scholarly journals Creation of an unexpected plane of enhanced covalency in cerium(III) and berkelium(III) terpyridyl complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alyssa N. Gaiser ◽  
Cristian Celis-Barros ◽  
Frankie D. White ◽  
Maria J. Beltran-Leiva ◽  
Joseph M. Sperling ◽  
...  
Keyword(s):  
Electron Density ◽  
Heavy Element ◽  
Electronic States ◽  
Relativistic Effects ◽  
Induced Polarization ◽  
Ligand Field ◽  
Spin Orbit ◽  
Experimental Control ◽  
Heavy Element Complexes ◽  
Metal Ligand

AbstractControlling the properties of heavy element complexes, such as those containing berkelium, is challenging because relativistic effects, spin-orbit and ligand-field splitting, and complex metal-ligand bonding, all dictate the final electronic states of the molecules. While the first two of these are currently beyond experimental control, covalent M‒L interactions could theoretically be boosted through the employment of chelators with large polarizabilities that substantially shift the electron density in the molecules. This theory is tested by ligating BkIII with 4’-(4-nitrophenyl)-2,2’:6’,2”-terpyridine (terpy*), a ligand with a large dipole. The resultant complex, Bk(terpy*)(NO3)3(H2O)·THF, is benchmarked with its closest electrochemical analog, Ce(terpy*)(NO3)3(H2O)·THF. Here, we show that enhanced Bk‒N interactions with terpy* are observed as predicted. Unexpectedly, induced polarization by terpy* also creates a plane in the molecules wherein the M‒L bonds trans to terpy* are shorter than anticipated. Moreover, these molecules are highly anisotropic and rhombic EPR spectra for the CeIII complex are reported.

Nickel-macrocycle interaction in nickel(II) porphyrins and porphyrazines bearing alkylthio β-substituents: A combined DFT and XPS study

2017 ◽  
Vol 21 (04-06) ◽  
pp. 371-380 ◽  
Author(s):  
Maria Rachele Guascito ◽  
Giampaolo Ricciardi ◽  
Angela Rosa
Keyword(s):  
Electron Density ◽  
Binding Energies ◽  
Central Metal ◽  
Spin Orbit ◽  
Xps Spectra ◽  
Ligand Interactions ◽  
Xps Study ◽  
Induced Changes ◽  
Back Donation ◽  
Metal Ligand

An electronic structure analysis of two nickel(II) tetrapyrrole complexes bearing β-alkylthio substituents, NiOMTP and NiOETPz, has been carried out through a combination of high-resolution XPS experiments and DFT calculations. The Ni 2p XPS spectra show a 0.5 eV shift to higher energy of the Ni 2p[Formula: see text] and Ni 2p[Formula: see text] binding energies on going from the porphyrin to the porphyrazine complex. This shift, which is well-reproduced by relativistic spin-orbit ZORA calculations, is indicative of a depletion of electron density on the central metal. Such a depletion of electron density is related to the macrocycle-induced changes in the metal-ligand interactions. In the porphyrazine complex both the ligand to metal [Formula: see text] donation and the metal to ligand [Formula: see text]-back donation increase. The latter increases slightly more than the former, however, leading to a decrease of electron density on the central metal.

Introduction to Relativistic Quantum Chemistry

2007 ◽  
Author(s):  
Kenneth G. Dyall ◽  
Knut Faegri
Keyword(s):  
Dirac Equation ◽  
Quantum Chemistry ◽  
Relativistic Theory ◽  
Density Functional ◽  
Relativistic Quantum ◽  
Relativistic Effects ◽  
Basis Sets ◽  
Spin Orbit ◽  
Approximate Methods ◽  
Nonrelativistic Theory

