Reductive Formation of a Vanadium(IV/V) Oxide Cluster Complex [V<sub>8</sub>O<sub>19</sub>(4,4′‑<sup><i>t</i></sup>Bubpy)<sub>3</sub>] Having a <i>C</i><sub>3</sub>‑Symmetric Propeller-Shaped Nonionic V<sub>8</sub>O<sub>19</sub> Core

A novel <i>C</i><sub>3</sub>-symmetric propeller-shaped vanadium­(IV/V) oxide cluster complex, [V<sub>8</sub>O<sub>19</sub>(4,4′-<sup><i>t</i></sup>Bubpy)<sub>3</sub>] (<b>V</b><sub><b>8</b></sub><b>′</b>), has been synthesized from the reaction of the windmill-shaped vanadium­(V) oxide cluster complex [V<sub>8</sub>O<sub>20</sub>(4,4′-<sup><i>t</i></sup>Bubpy)<sub>4</sub>] (<b>V</b><sub><b>8</b></sub>) with PPh<sub>3</sub> under N<sub>2</sub>, whereas refluxing <b>V</b><sub><b>8</b></sub> in methanol or ethanol under N<sub>2</sub> provides tetranuclear oxido­(alkoxido)­vanadium­(IV/V) complexes [V<sub>4</sub>O<sub>6</sub>(OR)<sub>6</sub>(4,4′-<sup><i>t</i></sup>Bubpy)<sub>2</sub>] [R = Me (<b>V</b><sub><b>4</b></sub><b>′-Me</b>) and Et (<b>V</b><sub><b>4</b></sub><b>′-Et</b>)]. The mixed-valent vanadium­(IV/V) clusters <b>V</b><sub><b>8</b></sub><b>′</b> and <b>V</b><sub><b>4</b></sub><b>′</b> are converted back to <b>V</b><sub><b>8</b></sub> under O<sub>2</sub>. Interconversions of <b>V</b><sub><b>4</b></sub><b>′</b> and the oxido­(alkoxido)­vanadium­(V) complexes [V<sub>4</sub>O<sub>8</sub>(OMe)<sub>4</sub>(4,4′-<sup><i>t</i></sup>Bubpy)<sub>2</sub>] (<b>V</b><sub><b>4</b></sub>) and [V<sub>7</sub>O<sub>17</sub>(OEt)­(4,4′-<sup><i>t</i></sup>Bubpy)<sub>3</sub>] (<b>V</b><sub><b>7</b></sub><b>-Et</b>) are also presented.