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were determined on an Edinburgh Analytical Instruments FL900CD spectrometer (Edinburgh
Instruments, Edinburgh, U.K.) and by the time-correlated single-photon-counting method with a
time resolution of 0.5 ns. A self-oscillating discharge lamp filled with hydrogen gas was employed
as a pulsed light source, and the excitation light was made monochromatic by a 10cm
monochromator. The emission from the sample was passed through an appropriate filter (Toshiba
UV-35) placed before the detector in order to eliminate scattered excitation light. Maximum counts
of up to 10000 were collected for each measurement. The accumulated signals were then processed,
and the lifetimes were determined by deconvolution with nonlinear leasts-quares fit.
2.2 TEM Measurement
A 50 µL portion of sample solution was dropped on a copper grid. The grid was then air-dried.
The samples were examined by a high-resolution TEM (Philips Tecnai G2 20 S-TWIN microscope)
operating at an accelerating voltage of 200 keV.
2.3 Synthesis of mono [6 - (3 - lipoiccarboxamide) ethylenediamino – 6 - deoxy]
- β - CD 1
To a solution of DMF (40mL) containing lipoic acid (0.4 g) and dicyclohexylcarbodiimide
(0.3 g) was added 1.3g of mono(6-ethylenediamino-6-deoxy)-β-CD. The resultant mixture was
stirred for one day in an ice bath and another 3 days at room temperature until no more precipitation
deposited. The precipitate was removed by filtration, and the filtrate was evaporated to dryness
under reduced pressure. The residue was dissolved in a minimum amount of hot water and then
poured into 300 mL of acetone to give a slight yellow precipitate. Such an operation was repeated
twice. The crude product obtained was dried in vaccum and purified by column chromatography
over Sephadex G-25 to give 0.6 g (37% yield) of 1 as a light yellow solid. ESI-MS m/z 1383.7 (M
+ NH4+); 1H NMR (D2O) δ 1.19-1.62 (m, 6H), 1.90-3.20 (m, 11H), 3.35-3.83 (m, 42H),
4.95-5.01 (m, 7H); FT-IR (KBr) ν 3336.1, 2926.1, 1652.0, 1558.3, 1455.2, 1333.5, 1153.7, 1078.8,
1031.8, 943.3 cm-1; Elemental analysis data (%) Calcd for C52H88O35N2S2⋅9H2O: C, 40.89; H,
6.99; N, 1.83; S, 4.20; Found: C, 40.74; H, 7.03; N, 1.97; S, 4.00.
2.4 Synthesis of gold nanoparticles 4
40 mg of HAuCl4⋅4H2O was dissolved in 20 mL of DMSO. This solution was quickly mixed
with another 20 mL of DMSO containing 75.5 mg of NaBH4 and 20 mg of 1, and the reaction
mixture turned deep brown immediately. After stirring the reaction mixture for 24 hours at room
temperature, 40 mL of CH3CN was added to give a black precipitate. The product was collected by
centrifugation, washed two times with 60 mL of CH3CN:DMSO (v:v = 1:1) and 60 mL of ethanol,
and dried under vacuum for 12 hours at 80°C to give 80 mg of 4 as a black powder. 1H NMR (D2O,
ppm) δ 1.19-1.72 (m, 6H), 1.90-3.25 (m, 11H), 3.35-3.93 (m, 42H), 4.95-5.1 (m, 7H); FTIR
(KBr):ν 3353.4, 2903.9, 1651.9, 1559.7, 1434.8, 1337.5, 1155.6, 1032.9 cm-1. Elemental analysis
data (%): C, 12.25; H, 2.92; N: 0.31. ICP-AES (%): Au 40.64.