On Biomimetics by Lilyana Pramatarova

Iron and Manganese-Containing Flavonol 2,4-Dioxygenase Mimics
39

dioxygenation of FeIII(fla)(salen) measured at 40 ºC (Fig. 12) resulted in a rate equation with
first order dependence on Fe(fla)(salen), dioxygen and triphenylacetate (k = (5.02 ± 0.35) ×
102 M-2 s-1, H# = 35 kJ mol-1, S# = -120 J mol-1 K-1 at 313.16 K).

8

10

12

14

16

18

0 1020304050

10

3 /M

-1cm

-1

t/min

0

5

10

15

20

350 400 450 500 550 600 650 700 750 800

10

3 

/M

-1cm

-1

λ/nm

(b)

(a)

(A) t

(B)

Fig. 12. (a) (A) Visible spectral change for the decay of Fe(salen)(fla) in the presence of 10 eq.
Ph 3 CCO 2 - in DMF at 40 ºC, (B) in the presence of NBT. (b) Time-dependent conversion of
Fe(fla)(salen) under the condition described above monitored at 407 nm (Baráth et al., 2009).

N N

O FeIIIO

O

O

Ph

O

N N

O O

FeIII

O

O

Ph

O

O

C

R

O

N N

O FeIIO

O

O

Ph

O

N N

O O

FeIII

O

O

Ph

O

O

C

R

O

-O 2 +O 2

+O 2 +O 2

N N

O FeIIIO

O

O

O

Ph

O

N N

O O

FeIII

CO

O

O

Ph

O

O

C

R

O

C

K 1

krds krds

K 2

RCO 2

R=Ph 3 C; Ph 2 CH, PhCH2,CH 3

RCO 2

K 1

(a ) (b )

Fig. 13. Mechanistic differences between the direct and carboxylate-enhanced oxygenation
of Fe(fla)(salen) (Baráth et al., 2009).

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