Supporting InformationSynthesis, X-ray crystal structures, spectroscopic and electrochemical studies of Zn(II),

Cd(II), Ni(II) and Mn(II) complexes of N1,N4-bis(pyridoxylidene)triethylenetetramine

Satyajit Mondala, Piyali Adaka, Chandrima Dasa, Sumita Naskara, Bholanath Pakhiraa, Arnold L.

Rheingoldb, Ekkehard Sinnc, Carla Eribalc, and Shyamal Kumar Chattopadhyaya*

aDepartment of Chemistry, Indian Institute of Engineering Science and Technology†, Shibpur,

Howrah 711103, India. E mail: shch20@hotmail.com

bDepartment of Chemistry, University of California, San Diego, Urey Hall 5128, La Jolla, CA

92093-0358, U. S. A

cChemistry Department, Western Michigan University, Kalamazoo, MI 49008-5413, U. S.A.

* Corresponding author: Tel.: +91 33 2668 0521; fax: +91 33 2668 2916. e-mail: shch20@hotmail.com (SKC)

†erstwhile Bengal Engineering and Science University, Shibpur

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Table of ContentsMass Spectra of Ligand (Fig.S1) 3

1H NMR of Ligand ( Fig. S2) 4Mass Spectra of Metal complexes ( Fig. S3-S5) 5-71H NMR of Complexes (Fig. S6-S7) 8-9Optimized geometry of ligand (Fig. S8) 10Theoretical and Experimental 1H NMR data of ligand (Table S1) 10Some selected bond distances (Å) of ligand in the optimized geometry (Table S2) 10Crystal data and structure refinement for 1, 2, 3 and 4. (Table S3) 11ORTEP diagram (50% probability level) for 3. (Fig. S9) 12Hydrogen bonds for 1 [Å and °] (Table S4) 12Hydrogen bonded three dimensional networks in 3 (Fig. S10) 13Hydrogen bonds for 3 (Table S5) 13Hydrogen bonded three dimensional networks in 4 (Fig.S11) 14Hydrogen bonds for 4 [Å and °] (Table S6) 14Hydrogen bonded three dimensional networks in 2 (Fig. S12) 15Hydrogen bonds for 2 [Å and °] ( Table S7) 15Electrochemical data for complexes (Table S8) 16UV–VIS spectrophotometric titrations of the ligand (LH2) with acetate salts of metals (Fig. S13) 17UV–VIS spectrophotometric titrations of the ligand (LH2) with acetate salt of Mn2+(Fig. S14) 17Fluorescence titrations of ligand with Zn(II),Cd(II) and Ni(II) (Fig S15) 18Fluorescence titrations of other bivalent metal ions ( Fig. S16) 19The change in the emission intensity of the ligand after the addition of 3 equivalents of each of the guest cations ( Fig. S17)

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Fluorescence intensity of solutions containing Zn(II), the Ligand (LH2) and other metal ions in 1:1: 3 molar ratios ( Fig. S18)

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Benesi–Hildebrand plot from fluorescence titration data of ligand with Zn(II) ,Co(II), Ni(II) and Cu(II) ( Fig S19-Fig S22)

21-22

Binding constant values of Zn(II), Co(II), Ni(II) and Cu(II) ( Table S9) 23Spectrophotometric titration of Mn(II) and Ni(II) with CAN in DMF ( Fig S23-Fig S24) 23FMOs of Zn(II), Cd(II), Ni(II) and Mn(II) complexes ( Fig S25-Fig S28) 24-25TG-DTA curve for 1 and 2 ( Fig S29-Fig S30) 26Mullikan Population analysis ( Table. S10) 27Percentage contributions of the metal ion towards selected molecular orbitals in NiL and MnL complexes (Table. S11)

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Coordinates of the optimized ligand 27-28

2

Figure S1. Mass spectrum (ESI-MS positive ion mode) of Ligand (LH2) in Methanol.

3

Figure S2. 1H NMR spectra of Ligand (LH2) in DMSO-d6+ D2O.

