S Y N T H . R E A C T . I N O R G . M E T . - O R G . C H E M . , 32(3), 489-508 (2002)
PREPARATION AND CHARACTERIZATION OF NEW In(III), Re(III), AND Re(V) COMPLEXES WITH THENOYLTRIFLUOROACETONE AND SOME BIDENTATE HETEROCYCLIC LIGANDS 1
Refaat M. Mahfouz, * Khalid A. Al-Farhan, Gamila Y. Hassen, Abdulaziz I. Al-Wassil, Saad M. Alshehri, and Ami A. Al-Wallan 2
1
1
1
1
'Department of Chemistry, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia d e p a r t m e n t of Chemistry, Faculty of Science, Alexandria University, Egypt
ABSTRACT New In(III), Re(III) and Re(V) complexes with the thenoyltrifluoroacetone ligand ( H T T A ) of the general formulae [In( n A ) ( H 0 ) ] S 0 , [ R e ( T T A ) ( H 0 ) ] C l . and [ReO(TTA) _( H 2 0 ) ] C l . (where n and x refer to the number of [TTA] moieties and H ? 0 molecules, respectively) have been prepared 2
x
4
3
4
n
2
x
3
n
n
*Corresponding author. E-mail:
[email protected] 489
n
MAHFOUZ ET AL.
490
and characterized by spectroscopy, thennogravimctry, elemental analyses and X-ray diffraction. The charge densities on the ligand atoms were calculated via C N D O - S C F calculations. The newly prepared complexes [ I n ( T T A ) ( H 0 ) ] S 0 2 and [ R e 0 ( T T A ) ( H 0 ) ] C L were employed as precursors for the synthesis of the mixed-ligand complexes [In(TTA)(HOCTA) ], [In(TTA)(TZT) ] and [RcO(TTA)(HOTCA)]Cl using R(-)-2oxothiazolidine 4-carboxylicacid ( H O T C A ) and IH-1,2,4triazole-3-thiol ( H T Z T ) as ligands. The synthesized mixedligand complexes were characterized by the conventional physical and chemical methods of analysis applied earlier for the characterization of the precursors. T h e investigated complexes are soluble in water, ethanol and acetonitrile, insoluble in non-polar solvents and could be of potential use for clinical studies. The antibacterial activity of the investigated complexes has been tested and evaluated. 2
2
2
[n(III), Re(III), AND Re(V) COMPLEXES
491
techniques of analysis and their antibacterial activity was tested. No previous work concerning the preparation of these complexes has been reported.
4
EXPERIMENTAL
2
2
Materials and Instrumentation
2
2
2
All chemical used were of analytical grade and were used without further purification. IR spectra were recorded in K B r pellets on a Perkin Elmer F T - I R spectrometer. "Spectrum 1000". UV-Vis spectra in ethanolic solutions were recorded on a Cecil 599 spectrophotometer using 1 cm matched silica cells. 'H and C N M R spectra were measured in D M S O - d as solvent on a J E O L N M R 400 M H Z spectrometer. Elemental analyses were carried out on a Perkin Elmer 2400 C H N S O elemental analyzer. I i d i u m contents in the investigated indium complexes were determined by the analytical laboratory at SABIC (R&D) (Saudi Arabia). TG measurements we e carried out using a Netzsch STA-429 thermal analyzer. The weight loss was measured from ambient temperature up to 700 ° C ' a t a heating rate of 10 ° C / m i n . X-ray diffraction patterns of the complexes were recorded using a X R D 5000 Siemens diffractometer with Cu-target. , 3
6
r
INTRODUCTION Metals offer many opportunities for designing radiopharmaceuticals by modifying the environment around the metal and allowing specific in vivo targeting to be incorporated into the molecule. The coordination compounds of certain transition metals have wide applications as pharmaceuticals and radiopharmaceuticals. Important considerations in the design and use of the complexes in biological systems were their stability and behavior in biological o r g a n s . Many " ' i n and R e chelates were successfully applied as radiodiagnostic and radiotherapeutic agents. F o r instance, " ' i n D T P A is used for radiographic cisternography studies (evalution of cerebral spinal fluid pathways) , " ' i n - O x i n e (indium In 111 oxyquinoline solution, Amersham International) has been approved for the labeling of leukocytes (white blood cells) which are used for imaging sites of infections or inflammations . R e - D M S A displays selective uptake in tumors of kidney tissue analogous to that of the Tc species and offers the possibility of therapeutic treatment of this disease . It has been, therefore, a great impetus for researchers to explore the synthesis of new indium and rhenium, complexes using new classes of aliphatic or alicyclic ligands. In the present study new complexes of indium and rhenium have been prepared using thenoyltrifluoroacetone and other ligands containing NS or NO donor sites. The complexes were characterized using conventional physico-chemical 1 - 5
General Method for the Preparation of [Re(TTA)(H 0) ]Cl (1), [Re(TTA) (H 0) ]Cl (2), [ R e O ( T T A ) ( H 0 ) | C l (3), [ReO(TTA) ]Cl (4), and [ I n ( T T A ) ( H 0 ) ] S 0 (5) 2
2
2
2
2
2
2
2
4
2
2
4
4
1 K 6
The amounts in mmoles of R e C l , ReCls, I n ( S 0 ) (anhydrous) and H T T A required for the preparation of 1:1 and 1:2 metahligand molar rations complexes are listed in Table I. 3
2
4
3
6
7
Table I.
