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(η5-Cp)­(BDI)] (1; Cp = cyclopentadienide, BDI = N,N′-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 1 gives a rare
example of a rhenium­(II) compound Re­(η5-Cp)­(BDI)
(2), while protonation of 1 yields the rhenium­(III)
hydride complex Re­(H)­(η5-Cp)­(BDI) (3). The reaction of 1 with ZnCl2 generated
both 2 and the zinc­(I) compound [ZnRe­(η5-Cp)­(BDI)]2 (4), which features a linear,
tetrametallic Re­(I)–Zn­(I)–Zn­(I)–Re­(I) core. Computational
studies of 4 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 4 yielded both 2 and the triflate-bridged zinc­(II) complex [(μ-OTf)­ZnRe­(η5-Cp)­(BDI)]2 (5, OTf = trifluoromethanesulfonate).

本报告揭示了阴离子铼(I)化合物Na[Re(η5-Cp)(BDI)]（1；Cp = 环戊二烯基，BDI = N,N'-双(2,6-二异丙基苯基)-3,5-二甲基-β-二酮亚胺）的合成及其作为强化学还原剂和金属配体的初步研究。化合物1的化学氧化产生了罕见的铼(II)化合物Re(η5-Cp)(BDI)（2），而1的质子化则生成了铼(III)氢化配合物Re(H)(η5-Cp)(BDI)（3）。1与ZnCl2的反应生成了2和锌(I)化合物[ZnRe(η5-Cp)(BDI)]2（4），其中具有线性、四金属Re(I)-Zn(I)-Zn(I)-Re(I)核。对4的计算研究旨在表征金属-金属键合相互作用；结果显示铼与锌之间存在配位相互作用，以及两个锌中心之间的共价键。4的单电子氧化产生了2和三氟甲烷磺酸桥连的锌(II)配合物[(μ-OTf)-ZnRe(η5-Cp)(BDI)]2（5，OTf = 三氟甲烷磺酸根）。