Beschreibung:
<jats:p>The new compound [Cr<jats:sub>3</jats:sub>(dpa)<jats:sub>4</jats:sub>Cl<jats:sub>2</jats:sub>][CuCl<jats:sub>2</jats:sub>] (1) (dpa = di-2,2'-pyridylamido) was synthesized by reacting Cr<jats:sub>2</jats:sub>(dpa)<jats:sub>4</jats:sub> and anhydrous CuCl<jats:sub>2</jats:sub> in dry tetrahydrofuran. Partial oxidation of Cr<jats:sub>2</jats:sub>(dpa)<jats:sub>4</jats:sub> by Cu(II) forms Cr<jats:sup>3+</jats:sup> ions, which coordinate to the free N donor atoms of the dpa ligands, and led to the formation of a trinuclear chain cation [Cr<jats:sub>3</jats:sub>(dpa)<jats:sub>4</jats:sub>Cl<jats:sub>2</jats:sub>]<jats:sup>+</jats:sup>. Recrystallization from CH<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub>/ethyl ether yielded dark-brown, block-shaped crystals suitable for X-ray structure determination (Pccn (no. 56), a=1246:8(5), b=1487:3(3), c=2184:8(1) pm, V =4051.6(8) ·10<jats:sup>6</jats:sup> pm<jats:sup>3</jats:sup>, Z =4). The crystal structure is composed of discrete [Cr<jats:sub>3</jats:sub>(dpa)<jats:sub>4</jats:sub>Cl<jats:sub>2</jats:sub>]<jats:sup>+</jats:sup> cations and [CuCl<jats:sub>2</jats:sub>]<jats:sup>-</jats:sup> anions. The Cr<jats:sub>3</jats:sub> chain comprises quadruply-bonded diamagnetic (Cr<jats:sub>2</jats:sub>)<jats:sup>4+</jats:sup> dimers and a pseudo-octahedrally coordinated, paramagnetic Cr<jats:sup>3+</jats:sup> ion, manifesting itself in the effective magnetic moment μ<jats:sub>eff</jats:sub> of 3:54μ<jats:sub>B</jats:sub> (d3, S = 3=2) and the almost ideal Curie-paramagnetic behavior observed between 2 and 300 K with a Weiss constant θ = -0:25(4)K and χ0 = 4:9(7)×10<jats:sup>-4</jats:sup> emu mol<jats:sup>-1</jats:sup>
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