Supplementary. A multi-analyte responsive chemosensor vanilinyl Schiff base: fluorogenic. sensing to Zn(II), Cd(II) and I -

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1 Electronic Supplementary Material (ESI) for ew Journal of Chemistry. This journal is The Royal Society of Chemistry and the Centre ational de la Recherche Scientifique 2018 Supplementary A multi-analyte responsive chemosensor vanilinyl Schiff base: fluorogenic sensing to Zn(II), Cd(II) and I - Rakesh Purkait, Sunanda Dey and Chittaranjan Sinha* Fig. S1 MS of H 3 L

2 Fig. S2 1 H MR of H 3 L in CDCl 3 Fig.S3 IR of H 3 L

3 Fig.S4: Interferences study by various metal ions on Zn 2+ sensitivity Fig.S5: Interferences study by various metal ions on Cd 2+ sensitivity

4 Fig.S6 Effect of ph variation on Zn 2+ sensitivity Fig.S7 Effect of ph variation on Cd 2+ sensitivity Determination of detection limit: The detection limit was calculated based on the fluorescence titration. To determine the S/ ratio, the emission intensity of H 3 L without any analyte was measured by 10 times. The limit of detection (LD) of H 3 L for Zn 2+ and Cd 2+ was determined from the following equation: LD = K Where K = 3 in this case and = (Sb 1 )/(S); Sb 1 is the standard deviation of the blank solution; S is the slope of the calibration curve. For Zn 2+, From the graph we get slope = , and Sb 1 value is (Fig. S8).Thus using the formula we get the LD =

5 M. For Cd 2+, From the graph we get slope = , and Sb 1 value is (Fig. S9).Thus using the formula we get the LD = M. Fig S8 LD plot for Zn 2+ Fig S9 LD plot for Cd 2+

6 Table S1. Comparison of LD of similar type fluorogenic probe to Zn 2+ / Cd 2+ Serial o. 1 S Probe Sensitivity LD Reference S Zn M. 8 H H 2 S S Zn M 39 H H 3 Zn H H 4 H Zn M 46 5 S Zn M 47 6 H 2 Zn 2+, Cd H

7 7 Zn 2+, Cd M, M 49 8 Zn 2+, Cd 2+,Cu H H H H H 9 Zn 2+, Cd M, M Zn M 52 H 11 H 2 Cd M Cd M Cd M 55 H H H

8 14 Cd M Zn M 57 H H 16 Zn Fig.S10The Job s plot obtained by fluorescence experiment for Zn 2+

9 Fig. S11 The Job s plot obtained by fluorescence experiment for Cd 2+ Determination of binding constant : The binding constant value of Zn 2+ and Cd 2+ with H 3 L has been determined from the emission intensity data following the modified Benesi Hildebrand equation, 1/ F = 1/ F max +(1/K[C])(1/ F max ). Here F = F-F min and F max = F max -F min, where F min, F, and F max are the emission intensities of H 3 L considered in the absence of ions, at an intermediate ions concentration, and at a concentration of complete saturation where K is the binding constant and [C] is the anions concentration respectively. In this report we represent F min as F 0. From the plot of (F max -F 0 )/(F-F 0 ) against [C] -1 for ions, the value of K has been determined from the slope. The association constant (K d ) as determined by fluorescence titration method for H 3 L with Zn 2+ is found to be M -1 (error < 10%) and for H 3 L with Cd 2+ is found to be M -1 (error<10%).

10 Fig.S12 Benesi Hildebrand plot for addition of Zn 2+ with H 3 L Fig. S13 Benesi Hildebrand plot for addition of Cd 2+ with H 3 L

11 Fig. S14 MS of Zn complx

12 Fig. S15 MS of Cd complx H Zn Fig.S16: 1H MR titration of H 3 L with Zn 2+ in DMS-d 6 Cd H H Fig.S17: 1H MR titration of H3L with Cd 2+ in DMS-d 6

13 Fig. S18 Fluorimetric titration determines the binding constant for I - (Benesi Hildebrand plot) Fig. S19: ESI-MS spectrum of H 3 L-I -

14 Fig. S20: LD plot for I - Table S2: Comparison of Iodide (I - ) sensor efficiency Serial o. Probe LD Reference M 14 H H H M 59 + PF - 6

15 3 Hg complex of M 60 R H 4 H H X M 61 H 2 5 Hg complex of - 62 S 6 H 2 H M 63 B B H H M 64

16 Fig.S21: Interferences study by various metal ions on I - sensitivity Fig. S22 Effect of ph variation on I - sensitivity

17 Table S3 optimised structure and bond parameters of H 3 L-Zn 2+ ptimise structure of H 3 L-Zn 2+ complex Bond Length Bond angle Zn(42) - (8), 2.22 Å Zn(42) - (14), 2.22 Å Zn(42) - (27), 1.96 Å Zn(42) - (28), 1.97 Å Zn(42) - (13), 2.13 Å (8) - Zn(42) - (14), (14) - Zn(42) - (27), (27) - Zn(42) - (28), (28) - Zn(42) - (13), (13) - Zn(42) - (8), Table S4 optimised structure and bond parameters of H 3 L-Cd 2+ ptimized structure of H 3 L-Cd 2+ complex Bond Length Bond angle Cd(58) - (5), 2.22 Å Cd(58) - (8), 2.41 Å Cd(58) - (16), 2.29 Å Cd(58) - (17), 2.23 Å Cd(58) - (6), 2.36 Å (5) - Cd(58) - (8), 74.4 (8) - Cd(58) - (16), (16) - Cd(58) - (17), (17) - Cd(58) - (6), (6) - Cd(58) - (5), 78.14

18 Table S5 optimised structure and bond parameters of H 3 L-I - ptimise structure of H 3 L-I - complex Bond Length Bond angle I(59) - H(39), 3.88 Å I(59) - H(42), 3.10 Å I(59) - H(51), 2.57 Å I(59) - H(50), 2.78 Å H(39) - I(59) - H(42), H(42) - I(59) - H(51), H(51) - I(59) - H(50), H(50) - I(59) - H(43), I(59) - H(43), 3.41 Å H(43) - I(59) - H(39), Table S6 comparison of experimental and theoretical transitions Ligand/Complex Absorbance wavelength H 3 L λ(expt) 310 λ(theo) H 3 L λ(expt) 337 λ(theo) H 3 L λ(expt) 350 λ(theo) H 3 L λ(expt) 380 λ(theo) H 3 L λ(expt) 394 λ(theo) H 3 L-Zn 2+ λ(expt) 425 λ(theo) H 3 L-Cd 2+ λ(expt) 480 λ(theo) H 3 L-I - λ(expt) 555 λ(theo) Excitation transitions energy ev (67%) HM-4 LUM ev (87%) HM-3 LUM ev (87%) HM-1 LUM ev (56 %) HM-2 LUM ev (92%) HM LUM ev (91%) HM LUM ev (89%) HM LUM ev (54%) HM LUM+1

19 Fig.S23 reversibility with anions of Zn complex Fig. S24reversibility with anions of Cd complex

20 Fig. S25: Calibration plot between emission intensity of the probe H 3 L at 545 nm vs Zn 2+ ion for the quantitative analysis of Zn 2+ ion in drinking water. Fig. S26: Calibration plot between emission intensity of the probe H 3 L at 560 nm vs Cd 2+ ion for the quantitative analysis of Cd 2+ ion in drinking water.