| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
In order to investigate the influence of the substituted functional group on the IV-CT states of the organic IV compounds, we have carried out the synthesis of a nitroxide-group-substituted meta-terpheny1-4,4"-diamine 1. It is confirmed that the radical cation of an unsubstituted meta-terphenyl-4,4"-diamine 2 can be regarded as Class II IV compound. The. nitroxide radical group as a spin-bearing unit is substituted at the 5'-position of the central phenyl ring of meta-terphenyl backbone in order to retain the symmetrical arrangement of the two redox sites. Moreover, two triarylamine redox sites and the nitroxide radical group are connected to each other via meta-linkage. It was expected that such a substitution do not-essentially affect the IV-CT between symmetrically arranged two redox-active sites as is observed in 2^+. However, in 1^+, we could not observe the characteristic IVCT absorption band at around 1500 nm observed in 2^+. Although the reason is unclear at the present stage, there exist two possible explanations : (i) the change of the electron transfer path from the IV-CT between the two triarylamine sites into the IVCT between the nitroxide radical group and one of the two triarylamine sites, and (ii) the generated charge (or spin) is completely localized on one triphenylamine site. From the theoretical consideration, however, it was strongly suggested that the charge transfer path in 1^+ is changed from one between the two triarylamine sites to one between the triarylamine site and the nitroxide radical site. In any case, the diradical cation of 1 gives an intriguing example for tuning the ICT process by functional group substitution into the bis(triarylamine) IV-CT system.
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