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S1 Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling Biswonath Biswal and Bamaprasad Bag* Colloids and Materials Chemistry Department, CSIR-Institute of Minerals and Materials Technology, P.O.: R.R.L., Bhubaneswar-751 013, Odisha, India. Email: [email protected] Supplementary information Materials and Methods: S2 Absorption and emission spectral of 1 -4 in various solvents: S3-S4 Absorption peak position (λ, nm), corresponding molar S5 extinction coefficients (ε, dm 3 mol -1 cm -1 ) and emission maxima of the probes 1-4 in different solvents (Table-ST1) Metal ion induced optical signal modulation under various conditions, determination of association constants, Solid state fluorescence profile: S6-S12 Characterization (NMR and ESI-MS) Spectra: S13-S19 Electronic Supplementary Material (ESI) for Organic & Biomolecular Chemistry This journal is © The Royal Society of Chemistry 2013
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Preferences of rhodamine coupled (aminoalkyl)-piperazine ... · Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling

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Page 1: Preferences of rhodamine coupled (aminoalkyl)-piperazine ... · Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling

S1

Preferences of rhodamine coupled (aminoalkyl)-piperazine probes

towards Hg(II) ion and their FRET mediated signaling

Biswonath Biswal and Bamaprasad Bag*

Colloids and Materials Chemistry Department, CSIR-Institute of Minerals and Materials

Technology, P.O.: R.R.L., Bhubaneswar-751 013, Odisha, India. Email: [email protected]

Supplementary information

Materials and Methods: S2

Absorption and emission spectral of 1 -4 in various solvents: S3-S4

Absorption peak position (λ, nm), corresponding molar S5

extinction coefficients (ε, dm3

mol-1

cm-1

) and emission

maxima of the probes 1-4 in different solvents (Table-ST1)

Metal ion induced optical signal modulation under

various conditions, determination of association constants,

Solid state fluorescence profile: S6-S12

Characterization (NMR and ESI-MS) Spectra: S13-S19

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

Page 2: Preferences of rhodamine coupled (aminoalkyl)-piperazine ... · Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling

S2

Materials and Methods

All the reagent grade chemicals were used without purification unless otherwise

specified. Rhodamine B, rhodamine-6G, 1,4-bis-(aminopropyl)-piperazine, anthracene-9-

carboxaldehyde, 4-chloro-7-nitrobenzofurazan, 1-(2-aminoethyl)-piperazine and metal

perchlorate salts were obtained from Sigma-Aldrich (USA) and used as received. Anhydrous

sodium sulfate, sodium borohydride, triethylamine, acids, buffers and the solvents were received

from S. D. Fine Chemicals (India). All the solvents were freshly distilled prior to use following

the literature procedures and the reactions were carried out under N2 atmosphere.

Chromatographic separations were done by column chromatography using 100–200 mesh silica

gel.

The compounds were characterized by elemental analyses, 1H-NMR,

13C-NMR and mass (ESI)

spectroscopy. 1H-NMR and

13C-NMR spectra were recorded on a JEOL JNM-AL400 FT V4.0

AL 400 (400 MHz and 100 MHz respectively) instrument in CDCl3 with Me4Si as the internal

standard. Electrospray mass spectral data were recorded on a MICROMASS QUATTRO II triple

quadruple mass spectrometer. The dissolved samples of the compounds in suitable solvents were

introduced into the ESI source through a syringe pump at the rate of 5µL/min, ESI capillary was

set at 3.5 kV with 40V cone voltage and the spectra were recorded at 6 s scans. Melting points

were determined with a melting point apparatus by PERFIT, India and were uncorrected.

Elemental analyses were done in an Elementar Vario EL III Carlo Erba 1108 elemental analyzer.

UV-visible spectra were recorded on a Perkin Elmer Lambda 650 UV/VIS spectrophotometer at

298 K in 10−4

-10−6

M concentration. Steady-state fluorescence spectra were obtained with a

Fluoromax 4P spectrofluorometer at 298 K. The solid-state emission spectra were also recorded

in Fluoromax 4P spectrofluorometer at 298K excited at requisite wavelength with 450WXenon

lamp, band pass 2 nm and slapped through 1 nm during recording the spectra with integration

time 0.2 s.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

Page 3: Preferences of rhodamine coupled (aminoalkyl)-piperazine ... · Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling

