Supplementary Information

Nickel(II) complexes of ONS donor Schiff base ligands: Synthesis, combined DFT-experimental characterization, redox, thermal and in vitro biological investigation

R. C. MAURYA*, B. A. MALIK, J. M. MIR, P. K. VISHWAKARMA, D. K. RAJAK and N. JAIN

Thermodynamic studies based on TGA spectra

In the present studies of the metal complexes, non-isothermal mode for TGA/DTA techniques is

selected representatively for complex [Ni(dha-mtsc)(H2O)] (3). From Broido graphical method

(mathematical aspect given in supplemental data for clarity) and Broido plots [S1] (figure S11)

the activation energy and order at a particular step were calculated and the results are given in

table S3. The overall thermodynamic and kinetic evaluation results are given in table S4. From

the thermal behavior of the complex, it is quite evident that the change in activation energies and

decrease in the order of the decomposition against the pyrolytic steps determine the order of

stability that the metal oxide attains on getting fully decomposed. The structural rigidity of the

remaining compound gets increased after the expulsion of one or more species, as compared with

the precedent complex. It is known that the order has no intrinsic meaning, but is rather a

mathematical smoothing parameter. No regular trend is observed in the values of either Ea,

because of the fact that TS increases from one step to another.

A. Broido has suggested a simple and sensitive graphical method for the treatment of TGA data.

According to this method the weight at any time t (W t) is related to the fraction of initial

molecular weight as shown below,

Y= NN 0

=W t−W a

W 0−W a. . . (1)

where Wo is the initial weight of the materials and Wa is the weight of residue at the end of

decomposition:

1

For isolated pyrolysis,

dydt

=−K yn . . . (2)

If, K= A e−E/RT . . . (3)

and if T is linear fraction of time t, therefore:

T=T 0+β t . . . (4)

dydn

=−Aβ

e E /RT . dt . . . (5)

where β=dTt , the heating rate

Eq. (v) is integrated as:

(i) ∫Y

1 dydn

=¿ Aβ ∫

T0

T

e−E /RT . dt ¿ . . . (6)

For the first order kinetics (n= 1) in which complex degrades usually:

(ii) ∫Y

1 dyy

=¿−lny=ln ( 1y)¿ . . . (7)

On integrating and taking log of both sides of Eq. (vi), following equation is obtained.

ln [ ln( 1y )]=( E

R Tm+1 )lnT +Constant . . . (8)

Thus a plot of ln [ ln( 1y )] v/s 1/T yields straight line, whose slope is directly related to Ea:

-Ea = Slope × 2.303×R . . . (9)

where Ea is the activation energy and R is the gas constant. Application of this method is used to

determine the kinetic parameter for the complexes. Activation energies against Step (I), Step (II)

and Step (III) were also analyzed.

2

The order ‘n’ is calculated by the application of Horowitz-Metzger equation [S2] as given below

Cs = n1

(1−n) . . . (10)

Cs = W t−W a

W 0−W a, . . . (11)

where Cs is the mass fraction of the substance.

References

S1. A. Broido. J. Polym. Sci., Part A-2, 7, 1761 (1969).

S2. H.H. Horowitz, G. Metzger. Anal. Chem., 35, 1464 (1963).

Figure S1. Keto-enol and thione-thiol tautomerisation of Schiff bases.

3

Figure S2. IR spectra of Schiff base ligand (H2dha-mtsc) (III).

4

Figure S3. IR spectra of [Ni(dha-mtsc)(H2O)] (3).

5

Figure S4. IR spectra of [Ni(dha-mtsc)(H2O)] (3). (a) Experimental (b) Theoretical.

6

Figure S5. Electronic spectra of [Ni(dha-mtsc)(H2O)] (3) (A) in solution form (B) in solid form.

7

Figure S6. Electronic spectra of [Ni(dha-ptsc)(H2O)] (1); (A) in solution (B) in solid form.

8

Figure S7. 1H NMR spectrum of (H2dha-mtsc) (III).

9

Figure S8. 1H NMR spectrum of [Ni(dha-mtsc)(H2O)] (3).

10

Figure S9. 13C NMR spectrum of (H2dha-mtsc) (III).

11

Figure S10. 13C NMR spectrum of [Ni(dha-mtsc)(H2O)] (3).

12

13

Figure S11. Broido plots of [Ni(dha-mtsc)(H2O)] (3).