Stoichiometric Amounts of the Reactants
l 8 6
6
Type of the Complexes (1) (2) (3) (4) (5)
[Re(TTA)(H 0) ]Cl [Re(TTA) (H 0) ]Cl [RcO(Tf A)(H 0) ]C1 [ReO(TTA) ]Cl [ln(TTA)(H 0) ]S0 2
2
4
2
2
2
2
2
2
2
4
4
2
[HTTA] mmol (g)
[ReCl ] mmol (g)
1 (0.222) 2 (0.444) 1 (0.222) 2 (0.444) 1 (0.222)
1 (0.292) 1 (0.292)
3
[ReCl ] mmol (g) 5
[In (S0 ) ] mmol (g) 2
4
3
1 (0.363) 1 (0.363) 1 (0.517)
MAHFOUZ ET AL.
492
The required amounts of metal salt were dissolved separately in 10 mL water and added dropwise to l O m L of an ethanolic solution containing the corresponding amount of H T T A while stirring. The reaction mixture in each case was rciluxed for about an hour while a few drops of acetate buffer (pH « 5) were added dropwise to the reaction mixture. A solid product in each case was precipitated. The solutions were rotary evaporated to about 1/3 of the total volume and these allowed to stand in air over night. The resulting solid products were collected and washed several times with diethyl ether.
[n(Hl), Re(III), AND Re(V) COMPLEXES
493
indium or rhenium salts were dissolved separately in 10 mL water. T h e amounts of H T T A / H O C T A or H T T A / H T Z T in ethanol (10 mL) were added slowly with stirring to the aqueous metal ion solutions while stirring with the addition of few drops of acetate of few drops of acetate buffer solution of p H « 5 . The reaction mixture wasrefluxed as previously to give solid products analogous to those obtained starting with the precursors I n ( T T A ) ( H 0 ) ] S 0 (5) and [ R e O ( T T A ) ( H 0 ) ] C l (3). 2
2
f
2
4
4
2
2
2
RESULTS AND DISCUSSION General Method for the Preparation of |In(TTA)(HOTCA)J (6), IIn(HTTA)(HTZT) l (7), and [ReO(TTA)(HOTCA)]Cl (8)
T h e metal complcxation reactions were carried out according to the following equations:
2
The stoichiometric molar amounts in mmoles of the precursors [ l n ( T T A ) ( H 0 ) ] S 0 (5), [ R e O ( T T A X H 0 ) ] C l (3), the ligands H O T C A and H T Z T required for the preparation of complexes (6), (7) and (8) are listed in Table II. The calculated molar amounts of the precursors were dissolved separately in 10 mL water and added dropwise to the ethanolic solutions (10 mL) of the ligands while stirring. The reaction mixture was heated under reflux for an hour and the volumes were reduced to about I /3 of the total volumes by rotatory evaporation. After standing over night solid products were precipitated, which were collected and washed with diethyl ether. 2
4
4
2
2
2
ReCl., + H T T A + 4 H 0 - [ R e ( T T A ) ( H 0 ) ] C l 2
2
4
2
(1) + HC1
2
2
5
Table II.
