Synthesis of Poly (thioether) s by Nucleophilic Substitution of Chromium-Arene Complex

以对二氯苯和六羰基铬为原料合成了铬-芳烃配合物。以文献报道的六羰基铬和对二氯苯为原料，合成了该配合物，并研究了该配合物在有机溶剂中的稳定性和对芳香亲核取代反应的活性。将最终纯化工艺变更为升华而非柱色谱法。光谱数据和熔点与文献值一致，通过325 nm处吸收光谱的变化研究了配合物在有机溶剂中的稳定性。在非极性溶剂中，1 h后吸收从初始吸收降低至70%。这种减少与水和氧的存在无关。溶液中可能存在配体的交换反应或解离反应，在DMSO中于100 ℃进行了苯酚和苯硫酚的亲核取代反应，用HPLC测定了未经分离的粗产物中单取代和双取代产物的比例。以苯硫酚为原料，经反应得到二取代产物。结果表明，苯硫酚的二次取代反应进行顺利，而醚键阻碍了苯酚的二次取代反应。由于配合物在有机溶剂中的稳定性不高，因此没有研究过配合物的聚合反应。需要快速增长反应以使用络合物作为缩聚的单体。

Chromium-arene complex was prepared from p-dichlorobenzene and chromium hexacarbonyl. Stability in organic solvents and reactivity of the complex for nucleophilic aromatic substitution were investigated in detail.The complex was prepared from chromium-hexacarbonyl and p-dichlorobenzene, as reported in literature. The final purification process was changed to sublimation instead of column chromatography. Spectroscopic data and its melting point were consistent with those in literature.Stability of the complex in organic solvents is investigated by the change of absorption at 325 nm. The absorption decreased to 70% from the initial one after 1 h in non-polar solvents. The decrease is independent on the presence of water and oxygen. Exchange reaction or dissociation of ligand may exist in the solution.Nucleophilic aromatic substitutions by phenol and thiophenol were carried out in DMSO at 100ﾟC.The ratio of mono and disubstituted product was estimated from the crude product without isolation by HPLC measurements. Disubstituted product was obtained by the reaction of thiophenol. The fact indicates that second substitution by thiophenol proceeds smoothly whereas ether bond retard the second substitution by phenol. Decomplexation reaction proceeded efficiently by oxidation by I_2.Polymerization of the complex has not been investigated because the complex is not very stable in organic solvents. Rapid propagation reaction is required to use the complex as a monomer for polycondensation.