Peroxo Vanadium(V)
  

2001, Vol. 45, No. 3

Printed in the Republic of Korea

213

Peroxo Vanadium(V)
    

  

 

  

(2001. 3. 29 )

Studies on the Oxygen-Atom-Transfer Reactions of Peroxo Vanadium(V) Complexes

Tae-Jin Won

Department of Chemistry, Changwon National University
Changwon 641-773, Korea (Received March 29, 2001)

. Peroxo-vanadium(V)   VO(O²)2(pic)²⁻ VO(O²)(nta)²⁻ VO(O²)(dipic)⁻ pH 4.0   thiolato-cobalt(III)   (en)²Co(SCH2CH2NH2)²⁺     !"#

$. %     && (35±1) (4.8±0.4)'10⁻²  (8.6±0.5)'10⁻⁴ ()*(M⁻¹s⁻¹) + ,-$. VO(O²)2(pic)²⁻ ./01 2 peroxide     34 0156 VO(O²) (nta)²⁻ VO(O²)(dipic)⁻ ./01 2 peroxide 734 8$. 9  :; peroxo vanadium (V)       <= >4 peroxide ?@A >B4 substrate CD

 EF G1H$ IEJ$.

ABSTRACT. The reaction of peroxo vanadium(V) complexes, VO(O2)2(pic)²⁻, VO(O2)(nta)²⁻, and VO(O2) (dipic)⁻ with thiolato-cobalt(III), (en)2Co(SCH2CH2NH2)²⁺ resulted in an oxygen-atom transfer in aqueous solu- tions. Rate constants (M⁻¹s⁻¹) for these reactions were (35±1), (4.8±0.4)×10⁻², and (8.6±0.5)×10⁻⁴, respectively.

The coordinate peroxide was activated in the oxygen-atom-transfer reaction of VO(O2)2(pic)²⁻, but it is not the case for VO(O2)(nta)²⁻ and VO(O2)(dipic)⁻. In this paper, we proposed that the direct attack of an electrophilic per- oxide to a nucleophilic substrate occurs in the oxygen-atom transfer pathway of peroxo vanadium(V) complexes.

 

Group V, VI, VII (K  L(% M d⁰

  .N+ O2 L( P%Q  

   RST EF peroxo transition metal  U4K$.^1-4!D"= peroxo 

%Q V&WX YZ+ O 7./  = E6

oxo group E6 [ \] side-on U^ peroxide + O 2$.

 6_5 ./  ` [ aA8 mono- [ multidentate ?@A bK$. L(

./8 peroxide >4c >B4 substrate

  !"#$ def 2$.^5,6 Peroxo tran- sition metal   4Q peroxideA b01 2 L( P gh ij kT lEc, mm L ( P%Q b8 peroxide+ 34 no p=q peroxide U^ H²O2 K  r$ s Rt

 !"#$. 7u Re(VII) 6u W(VI)

peroxo  (CH3)ReO2(O2) WO(O2)2(H2O)

peroxo  % M Av Rt   !"

w  = def 2"c, Mo(VI) peroxo  %) Rt   r$.^7-10 xy z= de H Cr(VI)) H²O2 EF peroxo chromium(VI)  U4E6, %Q   7{EF U 4 |n }~0 n€E "= def 2$.^11,12 5u V(V)+ ‚ƒE peroxo   <9 $t peroxo transition metal   „EF  

 *D"= {K  U4Ec [K …†

 ‡ˆ‰(insulin-mimic)= def 2$.^13-15 …†

‡ˆ‰ AŠ4 AH peroxo   VO(O²) (nta)²⁻ biological thiol E6 cysteine 

‹EF cysteine  8 U^ cystine U4K

$ r0-$.¹⁶

Œ Y …† ‡ˆ‰= deH VO(O2)2

(pic)²⁻ VO(O²)(dipic)⁻ …† ‡ˆ‰= A

Š4 O 2 VO(O²)(nta)²⁻ thiolato-cobalt(III)       EF ()D

Ž ‹EF „ YEJ$(pic=picolinic acid, dipic=2,6-pyridinedicarboxylic acid, nta=nitrilotriacetic acid). Y=‘ hetero ?@ gh peroxide

