Supporting Information

A rhodamine based fluorescent trivalent sensor (Fe3+,Al3+,Cr3+) with potential applications for a live cell imaging and combinatorial logic circuit and memory device.†

Rabiul Alama, Rahul Bhowmicka, Abu Saleh Musha Islama, Atul katarkarb, Keya Chaudhurib, Mahammad Ali*,a

a Department of Chemistry, Jadavpur University, Kolkata 700 032, India, Fax: 91-33-2414-6223, E-mail: m_ali2062@yahoo.com,

b Department of Molecular & Human Genetics Division , CSIR-Indian Institute of Chemical Biology , 4 Raja S.C. Mullick Road, Kolkata-700032, India

Table of contents

1 . 1H NMR spectrum of HL3 in CDCl3, in Bruker 300 MHz instrument. Fig. S1a.

2. 1H NMR spectrum of HL4 in CDCl3, in Bruker 300 MHz instrument Fig. S1b.

3. 1H NMR spectrum of HL5 in CDCl3, in Bruker 300 MHz instrument Fig. S1c.

4. 13

C-NMR of HL5 in DMSO-d6 in Bruker 300 MHz instrument. Fig. S2

5. Mass spectrum of HL5 in MeOH . Fig. S3

6. Mass spectrum of HL5 +Al3+ in MeOH, Fig. S3a

7. Mass spectrum of HL5 +Cr3+ in MeOH. Fig. S3b

8. Mass spectrum of HL5 +Fe3+ in MeOH Fig. S3c

9. IR spectra of HL5 (L), [HL5 +Al3+] and [HL5 +Cr3+] complex in MeOH. Fig. S4

10. UV-vis spectra of the HL5 +Al3+ + complex in MeOH-H20 mixture(1:1). Fig. S5(a)

11. UV-vis spectra of the HL5 +Cr3+ complex in. MeOH-H20 mixture(1:1). Fig. S5(b).

Electronic Supplementary Material (ESI) for New Journal of Chemistry.This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2017

12. Job’s plot for M3+ Fig.S6

13. Flurescence spectra of the HL5 —Cr3+ complex in MeOH-H20 mixture(1:1). Fig. S7a

14. Flurescence spectra of the HL5 —Al3+ complex in MeOH-H20 mixture(1:1). Fig.S7b

15. Fluorescence emission changes of HL5 (50 μM) with variable content of H2O:MeOH Fig. S8

16. Fluorescence bar diagram for the selective response of HL5(50 μM) towards M3+(M=Al) over other metal ions

Fig.S9a

17. Fluorescence bar diagram for the selective response of HL5(50 μM) towards M3+(M=Cr) over other metal ions

Fig.S9b

18. Fluorescence bar diagram for the selective response of HL5(50 μM) towards M3+(M=Fe) over other metal ions

Fig.S9c

19. LOD determination. Fig. S10

20. pH dependence of fluorescence responses. Fig. S11

21. NMR Shift of the HL5 after addition of 1.5 equivalents Al3+ in CD3OD. Fig. S12

22. Frontier molecular orbitals involved in the UV-Vis absorption of HL5in H2O Fig. S13

23. Frontier molecular orbitals involved in the UV-Vis absorption of HL5-Al3+in H2O.

Fig. S14

24. Four-input OR-INHIBIT logic gate representation of the emission of HL5 with different input at 555 nm.

Fig. S15

25. Cascade fluorescence ON-OFF-ON response of HL5 with sequential addition of Al3+ and AsO4

3‒.Fig. S16

26. Cell viability detection by using MTT assay of HL5 on HepG2 cells treated for 12 hr. Fig. S17

27. Phase contrast and fluorescence images of banana pith Fig. S18

28. 1H-NMR chemical shifts in ppm of selected H-atoms in CD3OD. Table S1

29. Selective bond distance and bond angles of HL5 and HL5-Al3+ complex Table S2

30. Selected parameters for the vertical excitation (UV-VIS absorptions) of HL5 Table S3

31. Selected parameters for the vertical excitation (UV-VIS absorptions) of HL5-Al3+ Table S4

Fig. S1a. 1H NMR spectrum of HL3 in CDCl3, in Bruker 300 MHz instrument.

Fig. S1b. 1H NMR spectrum of HL4 in CDCl3, in Bruker 300 MHz instrument.

Fig. S1c. 1H NMR spectrum of HL5 in CDCl3, in Bruker 300 MHz instrument.

Fig. S2. 13

C-NMR of HL5 in DMSO-d6 in Bruker 300 MHz instrument.

Fig. S3. Mass spectrum of HL5 in MeOH.

Fig. S3a .Mass spectrum of HL5 +Al3+ in MeOH

Fig. S3b. Mass spectrum of HL5 + Cr3+ in MeOH.

Fig. S3c. Mass spectrum of HL5 +Fe3+ in MeOH.

Fig.S4. IR spectra of HL5 (L), [HL5 –Al3+] and [HL5 +Cr3+] complex in MeOH.

