S1

Electronic Supporting Information

Rational designing of first furoquinolinol based molecular systems for easy detection of

Cu2+ with potential applications in the area of membrane sensing

Manoj Kumar,a,‡ Lokesh Kumar Kumawat,a,‡ Vinod Kumar Guptaa,b and Anuj Sharmaa,*

aDepartment of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, India

bDepartment of Applied Chemistry, University of Johannesburg, Johannesburg, South-Africa

*Corresponding author

Phone: +9113 3228 4751

Fax: +9113 3227 3560

e-mail: anujsharma.mcl@gmail.com, anujsfcy@iitr.ac.in

‡Contributed equally as co-first authors.

Electronic Supplementary Material (ESI) for RSC Advances.This journal is © The Royal Society of Chemistry 2015

S2

Title Page..............................................................................................S1

Content Page........................................................................................S2

Analytical data......................................................................................S3

Spectra, Figures, Tables..................................................................S4-S30

S3

Analytical data

3-(4-bromophenyl)-2-((2-morpholinoethyl)amino)furo[3,2-c]quinolin-4-ol (FQ1).

Yellow solid (81%), mp (decomp.) = 258-259°C, IR (KBr, cm-1): ʋmax = 3369, 2963, 2864, 2821, 1655, 1602, 1498. 1H NMR (400 MHz,

CDCl3): δH = 2.47 (br s, 4H), 2.61 (br s, 2H), 3.48 (br s, 2H), 3.66 (br s, 4H), 5.26 (br s, 1H), 7.21–7.29 (m, 3H)*, 7.38 (td, 1H, J = 7.3 & 1.2

Hz), 7.54 (s, 4H), 7.82 (d, 1H, J = 7.8 Hz), 10.49 (s, 1H). 13C NMR (100 MHz, CDCl3): δc = 37.2, 48.5, 52.8, 62.2, 89.9, 103.3, 106.0, 115.1,

117.7, 120.0, 123.6, 125.9, 126.6, 128.5, 130.4, 141.0, 155.0, 155.4, 160.8. HRMS (ESI) m/z calcd. for C23H22BrN3O3 [M-H]+ : 466.0760,

found: 466.0765.

3-(4-chlorophenyl)-2-(pentylamino)furo[3,2-c]quinolin-4-ol (FQ2).

Yellow solid (78%), mp = 218-220 °C, IR (KBr, cm-1): ʋmax = 2827, 1661, 1606, 1500, 1416. 1H NMR (400 MHz, CDCl3): δH = 0.87–0.94 (m,

3H), 1.36 (m, 4H), 1.64 (quint, 2H, J = 7.2 Hz), 3.39 (t, 2H, J = 7.1 Hz), 4.38 (br s, 1H), 7.14–7.26 (m, 2H)*, 7.32 (m, 2H), 7.39 (d, 2H, J = 8.5),

7.58 (dt, 2H, J = 8.5 & 1.8 Hz), 7.82 (d, 1H, J = 7.8 Hz), 11.17 (s, 1H). 13C NMR (100 MHz, CDCl3): δc = 14.0, 22.9, 29.2, 29.8, 42.6, 94.6,

107.9, 110.7, 122.4, 124.6, 128.2, 129.9, 130.4, 130.9, 131.3, 133.0, 145.7, 159.6, 160.1, 165.4. HRMS (ESI) m/z calcd. for

C22H21ClN2O2[M+H]+ : 379.1207, found: 379.1207.

* Solvent peak at 7.26 is overlapped with this peaks, hence higher integration is obtained.

See 1H NMR spectra of both compounds at page S4 and S7 of ESI.

S4

Figure SS1: 3-(4-bromophenyl)-2-((2-morpholinoethyl)amino)furo[3,2-c]quinolin-4-ol (FQ1): 1H NMR

S5

Figure SS2: 3-(4-bromophenyl)-2-((2-morpholinoethyl)amino)furo[3,2-c]quinolin-4-ol (FQ1): 13C NMR

S6

Figure SS3: 3-(4-bromophenyl)-2-((2-morpholinoethyl)amino)furo[3,2-c]quinolin-4-ol (FQ1): HRMS

S7

Figure SS4: 3-(4-chlorophenyl)-2-(pentylamino)furo[3,2-c]quinolin-4-ol (FQ2): 1H NMR

S8

Figure SS5: 3-(4-chlorophenyl)-2-(pentylamino)furo[3,2-c]quinolin-4-ol (FQ2): 13C NMR

S9

Figure SS6: 3-(4-chlorophenyl)-2-(pentylamino)furo[3,2-c]quinolin-4-ol (FQ2): HRMS

S10

Figure SS7: UV-Vis Spectra of FQ1 (20μM in DMSO:MeOH = 1:9) in the presence of different ions (10 equiv.). The distinct behaviour

of Cu2+ (equimolar) is apparent from figure.