?@ A %  1’K “” •N5+

–—EJ"c,  b%=‘ AŠK   

  <=+ IEJ$. !D"= % peroxo transition metal   K    <

= ˜™š def 25 ›"6, L( P ./8 peroxideA substrate C E <9 sub- strateA peroxide E  Mœ L( b E U^ \ A5  <=A ž01H$. [ K …† ‡ˆ‰= €E5 › $t  L(

peroxo   ()D"= 1’K Ÿ+ r

5+ „ –—EJ$.  Ž  +

E substrate=  8 thiolato-cobalt(III)  Q     Y ¡¢ pK sub- strate= %Q H²O2 EF  01 sulfenato- cobalt(III)+ U4K$.⁷

  £ cobalt  Q & $t ¤v

 `9 ¥ ¦§ ¨+ O 2"©=,  <

ª  b  ™ ¡¢ E$. D"=

  `9 7{K tetraperoxo vanadium(V), V(O2)43− thiolato-cobalt(III)    {4 D"= –—0-$.  Y tetraperoxo transition

metal   4 K « ¬­ Y b=

®¯°5 ;± r8 D ²-$.

 

  .  8 n³%, V²O5, Co(ClO4)2´ 2H2O, ethylenediamine, picolinic acid, 2,6-pyridinedi- carboxylic acid, nitrilotriacetic acid µQ Aldrich

Y¶EF {I²  EJ$. Œ Y UV-vis }§= Shimadzu UV-2401PCA  0-$.

K2[VO(O2)(nta)] .¹⁶ V2O2(2 g) KOH(4 g) + 20 mL  · ³ 70^oC= A¸EF ¹˜K

K º»¼  ,1½$.   nitrilo- triacetic acid(4.2 g)+ ZL¾ aAE¿ HK ÀÁ¼

"= lEJ$.   Âà ( ³ 2^oC {)= Ä&EJ$.   30% H2O2+ K ˆ ž aAEF ÆQ VÇ5 ¼  ,-$. 

 ³ 10 mL ÈÉ aAE ÆQ VÇ5

¼ Ê Ë¿ &U b{ U4Ì Í°5 ³ 5-6

!? ŽP Îxn#$. ,1H b{Q ÈÉ= Ï Ð £ ÑZnÒ$.

K2[VO(O2)2(pic)] .¹⁷ V2O5(3.6 g), KOH(6.0 g)  picolinic acid(5 g)+ 60 ml Îh Á J$.   ³ 2^oC= Ä&n# £ ³ 30 ml

H2O2(30 %)+ K ˆÅ¾ aAEJ$. ³ 2^oC= EG {) Ä&nw¿ ÓÔ¼ Õ  U48$.  Õ

ÈÉ ÖS= ÏÐEF ÑZnÒ$.

K[VO(O2)(dipic)(H2O)] .¹⁸ ³ 70^oC Îh (100 ml) V²O5(4.5 g) 2,6-pyridinedicarboxylic acid(4.8 g) ÁJ$.   2^oC {)= Ä&n#

£ 30% H2O2(3 ml)+ KˆÅ¾ aAEJ$. ‚ *^

 KCl  ÆQ ¼ Õ  ×Ø Í°5 

š aAEJ$. Õ  U40 n€E¿ Õ

 U4 ÙÚÌ Í°5 ³ 2^oC P)+ p5EJ

$. ,1H Õ Q ³ 40^oC  ÁF ¯b{n

# £ ÈÉ ÖS= ÏÐK £ ÑZnÒ$.

[(en)2Co(SCH2CH2NH2)](ClO4)2 .¹⁹ Thiolato- cobalt(III)   bis(ethylenediamine)(2-mercap- toethylamie-N,S)cobalt(III) Nosco Dentsch 

4Û EF ܄01½$. Co(ClO4)2´H2O(15 g) Îh 60 ml Á £ ³ 30}| N²‰= bub- bling nÒ$.   ethylenediamine(8.5 ml) Ý Ýš aAE¿ VÞ5¼ Õ  ×ß$. [ $t

„à cystamine´2HCl(4.8 g) Îh 30 ml Á

 N² ‰= 30}? bubblingEJ$. \ 

á1 30}? N2‰= bubblingnÒ$. Í HK HClO4(7.5 ml)+ aAE filteringnÒ$. HClO⁴(12 ml)+ âA= filtrate aAE ã{¼ b{ U4 Ì Í°5 ³ 2^oC= Ä&nÒ$. U48 ã{¼ b{

Q ÈÉ= ÏÐ £ ³ 50^oC Îh ÁF ¯b {n# £ ÑZnÒ$.

