A DFT computational study of spin crossover in iron(iii) and iron(ii) tripodal imidazole complexes. A comparison of experiment with calculations

2006 ◽  
pp. 5617 ◽  
Author(s):  
Greg Brewer ◽  
Myro Joy Olida ◽  
Ann M. Schmiedekamp ◽  
Carol Viragh ◽  
Peter Y. Zavalij
Keyword(s):  
Spin Crossover ◽  
Computational Study ◽  
Imidazole Complexes

scholarly journals The Role of Vibrational Anharmonicity in the Computational Study of Thermal Spin Crossover

2019 ◽  
Vol 5 (3) ◽  
pp. 49 ◽  
Author(s):  
Jianfang Wu ◽  
Carmen Sousa ◽  
Coen de Graaf
Keyword(s):  
Computational Chemistry ◽  
Spin Crossover ◽  
Computational Study ◽  
Accurate Determination ◽  
Zero Point ◽  
Energy Difference ◽  
Electronic Energy ◽  
Point Energy ◽  
A Minor ◽  
The Impact

Spin crossover in transition metal complexes can be studied in great detail with computational chemistry. Over the years, the understanding has grown that the relative stability of high-spin (HS) versus low-spin (LS) states is a subtle balance of many factors that all need to be taken into account for a reliable description. Among the different contributions, the zero-point energy (ZPE) and the entropy play key roles. These quantities are usually calculated assuming a harmonic oscillator model for the molecular vibrations. We investigated the impact of including anharmonic corrections on the ZPE and the entropy and indirectly on the critical temperature of spin crossover. As test systems, we used a set of ten Fe(II) complexes and one Fe(III) complex, covering different coordination modes (mono-, bi-, and tri-dentate ligands), decreasing coordination number upon spin crossover, coordination by second- and third-row atoms, and changes in the oxidation state. The results show that the anharmonicity has a measurable effect, but it is in general rather small, and tendencies are not easily recognized. As a conclusion, we put forward that for high precision results, one should be aware of the anharmonic effects, but as long as computational chemistry is still struggling with other larger factors like the influence of the environment and the accurate determination of the electronic energy difference between HS and LS, the anharmonicity of the vibrational modes is a minor concern.

scholarly journals Valence tautomerism and spin crossover in pyridinophane–cobalt–dioxolene complexes: an experimental and computational study

2019 ◽  
Vol 48 (31) ◽  
pp. 11674-11689 ◽  
Author(s):  
Tina Tezgerevska ◽  
Elodie Rousset ◽  
Robert W. Gable ◽  
Guy N. L. Jameson ◽  
E. Carolina Sañudo ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Computational Study ◽  
Temperature Dependent ◽  
Valence Tautomerism ◽  
Ancillary Ligands

Variation of alkyl substituents on pyridinophane ancillary ligands governs temperature-dependent valence tautomeric or spin crossover equilibria in a family of cobalt–dioxolene complexes.

scholarly journals Tuning the Spin-Crossover Properties of the [(Cp1-R)2Mn] Metallocenes

2021 ◽  
Author(s):  
Florian Matz ◽  
Jordi Cirera
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Transition Temperature ◽  
Density Functional ◽  
Rational Design ◽  
Spin Crossover ◽  
Computational Study ◽  
Fine Tuning ◽  
Functional Theory ◽  
Cyclopentadienyl Ligand

<p> In this work, we present a computational study using density functional theory (DFT) on how the single functionalization of the cyclopentadienyl ligand in<br> [(Cp<sup>1-R</sup>)<sub>2</sub>Mn] systems can be used to tune the spin-crossover properties in such systems. Using the OLYP functional, accurate values for the transition temperature (<i>T</i><sub>1/2</sub>) can be obtained, and our DFT methodology can be used to explore the effect that different substituents have on tuning such quantity. In particular, we show that the electronic structure of the [(Cp<sup>1-R</sup>)<sub>2</sub>Mn] can be tuned via the R group, allowing for a fine-tuning degree of the <i>T</i><sub>1/2</sub> that expands between 0 and 400 K. Our results allow for a rational design of new manganocene based systems with tailored SCO properties.</p>

scholarly journals Tuning the Spin-Crossover Properties of the [(Cp1-R)2Mn] Metallocenes

2021 ◽  
Author(s):  
Florian Matz ◽  
Jordi Cirera
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Transition Temperature ◽  
Density Functional ◽  
Rational Design ◽  
Spin Crossover ◽  
Computational Study ◽  
Fine Tuning ◽  
Functional Theory ◽  
Cyclopentadienyl Ligand

<p> In this work, we present a computational study using density functional theory (DFT) on how the single functionalization of the cyclopentadienyl ligand in<br> [(Cp<sup>1-R</sup>)<sub>2</sub>Mn] systems can be used to tune the spin-crossover properties in such systems. Using the OLYP functional, accurate values for the transition temperature (<i>T</i><sub>1/2</sub>) can be obtained, and our DFT methodology can be used to explore the effect that different substituents have on tuning such quantity. In particular, we show that the electronic structure of the [(Cp<sup>1-R</sup>)<sub>2</sub>Mn] can be tuned via the R group, allowing for a fine-tuning degree of the <i>T</i><sub>1/2</sub> that expands between 0 and 400 K. Our results allow for a rational design of new manganocene based systems with tailored SCO properties.</p>

Spin-crossover in an iron(iii) complex showing a broad thermal hysteresis

2021 ◽  
Author(s):  
Cyril Rajnák ◽  
Romana Mičová ◽  
Ján Moncoľ ◽  
Ľubor Dlháň ◽  
Christoph Krüger ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Mononuclear Complex ◽  
Hysteresis Width ◽  
Thermally Induced

A pentadentate Schiff-base ligand 3,5Cl-L2− and NCSe− form a iron(iii) mononuclear complex [Fe(3,5Cl-L)(NCSe)], which shows a thermally induced spin crossover with a broad hysteresis width of 24 K between 123 K (warming) and 99 K (cooling).

Dynamic and static muon-spin relaxation observed above and below the spin-crossover in Fe(II) complexes

2004 ◽  
Vol 114 ◽  
pp. 601-605 ◽  
Author(s):  
S. J. Blundell ◽  
T. Lancaster ◽  
F. L. Pratt ◽  
C. A. Steer ◽  
M. L. Brooks ◽  
...  
Keyword(s):  
Spin Relaxation ◽  
Spin Crossover ◽  
Muon Spin ◽  
Muon Spin Relaxation
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