UV-Vis Studies.

Fig. S5a. Changes in UV-vis absorption spectra of HL5 (50 μM) in methanol/H2O (1:1, v/v, pH 7.2) solutions with various amounts of Al3+ ions (0-1.3 equiv).

Fig. S5b. Changes in UV-vis absorption spectra of HL5 (50 μM) in methanol/H2O (1:1, v/v, pH 7.2) solutions with various amounts of Cr3+ ions (0-1.3 equiv).

Fig. S6a. Job’s plot for Fe3+

Fig. S6b. Job’s plot for Cr3+

Fig. S6c. Job’s plot for Al3+

Fig. S7a. Fluorescence emission changes of HL5 (50 μM) in methanol/H2O (1:1, v/v, pH 7.2, 40 mM HEPES buffer) solutions upon addition of Cr3+(0-2 equiv). Each spectrum was acquired 15 min after Cr3+ addition, λex= 510 nm.

Fig. S7b. Fluorescence emission changes of HL5 (50 μM) in methanol/H2O (1:1, v/v, pH 7.2, 40 mM HEPES buffer) solutions upon addition of Al3+(0-1.5 equiv). Each spectrum was acquired 15 min after Al3+ addition, λex= 510 nm. λem = 555 nm

Fig. S8. Fluorescence emission changes of HL5 (50 μM) with variable content of water:MeOH, λex= 510 nm. λem = 555 nm.

Fig.9a. Fluorescence bar diagram for the selective response of HL5 (50 μM) towards M3+(M=Al) over other metal ions in methanol/H2O (1:1, v/v, pH 7.2, 40 mM HEPES buffer)(λex = 510 nm,λem=555nm)

Fig.9b. Fluorescence bar diagram for the selective response of HL5(50 μM) towards M3+(M=Cr) over other metal ions in methanol/H2O (1:1, v/v, pH 7.2, 40 mM HEPES buffer)(λex = 510 nm,λem=555nm)

Fig.9c. Fluorescence bar diagram for the selective response of HL5(50 μM) towards M3+(M=Fe) over other metal ions in methanol/H2O (1:1, v/v, pH 7.2, 40 mM HEPES buffer)(λex = 510 nm,λem=555nm)

Quantum Yield Determination:

Fluorescence quantum yields (Φ) were estimated by integrating the area under the

fluorescence

curves with the equation: Φ sample = × × Φstdsample

std

ODOD

std

sample

AA

where, A was the area under the fluorescence spectral curve, OD was optical density of

the compound at the excitation wavelength and η was the refractive indices of the

solvent. Rhodamine-6G was used as quantum yield standard (quantum yield is 0.94 in

ethanol) for measuring the quantum yields of HL5 and HL5 —Fe3+ and HL5 —Cr3+ and [HL5

—Al3+ complexes .

Calculation for LOD value:

To determine the detection limit, fluorescence titration of HL5 with Fe3+ , Al3+, Cr3+ was

carried out by adding aliquots of micromolar concentration of Fe3+ , Al3+, Cr3+. However,

The detection limit (LOD) of HL5 -Fe3+ , HL5 -Al3+ , HL5 -Cr3+ are calculated by 3σ method.

where Sd is the standard deviation of the blank, and Slope is from the plot of emission

intensities versus Fe3+ , Al3+, Cr3+ respectively.

Fig. S10. Determination of Sd Of the blank, ligand (HL5) solution.

Fig.S10a.Linear dynamic plot of FI (at 534 nm) vs. [Cr3+] for the determination of S (slope); [HL5] =50 μM

LOD(Cr3+)= (3x626.49)/3.58x109

= 0.31 μM

Fig.S10b.Linear dynamic plot of FI (at 536 nm) vs. [Fe3+] for the determination of S (slope); [HL5] =50 μM.

LOD (Fe3+) = (3x373)/3.84x109

=0.29 μM

Fig.S10c. Linear dynamic plot of FI (at 536 nm) vs. [Al3+] for the determination of S (slope); [HL5] = 50 μM.

LOD (Al3+) = (3x373)/3.31x109

=0.34 µM.

Fig. S11a. pH dependence of fluorescence responses of HL5 and its [HL5 +Cr3+] complex.

Fig.S11b. pH dependence of fluorescence responses HL5 and its [HL5+Al3+] complex.

Fig.S12. NMR Shift of the HL5 after addition of 1.5 equivalent Al3+ in CD3OD.

Fig. S13. Frontier molecular orbitals involved in the UV-Vis absorption of HL5in H2O.

Fig. S14. Frontier molecular orbitals involved in the UV-Vis absorption of HL5-Al3+in H2O.

Fig. S15. Four-input OR-INHIBIT logic gate representation of the emission of HL5 with different input when monitoring the emission at 555 nm.

Fig. S16. Cascade fluorescence ON-OFF-ON response of HL5 with sequential addition of Al3+ and AsO4

3‒.