4

Figure S3. Mass spectrum (ESI-MS positive ion mode) of ZnL·2H2O (1) in Methanol.

5

Figure S4. Mass spectrum (ESI-MS positive ion mode) of CdL·2H2O (2) in Methanol.

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Figure S5. Mass spectrum (ESI-MS positive ion mode) of NiL·2H2O (3) in Methanol.

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Figure S6. 1H NMR spectra of ZnL·2H2O (1) in DMSO-d6.

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Figure S7. 1H NMR spectra of CdL·2H2O (2) in DMSO-d6.

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Figure S8: Optimized geometry of the ligand (LH2).

Table S1. Theoretical and Experimental 1H NMR data of ligand

Table S2. Some selected bond distances (Å) of ligand in the optimized geometry

Bond Bond distance (Å)

C1−N9 1.473C2−N7 1.467C11−N7 1.466C17−N9 1.470C12−N23 1.480C18−N24 1.481C25−N23 1.288C27−N24 1.280C30−O63 1.393C37−O59 1.409C36−C37 1.397C37−C39 1.402C29−C30 1.411C30−C32 1.403

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Type of protons Chemical shift:Reference: TMS

B3LYP/6-311+G(2d,p) GIAO

Chemical shift:Reference: TMS

Experimental

-N=CH- 8.6 8.6Aromatic H 7.4 7.7

-CH2OH 5.7 4.6-CH2- 4.1-4.3 2.6-2.2 -CH3 3.6 1.7

Table S3

Crystal data and structure refinements for 1, 2, 3 and 4.

Compound 1 2 3 4Formula C22 H34Zn N6 O6 C22 H32Cd N6 O6 C22 H34 N6 Ni O6 C22 H34 Mn N6 O6

Formula weight 543.92 589.69 537.26 533.49Crystal size(mm3) 0.36×0.28×0.13 0.50 × 0.40 × 0.40 0.50 × 0.15 × 0.08 0.50 × 0.15 ×

0.08Temperature 100(2)K 100(2) K 100(2) K 100(2) KCrystal system Monoclinic Triclinic Monoclinic OrthorhombicSpace group C2/c P-1 C2/c Pbcna (Å) 21.043(3) 8.9365(4) 21.102(2) 16.9448(17)b (Å) 10.388(2) 10.8084(5) 10.3676(11) 10.4990(11)c(Å) 13.839(2) 14.5318(6) 13.742(3) 13.9815(14)α(°) 90 72.0010(10) 90 90β(°) 127.726(8) 88.1420(10) 128.2200(10) 90γ(°) 90 68.5880(10) 90 90dcal (g/cm3) 1.511 1.582 1.511 1.425Z 4 2 4 4µ(mm-1) 1.078 0.932 0.873 0.580F(000) 1144 606 1136 1124Total Reflections 12689 11208 8958 10530Unique Reflections 2447 4501 2732 2897Observed data 2261 4385 2457 2198[ I>2σ(I)] 0.0308 0.0246 0.0336 0.0465R(int) 0.0247,0.0562 0.0238, 0.0621 0.0312, 0.0764 0.0409, 0.0851R1, wR2 [I>2σ(I)] 0.0279,0.0567 0.0244, 0.0625 0.0361, 0.0802 0.0633, 0.0977

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Figure S9. ORTEP diagram (50% probability level) for 3

Table S4.

Hydrogen bonds for 1 [Å and °].

________________________________________________________________________

D-H...A d(D-H) d(H...A) d(D...A) <(DHA)

________________________________________________________________________

O(5)-H(14)...O(3)#1 0.85(3) 2.12(3) 2.963(3) 167(2)

O(5)-H(16)...N(1)#2 0.80(3) 2.08(2) 2.882(2) 176(2)

N(4)-H(13)...O(5) #3 0.86(2) 2.31(2) 3.053(2) 144(2)

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O(3)-H(17)...O(1)#4 0.82(3) 1.86(2) 2.671(2) 174(2)

__________________________________________________________________________

#1 ½ −x, ½ −y, 1−z; #2 −x, −y, ½ −z; #3 x, 1+y, z; #4 −x,1−y, 1−z

Figure S10. Hydrogen bonded three dimensional networks in 3.

