S1

Supporting Information

Tuning of multiple luminescence output and white-light emission from a single gelator molecule through ESIPT coupled AIEE process

Arunava Maity,a Firoj Ali,a Hridesh Agarawal,a Bihag Anothumakkoolb and

Amitava Dasa

aOrganic Chemistry Division, bPhysical & Materials Chemistry Division, CSIR-

National Chemical Laboratory, Pune-411008, Maharashtra, India; E-mail:

a.das@ncl.res.in; Fax: +91 2025902629; Tel: +91 2025902385.

Electronic Supplementary Material (ESI) for ChemComm.This journal is © The Royal Society of Chemistry 2014

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Table of contents: Page No

Materials and methods S3

General description of different experimental techniques S4

Synthetic scheme S5

Synthesis and characterization of [4] S6

Synthesis and characterization of [1] and [2] S6

References S7

1H NMR spectra of [4] S8

13C NMR spectra of [4] S9

Mass spectra of [4] S10

1H NMR spectra of [1] S11

13C NMR spectra of [1] S12

Mass spectra of [1] S13

1H NMR spectra of [2] S14

13C NMR spectra of [2] S15

Mass spectra of [2] S16

UV-Vis absorption spectra of [1] S17

Variable-temperature UV-Vis absorption spectra of [1] S17

Weight-loss profile (TGA plot) of [1] S18

Comparisons between absorption and excitation spectra of [1] S18

UV-Vis absorption spectra of [2] S20

Solvent dependent emission spectra of [2] S21

Emission spectra of [1] in different polarities of solvents S21

Comparisons of FT-IR spectrum between compound [1] and [2] S22

Gelation study of [2] S23

Photographs showing the changes of emission color of [1] S23

Schematic route for gelation of [1] S24

Rheological property of [1] S25

XRPD pattern of [1] S25

I-V characteristic plot of [1] S26

Solvent dependent FESEM images of [1] S26

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Materials and methods:

Unless otherwise stated, all reagents used for synthesis purpose were purchased from

commercial suppliers, and used as such without further purification. Organic solvents were

purified according to the standard procedure.1 HPLC grade solvents were used for recording

spectrometric data. FTIR spectra were recorded as KBr pellets in a cell fitted with a KBr

window, using a Perkin-Elmer Spectra GX 2000 spectrometer. 1H and

13C NMR spectra have

been recorded on a Bruker 200/400/500 MHz FT NMR (Model: Avance-DPX 200/500) and all

spectra were calibrated against TMS. Mass spectrometric data were acquired by an electron

spray ionization (ESI) technique on a Q-tof-micro quadruple mass spectrometer (Micro mass).

High-resolution mass spectra were recorded on JEOL JM AX 505 HA mass spectrometer.

Thermo-gravimetric analyses (TGA) were carried out on a TG50 analyzer (Mettler-Toledo) or a

SDT Q600 TG-DTA analyzer under a N2 atmosphere at a heating rate of 10°C min

-1 within a

temperature range of 20–800 oC. UV-Vis spectra were recorded using a PerkinElmer Lambda-

950 UV-Vis spectrometer equipped with a peltier system for variable temperature experiments,

while fluorescence as well as fluorescence excitation spectra were recorded using Qunata Master

400, PTI spectrofluorometer. FESEM images were obtained using Nova Nano SEM 450 and

Quanta™ Scanning Electron Microscope. TEM images were recorded using a FEI Tecnai G2

F20 X-TWIN TEM at an accelerating voltage of 200 kV. Rheology was performed using a TA-

ARES rheometer equipped with a force rebalance transducer. X-ray powder diffraction (XRPD)

of air dried THF gel of 1 were recorded on a Phillips PANalytical diffractometer for Cu Kα

radiation (λ = 1.5406 Å).

