Investigation of the synthesis of {Mo(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)(CO)<sub>3</sub>}<sup>+</sup>fragments partnered with the monoanionic carboranes [closo-CB<sub>11</sub>H<sub>11</sub>Br]<sup>−</sup>, [closo-CB<sub>11</sub>H<sub>6</sub>Br<sub>6</sub>]<sup>−</sup>and [closo-HCB<sub>11</sub>Me<sub>11</sub>]<sup>−</sup>by silver salt metathesis and hydride abstraction
作者:Nathan J. Patmore、Michael J. Ingleson、Mary F. Mahon、Andrew S. Weller
DOI:10.1039/b303537a
日期:——
Abstraction of iodide from [Cp(CO)3MoI]
(Cp =
η5-C5H5) using the silver salt of the weakly coordinating anion [closo-CB11H11Br]â, initially affords an intermediate dimeric complex, [MoCp(CO)3I·Ag(CB11H11Br)]2, which has a central AgI}2 core appended by two carborane anions in the solid state. Prolonged reaction does result in elimination of AgI to form [MoCp(CO)3(CB11H11Br)], but not cleanly. This complex can be isolated in good yield by hydride abstraction from [Cp(CO)3MoH] using the new trityl salt [CPh3][closo-CB11H11Br]. Similarly, reaction of this hydride source with [CPh3][closo-CB11H6Br6] in CD2Cl2 results in hydride abstraction, but a mixture of products is formed, suggested to consist of the hydride bridged dimer, [Cp(CO)3Mo}2(μ-H)][closo-CB11H6Br6], the anion coordinated complex [Cp(CO)3Mo(closo-CB11H6Br6)] and the solvent adduct [Cp(CO)3Mo(ClCD2Cl)][closo-CB11H6Br6]. Reaction of Ag[closo-HCB11Me11] with [Cp(CO)3MoX]
(X = Cl, I) results in a intermediate complex which has a [Cp(CO)3MoX]6Ag2 central core (crystallographically characterised for X = I) with no interactions from the permethylated carborane anions. Prolonged reaction does result in partial AgX elimination to form the halide-bridged dimers [CpMo(CO)3}2(μ-X)][closo-HCB11Me11]. Hydride abstraction from [Cp(CO)3MoH] using the new trityl salt [CPh3][closo-HCB11Me11] resulted in the clean formation of the hydride-bridged dimer [Cp(CO)3Mo}2(μ-H)][closo-HCB11Me11]. The two anions [closo-CB11H6Br6]â and [closo-HCB11Me11]â have been compared with [B(ArFâ²)4]â
[ArFâ²
= 3,5-bis(trifluoromethyl)phenyl] in Bullock's ionic hydrogenation of 3-pentanone using [Cp(CO)2(PPh3)Mo]+ catalysts. The permethylated anion slightly outperforms its hexabrominated congener in catalysis, but is still slower than [B(ArFâ²)4]â.
从 [Cp(CO)3MoI] 中提取碘化物
(CP =
η5-C5H5) 使用弱配位阴离子 [closo-CB11H11Br]· 的银盐,最初提供中间二聚复合物 [MoCp(CO)3I·Ag(CB11H11Br)]2,其具有中心 AgI}2 核心附有两个固态碳硼烷阴离子。长时间的反应确实会导致 AgI 消除,形成 [MoCp(CO)3(CB11H11Br)],但不完全。使用新的三苯甲基盐 [CPh3][closo-CB11H11Br] 从 [Cp(CO)3MoH] 中提取氢化物,可以以良好的产率分离出该配合物。类似地,该氢化物源与 CD2Cl2 中的 [CPh3][closo-CB11H6Br6] 反应导致氢化物提取,但形成了产物混合物,表明由氢化物桥联二聚体 [Cp(CO)3Mo}2( μ-H)][closo-CB11H6Br6],阴离子配位络合物[Cp(CO)3Mo(closo-CB11H6Br6)]和溶剂加合物[Cp(CO)3Mo(ClCD2Cl)][closo-CB11H6Br6]。 Ag[closo-HCB11Me11] 与 [Cp(CO)3MoX] 的反应
(X = Cl, I) 产生具有 [Cp(CO)3MoX]6Ag2 中心核心(X = I 的晶体学特征)的中间复合物,与全甲基化碳硼烷阴离子没有相互作用。长时间的反应确实会导致部分 AgX 消除,形成卤化物桥联二聚体 [CpMo(CO)3}2(μ-X)][closo-HCB11Me11]。使用新的三苯甲基盐 [CPh3][closo-HCB11Me11] 从 [Cp(CO)3MoH] 中提取氢化物导致氢化物桥联二聚体 [Cp(CO)3Mo}2(μ-H)][ 的干净形成closeso-HCB11Me11]。已将两种阴离子 [closo-CB11H6Br6]‐ 和 [closo-HCB11Me11]‐ 与 [B(ArF‐²)4]‐ 进行了比较
[ArFâ²
= 3,5-双(三氟甲基)苯基],使用 [Cp(CO)2(PPh3)Mo]+ 催化剂进行 3-戊酮的布洛克离子氢化。全甲基化阴离子的催化性能略优于其六溴化同系物,但仍比 [B(ArF‐)4]‐ 慢。