Fig. S17. Cell viability detection by using MTT assay of HL5 on HepG2 cells treated for 12 hr.

Fig.S18. The phase contrast and fluorescence images of banana pith to capture intracellular Fe3+ pools. Banana pith was incubated with HL5 for 30 min at room temperature followed washing with 1X PBS. The image of banana pith shows the strong red florescence with intracellular Fe3+.

Table S1. 1H-NMR chemical shifts in ppm of selected H-atoms in CD3OD.

Compound -NH CH=N(m) q -OH(t)

HL5 4.37 7.88 5.14 12.51

HL5– Al3+ (Broadening)

9.30 5.30 (vanishes

)

Table S2a: Selective bond distance and bond angles of HL5.

Bond distance(Å) Bond-angles(o)

C16-O1 1.398 N3-C15-O2 125.70

C17-O1 1.399 C17-O1-C16 118.89

C15-O2 1.25 C71-C68-O75 123.15

N89-N90 1.467 N89-N90-C86 107.44

C58-N3 1.46

C61-N64 1.468

C65-N64 1.288

Table S2b: Selective bond distance and bond angles of Al-complex.

Bond distance(Å) Bond angles(°)

O77-Al97 1.8777 O77- Al71- O104 89.41

Al97-N64 1.9824 O98- Al71- O77 75.60

N64-Al97 1.9824 N64- Al71- O77 90.59

O2 -Al97 1.9277 O104- Al71-N64 179.99

O98-Al97 2.0409 O104- Al71- O2 92.75

Table S3: Selected parameters for the vertical excitation (UV-VIS absorptions) of HL5; electronic excitation energies (eV) and oscillator strength (f), configurations of the low-lying excited states of HL5; calculation of the S0Sn energy gaps on optimized ground- state geometries (UV-vis absorption).

Electronic

transition

Composition Excitation

energy

Oscillator

Strength(f)

CI Assignment λexp (nm)

S0S15 HOMO-5LUMO+3

4.1034 eV 0.5316 0.22237 ILCT 301

S0S12 HOMO-3LUMO+3

3.7962 eV 0.9202 0.42954 ILCT 334

S0S4 HOMOLUMO+3 2.9463 eV 0.1902 0.19766 ILCT 428

Table S4 : Selected parameters for the vertical excitation (UV-VIS absorptions) of HL5-Al3+; electronic excitation energies (eV) and oscillator strength (f), configurations of the low-lying excited states of HL5-Al3+ ; calculation of the S0Sn energy gaps on optimized ground- state geometries (UV-vis absorption).

Electronic transition

Composition Excitation

energy

Oscillator

Strength(f)

CI Assignment λexp (nm)

S0S1 HOMOLUMO

HOMOLUMO+2

2.1883 eV 0.3504 0.54902

0.15398

MLCT/ILCT

MLCT/ILCT

529

S0S9 HOMO-1LUMO 3.6074 eV 0.2967 0.35694 MLCT/ILCT 348

Table S5. A list of trivalent sensors along with some important parameters

Probe Solvent ex (em)/ nm

LOD Kf(M-1) Ref no.

1 Pure CH3CN 437(475) 0.5M (Cr3+)0.3M(Al3+)0.2M(Fe3+)

1.58 x 104M-1 (Cr3+);

6.46 x 109 M-2 (Al3+)

1.26 x 105 M-1 (Fe3+);

23

2 CH3CN–HEPES buffer solution

(40/60, v/v, pH = 7.4)

342 (484) 25M(Cr3+)23M(Al3+)20M(Fe3+)

1.0852 x 104 M-

1(Fe3+)8.770 x 103 M-1

(Al3+)5.676 x 103 M-

1(Cr3+)

24

3 CH3CN–HEPES buffer solution (1:1

, pH = 7.4)

460 (675) 93 nM(Cr3+)32 nM (Al3+)90 nM(Fe3+)

Not determined 25

4 THF–H2O (8:2) mixture

330 (430) 0.36 nM (Cr3+)0.38 nM (

Fe3+)0.38 nM (Al3+)

Not determined 26

5 H2O:EtOH = 8:2 390(563)390(527)

0.20μM(Cr3+)0.50μM(Al3+)

5.50 x 104 M-1 (Cr3+)

2.00x 104 M-1 (Al3+);

27

6 CH3OH–H2O (6 : 4, v/v)

330(582) 1.74 nM (Al3+)2.36 μM (Cr3+)

2.90 μM ( Fe3+)

1 x 104 M-1 (Al3+);2.6 x 102 M-1

(Cr3+)1.2 x 102 M-1

(Fe3+);

29

7 H2O: MeOH (1: 1) mixture.

510 (555) 0.31 μM(Cr3+)0.34 μM(Al3+)

0.29 μM( Fe3+)

6.0 x 104 M-1 (Cr3+)

6.7 x 104 M-1 (Fe3+);

8.2 x 104 M-1 (Al3+);

In this work