A new fluorogenic sensing platform for salicylic acid derivatives based on - and NH- interactions between

electron-deficient and electron-rich aromatics

Anup Pandith, Giridhari Hazra and Hong-Seok Kim*

Department of Applied Chemistry, School of Applied Chemical Engineering,

Kyungpook National University, Daegu 41566, Republic of Korea

*Corresponding author. E-mail: kimhs@knu.ac.kr; Tel: +82 53 9505588; Fax: +82 53 9506594

Contents

1) 1H NMR, 13C NMR spectral data of probes 1, 2 and 3…………………………………………………………….…3-6.

2) High resolution FAB-mass spectral data of probes 1, 2 and 3 …………………………………………….…6-7.

3) Fig. S1. Structure of various fluorescent probes, derived from aminopropylimidazole moiety and electron deficient analytes………………………………………………………………………………………………………..08.

4) Fig. S2. UV-vis spectra of probe 1 (1 M) with various 10.0 eq. of SA’s derivatives in EtOH……………………………………………………………………………………………………………………………………….…08.

5) Fig. S3. UV-Vis titration studies of the probe 1 (1.0 M) with 5 eq. of 5-ASA in EtOH….…09.

6) Fig. S4. Fluorescence spectra of probe 1 (20 nM) in ethanol at different excitation wavelengths………………………………………………………………………………………………………………………………09.

7) Fig. S5. Curve fitting of fluorescence titrtion data of probe 1 with 5-ASA at 448 nm, through the non linear regression analysis (reduced chisquare method) via double fitting in origin 8. software package followed by GNU. Plot ver. 5.1 to achive smooth fitting (c = Ka = 1.36 x 107 M-1) with ± 2.77% error bound…………………………………………………………………………………………………………………….10.

8) Fig. S6. Job’s plot of the probe 1 (20 nM) with 5-ASA (20 nM) in EtOH at ex = 440 nm, em = 448 nm…………………………………………………………………………………………………………………………..…10.

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9) Fig. S7. a) Fluorescence titration studies of probe 1 (20 nM) in MeOH-DMSO (99.5:0.5, v/v) with 5-ASA at ex = 440 nm; b) Inset shows the fluorogenic response of the probe 1 (20 nM) with various eq. of 5-ASA (0 to 5.0) at em = 448 nm; b) Non linear regression analysis curve fitting of fluorescence titartion data at em = 448 nm through reduced chisquare method (c = Ka = 8.82 x 106 M-1 ) with ± 5.28% error bound……………………………………………………………………………………………11.

10) Fig. S8. DFT based energy minimized structure of probe 1 with 4-ASA in EtOH as an implicit medium…………………………………………………………………………………………………………………………………….11.

11) Fig. S9. DFT based energy minimized structure of probe 1 with 4-MeSA in EtOH as an implicit medium………………………………………………………………………………………………………………………………….…12.

12) Fig. S10. DFT based energy minimized structure of probe 1 with 4-HSA in EtOH as an implicit medium…………………………………………………………………………………………………………………………………….12.

13) Fig. S11. DFT based energy minimized structure of probe 1 with 4-ISA in EtOH as an implicit medium………………………………………………………………………………………………………………………………….…13.

14) Fig. S12. DFT based energy minimized structure of probe 1 with 4-BrSA in EtOH as an implicit medium………………………………………………………………………………………………………………………………….…13.

15) Fig. S13. DFT based energy minimized structure of probe 1 with 4-ClSA in EtOH as an implicit medium…………………………………………………………………….………………………………………………………………14.

16) Fig. S14. DFT based energy minimized structure of probe 1 with SA in EtOH as an implicit medium…………………………………………………………….………………………………………………………………………14.

17) Fig. S15. DFT based energy minimized structure of probe 1 with 5-NSA in EtOH as an implicit medium…………………………………………………………………………………………………………………………………….15.

18) Fig. S16. DFT based energy minimized structure of probe 1 with 3,5-DNSA in EtOH as an implicit medium…………………………………………………………………………………………….………………………….15.

19) Fig. 17. UV-Vis spectra of probe 2 (1.0 M) with 10.0 eq. of various SA derivatives in EtOH …...16.

20) Fig. 18. UV-Vis spectra of probe 3 (1.0 M) with 10.0 eq. of various SA derivatives in EtOH…...16.

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21) Fig. S19. Fluorescence studies of probe 3 (20 nM) with 5.0 eq. of various SA derivatives in EtOH at ex = 440 nm………………………………………………………………………………………………..…17.

22) Fig. S20. Multiple plots of probe 1 with various SA’s derivatives showing variations in interaction energies (kJ/mol) with binding constants calculated through the fluorescence titration studies in absolute EtOH curve fitting at ex = 440 nm: Interaction energies were calculated using DFT based results in EtOH as an implicit medium (SM8 model)……………………………….……………………….17.

23) Fig. S21. Fluorescence intensity enhancement ratio’s {(I-I0/I0) x 100} bar diagram of probe 1 (20 nM) with various 5.0 eq. of SA’s derivatives in 10 % aq. EtOH medium at ex = 440 nm, where I0

and I is the intensity of probe 1 (20 nM) in the absence and presence of SA’s respectively…….…18.

24) Fig. S22. Multiple plot showing the emission intensity ratio’s {(I-I0/I0) x 100} variations of 1●5-ASA complex in various polar aprotic and protic solvents with different dielectric constants () at ex = 440 nm and em = 448 nm. Where I0 and I is the intensity of probe 1 (20 nM) in the absence and presence of SA’s respectively…………………………………………………………………………………………….18.