[(en)2Co(S{O}CH2CH2NH2)]²⁺ .²⁰ Sulfenato- cobalt(III)   bis(ethylenediamine)(2-sulfenatoe- thylamine-N,S)cobalt(III) thiolato-cobalt(III) 

  ³ 10.  + no 365 nm ¦§)+ ž{EF b{EJ$.

K3[V(O2)4] .²¹ Œ Ž ;±   8 NaOH ä KOH+  EF tetraperoxo vanadium (V)+ ,-$. V²O5(3 g) KOH(10 g) 30 ml Î h Á £ ³ 2^oC {)= Ä&nÒ$.  

 H2O2(60 ml)+ š aAE¿ HK rj¼ 

 ,1H$.   EG {) ³ 2^oC{)=

p5nw¿ HK rj¼ Õ  U40-$.  Õ

 åæg= åt £ ÈÉ ÖS= ÏÐK

£ ÑZnÒ$.

 . ‡ç ()D ŽQ 23^oC

pH 4.0(0.01 M acetate buffer) Ùè  H é0-$(V(O²)43− <9 0.01 M [OH⁻]  

 Hé0-$). Peroxo vanadium(V)   thiolato- cobalt(III) Q ×4  sulfenato-cobalt(III)

U4 365 nm ž{EJ$. Œ Y initial

rate method+ EF ¦§) l + ž{EF 

()*+ YEJ$.²²



pH 4.0   peroxo vanadium(V)  , VO(O2)2(pic)²⁻ VO(O²)(nta)²⁻ VO(O²)(dipic)⁻

ÁJ <9, %Q *êš {Ec 320 nm

440 nm   ¦§)+ O$. Thiolato-cobalt(III)  Q % Ï peroxo  % K  

  ‹EF sulfenato-cobalt(III)  = l K$.

Peroxo-V(V) + [(en)2Co(SCH2CH2NH2)]²⁺ë V(V)-product + [(en)2Co(S{O}CH2CH2NH2)]²⁺

!D"= sulfenato-cobalt(III)  Q ¨(~

sulfinato-cobalt(III)  , (en)2Co(S{O}2CH2CH2NH2)²⁺

=  05ì,²⁰  () thiolato-cobalt(III)A sulfenato-cobalt(III)=  0 « ¬­  ()

„EF *D"= `9 í©= în01z  2"

c Œ ŽZÑ) –—0155 ›$. pH 4.0

  thiolato-cobalt(III) sulfenato-cobalt(III)  Q $à ïQ ¦§)+ O$: thiolato-Co(III) (283 nm, 11,700 M⁻¹cm⁻¹); sulfenato-Co(III)(365 nm, 6400 M⁻¹cm⁻¹). Fig. 1 ï, [peroxo-V(V)][thiolato- Co(III)] vs initial rate ðñ Cò 6óôc i j    Q peroxo vanadium(V)

thiolato-cobalt(III) EF && 1Ÿ $.

d Sulfenato Co III[ – [ ]] ---dt

=k[Peroxo V V– ( )][Thiolato Co III– [ ]]

Fig. 1. The plots of [Peroxo-vanadium(V)][Thiolato-cobalt (III)] vs initial rate. inset; (A)VO(O2)(nta)²⁻; (B) VO(O2) (dipic)⁻.

Table 1 Ï peroxo  % Ž ZÑ º

()(initial rate)% 6óô-$.  Ùb8 £ U48 sulfenato-cobalt(III)   yield 365 nm

 ¦§)+ ž{EF b{0-"c ‡\ 90%*

,1½$.

[VO(O2)2(pic)]²⁻ . Bidentate ?@ pic

\ ] peroxide ?@A b01 2 VO(O²)2

(pic)²⁻ pH 4.0  ÁJ Í 328 nm

¦§)+ O$(ε328= 973 M⁻¹cm⁻¹). VO(O2)2(pic)²⁻

 Q Fig. 1 ï [VO(O²)2(pic)²⁻][thilato- Co(III)] vs initial rate ðñ Cò 6óôc,  ðñ Å=‘(35±1) 2Ÿ () *(M⁻¹s⁻¹)+

,-$.

[VO(O2)(nta)]²⁻ . Tetradentate ?@ nta

 bE 2 VO(O²)(nta)²⁻ E6 oxo

peroxideA b01 2 monoperoxo  = ` 9 {EF, 4 ª M4   15! 

* }~05 › {ET õ¯K$. pH 4.0 

  VO(O²)(nta)²⁻ 429 nm ¦§)(ε⁴²⁹=

340 M⁻¹cm⁻¹)+ 6óôc thiolato-Co(III)  

(4.8±0.4)'10⁻² 2Ÿ () *(M⁻¹s⁻¹)+ , -$(Fig. 1(A)).

