P: ISSN No. 0976-8602 RNI No.  UPENG/2012/42622 VOL.- XIII , ISSUE- III July  - 2024
E: ISSN No. 2349-9443 Asian Resonance
Conductometric Studies on Mn (II)-Thiosemicarbazone Systems
Paper Id :  19111   Submission Date :  2024-07-18   Acceptance Date :  2024-07-21   Publication Date :  2024-07-25
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DOI:10.5281/zenodo.14051588
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Uma Rathore
Assistant Professor
PG Department Of Chemistry
Govt. Dungar College, MGS University
Bikaner,Rajasthan, India
Abstract
Thiosemicarbazone complexes processes potential biological implications. These complexes also have therapeutic importance. Present research describes the conductometric investigations on few Mn (II)- thiosemicarbazone complexes. The conductometric studies have been carried out in doubly distilled water, Triton X-100 and Brij-35 mediums. Association constants and formation constants have been calculated and different types of stoichiometry [M  :  L]  have  been  observed  for  metal-ligand complexes as; 1: 2, 1: 3, 1: 4 etc.
Keywords Mn (II)-Thiosemicarbazone, Association Constants, Formation Constants, Triton X-100.
Introduction
Thiosemicarbazones have received considerable attention because of their binding ability with metal ions and for their antitumour, antiprotozoal, antibacterial or antiviral activities [1].
Objective of study
In  this  paper  we  are  reporting  the  association constant, Gibbs Free energies of Mn (II) complexes with  thiosemicarbazide  based  ligand:  3, 4, 5-Trimethoxybenzaldehyde thiosemicarbazone [3, 4, 5-TBT]
Review of Literature

Anticarcinogenic, antibacterial, anti-HIV, fungicidal, antiviral, antifungal and antitumour properties etc. have been reported involving transition metal ions with thiosemicarbazones [2]
Methodology
All the chemicals  used  were  of  AR  grade  and procured from Himedia. Metal salt were purchased from E. Merck and were used as received. All solvent used were of standard/spectroscopic grade. Ligand 3, 4, 5-TBT was synthesized by condensation reaction of thiosemicarbazide with benzaldehyde in presence of methanol according to the literature [3]. Metal-ligand complexes were  formed  by  conductometrically. Conductivity TDS Meter 307 is employed in present study for conductometric investigations.
Tools Used The conductometric titration of the ligand (1x10-3) mole/L in doubly distilled water, TX-100 and Brij-35 medium against the MnCl2 (1x10-4) mole/L was performed with definite amount of metal (MnCl2) solution [4,5]. The cell was calibrated with standard KCl solution [6].
Result and Discussion

 In all three medium the values of molar conductance were calculated at 298.15 K temperature. [7] 

The mediums were  water, Brij-35and TX-100 medium/m = (Ks-Ksolv.)Kcell x 1000/C   ---------(1) 

Ks = specific conductance of the solution, Ksolv = specific conductance of the solvent, Kcell = cell constant, C = molar concentration of the metal ion solution. 

The stoichiometric of complexes were decided by association and formation constants. The association constants of complexes were calculated by using equation (2) [8,9]  in  water,  TX-100  and  Brij-35 medium.

KA = [/₀2 (/₀ - / m )] / [4Cm2 γ± 2 /m3 S(z)]      ----------- (2)

KA = association constants, /m =molar conductance, /0 = limiting molar conductance of metal ion solution, γ± = activity coefficient, S(Z) = Fuoss-Shedlovsky factor [10]

Association constants (KA) and gibbs free energy (∆ GA) of Mn(II) with [3, 4, 5-TBT] were calculated in different medium (water, Triton X-100 and Brij-35) 

            

              






Figure-a                                                             


Figure-b                                                  

 Figure-c

                                               Plot of molar conductance Vs M/L ratio

Graph have been plotted between molar conductance and M/L ratio in water , TX100 and Brij 35 medium ( figure a, b and c respectively) .

The Gibbs free energies were obtained by employing equation (3) [11]

∆ GA = - R T ln KA ----------- (3)

here 

R = gas constant (8.314 J), T = absolute temperature

The result of Gibbs free energies were calculated.

Kf = [ΛM - Λ obs]/[(Λ obs- ΛML)[L]] ----------- (4)

The formation constants (Kf) [12,13] of complexes were calculated by applying above eq. 

here,

/M = molar conductance of the metal ion solution alone, /obs = observed molar conductance of solution,

/ML= molar conductance of the complex 

The calculated values (Kf) for complexes are presented in Tables (i-v).

Also the Gibbs free energies of complex formation constant were obtained using equation (5) and exhibited in

tables(i-v). 