2
4
Stoichiometric Amounts of the Reactants H OTCA H TZT [In(TTA)(H 0) ]S0 mmol (g) mmol (g) mmol (g)
Type of the Complexes
2
(6) [In(TTA)(HOTCA) ] (7) [In(TTA)(HTZT) ] (8) [ReO(TTA)(HOTCA)]CI 2
2
2 (0.3) 2 (0.2)
2
1 (0.15)
2
4
4
(ReOfTTA)(H 0) ]CI mmol (g) 2
2
2
ReCl + H T T A + 2 H 0 + ^ 0 - [ R e O ( T T A ) ( H 0 ) ] C I (3) + HC1 + CI 5
2
2
ReCls + 2HTTA + - 0
2
Comparison experiments were carried o u t for preparation of the complexes (6), (7), and (8) starting from the initial reagents, H T T A , H O C T A , H T Z T , R e C l and I n ( S 0 ) 3 . The stoichiometric amounts o f 2
2
2
2
2
2
-. [RcO(TTA) ]Cl (4) + 2HC1 + C l 2
2
2
I n ( S 0 ) , -I 2 H T T A + 8 H 0 -> 2 [ I n ( T T A ) ( H 0 ) ] S 0 (5) + H S 0
Comparison Experiments for Preparation of the Mixed Ligand Complexes
2
ReCh 4- 2 H T T A + 2 H 0 -» [ R e ( T T A ) , ( H 0 ) ] C l (2) + 2HC1
2
1 (0.53) 1 (0.53)
2
4
2
2
4
4
2
4
The microanalytical data of the investigated complexes are tabulated in Table III. Thenoyltrifluoroacetone. molecule (HTTA) has t h e , following tautomeric forms (Fig. 1) . . The charge densities calculations were performed via C N D O - S C F calculations in the singlet electronic ground state configuration (Fig. 2). The calculations indicated that the oxygen atoms of the carbonyl group (atoms N o . 10 and 14) exhibit higher values of electronic charge densities and would, accordingly, be favorable sites for coordination of In(III), Re(III), and Re(V) with the ligand . 8
Spectroscopic Measurements 1 (0.53)
The investigated complexes were subjected to extensive spectroscopic investigations using a combination of spectroscopic techniques.
Table III.
Analytical Data of the Investigated Complexes" Found (Calculated) Formula Weight
Empirical Formula
Complex (1) [Re(TTA)(H 0) ]Cl
2
C H, Cl, F 0 RcS
(2) [Re(TTA) (H 0) ]Cl
C, H, C1 F 0 R e S
2
2
4
2
2
(3) [ReO(TTA)(H 0) ]Cl 2
2
2
6
2
2
3
2
6
6
6
8
8
2
6
2
(5) [In(TTA)(H 0) ]S0 4
4
3
5
8
6
5
C Hi F InOioS 8
2
3
:
2
(6) [In(TTA)(HOTCA) ]
C| H F InN 0 S
(7) [In(TTA)(HTZT) ]
C H F InN 02S;,
2
2
2
C H Cl F 0 ReS C, H ClF 0 ReS
(4) [ReO(TTA) ]Cl 2
s
6
12
12
9
3
2
3
8
3
6
Yield
Decom. Temp
Colour
550
61
>300
White
700.10
50
>300
530.41
43
>550
680.06
42
>280
504.12
49
>270
628.29
52
>300
537.19
50
>300
1 8 ) IReO(TTA)(HOTCA)Cl)--CTjHgOFjNOeReSr -664T9£ -
-45 -- ^300
C
17.88 (17.46) 27.65 While (27.45) White 18.47 (18.12) White 28.13 (28.26) 18.88 Reddish while (19.06) White 30.72 (30.58) 27.12 While (26.83) White-- - 2X57— (23.82)
H
N
— 2.06 (2.20) 1.49 (1.73) 1.76 (1.52) 1.26 (1.18) 2.23 (2.39) 1.78 4.58 (4.46) (1.91) 15.32 1.81 (1.69) (15.64) _L48_ _ 2 J 9 _ (2.31) (1.33)
In-
-
28.03 (27.77) 18.11 (18.27) 21.58 (21.37)
—
a
[Re(TTA)(H 0)4]Cl2, tetraaquothenoylirifluoroacetonerhenium(III)chloride; [Re(TTA) (H 0) ]Cl, bis(aquo)bis(ihenoyltrifiuoroacetone)rhenrum(III) chloride; [ReO(TTA)(H 0) ]Cl , bis(aquo)bis(lhenoyItrifluoroacetone)monooxorhenium(V) chloride; [ReO(TTA) Cl2, bis(thenoyltrifluoroaceione)monooxorhenium(V) chloride; [In(TTA)(H 0) S0 . letraaquothenoyltrifluoroacetoneindium(III) sulphate, [In(TTA)(HOTCA) ], bis(oxothiazolidine-4-carboxylic acid)thenoyltrifluoroacetone indium(HI)complex; [In(TTA)(TZT) ], bis(triazole-3thiol)thenoyltrifluoroacetoneindium(III) complex, [ReO(TTA)(HOTCA)]CI, oxothiazolidine-4carboxylic acid thenoyltrifluoroacetonerhenium(V) chloride. 2
2
2
2
2
2
2
2
2
2
4
4
2
>
cN c
PJ
H
> r
MAHFOUZ ET AL.
