Polynuclear Iron(II) Complexes with 2,6-Bis(pyrazol-1-yl)pyridine-anthracene Ligands Exhibiting Highly Distorted High-Spin Centers.

Content Provider	Semantic Scholar
Author	Šalitroš, Ivan Herchel, Radovan Fuhr, Olaf González-Prieto, Rodrigo Ruben, Mario
Copyright Year	2019
Abstract	Two bis-tridentate ligands L1 and L2 that contain 2,6-bis(pyrazol-1-yl) pyridine N-donor embraces introduced on a anthracene-acetylene backbone were used for the synthesis of a tetranuclear compound [Fe4(L1)4](CF3SO3)8·7CH3CN (1) and a hexanuclear compound [Fe6(L2)6](CF3SO3)12·18CH3NO2·9H2O (2). The polynuclear structures of both complexes were confirmed by X-ray diffraction studies, which revealed a [2 + 2] grid-like complex cation for 1 and a closed-ring hexagonal molecular architecture for the complex cation in 2. Although both compounds contain anthracene moieties arranged in a face-to-face manner, attempts at [4 + 4] photocyclization remain unsuccessful, which can be explained either by steric restraints or by inhibition of the photo-cycloaddition. Magnetic studies identified gradual and half-complete thermal spin crossover in the tetranuclear grid 1, where 50% of ferrous atoms exhibit thermal as well as photoinduced spin state switching and the remaining half of iron(II) centers are permanently blocked in their high-spin state. On the contrary, the hexanuclear compound 2 exhibits complete blocking in a high-spin state. Analysis of the magnetic data reveals the zero-field splitting parameter | D| ≈ 6-8 cm-1 with a large rhombicity for all high-spin iron(II) atoms in 1 or 2. The electronic structures and the magnetic anisotropies were also investigated by the multireference CASSCF/NEVPT2 method, and intramolecular exchange interactions were calculated by density functional theory methods.
Starting Page	4310
Ending Page	4319
Page Count	10
File Format	PDF HTM / HTML
DOI	10.1021/acs.inorgchem.8b03432
PubMed reference number	30860817
Journal	Medline
Volume Number	58
Issue Number	7
Alternate Webpage(s)	http://www.ruben-group.de/lit/2019_238_Polynuclear_Highly%20Distorted%20High-Spin%20Centers.pdf
Alternate Webpage(s)	https://doi.org/10.1021/acs.inorgchem.8b03432
Journal	Inorganic chemistry
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article