S3

300 400 500 600 700 800

0

1

2

3

4

5

Ab

s

Hexane

n-Pr-OH

CHCl3

DCM

THF

Ethylacetate

EtOH

MeOH

MeCN

DMF

DMSO

1

(a)

Wavelength (nm)

300 400 500 6000

1

2

3

4

Ab

s

Wavelength(nm)

Hexane

CHCl3

DCM

THF

Ethyl Acetate

PrOH

EtOH

MeOH

Acetone

1,4-dioxane

MeCN

DMF

DMSO

2

(b)

300 400 500 600 700 8000.0

0.2

0.4

0.6

0.8

1.0

Abs

Wavelength(nm)

DCM

CHCl3

EtOH

MeOH

Ethyl Acetate

DMF

DMSO

THF

3

(c)

300 400 500 600 700 800

0

1

2

3

4

Ab

s

Wavelength (nm)

Hexane

PrOH

CHCl3

DCM

THF

Ethylacetate

EtOH

MeOH

MeCN

DMF

DMSO

4

(d)

Fig. S1: Absorption spectra of 1 - 4 in various solvents. Conc. of probes: 1 × 10−4

M (for 1, 2

and 4) and 1 × 10−5

M (for 3).

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S4

550 600 650 700 750 800

Hexane

THF

DCM

CHCl3

Acetone

Ethylacetate

MeOH

EtOH

i-PrOH

MeCN

DMF

DMSO

Flu

ore

sce

nce I

nte

nsity (

a.

u.)

Wavelength (nm)

1

(a)

400 450 500 550 600 650 700

Flu

ore

sce

nce

In

ten

sity (

a.

u.)

Wavelength(nm)

Hexane

CHCl3

DCM

THF

Ethyl acetate

PrOH

EtOH

MeOH

Acetone

1,4-dioxane

MeCN

DMF

DMSO2

(b)

450 500 550 600 650 700 750 800

DCM

CHCl3

EtOH

MeOH

Ethyl acetate

Acetone

THF

DMF

DMSO

Flu

ore

scence I

nte

nsity (

a.

u.)

Wavelength(nm)

3

(c)

550 600 650 700 750 800

Flu

ore

scence I

nte

nsity (

a.

u.)

Wavelength(nm)

Hexane

CHCl3

DCM

THF

Ethyl acetate

Acetone

PrOH

EtOH

MeOH

MeCN

DMF

DMSO

4

(d)

Fig. S2: Fluorescence spectra of (a) 1, (b) 2, (c) 3 and (d) 4 in different solvents. Concentration

of the probes: [1] = 1×10−7

M, [2] = 1×10−6

M, [3] = 1×10−6

M and [4] = 1×10−7

M; λex = 500 nm

for 1 and 4, 365nm for 2 and 420nm for 3 respectively; emission and excitation band pass =

5nm; T= 298 K; The error in fluorescence spectral data is within 10 %. The fluorescence quantum

yields (φF) were calculated by comparison of corrected spectrum with that of rhodamine G (φF =

0.95) in EtOH taking the area under the total emission, which was calculated to be < 0.001 in

each case.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S5

Table ST1: Absorption peak position (λ, nm), corresponding molar extinction coefficients (ε,

dm3

mol-1

cm-1

) and emission maxima of the probes 1-4 in different solvents. Probe Solvent λabs, nm

(ε, dm3 mol

−1 cm

−1)

λema Probe λabs, nm

(ε, dm3 mol

−1 cm

−1)