496
at 3.45 ppm relatives to T M S which arc assigned to the = C H (cnolic) protons and coordinated water, respectively. The signal at 8 3.7 ppm was assigned to the C H ketonic protons. The signals due to the thiophene ring protons were observed in the range 5 7.23—7.99 ppm. The C N M R spectrum of [ I n ( T T A ) ( H 0 ) ] S 0 4 (5) shows a signal due to C = 0 in the range 189—191 ppm. The signals due to the thiophene ring and C F carbon atoms were observed in the range 8 144—129 ppm. No N M R signals were recorded for the investigated rhenium complexes, which provide an evidence for the paramagnetic properties of the complexes. It is worthwhile to mention that high-spin behaviour is rarely observed in the 4d and 5d series of transition metals. Electronic absorption spectra of the complexes were measured at ambient temperature in ethanolic solutions. The solutions of the complexes exhibit n-n* intraligand transition bands with absorption maxima ( X ) in the range of 212—213 nm. Another absorption band due to a n-7t* intraligand transition with X in the range of 260—267 nm was observed in the spectra of the complexes. The electronic spectra of the Re(III) complexes show some d-d transitions with 336 nm and 335 nm absorption maxima for [ R e ( T T A ) ( H 0 ) ] C l and [ R e ( T T A ) ( H 0 ) ] C l , respectively. Since H T T A is a relatively weak-field ligand, and distorted octahedral Re(III) complexes are high-spin and the d-d transition for [ R e ( T T A ) ( H 0 ) l C l and [ R c ( T T A ) ( H 0 ) ] C I ( I ) c o u l d b e assigned t o the E - > T t r a n s i t i o n " ' . The distorted square-pyramidal structure for the [ R c O ( T T A ) ( H 0 ) ] C l (1) and [ReO(TTA)]Cl (4) complexes show also some d-d transition band attributed to the T | — > T transition similar to [VO(acac) ] (bisacetylacetonatovanadyl) where acac is acetylaceton. A feature of square-pyramidal structures is that there is the possibility of an additional ligand occupying the vacant axial site to produce six-coordinate complexes. This possibility has been tested by the small variations that have been observed in the electronic spectra of both [ R e O ( T T A ) ( H 0 ) ] C 1 (3) and [ReO(TTA) ]Cl (4) in different solvents that are believed to be caused by a solvent molecule being weakly binding at the sixth coordination site. There is evidence that good donor solvents sometimes also introduce a ligating a t o m cis to the rhenyl o x y g e n . ' A ligand to metal charge transfer band ( L M C T ) at X 336 nm was recorded for [ I n ( T T A ) ( H 0 ) ] S 0 . This charge transfer band could be assigned to transition from the weakly bonding n orbitals on the ligand to the anti bonding t or e* orbitals of the metal ion. It should be mentioned that the change of solvent influences the position of the charge transfer band. This influence may be attributed to some inherent polarity for the asymmetric geometry of the complex. T h e UV-Vis spectrum of the investigated complex [ I n ( T T A ) ( H 0 ) ] S 0 (5) was compared with that of the free
In(III), Re(III), AND Re(V) COMPLEXES
497
ligand in order to distinguish between the charge transfer band of the complex and the intraligand band. The spectroscopic data of the prepared complexes are summarized in Tables IV—VI.