25) Fig. S23. Molecular electrostatic potential map (MOP) a) 5-ASA and b) 5-Asalicylate, calculated through B3LYP/6-31G* as a basis set in EtOH (SM8) as an implicit medium……………………………...19.

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Fig. 1. 1H NMR spectra of probe 1 in CDCl3.

Fig. 2. 13C NMR spectra of probe 1 in CDCl3.

Fig. 3. 1H NMR spectra of probe 2 in DMSO-d6.4

Fig. 4. 13C NMR spectra of probe 2 in DMSO-d6.

Fig. 5. 1H NMR spectra of probe 3 in DMSO-d6.

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Fig. 6. 13C NMR spectra of probe 3 in DMSO-d6.

Fig. 7. FAB-High resolution spectra of probe 1.

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Fig. 8. FAB-High resolution spectra of probe 2.

Fig. 9. FAB-High resolution spectra of probe 3.

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Fig. S1. Structure of various fluorescent probes, derived from aminopropylimidazole moiety and electron deficient analytes.

Fig. S2. UV-vis, spectra of probe 1 (1.0 M), with 10.0 eq. of various SA derivatives in EtOH.

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Fig. S3. UV-vis titrtion studies of the probe 1 (1.0 M) with 5 eq. of 5-ASA in EtOH.

Fig. S4. Fluorescence spectra of probe 1 (20 nM) at different excitation wavelengths in EtOH.

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Fig. S5. Curve fitting of fluorescence titrtion data at 448 nm, through the non linear regression analysis (reduced chisquare method) via double fitting in Origin 8.0 software package followed by GNU. Plot ver. 5.1 to achive smooth fitting (c = Ka = 1.36 x 107 M-1) with less error bound (See EXP sections for details).

Fig. S6. Job’s plot of the probe 1 (20 nM) with 5-ASA (20 nM) in EtOH at ex = 440 nm, em = 448 nm.

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Fig. S7. a) Fluorescence titration studies of probe 1 (20 nM) in MeOH-DMSO (99.5:0.5, v/v) with 5-ASA at ex = 440 nm; b) Inset shows the fluorogenic response of the probe 1 (20 nM) with various eq. of 5-ASA (0.0 to 5.0) at em = 448 nm; b) Non linear regression analysis curve fitting of fluorescence titartion data at em = 448 nm through reduced chisquare method (c = Ka = 8.82 x 106 M-1 ) with ± 5.28% error bound.

Fig. S8. DFT based energy minimized structure of probe 1 with 4-ASA in EtOH as an implicit medium.

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Fig. S9. DFT based energy minimized structure of probe 1 with 4-MeSA in EtOH as an implicit medium.

Fig. S10. DFT based energy minimized structure of probe 1 with 4-HSA in EtOH as an implicit medium.

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Fig. S11. DFT based energy minimized structure of probe 1 with 4-ISA in EtOH as an implicit medium.

Fig. S12. DFT based energy minimized structure of probe 1 with 4-BrSA in EtOH as an implicit medium.

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Fig. S13. DFT based energy minimized structure of probe 1 with 4-ClSA in EtOH as an implicit medium.

Fig. S14. DFT based energy minimized structure of probe 1 with SA in EtOH as an implicit medium. (labelled iiia due to shifted interaction process from center of the perylene moiety to upper side rings).

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Fig. S15. DFT based energy minimized structure of probe 1 with 5-NSA in EtOH as an implicit medium. (labelled ia and iiia due to weak protonation rather than secondary amine prton (NH-) interactions in multiple hydrogen bonding and shifted interaction process from center of the perylene to upper side rings).

Fig. S16. DFT based energy minimized structure of probe 1 with 3,5-DNSA in EtOH as an implicit medium. (labelled ia and iiia due to weak protonation rather than secondary amine prton (NH-) interactions in multiple hydrogen bonding and shifted interaction process from center of the perylene to upper side rings).

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Fig. 17. UV-Vis spectra of probe 2 (1.0 M) with 10.0 eq. of various SA derivatives in EtOH.

Fig. 18. UV-Vis spectra of probe 3 (1.0 M) with 10.0 eq. of various SA derivatives in EtOH.

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Fig. S19. Fluorescence studies of probe 3 (20 nM) with 5.0 eq. of various SA derivatives in EtOH at ex

= 440 nm.

Fig. S20. Multiple plots of probe 1 with various SA’s derivatives showing variations in interaction energies (kJ/mol) with binding constants calculated through the fluorescence titration studies in EtOH curve fitting at ex = 440 nm: Interaction energies were calculated using DFT based results in EtOH as an implicit medium (SM8 model).

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Fig. S21. Fluorescence intensity enhancement ratio’s {(I-I0/I0) x 100} bar diagram of probe 1 (20 nM) with various 5.0 eq. of SA’s derivatives in 10% aq. EtOH, at ex = 440 nm, em = 448 nm, where I0 and I is the intensity of probe 1 (20 nM) in the absence and presence of SA’s respectively.

Fig. S22. Multiple plot showing the emission intensity ratio’s {(I-I0/I0) x 100} variations of 1●5-ASA complex in various polar aprotic and protic solvents with different dielectric constants () at ex = 440 nm and em = 448 nm, where I0 and I is the intensity of probe 1 (20 nM) in the absence and presence of SA’s, respectively.

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Fig. S23. Molecular electrostatic potential map (MOP) a) 5-ASA and b) 5-Asalicylate, calculated through B3LYP/6-31G* as a basis set in EtOH (SM8) as an implicit medium.

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