Table S5.

Hydrogen bonds for 3 [Å and °].

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D-H...A d(D-H) d(H...A) d(D...A) <(DHA)

____________________________________________________________________________

O(1W)-H(1WB)...N(2)#20.815(9) 2.070(10) 2.879(2) 171(2)

O(2)-H(2)...O(1)#3 0.80(2) 1.89(2) 2.6806(17) 171(2)

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O(1W)-H(1WA)...O(2) 0.815(9) 2.166(11) 2.9613(19) 165(2)

N(3)-H(3)...O(1W)#4 0.89(2) 2.35(2) 3.0747(19) 139.3(17)

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Symmetry transformations used to generate equivalent atoms:

#1 −x, y, −z+1/2; #2 x+1/2,−y+1/2, z+1/2; #3 −x,−y+1,−z+1; #4 −x+1/2,−y+3/2,−z+1

Figure S11. Hydrogen bonded three dimensional networks in 4.

Table S6.

Hydrogen bonds for 4 [Å and °].

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D-H...A d(D-H) d(H...A) d(D...A) <(DHA)

____________________________________________________________________________

O(1W)-H(2W)...O(2)#2 0.77(3) 2.18(3) 2.947(2) 175(3)

O(2)-H(2)...O(1)#3 0.83(3) 1.83(3) 2.659(2) 172(3)

O(1W)-H(3W)...N(3) 0.86(3) 2.04(3) 2.895(2) 176(3)

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____________________________________________________________________________

Symmetry transformations used to generate equivalent atoms:

#1 −x+1,y,−z+1/2 #2 x+1/2,−y+1/2,−z+1 #3 −x+1,−y+1,−z+1

Figure S12. Hydrogen bonded three dimensional networks in 2.

Table S7.

Hydrogen bonds for 2 [Å and °].

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D-H...A d(D-H) d(H...A) d(D...A) <(DHA)

____________________________________________________________________________

O(3)-H(11)...O(2W)#1 0.85(4) 1.85(4) 2.695(3) 170(4)

N(2)-H(2)...O(1W) 0.87(3) 2.31(3) 3.084(2) 148(2)

N(3)-H(3)...O(2W) 0.86(3) 2.10(3) 2.919(3) 158(2)

O(1W)-H(1W)...O(4)#2 0.82(3) 2.01(3) 2.820(2) 169(3)

O(1W)-H(2W)...N(6)#3 0.76(3) 2.14(3) 2.900(2) 178(3)

O(4)-H(4)...O(2)#4 0.73(3) 1.90(3) 2.637(2) 175(3)

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O(2W)-H(3W)...O(1)#5 0.84(4) 1.89(4) 2.736(2) 177(3)

____________________________________________________________________________

Symmetry transformations used to generate equivalent atoms:

#1 −x+1,−y+1,−z+1; #2 x+1,y−1,z; #3 x,y−1,z; #4 −x,−y+2,−z; #5 −x,−y+1,−z+1

Table S8.

Electrochemical data for complexes 1, 2, 3 and 4.[a]

[a] in DMF medium. [b] Potentials are referred against Ag/AgCl electrode.

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Complex E0/V (∆Ep/mV) values from cyclic voltammetry[b]

Peak potentials (V) in Differential pulse voltammetry [b]

ZnL∙2H2O (1) 1.6, −1.75 1.25, −1.41CdL∙2H2O (2) 1.1, −1.90 0.76, −1.78NiL∙2H2O (3) 1.2, 0.46 (107), −1.40 1.07, 0.44, −1.35MnL∙2H2O (4) 1.1, 0.024 (82), −1.75 1.0, 0.048, −1.60

Figure S13. UV–VIS spectrophotometric titrations of the ligand (LH2) solutions (1×10−4 M) in DMF, with acetate salts (1×10−3M) of (a) Zn2+ (b) Cd2+ (c) Ni2+. Insets show the corresponding Jobs plots at 385 nm.