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General description of different experimental techniques:

UV-Vis and Fluorescence spectrum measurements: Stock solutions of both compounds (1 and

2) were made in THF (1.0 μM). An aliquot (0.5 mL) was taken and was added with an

appropriate amount of THF and water (H2O) to adjust the desired solvent composition and final

concentration (10 µM). Each solution was allowed to equilibrate at room temperature for 1h

before spectral measurements. For variable-temperature experiments compound-1 solution in

THF/Water (3:7) was heated from lowest to highest temperature and allowed to equilibrate for

15 min at the desired temperature before each measurement. All luminescence measurements

were recorded using, λExt = 365 nm and 306 nm for compound 1 and 2 respectively with an

emission slit width of 2 nm. Fluorescence excitation spectra were recorded using the same

solution used for fluorescence studies.

General procedure for gelation study: Due to the limited solubility of 1 in common organic

solvent, gelation property of 1 was checked with three specified solvents, namely DMF, DMSO

and THF. Compound 1 was highly soluble in DMF and DMSO, which were not suitable for

studying the gelation phenomena. Whereas in case of THF solvent, A weighted amount 1 was

dissolved in THF (1.0 mL) by heating in closed vials. The clear solution was left to cool down in

air at 25oC without any disturbance. The gel formation was confirmed by the failure of the soft

mass to flow by inverting the glass vial.

Scanning electron microscopy (SEM): A solution of 1 (100 μM) in THF as well as in different

composition of THF/water mixture were drop-casted on silicon wafer and allowed to air dry for

6-7 hrs in a dust free place. Finally it was dried under desiccator for overnight. Before taking

images samples were coated with gold vapor.

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Transmission Electron Microscopy (TEM): TEM samples were prepared drop-casting the 1.0

mM THF solution of 1 onto carbon coated copper grids (200 mesh). TEM images were obtained

after drying the sample in vacuum for 24 hours.

Current (I) - voltage (V) measurements: The gel solution of 1 (10.0 mg/mL of THF) was drop-

casted on indium tin oxide (ITO) coated glass surfaces and dried for 24 hrs at room temperature.

I-V characteristic profile of this sample was measured in a two-probe electrode using a

KEITHLEY 4200-SCS programmable electrometer instrument.

Synthetic scheme:

Sceme-1: Methodologies that were adopted for synthesis of [1], [2], [3a & 3b], [4] and [5].

S6

Synthesis of [3a & 3b]: 3a and 3b were synthesized following the previously reported

procedure.2

Synthesis and characterization of [4]: In a 100 mL two neck RB 3,5-bisformyl-4-hydroxy

ethyl benzoate [3b]2 (200.0 mg, 0.9 mMol), commercially available benzyl bromide (169.5 mg,

0.99 mMol) , anhydrous K2CO3 were mixed in 20~25 mL dry acetonitrile (ACN) . Followed by a

pinch of tertiary butyl ammonium iodide (tBu)NH4+I- was added and was reflux for 24 h under

N2 atmosphere. The reaction mixture was cooled to room temperature; solvent was then removed

under reduced pressure using a rotary evaporator. Oily residue was taken in 80 mL of CHCl3,

and washed with distilled water (3 X 30 mL). Organic layer dried over anhydrous Na2SO4.

Finally solvent was evaporated to get crude product as a color less oil. It was purified by column

chromatography using silica gel as stationary phase and 25% ethyl acetate in hexane as eluent to

obtain pure product as white solid. Yield = 35%, 1H NMR (CDCl3, 200 MHz, TMS): δ (ppm) =

10.23 (2H, s, -CHO); 8.72 (2H, s, ArH); 7.41-7.36 (3H, m, ArH); 7.32-7.29 (2H, m, ArH); 5.24

(2H, s, -CH2); 4.47-4.36 (2H, q, J = 7Hz, -CH2 ester); 1.44-1.37 (3H, t, J = 7.2Hz, -CH3 ester);

13C NMR (CDCl3, 400 MHz, TMS): δ (ppm) = 14.72, 59.51, 61.84, 81.71, 127.52, 128.98,

129.06, 129.56, 130.57, 134.02, 138.35, 164.35, 165.81, 187.82; HRMS (ESI): m/z calculated

for C18H16O5Na [M + Na]+: 335.0890; found 335.0884.

