Electronic Supplementary Material

Ultrasensitive Determination of Mercury (II) using Glass Nanopores Functionalized with MacrocyclicDioxotetraamines

RuiGaoa, Yi-LunYinga*, Bing-Yong Yanb, ParvezIqbalc, Jon A. Preecec and XinyanWua

aKey Laboratory for Advanced Materials & Department of Chemistry, East China University of Science and Technology, Shanghai 200237, P. R. China

b School of Information Science and Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
c School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT , UK

* To whom correspondence should be addressed:

  1. Synthesis of C5

C5 were prepared via multistep synthetic routes. thenaphthalimide derivative 3 (scheme S1) is an integral component and the synthesis of this component was initiated by the synthesis of azide1 via reacting the commercially available 11-bromoundecene with sodium azide at an alleviated temperature. Azide1 was reduced to alkylamine2 in the presence of Zn and NH4Cl, which was reacted with the commercially available 4-bromo-18-naphthalic anhydride at alleviated temperature to give the desired naphthalimide derivative 3. The naphthalimide derivative 3 was alkylated with ethanolamine to give the naphthalimide alcohol 4. The conversion of the alcohol to bromine was achieved in the presence of triphenylphosphine and carbon tetrabromide to obtain bromo-naphthalimide5. Thioacetylation of bromo-naphthalimide5was performed under the presence of thioacetic acid and catalytic amount of AIBN to give thioacetate6. The macrocylicdioxotetraamine was alkylated with thioacetate6 to obtain the macrocyclethioacetate7 and the subsequent hydrolysis of thioacetate 7 inacidic conditionsgavethe desired molecule C5.

Macrocyclethioacetate7: 1H NMR (300 MHz, CDCl3, Me4Si, 25 oC) δHppm; 8.48-7.82 (m, 4H), 6.32 (br, 1H), 4.05-4.3.52 (m, 20H), 2.78 (t, 2H, J = 7.00 Hz), 2.42-3.32 (m, 8H), 2.25 (s, 3H), 1.89-1.72 (m, 2H), 1.67-1.62 (m, 2H), 1.51-1.45 (m, 4H), 1.43-1.20 (m, 14H); 13C NMR (75 MHz, CDCl3, Me4Si, 25 oC) δCppm 170.9, 164.4, 164.0, 148.0, 134.3, 131.1, 129.8, 125.8, 125.1, 123.3, 120.6, 111.7, 104.6, 53.0, 48.7, 47.0, 46.5, 44.8, 44.3, 42.0, 40.3, 38.2, 30.6, 29.3, 29.2, 29.1, 29.0, 28.8, 28.2, 28.0, 27.2; m/z (ESMS): 718 ([M + Na]+, 100%); m/z (HRMS): found 717.9109. Calc. Mass for C35H52N6O4SNa:717.9166.

Molecule C5: m/z (ESMS): 676 ([M + Na]+, 100 %); m/z (HRMS): found 675.8732. Calc. Mass for C35H52N6O4SNa: 675.8799.

Scheme S1. Synthesis of molecule C5; (i) NaN3, DMSO, reflux, 3h, 85 %; (ii) Zn/NH4Cl, H2O:EtOH (1:1), reflux, 1 h, 91 %, (iii) EtOH, reflux, 16 h, 96 %; (iv) NH2(CH2)2OH, MeO(CH2)2OH, reflux, 18 h, 90 %; (v) PPh3, CBr4, THF, rt, 16 h, 89 %; (vi) HSAc, AIBN, PhMe, reflux, 2 h, 52 %; (vii) K2CO3, MeCN, N2(g)atm, reflux, 16 h, 24 %; (viii) 0.1 M HCl, N2(g)atm, reflux, 4 h, 27 %.

  1. Comparisons between nanopore-based methods for the detection of Hg2+

Table S1.Features of recently reported nanopore-based methods for detection of Hg2+

Pore-forming materials / Strategy / LODs / General advantages / References
α-Hemolysin / Detection of translocation events1 / 7 nM / Design of an ssDNAprobe to detect Hg2+ / 1
α-Hemolysin / Detection of translocation events1 / 0.5 nM / Design of Hg2+-mediated DNA duplex to precluding background interference / 2
α-Hemolysin / Detection of translocation events1 / 25 nM / Design of the hairpins with small loops to improve the sensitivity2 / 3
Glass pipette / Rectification measurements / ~10 pM / Rapid, high mechanical stability, no requirements of probing DNA strands and time-consuming statistical analysis / This work

1The formation of T-Hg2+-T regulated translocation events of the probe DNA strand.2Thehairpin loop of the probe DNA strand contained the binding site for Hg2+.

  1. Reproducibility of C5-funtionalized glass nanopore

Fig S1.Reproducibility of C5-funtionalized glass nanopore for the detection of Hg2+. The rectification ratio were obtained in a 10 mMKCl solution with 1 nMHg2+ under the voltage of ± 500 mV.

Reference

1. Wen S, Zeng T, Liu L, Zhao K, Zhao Y, Liu X, Wu HC (2011) Highly sensitive and selective DNA-based detection of mercury(II) with alpha-hemolysin nanopore. J Am Chem Soc 133:18312-18317.

2. Zeng T, Li T, Li YR, Liu L, Wang XY, Liu QS, Zhao YL, Wu HC (2014) DNA-based detection of mercury( II ) ions through characteristic current signals in nanopores with high sensitivity and selectivity. Nanoscale, 6:8579-8584.

3. Wang GH, Zhao QT, Kang XF, Guan XY (2013) Probing Mercury (II) − DNA Interactions by Nanopore Stochastic Sensing. J. Phys. Chem. B, 117: 4763-4769.