Figure S14. UV–VIS spectrophotometric titrations of the ligand (LH2) solution (1×10−4 M) in DMF, with acetate salt (1×10−3M) of Mn2+.

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(a) (b) (c)

Figure S15. Fluorescence titrations (λex = 335 nm) of ligand (LH2) (5×10−6 M) with a) Cd2+ b) Ni2+ c) Mn2+ (5×10−5 M) in CH3OH/H2O (90/10, v/v) mixed solvent buffered at pH 7.5 by the Tris-buffer at room temperature

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Figure S16: Fluorescence titrations (λex = 335 nm) of the ligand (LH2) (5×10−6 M) with different divalent cations (Co2+, Cu2+, Fe2+, Hg2+, Mg2+, Pb2+,Sn2+) in CH3OH:H2O (9:1, v/v) mixed solvent buffered at pH 7.5 by the Tris-buffer at room temperature.

Figure S17. The change in the emission intensity (λex = 335 nm, λem = 460 nm) of the ligand after the addition of 3 equivalents of each of the guest cations in MeOH: H2O (9: 1, v/v, at pH 7.5) and a plot of the fluorescence intensity versus [Zn2+] (inset).

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Figure S18. Fluorescence intensity (λex = 335 nm, λem = 460 nm) of solutions containing Zn2+, the Ligand (LH2) and other metal ions in 1:1: 3 molar ratio.

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Figure S19. Benesi–Hildebrand plot from fluorescence titration data of ligand (5µM) with Zn2+.

Figure S20. Benesi– Hildebrand plot from fluorescence titration data of ligand (5µM) with Co2+.

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Figure S21. Benesi–Hildebrand plot from fluorescence titration data of ligand (5µM) with Ni2+.

Figure S22. Benesi–Hildebrand plot from fluorescence titration data of ligand (5µM) with Cu2+.

Table S9.

Binding constant values of Zn(II), Co(II), Ni(II) and Cu(II) for the ligand LH2 obtained by fluorescence titration method.

Figure S23. Spectrophotometric titration of MnL∙2H2O (1×10−4 M) with CAN (1×10−3 M) in DMF.

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M(II) Binding constant (kb)Zn(II) 4× 106 M−1

Co(II) 2.62 × 106 M−1

Ni(II) 2.42 × 105 M-1

Cu(II) 8.5 × 104 M−1

Figure S24. Spectrophotometric titration of NiL∙2H2O (1×10−4 M) with CAN (1×10−3 M) in DMF.

Figure S25. FMOs of ZnL with ISO value cut off 0.04.

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Figure S26. FMOs of CdL with ISO value cut off 0.04.

Figure S27. FMOs of NiL with ISO value cut off 0.04.

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Figure S28. FMOs of MnL with ISO value cut off 0.04.

Thermal analysis

Themogravimetric (TG) and differential thermal analysis (DTA) experiments of two

representative complexes 1 and 2 were carried out in order to investigate the nature of the water

molecules and their thermal stability. TG and DTA data shows that 1 starts losing water

endothermically around 54.5ºC and the loss in complete at 98 ºC (Figure S29).The observed loss

of weight is 6.36%, which agrees well with the calculated value of 6.62%, corresponding to loss

of two water molecules. For 2, the endothermic water loss occurs within 66-103 ºC (Figure S30)

and again there is good agreement between the observed weight losses of 6.59%, with the

calculated value of 6.10%

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Figure S29. TG-DTA curve for 1.

Figure S30. TG-DTA curve for 2.

Table S10.

Charges on selected atoms in the NiL and MnL complexes as calculated by Mullikan Population analysis

Table S11.

Percentage contribution of the metal ion towards selected molecular orbitals in NiL and MnL complexes.

Complex -HOMO-4 -HOMO-3 -HOMO-2 -HOMO-1 -HOMO -LUMO

NiL 13.29 4.99 11.50 3.70 2.63 0.71

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Complex Charge on Metal ion (a.u.)