[VO(O2)(dipic)]⁻ . Tridentate ?@ dipic

 b01 2  monoperoxo  Q oxo group

 trans /N H²O }A ³ET b01 2$.

  ) pH 4.0   `9 {Ec 431 nm 330 M⁻¹cm⁻¹ ¦§¨+ O$. Fig.

1(B) ï thiolato-cobalt(III)  [VO (O2)(dipic)⁻][thiolato-Co(III)] vs initial rate ðñ

Å=‘(8.7±0.5)'10⁻⁴ 2Ÿ () *(M⁻¹s⁻¹) A ,1½$.

[V(O2)4]³⁻ .   Q 4 ª ³ö4

  `9 7{EF {™K ¦§¨+ , 5 ÷EJ"6,  ö4 ÎAø» {4

 ÎAEF 560 nm ³ 270 M⁻¹cm⁻¹ ¦§ ¨ + ,-$([OH⁻] = 0.01 M). ö4([OH⁻] = 0.01)

  V(O²)43− thiolato-cobalt(III) 

nÒ Í 365 nm sulfenato-cobalt(III) U 4 –—0-$. [K ù thiolato-cobalt(III)    0- <9 U48 sulfenato-cobalt(III)   úQ  8 V(O2)43−ú 2. * ,1½

$. û, E6 V(O²)43− \ ] * sulfenato-cobalt (III)  U4K$. ü6   ()D

Ž b }ýQ Mþ8 |! ZÑ Ž ! {K ÿ ,5 ÷EJ"c, ij   

 () *+ b{E
ŽEJ$.

pH 4.0   H2O2 K thiolato-cobalt (III)      Q 1.2 M⁻¹s⁻¹ ( ) *+ O$.²³ û diperoxo   VO(O²)2

(pic)²⁻   () H2O2 K r$ ³ 30 . * RS$. ü6 monoperoxo   VO(O²) (nta)²⁻ VO(O²)(dipic)⁻ <9 H²O2r$ && 20.

 1000. * í†     –—0 1H$. ij Œ Y bì"=  Í, L(P

 b8 hetero ?@ ghì ¡j b8 peroxide ) peroxide ?@ 34  “”

Ü$ ×&ø  2$. ü6 peroxo molybdenum (VI)   <9, b8 peroxide ?@ 34 Table 1. The observed initial rates for reactions of peroxo-

vanadium(V) and thiolato-cobalt(III) in Aqueous solutions [Peroxo-V(V)]/M [Thiolato-Co(III)]/M Initial rate/Ms^-1

[VO(O2)(nta)]²⁻

1.03×10⁻³ 1.00×10⁻⁴ 5.98×10⁻⁹ 1.72×10⁻³ 1.67×10⁻⁴ 1.24×10⁻⁸ 3.09×10⁻³ 3.00×10⁻⁴ 3.88×10⁻⁸ 4.12×10⁻³ 4.00×10⁻⁴ 8.91×10⁻⁸ 5.15×10⁻³ 5.00×10⁻⁴ 1.19×10⁻⁷

[VO(O2)2(pic)]²⁻

0.85×10⁻⁴ 0.27×10⁻⁴ 4.46×10⁻⁸ 1.82×10⁻⁴ 0.67×10⁻⁴ 3.90×10⁻⁷ 1.97×10⁻⁴ 1.33×10⁻⁴ 8.26×10⁻⁷ 2.02×10⁻⁴ 2.00×10⁻⁴ 1.34×10⁻⁶ 2.96×10⁻⁴ 2.00×10⁻⁴ 2.06×10⁻⁶ 4.23×10⁻⁴ 2.00×10⁻⁴ 2.94×10⁻⁶

[VO(O2)(dipic)]⁻

9.44×10⁻⁴ 8.02×10^{−4 0}9.00×10⁻¹⁰ 1.60×10⁻³ 1.14×10⁻³ 1.96×10⁻⁹ 1.97×10⁻³ 2.10×10⁻³ 3.69×10⁻⁹ 2.40×10⁻³ 1.23×10⁻³ 3.18×10⁻⁹ 2.40×10⁻³ 1.85×10⁻³ 4.47×10⁻⁹ 2.96×10⁻³ 2.10×10⁻³ 5.70×10⁻⁹ experimenal conditions: pH 4.0 (0.01 M acetate buffer), T=23^oC

 peroxide ?@  hetero ?@ gh

å “” 5 ›$.^7,10ü6  \ gh L ( PQ b8 peroxide ?@+ 34 nw Š

 ¥ Ÿ+ r$. V(V) diperoxo  

<9 b8 peroxide ?@+ `9 ³ET 34 n w5ì, monoperoxo   <9 L( P b 05 ›Q p=q H2O2r$ s í†  r$.