14

Figure S12. Inhibition zones shown by Schiff bases and their complexes at 100 and 200 conc. µg/mL aginst E. coli.

15

Figure S13. HOMO-LOMO structure with energy level diagram of (H2dha-mtsc) (III).

16

Figure S14. HOMO-LOMO structure with energy level diagram of [Ni(dha-mtsc)(H2O)] (3).

17

Figure S15. Structure of with color range (a) Mulliken atomic charges (b) NBO atomic charges of [Ni(dha-mtsc)(H2O)] (3).

18

Figure S16. Molecular electrostatic potential MESP (a) [H2dha-mtsc] and (b) [Ni(dha-mtsc)(H2O)] (3) with color range along with scale.

19

Figure S17. (a) 1H NMR (b) 13C NMR spectrum of [Ni(dha-mtsc)(H2O)] (3).

20

Table S1. Characterization data of synthesized Schiff bases.

S.No Ligand(Empirical Formula) (M. W.)

Color Yield (%)

Elemental Analysis (Observed/Calculated) %

C H N S M.P.0C

I H2dha-ptsc(C15H15N3O3S)(317.08) White 65

56.67(56.77)

4.61(4.76)

13.01(13.24)

9.92(10.10)

200

II H2dha-tsc(C9H11N3O3S)(241.27)

Creamy white 60

44.52(44.80)

4.45(4.60)

17.32(17.42)

13.0(13.29)

190

III H2dha-mtsc(C10H13N3O3S)(255.07)

Light yellow 63

47.13(47.05)

5.02(5.13)

15.87(16.46)

11.87(12.56)

195

IV H2dha-psc(C15H15N3O4)(301.11)

Creamy white 62

59.51(59.79)

4.97(5.02)

13.76(13.95)

- 198

Table S2. Analytical data, colors, yields (%) and decomposition temperatures (DT) of the synthesized complexes.

Complex (empirical formulae) (molecular weight)

Color M

(Ohm-1

cm2/mole)

μeff

(B.M)Yield ( %)

DT 0C

Elemental Analysis, Observed/Calculated) %

C H N S Ni

[Ni(dha-ptsc)(H2O)] C15H15N3NiO4S (392.06)

Light brown 15.4 0.59 62 270

45.72(45.95)

3.76(3.86)

10.50(10.72)

8.02(8.18)

14.82(14.97)

[Ni(dha-tsc)(H2O)] C9H11N3NiO4S (315.96)

Light brown 14.2 0.44 61 280

34.01(34.21)

3.35(3.51)

13.10(13.30)

10.02(10.15)

18.30(18.58)

[Ni(dha-mtsc)(H2O)] C10H13N3NiO4S (329.00)

Reddish brown 14.3 0.61 64 290

36.24(36.40)

3.65(3.97)

12.52(12.73)

9.67(9.72)

17.65(17.79)

[Ni(dha-psc)(H2O)] C15H15N3NiO5 (375.04)

Deep brown 15.6 0.66 65 290

47.99(47.92)

4.22(4.02)

11.02(11.18)

- 15.39(15.61)

21

Table S3. Stepwise thermal behavior and thermodynamic parameters of [Ni(dha-mtsc)(H2O)].

Step I

Temp. C Temp K 1/K X 103 Residue % Wt Cs =Wt – Wa

Wo- Wa

Order 1/ Cs

180 453 2.207 84.537 1.791 0.838 1.1933190 463 2.159 83.628 1.772 0.829 1.2062200 473 2.114 82.719 1.748 0.817 1.2239210 483 2.070 81.810 1.733 0.810 1.2345220 493 2.028 81.790 1.733 0.810 1.2346230 503 1.988 79.992 1.695 0.791 1.2642240 513 1.949 78.174 1.656 0.774 1.2919250 523 1.912 76.356 1.617 0.753 1.3280

Step II

Temp. C Temp K 1/K X 103 Residue % Wt Cs =Wt – Wa

Wo- Wa

Order 1/ Cs

375 648 1.543 60.903 1.290 0.592 4 1.6891385 658 1.519 59.994 1.271 0.582 4 1.7161395 668 1.497 59.634 1.263 0.578 4 1.7280405 678 1.479 59.085 1.252 0.573 3 1.7442415 688 1.474 58.630 1.242 0.568 3 1.7593423 698 1.436 57.627 1.221 0.558 3 1.7917435 708 1.432 56.358 1.194 0.544 3 1.8355445 718 1.392 56.176 1.190 0.542 3 1.8422

