Tropolone-Terminated Oligomeric Fluorophores with Responsive Properties to External Environment
作者:Koji Takagi、Kazuhiro Saiki、Hirokazu Hayashi、Hiroyasu Ohsawa、Shin-ichi Matsuoka、Masato Suzuki
DOI:10.1246/bcsj.82.236
日期:2009.2.15
Tropolone-terminated oligomeric fluorophores (Tp2OP, Tp2OPV, and Tp2OPE) were prepared by palladium-catalyzed coupling reactions. A phenylene-type Tp2OP showed an emission maximum in the blue fluorescent region and the fluorescence quantum yield was relatively low. Tp2OPV and Tp2OPE, which included vinylene and ethynylene units as connecting groups, respectively, had emission maxima at longer wavelength regions than Tp2OP. The UV spectra of Tp2OP gradually red shifted as the dielectric constant of solvent increased. Tp2OP exhibited positive solvatofluorochromic behavior, which related to an increase of the dipole moment due to the charge-transfer characteristics of the emitting state. The fluorescence quantum yields (QYs) of fluorophores exponentially fell with increasing MeOH content in THF solution. Upon addition of CuCl2 to Tp2OP until the ratio of [Cu2+]/[Tp2OP] reached 1, the UV spectra exhibited a red-shift. The emission maximum wavelength of Tp2OP blue shifted and a remarkable decrease of the PL intensity was observed. Tp2OP showed metal ion-response, especially in PL spectra.
通过钯催化偶联反应制备了以邻苯二酚酮为端基的低聚荧光团(Tp2OP、Tp2OPV 和 Tp2OPE)。苯烯型 Tp2OP 在蓝色荧光区域显示出发射最大值,荧光量子产率相对较低。Tp2OPV 和 Tp2OPE 分别包含乙烯基和乙炔基单元作为连接基团,其发射最大值位于比 Tp2OP 更长的波长区域。随着溶剂介电常数的增加,Tp2OP 的紫外光谱逐渐红移。Tp2OP 表现出正溶解氟变色行为,这与发射态的电荷转移特性导致偶极矩增加有关。随着四氢呋喃溶液中 MeOH 含量的增加,荧光团的荧光量子产率呈指数下降。在 Tp2OP 中加入 CuCl2 直到[Cu2+]/[Tp2OP]之比达到 1 时,紫外光谱出现红移。Tp2OP 的发射最大波长发生蓝移,聚光强度显著下降。Tp2OP 显示出金属离子响应,尤其是在聚光光谱中。