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制备了铬-芳烃配合物。详细研究了亲核芳烃取代配合物在有机溶剂中的稳定性和反应性。根据文献报道，该配合物由六羰基铬和对二氯苯合成。最终的纯化过程由柱层析改为升华。光谱数据和熔点与文献一致。通过在325 nm处的吸收变化考察了配合物在有机溶剂中的稳定性。在非极性溶剂中吸附1h后，吸收率降至70%。这种减少与水和氧的存在无关。溶液中可能存在交换反应或配体解离。在甲基二甲基亚砜中，用苯酚和噻吩进行亲核芳香族取代。在未分离的情况下，用高效液相色谱法测定了粗产物中单取代产物和双取代产物的比例。噻吩反应得到双取代产物。结果表明，硫代酚的二次取代是顺利进行的，而醚键则阻碍了苯酚的二次取代。解合反应通过I_2氧化有效进行。由于该配合物在有机溶剂中不太稳定，因此尚未对该配合物的聚合进行研究。以该配合物为单体进行缩聚，要求反应速度快。

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.