Synthesis and properties of cyclopentadithiophene-based poly(silarylenesiloxane) derivatives

Synthesis and optical properties of poly(tetramethylsilarylenesiloxane) derivative bearing diphenylcyclopentadithiophene moiety

“…On the other hand, the F F s of 4,4-diphenylCPDT with dimethylsilyl groups (7, M1, P1) are higher than those of 4,4-dimethylCPDT with dimethylsilyl groups (CPDT1, CPDT2, Pb) as shown in Table 2 [27]. The introduction of dimethylsilyl moieties onto 2-and 6-position of 4,4-dimethylCPDT skeleton was not so effective to improve the F F , that is, the F F of 4,4-dimethylCPDT was 0.01 and those of CPDT1, CPDT2 and Pb were the almost constant values of 0.09 [27].…”

“…The introduction of dimethylsilyl moieties onto 2-and 6-position of 4,4-dimethylCPDT skeleton was not so effective to improve the F F , that is, the F F of 4,4-dimethylCPDT was 0.01 and those of CPDT1, CPDT2 and Pb were the almost constant values of 0.09 [27]. On the other hand, the introduction of dimethylsilyl moieties onto 4,4-diphenylCPDT skeleton effectively improve the F F , that is, the F F of 4,4-diphenylCPDT was 0.03 and those of 7, M1 and P1 were 0.41, 0.36 and 0.39, respectively, as mentioned above.…”

“…5(a) through s*ep* conjugations between the dimethylsilyl groups and aromatic moieties [7e13]. It has been reported [8,9,27] that lowering the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) causes the bathochromic effects by stabilization of the LUMO state through s*ep* conjugation. In addition, the increase in the dipole moments of the HOMO and LUMO states owing to the sep conjugation in the HOMO and the s*ep* conjugation in the LUMO [7e13] would cause the enhancement of the transition moment to result in the hyperchromic effects.…”

“…On the other hand, cyclopenta[2,1-b:3,4-b 0 ] dithiophene (CPDT) [24,25] is regarded as an analogous compound of fluorene where the benzene rings are replaced by thiophene rings and composed of a fused bithiophene ring. There have been few reports on the fluorescent properties of CPDT derivatives or conjugated polymers based on CPDT [26,27], while CPDT derivatives have been rigid precursors of polymeric semiconducting materials for the development of organic photovoltaic devices [28e32]. The effect of the introduction of dimethylsilyl moieties onto 2-and 6-position of 4,4-dimethylCPDT skeleton on the optical properties was investigated in our previous report [27], where the introduction of dimethylsilyl moieties onto 2-and 6-position of 4,4-dimethylCPDT skeleton was not so effective to improve the fluorescence quantum yield.…”

“…There have been few reports on the fluorescent properties of CPDT derivatives or conjugated polymers based on CPDT [26,27], while CPDT derivatives have been rigid precursors of polymeric semiconducting materials for the development of organic photovoltaic devices [28e32]. The effect of the introduction of dimethylsilyl moieties onto 2-and 6-position of 4,4-dimethylCPDT skeleton on the optical properties was investigated in our previous report [27], where the introduction of dimethylsilyl moieties onto 2-and 6-position of 4,4-dimethylCPDT skeleton was not so effective to improve the fluorescence quantum yield. Thus, we have kept the effect of the introduction of dimethylsilyl moieties onto 9,9-diphenylfluorene as mentioned above in mind and been interested in the substituent effect on spiro carbon (4-position) of CPDT skeleton.…”