λema

1 Hexane 271 (11231), 310 (3905) 539, 587 4 270 (n. d.), 310 (n. d.) 539,587

DCM 276 (12483), 317 (4685) 575 276 (20085), 315 (7779) 576

CHCl3 276 (14509), 317 (5719) 569 273 (25207), 317 (9890) 541,579

THF 273 (38227), 312 (13539) 588 273 (12655), 314 (4682) 587

Acetone 413 (741) 540,587 n. d. 540, 588

1,4-dioxane 273 (21548), 312 (7650) 540,586 273 (33272), 312 (11824) 539,589

Ethylacetate 273 (12507), 312 (4523) 587 271 (17155), 312 (6272) 588

MeCN 274 (27067), 315 (9898) 539,589 273 (48044), 317 (15685) 540

MeOH 273 (49370), 314 (15056) 564 273 (28721), 315 (10140) 564

EtOH 273 (19056), 315 (7780) 561 272 (37808), 314 (12584) 559

i-PrOH 273 (37887), 314 (13199) 560 273 (35028), 312 (12134) 563

DMF 273 (8769), 317 (3182) 540,588 274 (42887), 315 (15162) 542,587

DMSO 274 (35078), 320 (13404) 539,587 274 (41780), 317 (16101) 540,588

Probe Solvent λabs, nm (ε, dm3 mol

−1 cm

−1) λem

b

2 Hexane 270 (n. d.), 312 (n. d.), 345 (n. d.), 364 (n. d.), 383 (n. d.) 387, 409, 433

DCM 317 (35033), 348 (25359), 366 (36056), 386 (35230) 391, 141, 440

CHCl3 317 (28033), 368(30904), 388 (28662), 349 (20837) 392, 141, 440

THF 279 (33719), 314 (18053), 348 (13671), 366 (20536),

386 (18820)

390, 412, 437

Acetone 347 (8191), 365 (11988), 385 (10820) 388, 411, 434

1,4-dioxane 315 (8179), 348 (6258), 366 (9595), 385 (9224) 388, 412, 437

Ethylacetate 314 (28033), 347 (21073), 364 (31533), 385 (30275) 387, 409, 436

MeCN 272 (15011), 323 (5845), 364 (6429), 383 (6028) 387, 411, 434

MeOH 272 (23146), 317 (9353), 345 (6573), 364 (9454), 383(8623) 387, 409, 432

EtOH 271 (27974), 315 (10629), 347 (7744), 364 (11578),

385 (10811)

388, 410, 432

i-PrOH 315 (26382), 347 (19421), 365 (28859), 385 (26814) 388, 410, 433

DMF 320 (11617), 348 (8117), 365 (12404), 385 (11382) 389, 412, 436

DMSO 321 (7025), 350 (4724), 368 (7573), 388 (7025) 393, 415, 440

3 Hexane 274 (n.d.), 322 (n. d.), 463 (n. d.) 518c

DCM 274 (87292), 321 (46235), 467 (40022) 520 c

CHCl3 274 (83202), 320 (47887), 467 (39235) 528 c

THF 271 (63460), 321 (51112), 463 (44977) 525 c

Acetone 345 (7230), 478 (17658) 521 c

1,4-dioxane 273 (3769), 320 (1555), 470 (1768) 540 c

Ethylacetate 273 (78061), 318 (39685), 460 (36780) 543 c

MeCN 273 (18702), 320 (9280), 467 (9365) 540 c

MeOH 276 (89775), 321 (46629), 470 (56404) 539 c

EtOH 273(62536), 320(29634), 467(33837) 537 c

i-PrOH 273 (26718), 316 (11373), 346 (s, 4079), 475 (11077) 535 c

DMF 276 (96533), 321 (49162), 474 (45629) 533 c

DMSO 273 (78005), 323 (39747), 477 (38398) 533 c

λex = a 500nm,

b 365nm and

c 420nm.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S6

550 600 650 700 750 8000.0

0.2

0.4

0.6

0.8

1.0

Norm

aliz

ed F

luo

rescen

ce

In

tensity

Wavelength (nm)

DCM

CHCl3

λex = 500 nm

4

Fig. S3: Normalized fluorescence spectra of 4 alone in CHCl3 and DCM (~ 1×10−7

M) upon

excitation at 500nm, showing broad structure-less exciplex like emission at 710nm.

0.0 0.2 0.4 0.6 0.8 1.00.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Abs

Mole Fraction {[3] / ([3]+[Hg(II)])}

λλλλobs

= 557nm

0.0 0.2 0.4 0.6 0.8 1.00.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Abs

Mole fraction {[3] / [3]+[Pb(II)]}

λλλλobs

= 470nm

3

Fig. S4: Complexation stoichiometry determination as a function of change in absorption of 3 as

a function of mole fraction of added metal ion in MeCN-H2O (9:1 v/v). It exhibited 1:2 Ligand-

Metal stoichiometry of complexation when observed at 557nm (a) with Hg(II) ion, however, an

1:1 (L:M) stoichiometry was observed on monitoring at 470nm (b) with Pb(II) ion. This renders

insight to the step-wise complexation of both Hg(II) ion to 3 in its ‘amino-propyl-amino’

receptors.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

Page 7: Preferences of rhodamine coupled (aminoalkyl)-piperazine ... · Preferences of rhodamine coupled (aminoalkyl)-piperazine probes towards Hg(II) ion and their FRET mediated signaling

S7

300 400 500 600 700 8000.00

0.05

0.10

0.15

0.20

0.25

0.30

Abs

Wavelength (nm)

3

3 + Mn(II)

3 + Fe(II)

3 + Co(II)

3 + Ni(II)

3 + Cu(II)

3 + Zn(II)

3 + Hg(II)

3 + Ag(I)

3 + Pb(II)

3 + Cd(II)

MeCN-H2O (9:1 v/v)

Fig. S5: Absorption spectra of 3 alone and in presence of various metal ions in MeCN-H2O (9:1

v/v). [3]: 1 × 10−5

M, [M(I/II)]: 1 × 10−4

M.

