Table 4 Computed wavelengths (λ) and energy (E), difference between the theoretical and experimental values of wavelengths (Δλ) and oscillator strengths (f) of LETs for the Zn(MTB), Cu(MTB), and Fe(MTB) complexes.

From: Study of interaction of metal ions with methylthymol blue by chemometrics and quantum chemical calculations

Complex

No. HMs

Transitions from 500 to 700 nm

Preferred geometry

λ/nm (E/eV)

Δλ/nm (E, eV)

f

Zn(MTB)

8-Oh(4)

584 (2.12)

16 (0.06)

0.26

Oh(3)

35-Oh(3)

587 (2.11)

13 (0.05)

0.53

Oh(3)

31-SP(1)

595 (2.08)

5 (0.02)

0.22

SPY(1)

23-SP(1)

578 (2.14)

22 (0.08)

0.51

SPY(1)

20-Td(1)

606 (2.05)

6 (0.02)

0.09

Td(1)

Experiment

600 (2.07)

   

Cu(MTB)

8-Oh(4)

588 (2.11)

12 (0.04)

0.08

SPY(2)

21-Oh(1)

593 (2.09)

7 (0.02)

0.17

SPY(1)

27-Oh(4)

614 (2.02)

14 (0.05)

0.05

SPY(3)

37-Oh(3)

592 (2.09)

8 (0.03)

0.06

SPY(2)

38-Oh(3)

593 (2.09)

7 (0.02)

0.14

SPY(2)

40-Oh(2)

608 (2.04)

8 (0.03)

0.14

SPY(1)

16-SP(2)

578 (2.15)

22 (0.08)

0.57

SPY(2)

28-SP(2)

586 (2.12)

14 (0.05)

0.56

SPY(2)

37-SP(1)

585 (2.12)

15 (0.05)

0.23

SPY(1)

38-SP(1)

588 (2.11)

12 (0.04)

0.31

SPY(1)

39-SP(1)

586 (2.12)

14 (0.05)

0.12

SPY(1)

Experiment

600 (2.07)

   

Fe(MTB)

14-Oh(4)

501 (2.47)

3 (0.02)

0.27

Oh(4)

15-Oh(4)

517 (2.40)

19 (0.09)

0.51

Oh(4)

24-Oh(3)

486 (2.55)

12 (0.06)

0.11

Oh(3)

34-Oh(3)

518 (2.40)

19 (0.09)

0.61

Oh(3)

9-SP(2)

497 (2.49)

1 (0.00)

0.53

SP(2)

12-SP(2)

484 (2.56)

14 (0.07)

0.13

SPY(2)

14-SP(2)

508 (2.44)

10 (0.05)

0.61

SPY(2)

31-SP(1)

507 (2.45)

9 (0.04)

0.50

SPY(1)

32-SP(1)

491 (2.52)

7 (0.04)

0.07

SPY(1)

12-Td(2)

493 (2.52)

5 (0.03)

0.11

Oh(2)

Experiment

498 (2.49)

   
  1. The significances of bold show the final optimized HMSs for the Zn(MTB), Cu(MTB), and Fe(MTB) complexes.
  2. The number in parentheses indicates the number of water molecules involved in the coordination sphere.