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Supporting Information

Fluorometric Sensing of Hg2+ ions in aqueous medium by nano-aggregates of a tripodal receptor

Ajnesh Singha,†, Simanpreet Kaurb,†, Narinder Singha,* Navneet Kaur b,*

a Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Panjab 140001, India. b Centre for Nanoscience & Nanotecnology, Panjab University, Chandigarh, 160014, India.

† both authors have equal contributed

∗ Corresponding author: E-mail address; nsingh@iitrpr.ac.in (N. Singh), navneetkaur@ pu.ac.in (N. Kaur), Tel.: +91 1881242176/+91-1722534464.

Table of contents

Figure S1. FT IR spectrum of compound 1.

Figure S2. 1H NMR spectrum of compound 1.

Figure S3. 13C NMR spectrum of compound 1.

Figure S4. ESI Mass spectrum of compound 1.

Figure S5. FT IR spectrum of compound 2.

Figure S6. 1H NMR spectrum of compound 2.

Figure S7. 13C NMR spectrum of compound 2.

Figure S8. ESI Mass spectrum of compound 1.

Figure S9: Effect of water content (0-100%) on the formation of nanoparticles.

Figure S10. Determination of LOD

Figure S11. Fluorescence spectra of nano-aggregates N1 on addition on various tetrabutylammonium anions (F-, Cl-, Br-, I-, PO4

3-, ClO4-, HSO4

-, CN- and CH3COO-).

Figure S12. Fluorescence spectra of nano-aggregates N2 on addition on various tetrabutylammonium anions (F-, Cl-, Br-, I-, PO4

3-, ClO4-, HSO4

-, CN- and CH3COO-).

Figure S13. Fluorescence spectra of nano-aggregates N1 at different pH values.

Figure S14. Fluorescence spectra of nano-aggregates N1at different concentrations of TBA nitrate to evaluate the salt effect.

Figure S15. ESI Mass spectrum of complex [1.Hg2+.(NO3)2].H2O.

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Figure S1. FT IR spectrum of compound 1.

Figure S2. 1H NMR spectrum of compound 1.

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Figure S3. 13C NMR spectrum of compound 1.

Figure S4. ESI Mass spectrum of compound 1.

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3112

.90

2926

.16

2684

.01

1583

.41

1516

.00

1338

.98

1298

.74

1216

.62

1099

.93

1040

.17

970.

7893

2.04

874.

2880

5.23

776.

3874

7.65

694.

5565

8.95

630.

30

100015002000250030003500Wavenumber cm-1

9596

9798

9910

Tran

smitt

ance

[%]

Figure S5. FT IR spectrum of compound 2.

Figure S6. 1H NMR spectrum of compound 2.

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Figure S7. 13C NMR spectrum of compound 2.

Figure S8. ESI Mass spectrum of compound 2.

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0

0.1

0.2

0.3

0.4

0.5

0.6

250 300 350 400 450

100% acetonitrile40% water60% water80% water100% water

Abs

orba

nce

Wavelength(nm)

0

50

100

150

200

250

300

350

400

350 400 450 500 550

100% acetonitrile40% water60% water80% water100% water

Fluo

resc

ence

Inte

nsity

Wavelength (nm)

A B

Figure S9: Effect of water content (0-100%) on the formation of nanoparticles.

y = 0.8992x + 184.01R² = 0.9417

160

170

180

190

200

210

0 10 20 30

FL I

nten

sity

[Hg2+]/nM

Figure S10. Fluorescence Intensity (380 nm, excited at 285nm) of nano-aggregates N1(25µ M) as a function of Hg2+ concentration. The calibration curve in this concentration range is linear. The standard deviation (σ) of the emission intensity without any Hg2+ was determined to be 0.7237. Therefore, the detection limit was determined to be 2.41 × 10-9 M according to the 3σ method.

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Determination of the detection limit.

The detection limit (DL) of nano-aggregates of 1 for Hg2+ was determined from the following equation:

Where K = 3; Sb1 is the standard deviation of the blank solution; S is the slope of the calibration curve.

Figure S11. Fluorescence spectra of nano-aggregates N1 on addition on various tetrabutylammonium anions (F-, Cl-, Br-, I-, PO4

3-, ClO4-, HSO4

-, CN- and CH3COO-).

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8

0

100

200

300

400

500

600

700

300 400 500

Fluo

resc

ence

Inte

nsity

Wavelength(nm)

host

Fluoride

Chloride

Bromide

Iodide

Cyanide

Acetate

Hydrogen Sulphate

Nitrate

Perchlorate

Figure S12. Fluorescence spectra of nano-aggregates N2 on addition on various tetrabutylammonium anions (F-, Cl-, Br-, I-, PO4

3-, ClO4-, HSO4

-, CN- and CH3COO-).

0

50

100

150

200

250

300

350

400

340 390 440 490 540

Fluo

resc

ence

Inte

nsity

Wavelength(nm)

host 6.16.04 5.75.44 5.064.88 4.714.57 4.364.24 4.113.99 3.793.65 3.553.38 3.22.98 2.722.5 2.382.29 2.121.92

A B

Figure S13. Fluorescence spectra of nano-aggregates N1at different pH values.

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0

50

100

150

200

250

300

350

400

450

500

300 350 400 450 500

Fluo

resc

ence

Inte

nsity

Wavelength(nm)

host

5

10

15

30

60

100

200

Figure S14. Fluorescence spectra of nano-aggregates N1at different concentrations of TBA nitrate to evaluate the salt effect.

Figure S15. ESI Mass spectrum of complex [1.Hg2+.(NO3)2].H2O.

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Table S1: A comparison between the reported probes and present work.

Solvent System Linear range

(μM)

LOD Working mechanism

Ref. No.

CH3CN–HEPES buffer 0.001-1 7.4 nm Fluorescence on 14

Dichloromethane 0-2.0 50 nm Fluorescence on 15

Water:MeOH (1:2) 0.3-1.0 30 nm FRET 16

THF-Water (95:5) NA NA Bond energy Transfer 17

H2O–MeCN(99:1) 0.01-4.5 2.1nm Fluorescence on 18

Tris-HCl buffer 0.1-20 0.5 ppb Fluorescence off 19

HEPES buffer NA 200 nm Fluorescence on 20

THF/H2O (9:1) NA 4.5 nm Fluorescence off 21

Phosphate buffer 0-30 0.2 μM Fluorescence off 22

Acetonitrile :water (4:1) NA 1.74 μM Fluorescence off 23

Methanol NA 15 μM Fluorescence off 24

Water 1-10 2.4 nM Fluorescence on

Present work

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2014