2
1 3
2
4
Thermogravimetric Analysis
3
Thermal decomposition behaviour of the investigated complexes was followed using thermogravimetric (TG) and differential thermogravimetric ( D T G ) techniques. The decomposition occurred in one or more steps depending on the type of the complexes investigated. Table VII summarized the results of thermal decomposition of the investigated complexes. T h e decomposition ends with the formation of the metal oxides l n 0 or R e 0 . 2
3
2
3
m a x
Determination of Reaction Order of the Decomposition
m a x
2
4
2
2
2
2
2
s
2
4
2
2
10
2
Cs r= (W - Wf)/(Wj - Wf)
2 g
2
4
2g
was applied for the determination of the reaction ordcr(n) of the decomposition. Here W stands for the weight remaining at a given temperature T , i.e., the D T G peak temperature W and W are the initial and final weights
2
2
2
2
:nax
4
4
2g
2
4
4
s
s
:
Table IV.
r
UV-Vis Spectroscopic Data of the Investigated Complexes
2
13
2
(1)
s
2
3
g
n
2
5
g
5
1 / 1
The Horowitz and Metzger equation, Cs = ( n ) ~ where Cs is the weight fraction of the substance present at the D T G peak temperature, Ts, is given as
C o m
P
l c x
K»Ae,
(I) [Ri:(TTA)(H 0) ]Cl (2; (Re(TTA) (H 0),]Cl (3) [ReO0TA)(H O) ]Cl (4) [RcO(TTA) ]CI (5; [In(TTA)(H 0) JS0 (6; [In(TTA)(HOTCA) ] . (7) f!n(TTA)(HTZT),] (8) [RcO(TTA)(HOTCA)]CI 2
2
4
212 (250) 212 (410) 212 (410) 213 (380) 264 (710) 205 (320) 202 (470) 203 (390)
2
2
2
2
2
2
2
4
4
2
a
2
3
3
UV-Vis L m o r cm-'Y 1
264 (510) 265 (820) 260 (810) 267 (720) 336 (950) 225 (700) 263 (350) 263 (710)
336 335 336 33
(510) (800) (950) (950)
340 (300) 337 (220) 330 (900)
£ are in the range of 10 -10 for six-coordinate complexes of low symmetry (spinallowed, Laporte-forbidden).
Table V.
IR Spectroscopic Data of the Investigated Complexes IR(cirT') v(C=0) vC(=0), v(OH) v(C-O) sir. asym. v(M-O) v(M-N) v(M-S) bending str. v(Re=0) v(SH)
Vstr
v(NH)
Complex
(H 0) 2
1560 s 1563 m 1582 m 1581s 1570 s 1578 m 1580 s 1597 s
(1) [Re(TTA)(H 0) JCl 3431 s (2) [Re(TTA) (H 0) ]Cl 3441 s (3) [ReO(TTA)(H 0) ]a 3431m (4) [ReO(TTA) ]Cl (5) [In(TTA)(H 0) ]S0 3411s (6) [In(TTA)(HOTCA) ] 3440 s (7) [In(TTA)(HTZT) ] (8) [ReO(TTA)(HOTCA)]Cl 3410 s 2
2
4
2
2
2
2
2
2
2
2
4
4
2
2
1416m 1412m
529 m 525 m 522 m 518w 528 m 619w 644 m 581m
923 s 920 s 463 w 549 w 462 m
1422s
1320s
1411m
1355s
2360 w
400 w 909s
C r K
> t-
>
e ft
Table VI.
U
'H and C NMR Data cf the Investigated Indium Complexes
3
'H NMR (ppm) Complex
l3
5(CH) enolic
(5) [In(TTA)(H 0) ]S0 (6) [In(TTA)(HOTCA),] (7) [In(TTA)(HTZT) ] 2
4
6.62 s 6.61 s 6.63 s
4
2
( U ^ t e ^ I S ?q, 5i 5 Hz) a
S
h
tWO S i g n a
S
' ^
6
5 thiophene ring
5 (H 0)
8 (CH) ketonic
C NMR 5 (C=0)
7.23 (t, J = 4Hz), 7.99 (t, J = 4Hz) 7.24 (t, J = 4 Hz), 7.98 (t, J = 4 Hz) 7.24 (t, J = 4Hz), 7.97 (t, J = 4 H z )
3.45 s
3.7 s 3.71 s 3.69 s
190 s 191 s 192 s
6
'
9 4 P P m ( S
'
C
H
2
e n 0 i i C )
' ^
t h i
°P
h e n e r i
« g P^tons appears at 6 7 ^
no 2 r w X M v.
MAHFOUZ ET AL.
