Finding of Crystalline-State Reaction

Ohashi, Crystalline State Photoreactions Direct Observation of Reaction Processes and Metastable Intermediates, DOI 10.1007/978-4-431-54373-2 2, Springer Japan 2014 

Although it appears no clear limitation exists between the crystalline-state reaction and the SCSC transformation if there are only two states, initial and final states, during the reaction, the former reaction is completely different from the latter one. As shown in Fig. 2.1, the changes of the unit-cell dimensions in the crystalline-state photo-racemization are expressed exponentially and are well explained by first-order kinetics. 

On the other hand, the change of unit-cell length of b during the reaction observed in the SCSC polymerization of DCH is shown in Fig. 2.7. The conversion of the monomer crystal suddenly increased after the induction period and is expressed sigmoidally as shown in Fig. 2.7a. The diffraction spots during the conversion rates between 30 

If there is an intermediate state during the reaction as shown in Fig. 2.8, the intermediate structure can be observed only in the CTystalline-state reaction. Several examples are shown in the following chapters. It may be adequate to classify the SCSC transformation into a reaction between the solid-state reaction and crystalline-state reaction. 

Nakanishi et al. reported the [2-f2] photo-dimerization of 5-benzylidene-cyclopentanones in 1981 as shown in Schane 2.4a [8]. Although the change of the unit-cell dimensions was shown in a complicated manner in their original paper, it showed first-order kinetics in the later experiment [9]. Probably the process of the dimerization shonld be classified into the aystaUine-state reaction. 

---