Synthesis of [5]: Compound [5] was synthesized according to the previously reported

procedure.3

Synthesis and characterization of [1] and [2]: Synthetic procedure of both compounds was

followed according to reported procedure3 with slide modification

. A solution of compound [3a]

(136.2 mg, 0.7 mMol) or [4] (219.1 mg, 0.7 mMol) in methanol was added drop wise to a CHCl3

solution of compound [5] (638.0 mg, 1.4 mMol). The reaction mixture was stirred at room

S7

temperature for 9~10 hour, resulting precipitate [for compound-1 (yellow) and for compound-2

(color less)] was filtered off using G4-gooch crucible. Washed with (1:1) CHCl3/MeOH mixture

several times, dried under desiccator to obtain the pure product.

[1]: Yield = 90%; 1H NMR (DMSO-d6, 500 MHz, TMS): δ (ppm) = 13.30 (1H, s, -COOH);

12.18 (2H, s, -NH); 8.82 (2H, s, -CH=N); 8.34 (2H, s, ArH); 7.51-7.49 (8H, d, J = 7Hz, ArH);

7.45-7.40 (12H, m, ArH); 7.37-7.36 (8H, m, ArH), 7.28-7.27 (6H, m, ArH); 5.22 (8H, s,

ArCH2O); 5.04 (4H, s, ArCH2O); 13

C NMR (DMSO-d6, 400 MHz, TMS): δ (ppm) = 70.44,

74.22, 106.95, 120.23, 122.18, 127.65, 127.82, 127.91, 128.01, 128.11, 128.39, 130.84, 136.67,

137.30, 140.30, 145.15, 152.08, 159.82, 162.27, 166.37; HRMS (ESI): m/z calculated for

C65H55O11 N4 [M + H]+: 1067.3862; found 1067.3861.

[2]: Yield = (84%); 1H NMR (DMSO-d6, 400 MHz, TMS): δ (ppm) = 11.94 (2H, s, -NH); 8.75

(2H, s, -CH=N); 8.57 (2H, s, ArH); 7.56-7.54 (2H, m, ArH); 7.50-7.48 (6H, m, ArCH2O);7.43-

7.34 (26H, m, ArH); 7.29-7.27 (5H, m, ArH); 5.22 (8H, s, ArCH2O); 5.04 (6H, s, ArCH2O);

4.42-4.41 (2H, board, -CH2 ester); 1.37 (3H, board, -CH3 ester); 13

C NMR (DMSO-d6, 500 MHz,

TMS): δ (ppm) = 14.22, 61.22, 70.48, 74.25, 78.44, 107.05, 126.56, 127.56, 127.87, 127.94,

128.05, 128.15, 128.34, 128.41, 128.58, 128.92, 129.20, 135.29, 136.71, 137.31, 140.25, 141.57,

152.07, 159.11, 162.80, 164.77; HRMS (ESI): m/z calculated for C74H65O11N4 [M + H]+:

1185.4644; found 1185.4647.

References:

1. Perrin, D. D.; Armarego, W. L. F. Perrin, D. R. Purification of Laboratory Chemicals,

2nd ed., Pergamon, Oxford, 1980

2. Naama Karton-Lifshin, Lorenzo Albertazzi, Michael Bendikov, Phil S. Baran and Doron

Shabat, J. Am. Chem. Soc., 2012, 134, 20412.

3. P. Rajamalli and E. Prasad, Org. Lett., 2011. 13, 3714.

S8

1H NMR spectra of [4]:

SI Fig.S1: 1H NMR spectra of [4] in CDCl3 recorded in 200 MHz.

S9

13C NMR spectra of [4]:

SI Fig.S2: 13

C NMR spectra of [4] in CDCl3 recorded in 400 MHz.

S10

Mass spectra of [4]:

AMB2-36 #911 RT: 4.06 AV: 1 NL: 7.64E7

T: FTMS + p ESI Full ms [60.00-900.00]

260 270 280 290 300 310 320 330 340 350 360

m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Re

lativ

e A

bu

nd

an

ce

335.0884

R=61807

C18 H16 O5 Na = 335.0890

-1.8379 ppm

288.9214

R=66102

301.1404

R=64402 350.8919

R=60102282.9045

R=65702264.9540

R=67402327.1221

R=60807

343.0694

R=59307311.0432

R=61002

362.9261

R=56002294.9382

R=59002273.1666

R=56500

320.0435

R=61800

255.7743

R=37300

[M + Na]+

SI Fig.S3: HRMS spectrum of [4].