500 oo
oo oo O N oo ON O N O N O N ON
O
o
o
O N ON ON
O
o o
14
_ , .— — »n C N CN C N cN
O .—. CN —' NO ~ r~- CN CN CN > 0 OO o o IRI h « ) » N T » N
VI
< c c - E
501
of substance, respectively. The calculated values of Cs are in range 0.3—.04 which indicates that the decomposition follows first order kinetics for both the dehydration and the main decomposition s t e p s . For a first order process the following Coats-Redforn and HorowitzMetzger equations were applied for determination of activation energy E and Arrhenius constant, A, of the d e c o m p o s i t i o n .
iri c o oo C O O N in
r— m r~ r~- w~> oo
In(III), Re(III), AND Re(V) COMPLEXES
1
CM
ci
'/*N — r-; CM
r ^ N O O N N O o c O N c c ' ^ i
a
14,15
i
*
NO
o
ON
^
ON
~
C l ON
—'
NO
ON
ci
ON
CI
CN
ON
rNl
«
NO
ON
^ — ^ u n — ^ C I N O C I O C ^ O N N O O N N O N O N O O N
O o -» — "2 -r
O S
n
o
ON
•ln(l-«)l In
* o X g
CM
CN
uri »AI
oo C N o o c i o o O N
i/i
W)
CN
CN
—
CN
oo
O
ON
•—«
ON
M
0 3 rl C O • — • O ' — CN OO N O 0 0
^ O
«£
^
•—;
ON
ON
rO
-
ON ON
-
n
"
ON»—
T
CN " T O
2
!
- E ^ A R
RT
(pE
( 2 )
a
Wl N O ' A OO
l n [ ~ l n ( l - a ) ] = ^ l ^
ON "~\ C I O NT ON
CN O 0 O ^
(3)
T 7 T 7 7 7 7
6o
/here a is the fraction decomposed at time t and is given by
U
X)
c> ^ & ^ ^ S M - i m CM J »
« o
—
CM
~
CM
—
CM
—
CN
—
CN
m
u-i C N
O C N NO c > i n
CN
—
CN
—
n
-
m .
CN
m - m Q
•a c
0
0
s
P
- £
-t
5
* s «
m m —. i n
a
w
5
n NO
N
NT t—
t »I r> "I OO - J, I ^T O ^T (M
U
s
-C
o
o. o
o
ci
O
o p
p
o
o c i " 3 - c; cN £ C N w"> C N "j> < N wj> > «R
ft c o
© n CN
8
o
o
o
o
o >r\
r o >n
7 7. 7N O o
o
CI NT OO — CI CN
o
M
o © O
B)
Q «
Si op
CO
>-
•o
*o
U, c/5 H« co
0
54
O
O X
x
0.95) is computed using the least-square method for eqs. (2) and (3). The activation entropy, S*, the activation enthalpy H* and the free energy of activation G* were calculated using the following equations. Q
•2 a « s
O IX,
o 2 Q
f
< O
c
u
0«
S
K and h are the Boltzman and Planck constants, respectively. The temperature T involved in the calculations was selected as the temperature at the end of the decomposition step. The calculated kinetic and thermodynamic value a/e reported in Table VII for the various decomposition steps.
MAHFOUZ ET AL.
502
The kinetic parameters, especially E and S*, are helpful in assigning the strength of the bonding of both water molecules and ligand moieties with the metal ion. The values of the major decomposition step of the studied compounds i.e., the stages of the decomposition to volatile products are in the range 220—285 k J i n o l which indicates that the ligand is strongly bound to the metal ion. The activation energy for the dehydration step of the complexes lies in the range 100—130 k J / m o l . These values are comparable of the generally accepted values of activation energy for coordinated w a t e r . T h e negative values indicate that the activated complexes have a more ordered structure than the reactants and that the complexation reactions are slower than n o r m a l . Two of the prepared complexes, [ I n ( T T A ) ( H 0 ) 4 ] S 0 (5) and [ R e O ( T T A ) ( H 0 ) ] C I (3), were employed as precursors for the preparation of mixed-ligand complexes using the following ligands in Fig. 3. a
- 1
In(III), Re(III), AND Re(V) COMPLEXES
503
Ligand atoms charge density calculations indicated that for the free ligand H O T C A the more attractive sites for coordination with In and Re atoms are the oxygen atoms of carboxylate ion (atoms N o . 11 and 12). The favorable coordination sites of the H T Z T ligand are suggested to be nitrogen atoms (atoms N o . 2 and 9). It was found that both [In(TTA)( H 0 ) ] S 0 (5) and [ R e O ( T T A ) ( H 0 ) ] C l (3) could undergo ligand exchange reactions according to the following equations. 2
2
2
4
4
2
2
2
16
[ I n ( T T A ) ( H 0 ) ] S 0 + 2 H O C T A - * [ I n ( T T A ) ( H O C T A ) ] (6) 2
4
4
2
2
17
2
2
2
+ 4H 0 + H S0
4
2
2
4
2
[ I n ( T T A ) ( H 0 ) j S 0 + 2 H T Z T - , [ I n ( T T A ) ( T Z T ) ] (7) + 4 H 0 2
4
4
2
2
+ H2SO4
( R e O ( T T A ) ( H 0 ) ' ] C i + H O C T A - ( R e O ( T T A ) ( H O T C A ) j C l (8) 2
2
2
+ 2 H 0 + HC1 2
The microanalytical, spectroscopic and thermal data of the investigated mixed ligand complexes are tabulated in Tables III-VII, respectively.