550 600 650 700 750 800

8.0 eq.

Flu

ore

scen

ce inte

nsity (

a.

u.)

Wavelength(nm)

0.0 eq.

Fig. S6: Fluorescence spectra of 1 alone and in presence of various equivalents of added Hg(II)

metal ions in MeCN-H2O (9:1 v/v), [1]: 1 × 10−6

M, λex = 500nm, RT, ex and em b. p. = 5nm.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S8

0 1 2 3 4

0.0

0.1

0.2

0.3

0.4

Ab

s (

λo

bs

557 )

[Hg(II)] (x 10-5 M)

Equation y = ((a*h*k1*x)+b*h*k1*k2*x^2))/(1+k1*x+k1*k2*x^2)

Adj. R-S 0.99196

Value Standard Error

y a 0.00104 0.00951

y b 0.41627 0.01059

y k1 1.33371E-5 3.26475E-7

y k2 2.09573E-6 2.6239E-7

(a)

0 2 4 6

(( ((I-I

0)) )) 5

80

[Hg(II)] (µM)

Eqn. y = ((a*h*k1*x)+b*h*k1*k2*x^2))/(1+k1*x+k1*k2*x^2)

Adj. R-sqr. 0.99287

Value Standard Error

h 5E-7

a 1.062E-4 0.00172

b 0.54999 3.754E-5

k1 2.14236E6 11493.412

k2 3.66285E10 1.78432E6

(b)

Fig. S7: Plot of change in (a) absorbance and (b) fluorescence intensity of 1 as a function of

added [Hg(II)] ions in MeCN-H2O (9:1 v/v). Experimental conditions: Emission; [1]= 5 × 10−7

M, λex = 500nm, RT, ex. and em. b. p. = 5nm; Absorption: [1]= 2 × 10−5

M. The plots determine

the binding constants k1 and k2 for step-wise complexation of both Hg(II) ion and exhibit their

positive cooperativity of complexation with 1.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S9

0 1 2 3 4 5 6

0.00

0.05

0.10

0.15

0.20

0.25

0.30

(A-A

0) 5

57

[Hg(II) (10µM)

Eqn. y = ((a*h*k1*x)+b*h*k1*k2*x^2))/(1+k1*x+k1*k2*x^2)

Adj. R-S

quare

0.99844

Value Standard Error

h 1E-5

a 0.00171 7.64E-5

b 2.68915E-5 0.00287

k1 16334.7149 104.86946

k2 1.73876E7 48397.0518

2

(a)

Fig. S8: Plot of change in absorbance of 2 as a function of added [Hg(II)] ion concentration in

MeCN-H2O (9:1 v/v), [2] = 1 × 10−5

M.

400 450 500 550 600 650

4.0 eq.

1.6 eq.

4.0 eq.

1.6 eq.

Flu

ore

sce

nce

Inte

nsity (

a.

u.)

Wavelength(nm)

0.0 eq.

1.5 eq.

Fig. S9: Fluorescence spectra of 2 alone and in presence of various equivalents of added Hg(II)

metal ions in MeCN-H2O (9:1 v/v), [2]: 1 × 10−6

M, λex = 365nm, RT, ex and em b. p. = 5nm.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S10

0 3 6 9 4 8 12 16

0

2

4

6

8

10

(I-I

0) 5

80

[Hg(II)] (µM)

Eqn. y =(1/(2*h))*((h+x+a)-(sqrt((h+x+a)^2-(4*(h)*x))))

Adj R sqr. 0.98999

Value std. error

h 1E-6

a (=1/Ks) 6.02895E-9 2.18363E-11

(a)

(A-A

0)/

(Ali

m-A

) (x

100)

[Hg(II)] (x10µM)

Eqn. y = a + Ks * x

Adj R sqr 0.99278

Value Std. error

a Intercept -3.98252 0.34911

Ks Slope 5.50337E6 1512.01345

(b)

Fig. S10: Plot of change in (a) absorbance and (b) fluorescence intensity of 4 as a function of

added [Hg(II)] ion concentration in MeCN-H2O (9:1 v/v). Experimental conditions: Emission;

[4]= 1 × 10−6

M, λex = 500nm, RT, ex and em b. p. = 5nm; Absorption: [4]= 1 × 10−5

M.

