1 research outputs found
Slow Magnetic Relaxation in a Series of Mononuclear 8‑Coordinate Fe(II) and Co(II) Complexes
A series of homoleptic
mononuclear 8-coordinate Fe<sup>II</sup> and Co<sup>II</sup> compounds,
[Fe<sup>II</sup>(<b>L</b><sup><b>2</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>2</b>), [Fe<sup>II</sup>(<b>L</b><sup><b>3</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>3</b>), [Fe<sup>II</sup>(<b>L</b><sup><b>4</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>4</b>), [Co<sup>II</sup>(<b>L</b><sup><b>1</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>5</b>), [Co<sup>II</sup>(<b>L</b><sup><b>2</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>6</b>), [Co<sup>II</sup>(<b>L</b><sup><b>3</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>7</b>), and [Co<sup>II</sup>(<b>L</b><sup><b>4</b></sup>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>8</b>) (<b>L</b><sup><b>1</b></sup> and <b>L</b><sup><b>2</b></sup> are 2,9-dialkylcarboxylate-1,10-phenanthroline
ligands; <b>L</b><sup><b>3</b></sup> and <b>L</b><sup><b>4</b></sup> are 6,6′-dialkylcarboxylate-2,2′-bipyridine
ligands), have been obtained, and their crystal structures have been
determined by X-ray crystallography. The metal center in all of these
compounds has an oversaturated coordination number of 8, which is
completed by two neutral homoleptic tetradentate ligands and is unconventional
in 3d-metal compounds. These compounds are further characterized by
electronic spectroscopy, cyclic voltammetry (CV), and magnetic measurements.
CV measurements of these complexes in MeCN solution exhibit rich redox
properties. Magnetic measurements on these compounds demonstrate that
the observed single-ion magnetic (SIM) behavior in the previously
reported [Fe<sup>II</sup>(<b>L</b><b><sup>1</sup></b>)<sub>2</sub>]Â(ClO<sub>4</sub>)<sub>2</sub> (<b>1</b>) is not a contingent
case, since all of the 8-coordinate compounds <b>2</b>–<b>8</b> exhibit interesting slow magnetic relaxation under applied
direct current fields