S11

1H NMR spectra of [1]:

SI Fig.S4: 1H NMR spectra of [1] in DMSO-d6 recorded in 500 MHz.

S12

13C NMR spectra of [1]:

SI Fig.S5: 13

C NMR spectra of [1] in DMSO-d6 recorded in 400 MHz.

S13

Mass spectra of [1]:

[M + H]+

[M + Na]+

SI Fig.S6: HRMS spectrum of [1].

S14

1H NMR spectra of [2]:

SI Fig.S7: 1H NMR spectra of [2] in DMSO-d6 recorded in 400 MHz.

S15

13C NMR spectra of [2]:

SI Fig.S8: 13

C NMR spectra of [2] in DMSO-d6 recorded in 500 MHz.

S16

Mass spectra of [2]:

[M + H]+

[M + Na]+

SI Fig.S9: HRMS Spectrum of [2].

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300 350 400 450

0.00

0.25

0.50

384

355

365

Ab

so

rba

nc

e

(nm)

THF

90% H2O

372

300 350 400 450

0.14

0.28

0.42

0.56

0.70

Ab

so

rba

nc

e

(nm)

THF, RT

70oC

60oC

50oC

40oC

30oC

20oC

10oC

UV-Vis absorption spectra of [1]:

SI Fig.S10: Absorption spectra of 1 in pure THF and THF-water (1:9; v/v) mixture solution.

Concentration used 10 μM.

Variable-temperature UV-Vis absorption spectra of [1]:

SI Fig.S11: Variable-temperature UV-Vis spectra of 1 (concentration used 10 μM) in THF-water

(3:7; v/v). Temperature varied from 10-70°C.

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0 150 300 450

50

75

100W

t lo

ss

%

Temperature (oC)

Compound-1

275 330 385 440

0

200

400

600

800

Inte

ns

ity

(a

.u.)

(nm)

Ems

= 454 nm

Ems

= 487 nm

(b)

275 330 385 4400.00

0.15

0.30

0.45

Ab

so

rba

nc

e

nm)

THF

(a)

Weight-loss profile (TGA plot) of [1]:

SI Fig.S12: Weight-loss profile for 1 obtained using thermogravimetric analysis (TGA).

Comparisons between absorption and excitation spectra of [1]:

SI Fig.S13: a) Absorption and b) fluorescence excitation spectra (λEms = 454 and 487 nm) of 1 in

THF.

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275 330 385 4400.00

0.15

0.30

0.45A

bs

orb

an

ce

(nm)

10% H2O

(c)

275 330 385 4400

30

60

90

120

Inte

ns

ity

(a

.u.)

nm)

Ems

= 487 nm(d)

300 360 420

60

120

180

240

Inte

ns

ity

(a

.u.)

(nm)

Ems

= 468 nm

Ems

= 551 nm

(f)

275 330 385 4400.0

0.1

0.2

0.3

0.4

Ab

so

rba

nc

e

(nm)

50% H2O

(e)

SI Fig.S14: a) Absorption and b) fluorescence excitation spectra (λEms = 487 nm) of 1 in THF-

water (9:1; v/v).

SI Fig.S15: a) Absorption and b) fluorescence excitation spectra (λEms = 468 and 551 nm) of 1 in

THF-water (1:1; v/v).

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275 330 385 440

0.00

0.11

0.22

0.33

Ab

so

rba

nc

e

(nm)

90% H2O

(g)

300 360 4200

60

120

180

240

Inte

ns

ity

(a

.u.)

(nm)

Ems

= 551 nm(h)

280 320 360 4000.0

0.2

0.4

0.6

Ab

so

rba

nc

e

(nm)

Compound-2

SI Fig.S16: a) Absorption and b) fluorescence excitation spectra (λEms = 551 nm) of 1 in THF-

water (1:9; v/v).

UV-Vis absorption spectra of [2].