¿ Mo(VI) <9 peroxide  hetero ?

@ gh “” 5 › H²O2r$ ³ 900.

* Rt    r$. Table 2 

% \ L( P ‚ƒE 2 peroxo  %

    () *+ „EJ$. b 8 peroxide+ ET 34 nw Mo(VI) <9 L( P K K 34 Š Í; b01 2 ?@% “” *D"= •³EF  ( ) ¥ “” ¢5 ÷K$ ×&01H$. V(V)

<9 L( P K 34 Š `9 ³Eå6 å ²"©=, b01 2 ?@% ghA ‰

 () “” •  2$. PeroxideA >

4©= peroxide ?@  ÎA peroxo   >4 ÎAn#$. [K hetero ?@

nta dipic <9, dipic s >BD ?@©=

nta ?@+ O2 peroxo   s K >

4 O$. [K &   ‰ E) ÃE

 peroxo   úE thiolato-cobalt(III)    () “”  2$. ŽI= Œ Ž

 b%Q {4D"= / ˜% !Nƒ r

$. ü6  && L( P% $t 34

Š r5  Ž bì"= ˜ø 

²-$.

Peroxo transition metal     K

 <=  K \ A5 AŠK 

<=+ žø  2$.

« ¬­  <=(i) substrateA peroxide

E  L( P  bE "=, ì³ L( P  [ ³K ./ + O2 5 › <9    !165 ›å6 *

D"= `9 í†  r! $. \ ¬­

 <=(ii) >4 peroxide ?@A >B4

 substrate C E <9=, L( P ¢/

  [ ³K ./ A õ¯E5 ›sj) 

   “” •N5 › $. VO(O2) (nta)²⁻  ./ + O25 ›"c, ‡ç ./

 ?@% L( P ET b01 2

 $. ¿ VO(O2)(dipic)⁻ oxo group

trans /N ³ET b012 H²O }+ O

2$. û E6  ./ + O 2$. ij

(i)  <=+ it$¿ VO(O2)(nta)²⁻  

  !"w5 ݌6  ./+ O 2

VO(O²)(dipic)⁻r$ í†  ž0156, Œ Ž

 b VO(O2)(nta)²⁻A VO(O2)(dipic)⁻r$ 50 . * Rt  r$. [K diperoxo   VO(O2)2(pic)²⁻)  ./ + O 25 ›"6

$t \ peroxo  r$ Rt  r$. Peroxo vanadium(V)   ïQ YZ+ O 2 Mo(VI)

 peroxo  ), ntaA b01 2 MoO(O²) (nta)⁻   dipic b012 MoO(O2)(dipic) r$ ³ 3. {) Rt  r$(Table 2). û peroxo    ./ A substrate 

  CD “” ¢5 ›$  d  2$. ij Œ Ž b=‘ peroxo  Q ./8 peroxideA substrate CD  E F     !16 \ ¬­(ii) 

 <=A ž01H$.

Tetraperoxo   V(O²)43− <9,  ]

Table 2. Comparison of rate constants for the oxidation of Thi- olato-cobalt(III) by peroxo complexes of vanadium(V) and molybdenum(VI)

Peroxo type

Peroxo complex

Rate constant,

M^-1s^-1 Reference Di [VO(O2)2(pic)]²⁻ 35 this work Mono [VO(O2)(nta)]²⁻ 4.8 × 10^-2 this work Mono [VO(O2)(dipic)]⁻ 8.6 × 10^-4 this work Di [MoO(O2)2(OH)]⁻ 2.4 × 10³ 7 Mono [MoO(O2)(nta)]⁻ 2.5 × 10³ 10 Mono [MoO(O2)(dipic)] 8.7 × 10² 10

H2O2 1.2 23

peroxideA side-on U^= b01 2 8./

dodecahedral YZ=   `9 7{E$.

