Activation of H2 with Dinuclear Manganese(I)-Phosphido Complexes
Activation of H2 with Dinuclear Manganese(I)-Phosphido Complexes
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DOI：
10.1021/acs.organomet.1c00603
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发表时间：
2021-12-29
期刊：
影响因子：
2.8
通讯作者：
Lacy, David C.
中科院分区：
文献类型：
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作者：
Abhyankar, Preshit;MacMillan, Samantha N.;Lacy, David C.
关于 H-2 跨金属-磷脂键的活化的报道很少，并且所有第一行金属例子都使用杂环磷脂基供体。在本报告中，我们重点介绍了使用带有烷基和芳基取代基的第一行过渡金属磷基络合物活化 H-2 的发现。将配合物[Mn(CO)(4)(mu-PPh2)](2) (1)用H-2处理(125℃，33小时)，得到[{Mn(CO)(4)}(mu-H)(mu-PPh2){Mn(CO)(3)(Ph2PH)}](2)。用 Mn-2(CO)(10) 处理 2 会导致 PH 键活化并形成 [{Mn(CO)(4)}(mu-H)(mu-PPh2){Mn(CO)(4)}] (3)。 1 到 3 的相互转化是可逆的，如用游离 Ph2PH 处理 3 所示，在 80 ℃ 下生成 2 或在 120 ℃ 下生成 1 和 H-2。 1 的异丙基类似物 [Mn(CO)(4)(mu-P(iPr)(2))](2) (5) 通过氧化加成合成[(iPr)(2)PP(iPr)(2)] (4) 与 Mn-2(CO)(10)。 5 的反应性与 1 类似，用 H-2 处理形成 [{Mn(CO)(4)}(mu-H)(mu-P(iPr)(2)){Mn(CO)(3)((iPr)(2)PH}] (6)，然后与 Mn-2(CO)(10) 反应，定量提供[{Mn(CO)(4)}(mu-H)(mu-P(iPr)(2)){Mn(CO)(4)}] (7) 使用 tBu 取代基时，化学性质会发生变化。用 Cl(tBu)(2)P 处理 Na[Mn(CO)(5)] 会形成双-(tBu(2)P) 六羰基络合物。 [Mn(CO)(3)(mu-PtBu2)](2) (8)，一种具有正式 M-M 双键（2.5983(5) 埃）的深绿色化合物，与 H-2 反应缓慢，形成游离的 tBu(2)PH 和 [MnH(CO)(4)(HPtBu2)] (10)。相反，即使在高温下，H-2 的活化也不完全。 [{Mn(CO)(3)(mu-PPh2)}(2)(mu-CO)] (1-CO) 容易活化 H-2，生成 2（84%，70 摄氏度，10 小时），这表明在氢化条件下 PCl 键活化的第一步是需要热力的 CO 解离。 Cl(iPr)(2)p 在 1 atm H-2 下生成 3 (R = Ph) 或 7 (R = iPr)，收率 50-60%，表明双磷基化合物的中间体。分离出[Mn(CO)(3)(H)((tBu(2))P)(2)H] (11)和双轴-[Mn(CO)(4)((tBu(2))PH)](2) (12)，表明使用H-2和Mn-2(CO)(10)将PCl键氢化成膦。
There are few reports of activation of H-2 across metal-phosphido linkages, and all of the first-row metal examples use Nheterocyclic phosphido donors. In this report, we highlight the discovery of H-2 activation using first-row transition-metal phosphido complexes with alkyl and aryl substituents. The complex [Mn(CO)(4)(mu-PPh2)](2) (1) was treated with H-2 (125 degrees C, 33 h), affording [{Mn(CO)(4)}(mu-H)(mu-PPh2){Mn(CO)(3)(Ph2PH)}] (2). Treating 2 with Mn-2(CO)(10) leads to PH bond activation and formation of [{Mn(CO)(4)}(mu-H)(mu-PPh2){Mn(CO)(4)}] (3). The interconversion of 1 to 3 is reversible, as indicated by the treatment of 3 with free Ph2PH, giving 2 at 80 degrees C or 1 and H-2 at 120 degrees C. The isopropyl analogue of 1, [Mn(CO)(4)(mu-P(iPr)(2))](2) (5), was synthesized by the oxidative addition of [(iPr)(2)PP(iPr)(2)] (4) with Mn-2(CO)(10). The reactivity of 5 is analogous to that of 1, forming [{Mn(CO)(4)}(mu-H)(mu-P(iPr)(2)){Mn(CO)(3)((iPr)(2)PH}] (6) on treatment with H-2, which in turn reacts with Mn-2(CO)(10), quantitatively affording [{Mn(CO)(4)}(mu-H)(mu-P(iPr)(2)){Mn(CO)(4)}] (7). The chemistry diverges upon use of the tBu substituent. Treating Na[Mn(CO)(5)] with Cl(tBu)(2)P results in formation of the bis-(tBu(2)P) hexacarbonyl complex [Mn(CO)(3)(mu-PtBu2)](2) (8), a dark green compound with a formal M-M double bond (2.5983(5) angstrom). 8 reacts sluggishly with H-2 to form free tBu(2)PH and [MnH(CO)(4)(HPtBu2)] (10). The activation of H-2 with 1 is incomplete even at high temperatures. In contrast, facile activation of H-2 occurs with [{Mn(CO)(3)(mu-PPh2)}(2)(mu-CO)] (1-CO) to yield 2 (84%, 70 degrees C, 10 h), implicating thermally demanding CO dissociation from 1 as the first step in the H-2 activation. PCl bond activation under hydrogenative conditions was also examined. The reactions between Mn-2(CO)10 and ClPh2P or Cl(iPr)(2)p under 1 atm of H-2 gave 3 (R = Ph) or 7 (R = iPr) in 50-60% yield, indicating the intermediacy of bisphosphido compounds. When Cl(tBu)(2)P was used instead, the compounds cis-[Mn(CO)(4)(H)((tBu(2))P)(2)H)] (10), [Mn(CO)(3)(H)((tBu(2))P)(2)H] (11), and diaxial-[Mn(CO)(4)((tBu(2))PH)](2) (12) were isolated, indicating PCl bond hydrogenation to phosphines using H-2 and Mn-2(CO)(10).