(PtI6-2RDG)n缔合纳米微粒体系的共振散射、荧光猝灭和减色效应研究

在0.02mol/L HCl介质中，罗丹明6G（RDG）分别在530nm和550nm处有一个吸收峰和荧光峰，PtI6^2-与RDG^ 主要通过静电引力形成疏水性的PtI6-2RDG缔合物分子。PtI6-2RDG分子间存在较强的分子和和疏水作用力而生成（PtI6-2RDG)n缔合纳米微粒，其粒径为40nm，在400nm、470nm和590nm产生3个共振散射，其中400nm和590nm处的2个峰为其特征共振散射峰，550nm荧光峰和530nm吸收峰的降低是由于纳米微粒形成后，只有裹露在（PtI6-2RDG)n纳米微粒界面的RDG荧光分子才能吸收激发光子跃迁到激发态，进而返回基态产生荧光，而体体相的RDG荧光分子无法与激发光作用产生荧光，即与激发光作用的RDG分子数大为降低。当该纳米微粒体系加入乙醇后，由于乙醇致使（PtI6-2RDG)n纳米微粒分解为PtI6-2RDG分子，体系的红紫色和共振散射峰消失，吸收峰和荧光峰恢复，研究结果表明，红紫色（PtI6-2RDG)n纳米微粒的形成是其共振散射增强、荧光猝灭、减色效应和产生特征共振散射峰的根本原因。

Resonance Scattering and Fluorescence Quenching and Hypochromic Effects of (PtI6-2RDG)n Association Nanoparticle

There is a maximum absorption peak at 530 nm and a fluorescence peak at 550 nm for rodamine 6G(RDG) in the medium of 0.02 mol/L HCl. The PtI+ 2--6 and RDG++ combine into hydrophobic PtI-6-2RDG association molecule by means of attraction force. There is strong Van de Waals force and hydrophobic force among PtI-6-2RDG molecules. So it form (PtI-6-2RDG)-n composite nanoparticle in size of about 40 nm and red-violet color. Which exhibits a resonance scattering peaks at 470 nm, two characteristic resonance scattering peaks at 590 nm and 400 nm, and enhanced resonance scattering effect. The fluorescence quenching at 550 nm and absorption decreasing at 530 nm are owing to that the RDG molecules in the body of the nanoparticle can not absorb the incidence photons and may be not excited by it. So that, the RDG molecules do not emit fluorescence, absorption photon RDG molecules in the system decrease greatly. The (PtI-6-2RDG)-n nanoparticle can be decomposed into PtI-6-2RDG association molecule by alcohol. Meanwhile, the resonance scattering peaks and the red-violet disappear. And the A- 520 nm and F- 550 nm/510 nm come back. The results demonstrate that the formation of (PtI-6-2RDG)-n association nanoparticle in red-violet color and the interface between the nanoparticle solid phase and the water phase is the results in its enhanced resonance scattering, two characteristic resonance scattering peaks at 590 and 400 nm, fluorescence quenching and hypochromic effects.