publications

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF₆]²⁻ and [IrF₆]²⁻

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF₆]²⁻ and [IrF₆]²⁻

cis-Tetrachlorido-bis(indazole)osmium(iv) and its osmium(iii) analogues: paving the way towards the cis-isomer of the ruthenium anticancer drugs KP1019 and/or NKP1339

Four-component relativistic density functional theory with the polarisable continuum model: application to EPR parameters and paramagnetic NMR shifts

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Calculations of the EPR g-tensor using unrestricted two- and four-component relativistic approaches within the HF and DFT frameworks

Cited by 15 publications

References 29 publications

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF6]2− and [IrF6]2−

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF6]2− and [IrF6]2−

cis-Tetrachlorido-bis(indazole)osmium(iv) and its osmium(iii) analogues: paving the way towards the cis-isomer of the ruthenium anticancer drugs KP1019 and/or NKP1339

Four-component relativistic density functional theory with the polarisable continuum model: application to EPR parameters and paramagnetic NMR shifts

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Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF₆]²⁻ and [IrF₆]²⁻

Relativistic DFT Calculations of Hyperfine Coupling Constants in 5d Hexafluorido Complexes: [ReF₆]²⁻ and [IrF₆]²⁻