R(-)-2-Oxothiazolidine-4-earboxylic acid (H OTCA) 2
7
X-Ray Powder Data of IReO(TTA) lCl (4) 2
Complex (4) was subject to a preliminary X R P D study. A Siemens D5000 X-ray powder diffractometer, powered at 40 kV and 35 m A , was used for data collection. D a t a were measured by using C u K radiation (X = 1.54056A). The data were collected by the continuous scanning m o d e with a step width of 0.04 and a step time of 2 s. The intensity of the diffraction lines was measured as peak heights and expressed in percentage of the strongest line. T h e source of the initial cell parameters was the indexing program DICVOL9I [ M = 36, F = 58.4(0.0023,148)1 . The cell was checked and refined by the C H E C K C E L L p r o g r a m ' , a = 22.8091(3), b= 10.5554(1), c= 10.9527 (I) A, p = 115.786(1)°, V- 2374.40 A . Possible space groups are the monoclinic P2\ or P2\/m. T h e X-ray powder diffraction data are presented in Table VIII. a
18
2 0
20
9
I
H5
0.278
1H-1,2,4-Triazole-3-thiol (H TZT)
3
2
Figure 3.
Ligands for the mixed-ligand complexes.
Based on the foregoing discussion the following structures are plausible for the investigated complexes as seen in Fig. 4.
MAHFOUZ ET AL. Table VIII. No.
2e.,
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
8.075 8.959 11.640 12.930 16.553 17.118 17.726 18.253 19.246 22.721 23.139 24.163 25.262 25.826 26.595 27.014 2X.125 29.897 31.856 32.791 33.237 33.831 35.577 36.825 37.331 38.371 41.171 41.826 42.718 43.254 44.763
ta
In(III), Re(III), AND Re(V) COMPLEXES
X-Ray Powder Dillraclion Data of [ReO('lTA) ]CI (4) 2
dobs 10.9400 9.8624 7.5962 6.8411 5.3510 5.1756 4.9995 4.8563 4.6079 3.9104 3.8407 3.6802 3.5225 3.4469 3.3489 3.2979 3.1701 2.9862 2.8068 2.7289 2.6933 2.6474 2.5213 2.4387 2.4068 2.3439 2.1908 2.1579 2.1149 2.0900 2.0229
l/lo 20.8333 100.0000 32.5000 10.0000 6.6667 20.0000 27.5000 30.8333 26.6667 23.3333 28.3333 6.6667 10.0000 3.3333 42.5000 10.0000 29.1 667 46.6667 10.8333 1 1.6667 9.1667 14.1667 60.0000 15.8333 10.0000 9.1667 6.6667 11.6667 4.1667 5.8333 11.6667
h
K
1
-1 0 1 -3 -1 2 -4 _2 _2 4 2 -4 -4 -3 -1 _2 -3 _2 5 -3 -5 -4 6 -5 -9 4 2 -8 -2 -6 -9
0 0 1 0 0 1 1 1 2
1 1 1 0 2 1 1 2 1 1 2 0 2 3 1 1 1 3 1 4 4 4 1 3 1 3 4 4 5 0 1
[)
0 2 2 1 3 3 3 2 2 0 0 1 2 3 1 0 0 2 0 4 3
OH
20„ -2e bs
cal
-0.0008 -0.0003 -0.0006 0.0093 0.0042 0.0001 0.0002 -0.0002 0.0045 0.0002 0.0001 0.0001 -0.0009 -0.0032 0.0044 -0.0014 -0.0007 -0.0004 0.0002 -0.0020 -0.0014 -0.0006 0.0001 -0.0007 0.0002 0.0006 0.0007 0.0060 -0.0004 -0.0009 -0.0068
H 0./
2+ 2
Olh
|
2
505
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2
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M = Re(III) or In(III)
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2
(2)
2+ H 0.. 2
II||
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"'Re'''
j
OH
o o.