SI Fig.S17: Absorption spectra of 2 in pure THF. Concentration used 10 μM.

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450 500 5500

5

10

15

20

Inte

ns

ity

(a

.u.)

nm)

0

10

20

30

40

50

60

70

80

90

95

99

Water fraction (%)

400 500 600 7000

200

400

600

Inte

ns

ity

(a

.u.)

(nm)

DMF

MeOH

Toluene

THF

Solvent dependent emission spectra of [2]:

SI Fig.S18: luminescence spectra of 2 (10 µM) in THF and THF-water mixed solvent medium

(Ext = 306 nm was used for luminescence studies).

Emission spectra of [1] in different polarities of solvents:

SI Fig.S19: Emission spectra of 1 (1 μM) in DMF, MeOH, THF and Toluene. λExt = 365 nm.

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1581 cm-1

1720 cm-1

1643 cm-1

1589 cm-1

1619 cm-1

1656 cm-1

3425 cm-1

1702 cm-1

3500 3000 1680 1400

Compound 2

Wavenumber (cm-1)

Compound 1

% T1606 cm

-1

Comparisons of FT-IR spectrum between compound [1] and [2]:

SI Fig.S20: Comparisons of FT-IR spectra of compound 1 and 2 at room temperature.

SI Table.S1: Important FT-IR frequency obtained from compound 1 and 2.

Compound-1 3425 cm-1

(-OHhydrogen bonded), 1702 cm-1

(-COOHstr), 1656 cm-1

(-C=Nstr),

1619 cm-1

(-C=Oamide, str), 1589 cm-1

(-NHamide, str)

Compound-2 1720 cm-1

(-COOEtstr), 1643 cm-1

(-C=Oamide,str), 1606 cm-1

(-C=Nstr), 1581

cm-1

(-NHamide,str)

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0%

H2O

10%

H2O

20%

H2O

30%

H2O

40%

H2O

50%

H2O

60%

H2O

70%

H2O

80%

H2O

90%

H2O

99%

H2O

(a)

(a) (b) (c)

Gelation study of [2]:

SI Fig.S21: Photographs of THF solution of compound 2 (a) immediately after dissolving the

compound (16.0 mg/mL of THF) by gentle heating; (b) after 24 hrs upon cooling to room

temperature; (c) under 365 nm UV light. Indicating Under identical condition or even higher

concentration [compare to compound- 1 (10.0 mg/ mL of THF)] compound-2 is unable to give

gel.

Photographs showing the changes of emission color of 1:

SI Fig.S22: (a) Photographs showing the changes of emission color with gradual increase of

water (%) into THF solution of 1.

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J-type lamellar arrangement

≡S

ingle

fib

ers

THF (Solvent ≡ )

Solvent entrapment

Gel network

THF gel of [1]

Schematic route for gelation of [1]:

SI Fig.S23: A schematic route for the synthesis of THF gel of 1 and its molecular arrangement.

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1 2 3 4

25

50

75

Inte

ns

ity

(a

.u.)

degree)

(a)

10 20 301

2

3

Inte

ns

ity

(a.u

.)

degree)

(b)

Rheological property of [1]:

SI Fig.S24: Dynamic frequency sweep measurement of storage modulus (G´) and loss modulus

(G´´) for THF gel (1.0 wt. %) of 1. Strain used was 0.1%.

XRPD pattern of [1]:

SI Fig.S25: (a) Small angle and (b) wide angle XRPD diffraction pattern of 1 in xerogel state.

1.0 1.5

2.7

3.0

3.3

log

(G"/P

a)

log

(G'/P

a)

log(frequency/ rad S-1)

log G'

2.7

3.0

3.3

log G"

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-10 -5 0 5 10

-0.4

-0.2

0.0

0.2

0.4

Cu

rre

nt(

)

Voltage (V)

I-V characteristic plot of [1]:

SI Fig.S26: I-V characteristic plot obtained from 1.

Solvent dependent FESEM images of [1]:

(a) (b) (c) (d)

SI Fig.S27: Solvent dependent FESEM images of 1 having (a) 0, (b) 10, (c) 50 and (d), 90 %

water content in THF. Concentration used was 100μM.