Step III

Temp. C Temp K 1/K X 103 Residue % Wt Cs =Wt – Wa

Wo- Wa

Order 1/ Cs

765 1038 0.963 32.724 0.693 0.298 1 3.355775 1048 0.954 31.815 0.674 0.288 1 3.472785 1058 0.945 29.997 0.635 0.269 1 3.717795 1168 0.856 29.088 0.616 0.260 1 3.846805 1078 0.927 27.270 0.577 0.241 ½ 4.419815 1088 0.919 24.543 0.520 0.213 ½ 4.694825 1098 0.190 23.634 0.500 0.203 ½ 4.926835 1108 0.902 22.725 0.481 0.193 ½ 5.181

22

Table S4. Overall TGA based thermodynamic and decomposition kinetic parameters of 3.

StepStep analysis (C)

Cs = (Wt –Wa) / (Wo –Wa)Order

(n) Ea (KJ)Ti Tmax Tf

I 180 210 250 0.838 28.57

II 375 405 445 0.592 4 7.10

III 765 805 835 0.298 1 57.87

Table S5. Selected geometrical optimization parameters of the representative complex.

S.No

Bond Connectivity

Length

Bond Connectivity

Angle Bond Connectivity Dihedral Angle

1 N(1)-C(2) 1.341 C(2)-N(1)-H(13) 115.014 N(13)-N(1)-C(2)-C(3) 177.6772 N(1)-N(13) 1.412 C(2)-N(1)-Ni(16) 126.006 N(13)-N(1)-C(2)-C(12) -4.0573 N(1)-N(16) 1.876 N(13)-N(1)-

Ni(16)118.866 Ni(16)-N(1)-C(2)-C(3) -6.272

4 C(2)-C(3) 1.464 N(1)-C(2)-C(3) 122.426 Ni(16))-N(1)-C(2)-C(12)

171.994

5 C(2)-C(12) 1.517 N(1)-C(2)-C(12) 117.686 C(2)-N(1)-N(13)-C(14) -177.2896 C(3)-C(4) 1.463 C(3)-C(2)-C(12) 119.866 Ni (16)-N(1)-N(13)

C(14)6.358

7 C(3)-C(6) 1.423 C(2)-C(3)-C(4) 118.703 C(2)-N(1)-Ni(16)-O(11) -5.0858 C(4)-O(5) 1.238 C(2)-C(3)-C(6) 123.134 C(2)-N(1)-Ni(16)-S(15) -3.6629 C(4)-O(10) 1.455 C(4)-C(3)-C(6) 118.138 C(2)-N(1)-Ni(16)-O(30) -22.17310 C(6)-C(7) 1.446 C(3)-C(4)-O(5) 129.669 N(13)-N(1)-Ni(16)-

O(11)170.828

11 C(6)-O(11) 1.321 C(3)-C(4)-O(10) 116.278 N(13)-N(1)-Ni(16)-S(15) -7.47312 C(7)-C(8) 1.708 O(5)-C(4)-O(10) 114.047 N(13)-N(1)-Ni(16)-

O(30)153.741

13 C(7)-H(19) 1.082 C(3)-C(6)-C(7) 120.923 N(1)-C(2)-C(3)-C(4) -164.60914 C(8)-C(9) 1.498 C(3)-C(6)-O(11) 123.124 N(1)-C(2)-C(3)-C(6) 13.52215 C(8)-O(10) 1.377 C(7)-C(6)-O(11) 115.949 C(12)-C(2)-C(3)-C(4) 17.16216 C(9)-H(20) 1.093 C(6)-C(7)-C(8) 120.429 C(12)-C(2)-C(3)-C(6) -164.70717 C(9)-H(21) 1.097 C(6)-C(7)-H(19) 118.416 N(1)-C(2)-C(12)-H(23) -154.94818 C(9)-H(22) 1.097 C(8)-C(7)-H(19) 121.152 N(1)-C(2)-C(12)-H(24) 86.21919 O(11)-

Ni(16)1.849 C(7)-C(8)-C(9) 127.244 N(1)-C(2)-C(12)-H(25) -31.696

20 C(12)-H(23) 1.088 C(7)-C(8)-O(10) 120.188 C(3)-C(2)-C(12)-H(23) 23.36421 C(12)-H(24) 1.097 C(9)-C(8)-O(10) 112.566 C(3)-C(2)-C(12)-H(24) -95.469