270 300 330 360 390 420 450

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

FQ

1A

l3+

gd3+

Ca2

+Fe3

+C

d2+

Cu2

+C

r3+

Co2

+K

+H

g2+

Li+

Mg2

+Pb2

+N

i2+

Na+

Mn2

+Z

n2+

Fe2

+

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

A0-A

FQ1 + Cu2+

FQ1 + Other metal

Abso

rban

ce (

a.u.)

Wavelength (nm)

S11

Figure SS8: UV-vis Spectra of FQ2 (20μM in DMSO:MeOH = 1: 9) in the presence of different ions (10 equiv.). The distinct behaviour

of Cu2+ (equimolar) is apparent from figure.

270 300 330 360 390 420 450

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

FQ

2A

l3+

Ca2

+C

o2+

Cu2

+

Li+

Cd2

+C

r3+

Fe2

+

K+

Fe3

+H

g2+

Pb2

+gd

3+M

g2+

Mn2

+N

a+N

i2+

Zn2

+-0.04

0.00

0.04

0.08

0.12

0.16

0.20

A0-A

FQ2 + Other metal

FQ2+Cu2+

Abso

rban

ce (

a.u.)

Wavelength (nm)

S12

Figure SS9: Fluorescence response of FQ1 (20μM in DMSO:MeOH = 1: 9) toward 10 equiv. of different metal ions after excitation at

370 nm.

400 450 500 550 600 650

0

3000

6000

9000

12000

15000

18000

21000

24000

FQ1, Ca2+

, Cd2+

, Co2+

, K+, Na

+, Li

+,

Hg2+

, Fe2+

, Nd3+

, Mg2+

, Mn2+

, Ni2+

,

Zn2+

, Pb2+

, Al3+

, Cr3+

, Gd3+

, Fe3+

.

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

Wave length (nm)

Cu2+

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Figure SS10: Fluorescence response of FQ1 (20μM in DMSO:MeOH = 1: 9) toward 10 equiv. different metal ions after excitation at 370

nm wavelength.

400 450 500 550 600 650

0

3000

6000

9000

12000

15000

18000

21000

Cu2+

FQ2, Ca2+

, Cd2+

, Co2+

, K+, Na

+, Li

+,

Hg2+

, Fe2+

, Mg2+

, Mn2+

, Ni2+

, Pb2+

,

Zn2+

, Al3+

, Cr3+

, Gd3+

, Fe3+

, Nd3+

.

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

Wavelength (nm)

S14

Figure SS11: Fluorescence responses of FQ1 (20μM in DMSO:MeOH = 1:9) in the presence of different metal ions.

S15

Figure SS12: Fluorescent titration of FQ1 (20 μM in DMSO:MeOH = 1:9) against Cu2+ (0.1 equiv. to 2.5 equiv.) after excitation at 370

nm wavelength.

400 440 480 520 560 600 640 680

0

3000

6000

9000

12000

15000

18000

21000

0 10 20 30 40 50

0

3000

6000

9000

12000

15000

18000

21000

Y = -865.1x + 18850

R² = 0.984

LOD = 1.52 x 10-7 M

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

(Concentration of Cu2+

(M)

0 200000 400000 600000 800000 1000000 1200000

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

0.0014

Y = 1.169E-09x + 2.478E-05

R² = 0.992

K = 2.11 x 104 M

-1

1/I

0-I

1/Cu2+

FQ1

Flu

ore

scen

t In

tensi

ty (

cps)

Wave length (nm)

0.0 equiv.

2.5 equiv.

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Figure SS13: Fluorescent titration of FQ2 (20 μM in DMSO:MeOH = 1:9) against Cu2+ (0.1 equiv. to 2.5 equiv.) after excitation at 370

nm wavelength.

400 450 500 550 600 650 700

0

3000

6000

9000

12000

15000

18000

21000

0 10 20 30 40 50

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

Y = -766.1x + 19272

R² = 0.985

LOD = 2.13 x 10-7 M

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

Concentration of Cu2+

(M)

0 200000 400000 600000 800000 1000000

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

0.0012

0.0014

0.0016

Y = 1.41E-09x - 2.65E-05

R² = 0.993

Ka = 1.87 x 104 M

-1

1/I

0-I

1/Cu2+

0.0 equiv.

