Supplementary Information. 2-Aza-1,3-butadiene ligands for the selective detection of Hg 2+ and Cu 2+ ions

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1 Supplementary Information 2-Aza-1,3-butadiene ligands for the selective detection of Hg 2+ and Cu 2+ ions Rosario Martínez, Fabiola Zapata, Antonio Caballero, Arturo Espinosa, Alberto Tárraga*, and Pedro Molina* Departamento de Química Orgánica. Facultad de Química. Universidad de Murcia. Campus de Espinardo, Murcia. Spain Contents Dedicated to Professor Benito Alcaide on the occasion of his 60 th anniversary Figure SI 1: Cyclic voltammogram of 7 Figure SI 2: Cyclic voltammogram of 9 Figure SI 3: Changes in the linear sweep voltammogram of 7 upon addition of increasing amounts of Cu 2+ cations and Hg 2+ cations. Figure SI 4: Changes in the linear sweep voltammogram of 9 upon addition of increasing amounts of Cu 2+ cations and Hg 2+ cations. Figure SI 5: Evolution of the DPV of 6 upon addition of increasing amounts of Zn 2+ cations. Figure SI 6: Changes in the absorption spectra of 6 and 7 in CH 3 CN upon addition of increasing amounts of Hg 2. Figure SI 7: Fluorescence emission spectra of ligands 6 and 8 in CH 3 CN upon titration with Hg 2. Figure SI 8: Evolution of the fluorescence emission spectra of 8 in CH 3 CN upon addition of increasing amounts of Zn 2+ Figure SI 9: Evolution of the UV/visible spectra of 10 in CH 3 CN upon addition of increasing amounts of Cu 2+ and Hg 2+ Figure SI 10: Evolution of the fluorescence emission spectra of 10 in CH 3 CN upon addition of increasing amounts of Cu 2+ and Hg 2+ Figure SI 11: Job s plot for 7 and 9 with Hg 2+ Figure SI 12: Job s plot for 10 and Cu 2+ Figure SI 13:Stepwise complexation/descomplexation cycles of ligands 7 and 9 with Hg 2+ Figure SI 14:Stepwise complexation/descomplexation cycles of S3 S3 S4 S4 S5 S5 S6 S6 S7 S7 S8 S8 S9 S1

2 ligand 10 and Cu 2+ Figure SI 15. Plot for determining the detection limit of 6 towards Hg 2+ Figure SI 16. Plot for determining the detection limit of 7 towards Hg 2+ Figure SI 17. Plot for determining the detection limit of 8 towards Hg 2+ Figure SI 18. Plot for determining the detection limit of 8 towards Zn 2+ Figure SI 19. Plot for determining the detection limit of 9 towards Hg 2+ Figure SI 20. Plot for determining the detection limit of 10 towards Hg 2+ Figure SI 21. Plot for determining the detection limit of 10 towards Cu 2+ Calculated structures: cartesian coordinates and energies S9 S10 S10 S11 S11 S12 S12 S13 S14 S2

3 Figure SI 1: Cyclic coltammogram of 7 in CH 3 CN using n-bu 4 NPF 6 0,1 M as the supporting electrolyte, AgCl/Ag as the reference electrode, and platinum wires as the counter and working electrodes, in the presence of DMFc as the internal standard. a) Different scanning rates were used to check the reversibility of the system: (blue) 0.10 V s -1, (green) 0.30 V s -1, (red) 0.5 V s -1. b) 0.50 V s -1. Figure SI 2: Cyclic coltammogram of 9 in CH 3 CN using n-bu 4 NPF 6 0,1 M as the supporting electrolyte, AgCl/Ag as the reference electrode, and platinum wires as the counter and working electrodes, in the presence of DMFc as the internal standard. a) Different scanning rates were used to check the reversibility of the system: (blue) 0.10 V s -1, (green) 0.30 V s -1, (red) 0.5 V s -1. b) 0.50 V s -1. S3

4 Figure SI 3: Changes in the linear sweep voltammogram of 7 ( 1 x 10-3 M ) in CH 3 CN with TBAP ( 0.1 M ) as supporting electrolyte, obtained using a rotating disk electrode at 100 mv s -1 and 1000 rpm, when metal cations are added: (a) upon addition of increasing amounts of Cu 2+ cations and (b) upon addition of increasing amount of Hg 2+ cations. Figure SI 4: Changes in the linear sweep voltammogram of 9 ( 1 x 10-3 M ) in CH 3 CN with TBAP ( 0.1 M ) as supporting electrolyte, obtained using a rotating disk electrode at 100 mv s -1 and 1000 rpm, when metal cations are added: (a) upon addition of increasing amounts of Cu 2+ cations and (b) upon addition of increasing amount of Hg 2+ cations. S4