 ŽQ di [ monoperoxo   $t YZ

 tetraperoxo  )     ‹E F thiolato-cobalt(III)  sulfenato-cobalt(III)  = lET E  ™EJ$. [K V(O²)43−

 thiolato-cobalt(III)    xD }

~ EF 560 nm V(O²)43− ¦§)A ‡\

 jH £) ¨(~ sulfenato-cobalt(III)   U4 –—0-$. Q « ¬­   £ U 4Ì "= ž0 triperoxo  6 diperoxo  % ¨(D   Í;"= ž8$.²¹ Tetraperoxo   thiolato-cobalt   ()

D Ž b }ý E5 ›T ì@ Q,

¡) tetraperoxo     7{

4 }~ { U4Ì  2 $t peroxo  % substrate (D  "= âž

8$.

Œ Y=‘ … ‡ˆ‰ [ …† ‡ˆ‰=

 AŠ4 O 2 peroxo vanadium(V)  %Q  r8   ì¹⁶ ¡j 

    ‹EF   !"#$

 d  2-"c,  Q L( P ./0 12 peroxideA substrate= CD  E F !1$  d  2-$.  …† ‡

ˆ‰ peroxo vanadium(V)  Q group VI

VII (K  L(% peroxo  (noninsulin- mimic)r$ ()D"= `9 í†   r

$. ij % peroxo vanadium(V)  % 

   <= ª ?@% “” 

 () –K Y 6 ‚ƒK =q  …† ‡ˆ‰ ]x `9 MEc, [K ®¯°5

˜™ET def 25 ›Q % …† ‡ˆ‰ ×

‰   <= ¡)   % 

Š ª  ()A MK ø ø "= âž

8$.

  

1. Connor, J. A.; Ebsworth, E. A. V. Adv. Inorg. Chem.

Radiochem. 1964, 6, 279.

2. Mimoun, H. In The Chemistry of Peroxides; Patai, S., Ed.; Interscience; New York, 1983; p 463.

3. Dickman, M. H.; Pope, M. T. Chem. Rev. 1994, 94, 569.

4. Butler, A.; Clague, M. J.; Meister, G. E. Chem. Rev.

1994, 94, 625.

5. Mimoun, H. Angew. Chem. Int. Ed. Engl. 1982, 21, 734.

6. Mimoun, H.; Mignard, M.; Brechot, P.; Saussine, L. J.

Am. Chem. Soc. 1986, 108, 3711

7. Ghiron, A. F.; Thompson, R. C. Inorg. Chem. 1988, 27, 4766.

8. Schwane, L. M.; Thompson, R. C. Inorg. Chem. 1989, 28, 3938.

9. Huston, P.; Espenson, J. H.; Bakac, A. Inorg. Chem.

1993, 32, 4517.

10. Won, T. J.; Sudam, B. M.; Thompson, R. C. Inorg.

Chem. 1994, 33, 3804.

11. Funahashi, S.; Uchida, F.; Tanaka, M. Inorg. Chem.

1978, 17, 2783.

12. Witt, S. N.; Hayes, D. M. Inorg. Chem. 1982, 21, 4014.

13. Kodota, S.; Fantus, I. G.; Deragon, G.; Guyda, H. J.;

Hersh, B.; Posner, B. I. Biochim. Biophys. Res. Com- mun. 1987, 147, 259.

14. Shaver, A.; Ng, J. B.; Hall, D. A.; Lum, B. S.; Posner, B. I. Inorg. Chem. 1993, 32, 3109.

15. Posner, B. I.; Faure, R.; Burgess, J. W.; Bevan, A. P.;

Lachance, D.; Zhang-Sun, G.; Fantus, I. G.; Ng, J. B.;

Hall, D. A.; Lum, B. S.; Shaver, A. J. Biol. Chem.

1994, 269, 4596.

16. Won, T. J. J. Korean Chem. Soc. 2000, 44, 1.

17. Quilizsch, U.; Wieghardt, K. Inorg. Chem. 1979, 18, 869.

18. Wieghardt, K. Inorg. Chem. 1978, 17, 57.

19. Nosco, D. L.; Deutsch, E. Inorg. Synth. 1982, 21, 859.

20. Adzamali, I. K.; Libson, K.; Lydon, J. D.; Elder, R. C.;

Deutsch, E. Inorg. Chem. 1979, 18, 303.

21. Won, T. J.; Barnes, C. L.; Schlemper, E. O.; Thompson, R. C. Inorg. Chem. 1995, 34, 4499.

22. Espenson, J. H. Chemical Kinetics and Reaction Mech- anisms; McGraw-Hill: New York, U.S.A., 1995; p 8.

23. Adzamli, I.; Deutsch, E. Inorg. Chem. 1980, 19, 1366.