Heterotetrametallic Re–Zn–Zn–Re Complex Generated by an Anionic Rhenium(I) β‑Diketiminate

We report the synthesis of an anionic rhenium­(I) compound, Na­[Re­(η<sup>5</sup>-Cp)­(BDI)] (<b>1</b>; Cp = cyclopentadienide, BDI = <i>N</i>,<i>N</i>′-bis­(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) and initial investigations of its use as a strong chemical reductant and metalloligand. Chemical oxidation of <b>1</b> gives a rare example of a rhenium­(II) compound Re­(η<sup>5</sup>-Cp)­(BDI) (<b>2</b>), while protonation of <b>1</b> yields the rhenium­(III) hydride complex Re­(H)­(η<sup>5</sup>-Cp)­(BDI) (<b>3</b>). The reaction of <b>1</b> with ZnCl<sub>2</sub> generated both <b>2</b> and the zinc­(I) compound [ZnRe­(η<sup>5</sup>-Cp)­(BDI)]<sub>2</sub> (<b>4</b>), which features a linear, tetrametallic Re­(I)–Zn­(I)–Zn­(I)–Re­(I) core. Computational studies of <b>4</b> were performed to characterize the metal–metal bonding interactions; the results indicate a dative interaction from rhenium to zinc and covalent bonding between the two zinc centers. One-electron oxidation of <b>4</b> yielded both <b>2</b> and the triflate-bridged zinc­(II) complex [(μ-OTf)­ZnRe­(η<sup>5</sup>-Cp)­(BDI)]<sub>2</sub> (<b>5</b>, OTf = trifluoromethanesulfonate).