Charge on phenolateOxygens (a.u.)

Zn L +1.000 −0.502 and −0.502Cd L +1.005 −0.501and −0.501NiL +0.295 −0.435 and −0.435MnL +0.700 −0.499 and −0.499

MnL 14.84 7.54 8.92 37.83 22.05 1.15

Coordinates of the optimized ligand:

C1 1.76608814 3.68164428 -1.20035409 C2 2.49333419 4.40004834 -0.05533400 H3 1.53054612 4.41825934 -1.99049915 H4 2.45498419 2.95247523 -1.62842112 H5 3.24407725 5.05789539 -0.50032104 H6 1.77715514 5.05344439 0.47610604 N7 3.18789624 3.48646827 0.85896607 H8 4.08144231 3.84162130 1.17589709 N9 0.56741304 2.95776323 -0.74448506 H10 -0.14265701 3.59272627 -0.38808803 C11 2.40161819 2.86970422 1.93111315 C12 3.12900924 1.69411613 2.60225820 H13 1.47546311 2.51080520 1.48510311 H14 2.12942216 3.59503228 2.72113521 H15 2.50543219 1.35013310 3.43869527 H16 4.08291932 2.02586415 3.01697323 C17 0.00229700 1.98604415 -1.69203813 C18 -1.06440408 1.13800309 -1.00151308 H19 0.80767006 1.33392710 -2.03339315 H20 -0.42949503 2.45826519 -2.59022220 H21 -0.60124305 0.59888305 -0.17121201 H22 -1.85763114 1.77562714 -0.60209205 N23 3.40931526 0.58339505 1.66542313 N24 -1.60641813 0.14795501 -1.96004815 C25 2.43388519 -0.20459602 1.37209911 H26 1.44665311 -0.07966101 1.81954214 C27 -2.68192220 -0.50385704 -1.72309813 H28 -2.98057723 -1.24342610 -2.46495319 C29 2.54245820 -1.30888410 0.40994603 C30 1.36713811 -2.01697416 0.08055501 C31 3.74478529 -1.70306813 -0.22660102 C32 1.39493711 -3.07443924 -0.84084106 C33 3.69166629 -2.76741221 -1.13069409 N34 2.55530120 -3.43326127 -1.42991311 H35 4.58878535 -3.09281024 -1.62836513 C36 -3.57898428 -0.38972903 -0.52378904 C37 -3.47440727 -1.31879910 0.51488204 C38 -4.58549435 0.59033605 -0.41669403 C39 -4.31133233 -1.26198609 1.63815812 C40 -5.38899939 0.58737405 0.72721206 N41 -5.26130541 -0.30528602 1.72727413 H42 -6.16904550 1.32682110 0.84931907 C43 5.05521539 -1.00917408 0.04030300 H44 4.99321439 0.04251300 -0.24578102 H45 5.29049441 -1.03001208 1.10628209 C46 0.16287101 -3.85326930 -1.21306609 H47 -0.27524102 -4.36497734 -0.34923703 H48 -0.61273805 -3.22047125 -1.65268812 H49 0.44432503 -4.60687035 -1.94467215

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C50 -4.80613337 1.63026313 -1.47997212 H51 -4.56313235 1.23654909 -2.46916419 H52 -5.85000644 1.95288015 -1.47269511 C53 -4.19937232 -2.24438517 2.77133522 H54 -3.20488525 -2.23132617 3.22747125 H55 -4.92592138 -1.97762515 3.53450027 H56 -4.41463134 -3.27202625 2.45573319 O57 -3.93694630 2.78004521 -1.17827309 H58 -4.00783131 3.45697627 -1.87609714 O59 -2.48944519 -2.31901518 0.39162503 H60 -2.62985120 -3.04802023 1.01966308 O61 6.10527345 -1.69195513 -0.72389306 H62 6.94389254 -1.20669909 -0.65278005 O63 0.19355801 -1.61931512 0.71655406 H64 -0.64204905 -1.98985215 0.36243503

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