Differing reactivities of PCMe and PCBu<sup>t</sup>towards a triphosphabenzene and a tetraphosphabarrelene: synthesis of new phosphaalkyne pentamers (P<sub>5</sub>C<sub>5</sub>Me<sub>n</sub>Bu<sup>t</sup><sub>5−n</sub>, n = 0, 1 or 2)
作者:Cameron Jones、Christian Schulten、Andreas Stasch
DOI:10.1039/b618515k
日期:——
The reaction of excess PCMe with the triphosphabenzene, 1,3,5-P3C3But3, yields a phosphaalkyne pentamer, P5C5Me2But3, which displays a pentaphosphaisolumibullvalene core structure. Its treatment with [W(CO)5(THF)] gives a complex of this cage, [W(CO)5}2(µ-η1:η1-P5C5Me2But3)], which has been structurally characterised. In contrast, the previously reported reaction of PCBut with 1,3,5-P3C3But3, affords, in addition to the known tetraphosphabarrelene, 1,3,5,7-P4C4But4, a new phosphaalkyne pentamer (P5C5But5), which has a partially unsaturated âopen cageâ core. Although PCBut does not react with 1,3,5,7-P4C4But4, the reaction of PCMe with the tetraphosphabarrelene is shown to give a mixture of products. Treatment of these with [W(CO)5(THF)] leads to the isolation of the tungsten carbonyl complex, [W(CO)5}W(CO)4}(µ-η1:η4-P5C5MeBut4)], which has been structurally characterised. This study suggests that PCMe has a significantly greater reactivity towards cycloadditions than its bulkier counterpart, PCBut.
过量的 PCMe 与三磷苯(1,3,5-P3C3But3)反应生成磷炔五聚体 P5C5Me2But3,它显示出五磷aisolumibullvalene 核心结构。用 [W(CO)5(THF)]对其进行处理后,得到了这种笼状结构的复合物 [W(CO)5}2(µ-δ-1:δ-1-P5C5Me2But3)],并对其进行了结构表征。与此相反,之前报道的 PCBut 与 1,3,5-P3C3But3 的反应,除了生成已知的四磷杂环戊烯 1,3,5,7-P4C4But4 外,还生成了一种新的磷杂环戊烯(P5C5But5),它具有一个部分不饱和的 "开笼 "核心。虽然 PCBut 不会与 1,3,5,7-P4C4But4 发生反应,但 PCMe 与四磷杂烯烃的反应却会产生一种混合物。用 [W(CO)5(THF)]处理这些产物后,分离出了钨羰基复合物 [W(CO)5}W(CO)4}(µ-δ-1:δ-4-P5C5MeBut4)],并对其进行了结构表征。这项研究表明,PCMe 的环加成反应活性明显高于其体积更大的对应物 PCBut。