FQ2F

luore

scen

ce I

nte

nsi

ty (

cps)

Wavelength (nm)

2.5 equiv.

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Figure SS14: Examination of selectivity of FQ1 (20 μM in DMSO:MeOH = 1:9) towards Cu2+ in the presence of interfering ions.

Al3

+Ca2

+Cd2

+Co2

+Cr3

+Fe

2+Fe

3+H

g2+

K+

Li+M

g2+

Mn2

+N

a+N

i2+

Pb2+

Zn2+

Nd3

+

0

3000

6000

9000

12000

15000

18000

21000

24000 FQ1+ various metal ions

FQ1+ Cu2+

+ various metal ions

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

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Figure SS 15: Examination of selectivity of FQ2 (20 μM in DMSO:MeOH = 1:9) towards Cu2+ in the presence of interfering ions.

Al3

+C

a2+

Cd2

+C

r3+

Co2

+N

d3+

Fe2+

Fe3+

Mg2

+H

g2+

Mn2

+N

a+ K+

Ni2

+Zn2

+Pb

2+ Li+

0

3000

6000

9000

12000

15000

18000

21000

24000 FQ2 + various metal ions

FQ2 + Cu2+

+ various metal ions

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

S19

Figure SS16: Change in fluorescence response with time at 465 and 460 nm respectively for compounds FQ1and FQ2.

0 10 20 30 40 50 60 70 80 90 100 110 120 130

0

5000

10000

15000

20000

25000

FQ1 + Cu2+

FQ2 + Cu2+

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

Time (Min.)

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Figure SS17: Job’s plot to determine binding stoichiometry of compounds FQ1 with Cu2+

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

FQ1/[FQ1+Cu2+

]

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Figure SS18: Job’s plot to determine binding stoichiometry of compounds FQ2 with Cu2+

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

FQ2/[FQ2+Cu2+

]

S22

Figure SS19: HRMS of possible complex of compound FQ1 with Cu2+

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Figure SS20: HRMS of possible complex of compound FQ2 with Cu2+

S24

Figure SS21: Reversibility Studies

S25

Figure SS22: NMR Titration (FQ1) in the presence of different conc. of Cu2+ (DMSO-d6 was used as NMR solvent and TMS as

internal standard).

S26

Figure SS23: NMR Titration (FQ2) in the presence of different conc. of Cu2+ (DMSO-d6 was used as NMR solvent and TMS as

internal standard).

S27

Figure SS24: Effect of pH on Fluorescence quenching

2 3 4 5 6 7 8 9 10 11

0

3000

6000

9000

12000

15000

18000

21000

FQ1

FQ1 + Cu2+

FQ2

FQ2 + Cu2+

Flu

ore

scen

ce I

nte

nsi

ty (

cps)

pH

S28

Figure SS25: DFT study (Optimized structure of FQ1 and FQ2)

S1

Table SS1: Comparison of reported FQs with some of the recently developed sensors for

Cu2+

(flur = fluorescence, NM = Not Mentioned)

S.No. Sensor/probe Interaction Association

constant (Ka) M-1

LOD in M pH range

1 FQs (This work) Turn off

(flur)

Reversible

2.11 × 104

1.87 × 104

1.52 × 10-7

2.13 × 10-7

5.5-11

24h

Turn off (flur)

Irreversible

NM 0.5 × 10-7 5-7

34i

Conc.

dependent

Turn off (flur)

6.82 × 104 4.0 × 10-7 NM

48a P-Qs Turn on (flur)

irreversible

NM 1.5 × 10-6 7-9

64j

Turn on (flur) 1.1 × 1010 0.15 × 10-6 NM

74k

Turn off (flur) NM 1.27 × 10-4 NM

88b

Turn off (flur) 5.0 × 104 1.5 × 10-6 4-11

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Table SS2: Photophysical properties of FQ1 and FQ2

Comp. Emission Quantum

Yield

Detection

Limit (M)

Binding

Constant (M-1)

R2 I/I0 Response

Time (Min.)

ex/nm em/nm

FQ1 370 465 0.3915 1.52 x 10-7 2.11 x 104 0.984 0.027 2-3 min.

FQ1 +Cu2+ 370 459 0.0253

FQ2 370 460 0.3856 2.13 x 10-7 1.87 x 104 0.985 0.159 2-3 min.

FQ + Cu2+ 370 452 0.0597