A new fluorescent molecule 1,7-diazaperylene (DP) has been investigated by means of time-resolved and steady-state polarized fluorescence spectroscopy, as well as X-ray spectroscopy. Absorption and fluorescence spectra of DP in solution are similar to those of perylene. However, absorption and fluorescence spectra of 2,8-dimethoxy DP and 2,8-dipentyloxy DP in solution are red-shifted by ca. 55 nm relative to perylene. The fluorescence decay of DP is exponential with a lifetime of 5.1 ns in ethanol, 4.9 ns in glycerol and 4.3 ns in paraffin oil. The radiative lifetime in ethanol was calculated to be 6.3 ns for DP, 8.0 ns for 2,8-dimethoxy DP and 7.6 ns for 2,8-dipentyloxy DP. The calculated fluorescence quantum yields of 0.8 for DP and its alkoxy derivatives in ethanol, are in good agreement with those obtained from measurements. The calculated Förster radius is 37.2 ± 1 Å for DP and 41.9 ± 1 Å for its alkoxy derivatives in ethanol. Examining the S0↔ S1 transition, we obtain a limiting fluorescence anisotropy of r0≈ 0.38 for DP and its alkoxy derivatives. The rotational rates of DP in paraffin oil and glycerol were compared to that of perylene. In paraffin oil both molecules show an almost identical biexponential decay of the fluorescence anisotropy, which is compatible with a rotational motion like an oblate ellipsoid. The fluorescence anisotropy is monoexponential for DP in glycerol, and DP appears to rotate like a spherical particle while perylene in glycerol appears to rotate like an oblate ellipsoid. Moreover, the rotational diffusion constant, corresponding to rotation about an axis in the aromatic plane (D⊥), is the same for both DP and perylene in glycerol.
通过时间分辨和稳态偏振荧光光谱以及X射线光谱,对一种新的荧光分子1,7-二氮杂
苝(DP)进行了研究。DP在溶液中的吸收和荧光光谱与
苝相似。然而,2,8-二甲氧基DP和2,8-二戊氧基DP在溶液中的吸收和荧光光谱相对于
苝红移约55 nm。DP的荧光衰减呈指数分布,在
乙醇中的寿命为5.1 ns,在
甘油中为4.9 ns,在石蜡油中为4.3 ns。在
乙醇中,DP的辐射寿命计算为6.3 ns,2,8-二甲氧基DP为8.0 ns,2,8-二戊氧基DP为7.6 ns。在
乙醇中,DP及其烷氧基衍
生物的计算荧光量子产率为0.8,与测量值非常吻合。在
乙醇中,DP及其烷氧基衍
生物的计算福斯特半径分别为37.2 ± 1 Å和41.9 ± 1 Å。通过研究S0↔ S1跃迁,我们得到了DP及其烷氧基衍
生物的极限荧光各向异性r0≈ 0.38。将DP在石蜡油和
甘油中的旋转速率与
苝的旋转速率进行了比较。在石蜡油中,两种分子的荧光