Intramolecular exciplex and intermolecular excimer formation of 1,8-naphthalimide-linker-phenothiazine dyads.
Steady-state fluorescence spectra were measured for 1,8-naphthahlimide-linker-phenothiazine dyads (NI-L-PTZ, where L = octamethylenyl ((CH2)8) and 3,6,9-trioxaundecyl ((CH2CH2O)3C2H4)), NI-C8-PTZ and NI-O-PTZ, as well as the NI derivatives substituted on the nitrogen atom with various linker groups without PTZ as the reference NI molecule in n-hexane. Normal fluorescence peaks were observed at 367-369 nm in all NI molecules together with a broader emission around 470 nm, which is assigned to the excimer emission between the NI in the singlet excited state (1NI*) and the NI moiety of another NI molecule (1[NI/NI]*). In addition, a broad peak around 600 nm was observed only for NI-L-PTZ, which is assigned to an intramolecular exciplex emission between donor (PTZ) and acceptor (NI) moieties in the excited singlet state, 1[NI-L-NI]*. The formation of an intramolecular exciplex corresponds to the existence of a conformer with a weak face-to-face interaction between the NI and PTZ moieties in the excited state because of the long and flexible linkers. The excited-state dynamics of the NI molecules in n-hexane were established by means of time-resolved fluorescence spectroscopy.
Cho
Dae Won
DW
The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
Fujitsuka
Mamoru
M
Choi
Kyung Hwa
KH
Park
Man Jae
MJ
Yoon
Ung Chan
UC
Majima
Tetsuro
T
D015057:1-Naphthylamine / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D006586:Hexanes / Q000737:chemistry; D015394:Molecular Structure; D010640:Phenothiazines / Q000737:chemistry*; D010777:Photochemistry; D013050:Spectrometry, Fluorescence
D006586:Hexanes; D010640:Phenothiazines; D015057:1-Naphthylamine