0 1 2 3 4 5 6 7 8

(I-I

0) 5

80

[Hg(II)] (µM)

3

MeCN-H2O(9:1 v/v)

Eqn. y = ((a*h*k1*x)+b*h*k1*k2*x^2)) /(1+k1*x+k1*k2*x^2)

Adj. R-Squ 0.99219

Value Standard Err

h 5E-7

a 3.06459 0.04745

b 4.97658E-6 3.42906E-8

k1 969864.7160 56999.24479

k2 1.83549E10 3.03573E6

Fig. S11: Plot of change in fluorescence intensity (I580) of 3 as a function of added [Hg(II)] ion

concentration in MeCN-H2O (9:1 v/v). Experimental conditions: Emission; [3]= 5 × 10−7

M, λex

= 465nm, RT, ex and em b. p. = 5nm.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S11

400 450 500 550 600 650

Fl. I

nt.

(a

. u.)

Wavelength (nm)

2 [MeCN]

2 + H+ [MeCN]

2 [MeCN-H2O(9:1 v/v)]

2 + H+ [MeCN-H

2O(9:1 v/v)]

Fig. S12: Fluorescence spectra of 2 alone and in presence protons (H+) in both MeCN and

MeCN-H2O (9:1 v/v), [2]: 1 × 10−6

M, λex = 365nm, RT, ex and em b. p. = 5nm.

400 450 500 550 600 650 400 450 500 550 600 650

Fl. I

nt.

(a

. u

.)

Wavelength (nm)

2 [MeCN]

2 [MeCN-H2O (9:1 v/v)]

2 [MeCN-H2O (7:3 v/v)]

2 [MeCN-H2O (1:1 v/v)]

Fl. I

nt.

(a

. u

.)

Wavelength (nm)

2 [pH =4.0]

2 [pH =7.0]

2 [pH =10.0]

Fig. S13: Fluorescence spectra of 2 in (a) various propertions of aqueous – organic mixture

(MeCN-H2O) and (b) at different pH. [2]: 1 × 10−6

M, λex = 365nm, RT, ex and em b. p. = 5nm.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S12

400 450 500 550 600 6500.0

0.2

0.4

0.6

0.8

1.0

Norm

aliz

ed f

luo.

Int.

Wavelength (nm)

2

2.(Hg(II))2 Complex

Fig. S14: Normalized solid state fluorescence spectra of 2 and its Hg(II)-complex (λex = 365nm).

550 600 650 700 750 800

Flu

ore

scence I

nte

nsity (

a.

u.)

Wavelength(nm)

Blank

Cl-

PO4

3-

NO3

-

I-

HCO3

-

SCN-

SO4

2-

AcO-

En

EDTA

Fig. 15: Fluorescence spectral of saturated solution containing 1 (1 equiv.) and HgII (5 equiv.)

upon addition of various anions (10 equiv.) and chelating agents such as ethylenediamine and

EDTA. [1] = 5 ×10−7

M, MeCN-H2O (9:1 v/v), [2]: 1 × 10−6

M, λex = 500nm, RT, ex / em b. p. =

5 nm.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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S13

Fig. S16: ESI-MS of 1.

Fig. S17: 1H-NMR spectra of 1 in CDCl3

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S14

Fig. S18 :

13C-NMR spectra of 1 in CDCl3.

Fig. S19:

1H-NMR spectra of 2 in CDCl3.

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S15

Fig. S20: 13

C-NMR spectra of 2 in CDCl3

Fig. S21: ESI-MS of 2.

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S16

Fig. S22: 1H-NMR spectra of 3 in CDCl3

Fig. S23: 13

C-NMR spectra of 3 in CDCl3

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S17

Fig. S24: ESI-MS of 3.

Fig. S25: 1H-NMR spectra of 4 in CDCl3

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S18

Fig. S26: 13

C-NMR spectra of 4 in CDCl3

Fig. S27: ESI-MS of 4.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013

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Fig. S28: ESI-MS of {1⊂⊂⊂⊂Hg(II)}2.

Electronic Supplementary Material (ESI) for Organic & Biomolecular ChemistryThis journal is © The Royal Society of Chemistry 2013