Topochemical diacetylene derivatives

Chart 10.7 Typical diacetylene derivatives capable of undergoing topochemical photopolymerization. Left classical examples [30]. Right Self-assembling bolaamphiphilic diacetylenes [67]. 

CHjNHjJj MtX are shown in Figs. 23a and b. They demonstrate effects on the photoreactivity due to a variation of the substituent R, and the inorganic salt MtXj From Fig. 23b a topochemical control of the reaction caused by the nature of the MF ions is evident. Similar effects are also reported for corresponding diacetylene derivatives (Chapt. 2.7). The butadiene polymerization in layer perovskite halide salts is schematically represented in Fig. 24 . ... 

Chart 3.7 Diacetylene derivatives capable of undergoing topochemical photopolymerization [56,65]. 

Polymerization of self-assembled LMOG molecules within the fibers of a molecular gel locks the scaffold-like structures and can make new stable materials [99,100]. Photopolymerization in the gels of diacetylenic cholesteryl derivatives, such as 63X-n [88,89], has been successfully employed to access organic nanowires with potential electrical conductivity, which could be used in molecular electronics. This strategy was based on the known propensity of diacetylenes to undergo topochemical soUd-state 1,4-addition reactions leading to conjugated polymers [101]. 

A theoretical model for predicting which diacetylene monomers will undergo topochemical polymerization has been developed. The semiempirical SCF-MO methods NfrroO, AMI, and PM3 have been used to carry out calculations based on this model. These methods were used to minimize the monomer geometries and the intermolecular distances and angles (R and a) between the monomer pairs. They have been applied to reactive and unreactive derivatives as well as some unknown derivatives. The results from these calculations suggest that this method may be applicable to a large variety of substituted diacetylene monomers. Specific examples of cases which show both the utility and the limitations of the model are discussed. 

Various polymerization route with unique starting monomer [64] have been developed, e.g., topochemical poly(diacetylene) synthesis with pyrrole-, thiophene-, -Si-groups dienophilic addition of maleic imides, Diels-Alder polymers via cyclopentadienone derivatives. 

---