有機磁性体の発生材料としてのポリジアゾ化合物の合成―ジアゾ化合物をビルディングブロックとする方法の展開―

Abstract

Many attempts have been made in order to realize organic ferromagnetic materials. Triplet carbenes are regarded as one of the most effective spin sources since magnitude of the exchange coupling between the neighboring centers is large. However, those systems have not employed extensively due to two disadvantages that hinder their further extension to usable magnetic materials. First, a triplet carbene unit is highly unstable and lacks the stability for practical application under ambient conditions. In order to overcome these difficulties, we have made great efforts to stabilize and succeeded in preparing fairly stable ones surviving for days. The second disadvantage that arises is that diazo groups are also generally labile and, hence, are usually introduced at the last step of synthesis.We found, more or less by chance, that a diphenyldiazomethane for a persistent triplet carbene is also persistent at the stage of the diazo compound and, hence, can be further modified, with the diazo group intact, into a more complicated diazo compound. Thus, the diazo compound can be used as a building block to prepare a poly (diazo) compound, which can then generate high-spin polycarbene with considerable thermal stability. Here we would like to summarize how we have used this method to prepare a series of poly (diazo) compounds. Attempts to modify the diazo compound to a more congested derivative by taking advantage of the stability are also mentioned.