∆Gf = - RT ln Kf ----------- (5)

 Table- (i)-Formation constants and Gibbs free energies of formation for 1:3 (M/L) Mn(II) complexes in water medium

/obs 

[L]

(/M-/obs)

(/obs-/ML)[L]

Kf

Δ Gf (k J/mol)

64

0.000632911

7

0.001164557

6010.869565

-21.53676406

64

0.000625

7

0.00115

6086.956522

-21.56789797

64

0.000617284

7

0.001135802

6163.043478

-21.59864512

65

0.000609756

6

0.001731707

3464.788732

-20.1731802

65

0.00060241

6

0.001710843

3507.042254

-20.20318194

66

0.000595238

5

0.002285714

2187.5

-19.03489463

66

0.000588235

5

0.002258824

2213.541667

-19.06418625

66

0.000581395

5

0.002232558

2239.583333

-19.09313527

67

0.000574713

4

0.002781609

1438.016529

-17.99659802

67

0.000568182

4

0.00275

1454.545455

-18.02488534

67

0.000561798

4

0.002719101

1471.07438

-18.05285301

67

0.000555556

4

0.002688889

1487.603306

-18.0805082

67

0.000549451

4

0.002659341

1504.132231

-18.1078578

67

0.000543478

4

0.002630435

1520.661157

-18.13490848

/ML = 62.16 Cm2Ohm-1mol-1

Table-(ii)-: Formation constants and Gibbs free energies of formation for 1:3 (M/L) Mn(II) complexes in water medium

/obs 

[L]

(/M-/obs)

(/obs-/ML)[L]

Kf

Δ Gf (k J/mol)

60

0.000847458

11

0.004076271

2698.544699

-19.55455279

61

0.000833333

10

0.004841667

2065.404475

-18.8927408

62

0.000819672

9

0.005581967

1612.334802

-18.27979692

62

0.000806452

9

0.005491935

1638.76652

-18.32004355

63

0.000793651

8

0.006198413

1290.653009

-17.72899755

63

0.00078125

8

0.006101563

1311.139565

-17.76797652

63

0.000769231

8

0.006007692

1331.62612

-17.80635113

/ML = 55.19 cm2ohm-1mol-1

Table - (iii)-: Formation constants and Gibbs free energies of formation for 1:3 (M/L) Mn(II) complexes in TX-100 medium

/obs 

[L]

(/M-/obs)

(/obs-/ML)[L]

Kf

Δ Gf (k J/mol)

55

0.000735294

12

0.001367647

8774.193548

-22.49934222

55

0.000735294

12

0.001367647

8774.193548

-22.49934222

55

0.000735294

12

0.001367647

8774.193548

-22.49934222

55

0.000735294

12

0.001367647

8774.193548

-22.49934222

56

0.000735294

11

0.002102941

5230.769231

-21.21757104

56

0.000735294

11

0.002102941

5230.769231

-21.21757104

56

0.000735294

11

0.002102941

5230.769231

-21.21757104

56

0.000735294

11

0.002102941

5230.769231

-21.21757104

56

0.000735294

11

0.002102941

5230.769231

-21.21757104

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

57

0.000735294

10

0.002838235

3523.316062

-20.23836783

/ML = 53.14 cm2ohm-1mol-1

Table (iv)-: Formation constants and Gibbs free energies of formation for 1:4 (M/L) Mn(II) complexes in TX-100 medium

/obs 

[L]

(/M-/obs)

(/obs-/ML)[L]

Kf

Δ Gf (k J/mol)

51

0.000769231

16

0.0008

20000

-24.54102476

52

0.000757576

15

0.001545455

9705.882353

-22.74941707

52

0.000746269

15

0.001522388

9852.941176

-22.78668121

53

0.000735294

14

0.002235294

6263.157895

-21.663927

53

0.000735294

14

0.002235294

6263.157895

-21.663927

53

0.000735294

14

0.002235294

6263.157895

-21.663927

54

0.000735294

13

0.002970588

4376.237624

-20.77556941

54

0.000735294

13

0.002970588

4376.237624

-20.77556941

54

0.000735294

13

0.002970588

4376.237624

-20.77556941

54

0.000735294

13

0.002970588

4376.237624

-20.77556941

/ML = 49.96 cm2ohm-1mol-1

Table  (v)-: Formation constants and Gibbs free energies of formation for 1:2 (M/L) Mn(II) complexes in Brij-35 medium

/obs 

[L]

(/M-/obs)

(/obs-/ML)[L]

Kf

Δ Gf (k J/mol)

61

0.000568182

18

0.000568182

31680

-25.65068975

61

0.000561798

18

0.000561798

32040

-25.67865743

61

0.000555556

18

0.000555556

32400

-25.70631261

61

0.000549451

18

0.000549451

32760

-25.73366221

61

0.000543478

18

0.000543478

33120

-25.76071289

61

0.000537634

18

0.000537634

33480

-25.78747114

/ML = 60 cm2ohm-1mol-1
Conclusion

The negative values of ∆G show the ability of the studied ligand to form stable complexes by conducto metrica. The ∆G values were found negative which prove that  stable metal ligand complexes were obtained by conductometric method.
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