5 Figure SI 5: Evolution of the DPV of 6 (1 x 10-3 M ) in CH 3 CN with TBAP (0.1 M ) as supporting electrolyte scanned at 0.1 V.s -1 from -0 to 1.2 V when Hg(ClO 4 ) 2 is added: from 0 (black line) to 1 equiv (blue line). Figure SI 6: Changes in the absorption spectra of 6 a) and 7 b) (1 x 10-4 M) in CH 3 CN upon addition of increasing amounts of Hg 2+ (2.5 x 10-2 M) in CH 3 CN. Arrows indicate the absorption that increase or decrease during the experiment. S5

6 Figure SI 7: Fluorescence emission spectra of ligands 6 (a) and 8 (b) in CH 3 CN (c = 2.5x10-5 M, λ exc = 310 nm) upon titration with Hg 2+. The initial spectra (blue) correspond to the free ligands 6 or 8 and the final spectra (red) correspond to the complexed forms 6 Hg 2+ and 8 Hg 2+ after addition of 1 equiv of Hg 2+. Figure SI 8: Fluorescence emission spectra of ligands 8 in CH 3 CN (c = 2.5x10-5 M, λ exc = 310 nm) upon titration with Zn 2+. The initial spectra (blue) correspond to the free ligands 8 and the final spectra (red) correspond to the complexed forms 8 Zn 2+. S6

7 Figure SI 9: UV/visible spectra obtained during the titration of 10 in CH 3 CN (c = 2.5x10-5 M) with Cu 2+ (a) and Hg 2+ (b). The initial spectra (black) correspond to the free ligand 10 and the final spectra (red) correspond to the complexed forms 10 Cu 2+ and 10 Hg 2+ after addition of 1 equiv of Cu 2+ or Hg 2+ respectively. Figure SI 10: Fluorescence emission spectra obtained during the titration of 10 in CH 3 CN (c = 2.5x10-5 M, λ exc = 350 nm)) with Cu 2+ (a) and Hg 2+ (b). The initial spectra (black) correspond to the free ligand 10 and the final spectra (red) correspond to the complexed forms 10 Cu 2+ and 10 Hg 2+ after addition of 1 equiv of Cu 2+ or Hg 2+ respectively. S7

8 Figure SI 11: Job s plot for 7 (a) and 9 (b) titrated with Hg 2+ indicating the formation of 1:1 complexes. The total [L] + [Hg 2+ ] = 1 x10-4 M, illustrating the 1:1 stoichiometry of the complexed formed Figure SI 12: Job s plot for 10 and Cu 2+ indicating the formation of 1:1 complexes. The total [10] + [Cu 2+ ] = 1 x10-4 M, illustrating the 1:1 stoichiometry of the complexed formed. S8

9 Figure SI 13:Stepwise complexation/descomplexation cycles of ligands 7 (a) and 9 (b) ( M in CH 3 CN) and Cu 2+, using EDTA as descomplexation agent; carried out by UV-Vis analysis. Figure SI 14:Stepwise complexation/descomplexation cycles of ligand 10 ( M in CH 3 CN) and Cu 2+, using EDTA as descomplexation agent; carried out by UV-Vis analysis. S9

10 Figure SI 15. Plot for determining the detection limit of 6 towards Hg 2+. Figure SI 16. Plot for determining the detection limit of 7 towards Hg 2+. S10

11 Figure SI 17. Plot for determining the detection limit of 8 towards Hg 2+. Figure SI 18. Plot for determining the detection limit of 8 towards Zn 2+. S11

12 Figure SI 19. Plot for determining the detection limit of 9 towards Hg 2+. Figure SI 20. Plot for determining the detection limit of 10 towards Hg 2+. S12

13 Figure SI 21. Plot for determining the detection limit of 10 towards Cu 2+. S13

14 Calculated structures: cartesian coordinates (in Å) and energies (au) computed for Hg(OTf) 2, compound 6 and complex 6 Hg(OTf) 2.- Hg(OTf) 2 (C i ): E MeCN = au E gas-phase = au Hg O S O O C F F F O S O O C F F F Compound 6: E MeCN = au E gas-phase = au C N C C H H H C C C C C C C C C C H H H H H H H C C C S14

15 C C H H H H Fe C C C C C H H H H H Complex 6 Hg(OTf) 2 : E MeCN = au E gas-phase = au E BSSE = au C N C C H H H C C C C C C C C C C H H H H H H H C C C C C H H H H Fe C S15

16 C C C C H H H H H Hg O S O O C F F F O S O O C F F F S16