Campidelli Stéphane, Sooambar Chloé, Lozano Diz Enrique, Ehli Christian, Guldi Dirk M, Prato Maurizio
INSTM and Dipartimento di Scienze Farmaceutiche, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy.
J Am Chem Soc. 2006 Sep 27;128(38):12544-52. doi: 10.1021/ja063697i.
We describe the synthesis and characterization of a series of single-wall carbon nanotubes (SWNTs) functionalized with polyamidoamine dendrimers. Importantly, the dendrimers are linked directly to the SWNT surface using a divergent methodology. This approach allows the number of functional groups on the nanotubes to be increased without provoking significant damage to the conjugated pi-system of the SWNTs. Several tetraphenylporphyrin moieties can be linked to the periphery of the dendrimers, and the photophysical properties of the resulting nanoconjugates have been investigated with a series of steady-state and time-resolved spectroscopy. The fluorescence kinetics provide evidence for two transient decays, one very short-lived (i.e., 0.04 +/- 0.01 ns) and one long-lived (i.e., 8.6 +/- 1.2 ns). A possible explanation is that some porphyrin units do not interact with the nanotubes, thus exhibiting a fluorescence lifetime similar to that of the free porphyrin. Complementary transient absorption measurements not only corroborate the fast decay of the photoexcited tetraphenylporphyrin but also confirm that intraconjugate charge separation evolves from the excited porphyrin to the SWNTs.
我们描述了一系列用聚酰胺胺树枝状大分子功能化的单壁碳纳米管（SWNTs）的合成与表征。重要的是，树枝状大分子使用发散法直接连接到SWNT表面。这种方法可以增加纳米管上的官能团数量，而不会对SWNTs的共轭π体系造成显著损害。几个四苯基卟啉部分可以连接到树枝状大分子的外围，并且已经用一系列稳态和时间分辨光谱研究了所得纳米共轭物的光物理性质。荧光动力学提供了两个瞬态衰减的证据，一个非常短寿命（即0.04±0.01纳秒），一个长寿命（即8.6±1.2纳秒）。一种可能的解释是，一些卟啉单元不与纳米管相互作用，因此表现出与游离卟啉相似的荧光寿命。互补的瞬态吸收测量不仅证实了光激发四苯基卟啉的快速衰减，而且证实了共轭体内的电荷分离从激发的卟啉向SWNTs演化。
