Simultaneous Detection and Removal of Metal Ions based on a Chemosensor
Composed of a Rhodamine Derivative and Cyclodextrin Modified Magnetic
Nanoparticles
Dongjian Shiab, Ming Nia, Jinfeng Zenga, Jin Yea, Peihong Nib, Xiaoya Liua and
Mingqing Chen*a
a
The Key Laboratory of Food Colloids and Biotechnology Ministry of Education,
School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P.
R. China
b
Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application,
Soochow University, 215123, P. R. China
Corresponding Author
Prof. Mingqing Chen
E-mail: mqchen@jiangnan.edu.cn
Contents :
1. Synthesis of AD-MAH-RhB.
2. Mechanism studies
3. Synthesis of CD-functionalized magnetic nanoparticles (CD-MNP)
4. Removal of metal ions
1. Synthesis of AD-MAH-RhB.
The chemsensor was synthesized as following (Scheme S1). Maleic anhydride (1
mmol)，RhB (1 mmol) and 4-dimethylamiopyridine (DMAP, 0.15 mmol) were
dissolved in DMSO. Then, 1-ethyl-3-(3-Dimethylaminopropyl) carbodiimide (EDC, 1
mmol), hydroxybenzotriazole (HOBt, 1 mmol) and 1-aminoadamantane (AD-NH2, 1
mmol)were added into the above solution. After predetermined time, solvent was
removed under reduced pressure to give an red powder and purified by slilica gel
column chromatography in CH2Cl2 to give purified AD-MAH-RhB probe.
Scheme S1. Synthesis of AD-MAH-RhB.
H NMR (400MHz，CDCl3，σ，ppm, Fig. S1): 7.88-7.85 (m, 1H), 7.45-7.42 (J=3.2,
2H), 7.09-7.07 (m, 1H), 6.44-6.26 (m, 8H), 3.37-3.26 (J=7.2, 12H), 2.11-1.88 (m, 2H),
1.90-1.70 (17H, adamantyl imine), 1.18-1.14 (J=7.2, 12H).
1
10
8
6
4
2
0
ppm
Fig. S1. 1H NMR spectrum of AD-MAH-RhB.
C NMR (400MHz，CDCl3，σ，ppm, Fig. S2): (a) carbon in benzene, (b) carbon in
amide, (c) carbon in unsaturated olefin, (d) carbon in methylene adjacent to nitrogen
atoms, (e) carbon in methyl, (f) quaternary carbon atom, and (h) carbon in all
methylene.
13
(e)
(e)
(a)
(h)
(h)
(c)
(d)
(f)
(b)
(d)
(b)
(b)
(e)
(h)
(f)
(c)
(a)
(d)
(b)
140
120
100
80
60
40
20
0
ppm
Fig. S2. 13C NMR spectrum of AD-MAH-RhB
Mass spectrum was shown in Fig. S3. The result showed ESI m/z [M+Na+] of
AD-MAH-RhB at 738.5.
Fig. S3. Mass spectrum of AD-MAH-RhB
Element analysis was also performed to analysis the structure. The results of each
element were C 70.43%, N 9.26%, and H 7.88%. Specifically, for AD-MAH-RhB
probe, the molecular structure is C44N5H53O4, and the theoretic amounts of C, N, and
H element were 73.84%, 9.79% and 7.41%, respectively. Thus, the theoretic result is
similar to the analytic result.
All these results indicated successful preparation of AD-MAH-RhB probe.
2. Mechanism studies.
The binging position of the complexes were also determined by 1H-NMR spectra
(Fig. S4). It could be seen that the chemical shift of the double carbon group om
AD-MAH-RhB@Hg2+ (Fig. S4a) had an obviously changed from 6.3 ppm to 6.7 ppm,
compared with AD-MAH-RhB (Fig. S4b). This indicated the unsaturated olefin was
changed by addition of Hg2+. For AD-MAH-RhB@Fe3+ complex (Fig. S4c), an
obviously shift at 2.5 ppm that belongs to the methylene adjacent to nitrogen atoms
was observed, suggesting formation the AD-MAH-RhB@Fe3+ complex between
nitrogen atoms and Fe3+.
Fig. S4. 1H NMR spectra of AD-MAH-RhB@Hg2+ (a), AD-MAH-RhB (b) and
AD-MAH-RhB@Fe3+ (c)
3. Synthesis of CD-functionalized magnetic nanoparticles (CD-MNP)
Fe3O4 nanoparticles were prepared by Fe2+ and Fe3+ in the present of NH3∙H2O,
according to the traditional co-precipitation method [29], and then modified by
APTES to get amine-functionalized MNP (MNP-NH2). Finally, pre-prepared
mono-6-deoxy-6-(p-tolysulfonyl)-β-cyclodextrin (6-Ts-O-β-CD) and MNP-NH2
suspended in dried N-methylpyrrolidone, and the mixture was sonicated for 20 min
before adding KI (0.010 g) under nitrogen at 70 oC. The products were obtained by
repeating the procedure of magnetic decantation for three times, and then dried in
vacuum. Figure S6 shows the TEM images of MNP-NH2 and CD-MNP. The sizes of
them were about 15 nm (Fig. S5a) and around 70 nm from TEM image (Fig. S5b).
(a)
(b)
Fig. S5. TEM images of magnetic nanoparticles (a) and CD modified magnetic
nanoparticles(b).
4. Removal of metal ions
After removal of AD-MAH-RhB by CD-MNP, the supernatant solution was titrated
by EDTA. Fig. S6 shows the remaining Hg2+ in the supernatant solutions before and
after removal by CD-MNP. The amount of remained Hg2+ was very low, suggesting
the Hg ions could be detected by AD-MAH-RhB and removed by CD-MNP.
3
n (Hg 2+) (10-6 mol)
2.5
2
1.5
1
0.5
0
bef1ore
af ter
2
Fig. S6. Remaining Hg2+ in the supernatant solutions before and after removal of
CD-MNP and AD-MAH-RhB-Hg2+ inclusion complex.