23

22 C(12)-H(25) 1.090 C(8)-C(9)-H(20) 110.936 C(3)-C(2)-C(12)-H(25) 146.61523 N(13)-C(14) 1.321 C(8)-C(9)-H(21) 110.285 C(2)-C(3)-C(4)-O(5) 9.27024 C(14)-S(15) 1.813 C(8)-C(9)-H(22) 110.209 C(2)-C(3)-C(4)-O(10) -171.13425 C(14)-N(17) 1.372 H(20)-C(9)-H(21) 109.109 C(6)-C(3)-C(4)-O(5) -168.95526 S(15)-Ni(16) 2.245 H(20)-C(9)-H(22) 109.015 C(6)-C(3)-C(4)-O(10) 10.04127 Ni(16)-

H(30)1.927 H(21)-C(9)-H(22) 107.199 C(2)-C(3)-C(6)-C(7) 173.980

28 N(17)-C(18) 1.463 C(4)-O(10)-C(8) 123.329 C(2)-C(3)-C(6)-O(11) -5.27429 N(17)-H(26) 1.013 C(6)-O(11)-

Ni(16)127.509 C(4)-C(3)-C(6)-C(7) -7.879

30 C(18)-H(27) 1.098 C(2)-C(12)-H(23) 111.258 C(4)-C(3)-C(6)-O(11) 172.86731 C(18)-H(28) 1.094 C(2)-C(12)-H(24) 110.437 C(3)-C(4)-O(10)-C(8) -6.78332 C(18)-H(29) 1.096 C(2)-C(12)-H(25) 109.169 O(5)-C(4)-O(10)-C(8) 172.37133 O(30)-H(31) 0.970 H(23)-C(12)-

