苯在化学史上是一个关键性分子。人们认为苯的基本化学已被研究过了,可是匹兹堡大学的Cooper和Robert L.Thompson等却发现了一项令人惊奇的结果,即苯能进行[2+2]环二聚作用。从正常情况来说,在加热条件下这是可能的。但在一些受激状态下通过光化学反应就能进行。从热力学观点看,自由的苯分子不利于进行这种光化学反应。在Cooper的方法里,因为苯与锰中心[Mn(CO)_3]被还原性激活,因而 Benzene is a key molecule in the history of chemistry. It is thought that the basic chemistry of benzene has been studied, but the University of Pittsburgh Cooper and Robert L. Thompson found the surprising result that benzene can undergo [2 + 2] cyclodimerization. Under normal conditions, this is possible under heating conditions. But in some excited state by photochemical reaction can be carried out. From a thermodynamic point of view, free benzene molecules are not conducive to this photochemical reaction. In the Cooper method, because the benzene and manganese center [Mn (CO) 3] is reductively activated,