This book provides an introduction to the essentials of relativistic effects in quantum chemistry, and a reference work that collects all the major developments in this field. It is designed for the graduate student and the computational chemist with a good background in nonrelativistic theory. In addition to explaining the necessary theory in detail, at a level that the non-expert and the student should readily be able to follow, the book discusses the implementation of the theory and practicalities of its use in calculations. After a brief introduction to classical relativity and electromagnetism, the Dirac equation is presented, and its symmetry, atomic solutions, and interpretation are explored. Four-component molecular methods are then developed: self-consistent field theory and the use of basis sets, double-group and time-reversal symmetry, correlation methods, molecular properties, and an overview of relativistic density functional theory. The emphases in this section are on the basics of relativistic theory and how relativistic theory differs from nonrelativistic theory. Approximate methods are treated next, starting with spin separation in the Dirac equation, and proceeding to the Foldy-Wouthuysen, Douglas-Kroll, and related transformations, Breit-Pauli and direct perturbation theory, regular approximations, matrix approximations, and pseudopotential and model potential methods. For each of these approximations, one-electron operators and many-electron methods are developed, spin-free and spin-orbit operators are presented, and the calculation of electric and magnetic properties is discussed. The treatment of spin-orbit effects with correlation rounds off the presentation of approximate methods. The book concludes with a discussion of the qualitative changes in the picture of structure and bonding that arise from the inclusion of relativity.

Spin-orbit coupling in low-lying electronic states of mercury hydride

2019 ◽  
Vol 229 ◽  
pp. 120-129
Author(s):  
Shuang Yin ◽  
Xiang Yuan ◽  
Yong Liu ◽  
Haifeng Xu ◽  
Bing Yan
Keyword(s):  
Electronic States ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

Ligand Field-Spin Orbit Energy Levels in the d4 and d6 Electron Configurations of Octahedral and Tetrahedral Symmetry

1974 ◽  
Vol 29 (1) ◽  
pp. 31-41 ◽  
Author(s):  
E. König ◽  
S. Kremer
Keyword(s):  
Strong Field ◽  
Energy Levels ◽  
Coulomb Repulsion ◽  
Orbit Interaction ◽  
Complete Agreement ◽  
Ligand Field ◽  
Spin Orbit ◽  
Tetrahedral Symmetry ◽  
Spin Orbit Interaction ◽  
Orbit Perturbation

The complete ligand field -Coulomb repulsion -spin orbit interaction matrices have been derived for the d4 and d6 electron configurations within octahedral (Oh) and tetrahedral (Td) symmetry. The calculations were perform ed in both the weak-field and strong-field coupling schemes and complete agreement of the results was achieved. The energy matrices are parametrically dependent on ligand field (Dq), Coulomb repulsion (B, C) and spin-orbit interaction (ζ). Correct energy diagrams are presentend which display the splittings by spin-orbit perturbation as well as the effect of configuration mixing. Applications to the interpretation of optical spectral data, to the detailed behavior at the crossover of ground terms, and to complete studies in magnetism are pointed out.

scholarly journals Ligand-Field Spin-Orbit Energy Levels in the d5 Electron Configuration of Octahedral and Tetrahedral Symmetry

1974 ◽  
Vol 29 (3) ◽  
pp. 419-428 ◽  
Author(s):  
E. König ◽  
R. Schnakig ◽  
S. Kremer
Keyword(s):  
Strong Field ◽  
Energy Levels ◽  
Orbit Interaction ◽  
Complete Agreement ◽  
Ligand Field ◽  
Electron Configuration ◽  
Spin Orbit ◽  
Tetrahedral Symmetry ◽  
Spin Orbit Interaction ◽  
Orbit Perturbation

The complete ligand-field, Coulomb interelectronic repulsion, and spin-orbit interaction matrices have been derived for the d5 electron configuration within octahedral (Oh) and tetrahedral (Td) symmetry. The calculations were performed in both the weak-field and strong-field coupling schemes and complete agreement of the results was achieved. The energy matrices are parametrically dependent on ligand field (Dq), Coulomb repulsion (B, C), and spin-orbit interaction (ζ). Correct energy diagrams are presented which display the splittings by spin-orbit perturbation as well as the effect of configuration mixing. Applications to the interpretation of electronic spectra, and to complete studies in magnetism are pointed out. The detailed behavior at the crossover of ground terms is considered

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