H(24)107.130 C(3)-C(6)-C(7)-C(8) 1.661

34 O(30)-H(32) 0.977 H(23)-C(12)-H(25)

111.322 C(3)-C(6)-C(7)-H(19) -177.707

35 H(24)-C(12)-H(25)

107.411 O(11)-C(6)-C(7)-C(8) -179.034

36 N(1)-N(13)-C(14) 115.507 O(11)-C(6)-C(7)-H(19) 1.59837 N(13)-C(14)-

S(15)123.188 C(3)-C(6)-O(11)-Ni(16) -9.823

38 N(13)-C(14)-N(17)

117.782 C(7)-C(6)-O(11)-Ni(16) 170.888

39 S(15)-C(14)-N(17)

119.026 C(6)-C(7)-C(8)-C(9) -178.523

40 C(14)-S(15)-Ni(16)

91.369 C(2)-C(3)-C(6)-O(11) -5.274

41 N(1)-Ni(16)-O(11)

95.725 H(19)-C(7)-C(8)-C(9) 0.826

42 N(1)-Ni(16)-S(15)

90.246 H(19)-C(7)-C(8)-O(10) -178.549

43 N(1)-Ni(16)-O(30)

177.111 C(7)-C(8)-C(9)-H(20) 0.166

44 O(11)-Ni(16)-S(15)

173.793 C(7)-C(8)-C(9)-H(21) -120.838

45 O(11)-Ni(16)-O(30)

81.515 C(7)-C(8)-C(9)-H(22) 121.000

46 S(15)-Ni(16)-O(30)

92.488 O(10)-C(8)-C(9)-H(20) 179.581

47 C(14)-N(17)- 125.176 O(10)-C(8)-C(9)-H(21) 58.577

24

C(18)48 C(14)-N(17)-

H(26)115.252 O(10)-C(8)-C(9)-H(22) -59.585

49 C(18)- N(17)-H(26)

119.482 C(7)-C(8)-O(10)-C(4) 0.650

50 N(17)-C(18)-H(27)

111.882 C(9)-C(8)-O(10)-C(4) -178.811

51 N(17)-C(18)-H(28)

108.581 C(6)-O(11)-Ni(16)-N(1) 13.332

52 N(17)-C(18)-H(29)

111.136 C(6)-O(11)-Ni(16)-S(15) 177.418

53 H(27)-C(18)-H(28)

108.610 C(6)-O(11)-Ni(16)-O(30)

-167.526

54 H(27)-C(18)-H(29)

108.053 N(1)-N(13)-C(14)-S(15) -0.444

55 H(28)-C(18)-H(29)

108.495 N(1)-N(13)-C(14)-N(17) 178.888

56 Ni(16)-O(30)-H(31)

129.143 N(13)-C(14)-S(15)-Ni(16)

-4.097

57 Ni(16)-O(30)-H(32)

108.712 N(17)-C(14)-S(15)-Ni(16)

176.579

58 H(31)-O(30)-H(32)

116.834 N(13)-C(14)-N(17)-C(18)

-178.321

59 N(13)-C(14)-N(17)-H(26)

-1.817

60 S(15)-C(14)-N(17)-C(18)

1.040

61 S(15)-C(14)-N(17)-H(26)

177.544

62 C(14)-S(15)-Ni(16)-N(1) 5.35363 C(14)-S(15)-Ni(16)-

O(11)-158.815

64 C(14)-S(15)-Ni(16)-O(30)

-173.716

65 N(1)-Ni(16)-O(30)-H(31)

-139.869

66 N(1)-Ni(16)-O(30)-H(32)

13.028

67 O(11)-Ni(16)-O(30)-H(31)

-157.063

68 O(11)-Ni(16)-O(30)-H(32)

-4.165

25

69 S(15)-Ni(16)-O(30)-H(31)

21.326

70 S(15)-Ni(16)-O(30)-H(32)

174.224

71 C(14)-N(17)-C(18)-H(27)

65.375

72 C(14)-N(17)-C(18)-H(28)

-174.768

73 C(14)-N(17)-C(18)-H(29)

-55.509

74 H(26)-N(17)-C(18)-H(27)

-110.992

75 H(26)-N(17)-C(18)-H(28)

8.865

Table S6. Representation data of Mulliken atomic charges and NBO analysis of [Ni(dha-mtsc)](H2O)] (3).

S. No.

Atom with the Numerical Assignment

NBO Partial Charges

Mulliken Partial Charges

S. No.

Atom with the Numerical Assignment

NBO Partial Charges

Mulliken Partial Charges

1 1 N -0.308554 -0.34199 17 17 N -0.331951

-0.64121

2 2 C 0.314189 0.35411 18 18 C -0.555487 -0.41500

3 3 C -0.077093 -0.30903 19 19 H 0.247162 0.23870

4 4 C 0.120588 0.78907 20 20 H 0.217664 0.22944

5 5 O -0.251456 -0.60106 21 21 H 0.240130 0.24700

6 6 C 0.411602 0.46695 22 22 H 0.238543 0.24651

7 7 C -0.450977 -0.36033 23 23 H 0.235609 0.24414

8 8 C 0.377162 0.43331 24 24 H 0.244951 0.25489

9 9 C -0.716364 -0.67125 25 25 H 0.245026 0.25184

10 10 O -0.286916

-0.56785 26 26 H 0.317705 0.42409

11 11 O -0.518215

-0.69053 27 27 H 0.233969 0.21410

12 12 C -0.699172 -0.67302 28 28 H 0.203703 0.21954

13 13 N -0.075244

-0.42876 29 29 H 0.237404 0.21887

26

14 14 C -0.123080 0.33898 30 30 O -0.702186

-0.90898

15 15 S -0.053078 -0.18729 31 31 H 0.433109 0.54288

16 16 Ni 0.387685 0.53039 32 32 H 0.443573 0.55148

27

Equation S1. The absolute electronegativity (cabs) and absolute hardness (h) are related to IA

and EA [62] as given below:

cabs = (IE + IA)/2 = (EHOMO + ELUMO) / 2

h = (IE - IA)/2 = (EHOMO - ELUMO) / 2

Equation S2.

Electrophilicity index (), Global softness (S) are given by

= 2/ 2h

S = 1/h

Equation S3.

Dipole moment (), Mean polarizability () and the total first static Hyperpolarizability (0) are given by

= (x2+y

2+z2)1/2

= 1/3(xx +yy +zz)

∆ α=[ ( α XX−α YY )2+(α YY−α ZZ )2+ (α ZZ−α XX )2

2 ]12

0 = (x2+y

2+z2 )1/2

and x = xxx + xyy + xzz

y = yyy + xxy +yzz

z = zzz +xxz + yyz

(or)

0 = [(xxx +xyy +xzz)2 +(yyy +yzz +yxx)2 +(zzz +zxx+zyy)2]1/2

28