Table 6 Compositions of some MOs for the Zn(MTB), Cu(MTB), Fe(MTB) and Fe2(MTB) complexes, respectively.

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

Complex

MO

%Comp

MO

%Comp

Ligand

ZnII

Ligand

ZnII

Zn(MTB)

Ho-1

100

0

L

100

0

Ho-5

99

1

L + 1

100

0

Ho-6

100

0

L + 3

100

0

Ho-7

99

1

L + 4

99

1

Ho-8

100

0

Ho-15

97

3

Complex

MO

%Comp

MO

%Comp

Ligand

CuII

Ligand

CuII

Cu(MTB)

αHo

100

0

αL

100

0

βHo

100

0

βL + 1

99

1

βHo-8

100

0

βL

36

64

αHo-9

100

0

αL + 2

100

0

βHo-9

100

0

αL + 3

94

6

αHo-13

97

3

βL + 4

95

5

βHo-13

95

5

αL + 4

100

0

βL + 5

100

0

Complex

MO

%Comp

MO

%Comp

Ligand

FeII

Ligand

FeII

Fe(MTB)

Ho-1

100

0

L

100

0

Ho-2

100

0

L + 2

59

41

Ho-7

15

85

Ho-8

18

82

Ho-11

100

0

Ho-12

100

0

Ho-13

100

0

Ho-21

99

1

Ho-23

94

6

Ho-24

97

3

Complex

MO

%Comp

MO

%Comp

Ligand

FeII(1)

FeII(2)

Ligand

FeII(1)

FeII(2)

Fe2(MTB)

Ho

99

1

0

L

100

0

0

Ho-2

15

0

85

L + 1

71

29

0

Ho-7

18

82

0

L + 2

79

21

0

Ho-8

99

0

1

L + 4

15

0

85

Ho-9

99

1

0

Ho-10

100

0

0

Ho-11

99

0

1

Ho-17

97

0

3

Ho-18

92

0

8

Ho-19

100

0

0

Ho-22

96

0

4