. a
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2
6h
(3)
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(4)
.0 \
In''
''In-''
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O V
2
N
P
(6)
'Re'
N
(7)
A
Antibacterial Activity The antibacterial activity of the free H T T A ligand and its complexes were tested against various gram-positive and gram-negative bacterial cultures by using the agar diffusion m e t h o d . The antibacterial activities of the investigated complexes a n d the free ligand were tested against various kinds of bacteria listed in Table VIII. The bacterial strains were grown in Mueller-
oh, (8)
20
2!" ^u^ investigated complexes. £ ( ° and ( refer t o TTA , HOTCA- and HTZT~, respectively. ^ V V 8 g e S t e d
s t r u c t u r e s
of t h e
N
c , c l
lo
MAHFOUZ ET AL.
508
6.
7.
8. 9.
10. 11.
Dilworth, J.R.; Parrot!, S.; In Directions in Radiopharmaceutical Research and Development Mather, S, Ed.; Kluwcr: Netherlands, 1996; 1 and other articles thcre-in. Chilton, H.M.; Burchiel, S.W.; Waston, N.E., Jr. In Pharmaceuticals in Medical Imaging; Swanson, D.P., Chilton, H . M . , Throll, J.H., Eds.; Macmillan Publishing Co: N e w York, 1990; 5 6 9 - 5 9 8 . Pople, J.A.; Beveridge, D.L. Approximate Molecular Orbital Theory; M c G r a w Hill: New York, 1970. Baluka, M.; H a n u z a , J.; Jezowska-Trzebia, T.B. Infrared and Electronic Spectra of the Technetium Oxy-Compounds. Bull. Acad. Polon. Sci. Ser. Sci. Chim. 1972, 20 (3), 2 7 1 - 2 7 8 . Figgis, B.N. Introduction to Ligand Fields; Wiley-Interscience: Newyork, 1966; 253. Figgis, B.N. Ligand Field Theory in Comprehensive Coordination Chemistry; Wilkinson, G. Gillard, R.D., McCleverty, J.A., Eds.; Pergamon Press: Elmsford, New York, 1987; Vol. 1. 243. Miessler, G.L.; Tarr, D.A. Inorganic Chemistry; 2nd Edn. 1999, 352. Kettle, S.F.A. Physical Inorganic Chemistry; Oxford University Press: 1998; 37. Horowitz, H.H.; Metzger, A. New Analysis of Thermogravimetric Traces. Anal Chem. 1963, 35, 1464-1468. Coats, A.W.; Rcdfcrn, J.P. Kinetic Parameters from Thermogravimetric Data. Nature 1964, 201, 6 8 - 6 9 . Garcicc, J.; Molla, M.C.; Borras, J.; Escriva, E. Thermal Study of Mepirizol Complexes with Co(II), Ni(IT), Cu(II) and Zn(II). Thermochim. Acta 1986, 106, 155-162. Mocllcr, T. International Reviews of Science; Inorg. Chem. Series 1. VII, Bagnal, K.W., Ed.; 2, 1972; 282. Al-Farhan, K.A. F A R H A N - a Qualitative and Quantitative PC Program for X - R a y Powder Diffraction. Powder Diffraction 1999, 14 (1), 16-21. Boultif, A.; Louer, D. Indexing of Powder Diffraction Patterns for Low Symmetry Lattices by the Successive Dichotomy M e t h o d . J. Appl. Cryst. 1991, 24, 9 8 7 - 9 9 3 . Patel, V.H.; Patel, A . K . Synthesis, Spectroscopic Studies and Antimicrobial Activities of Eu(III), Dy(III) and Tm(III) Heterochelates with 2,2'-Bipyridyl, Amine + Catechol. Synth. React. Inorg. Met.-Org. Chem. 1998, 28 (7), 1207-1219.
S Y N T H . R E A C T . I N O R G . M E T . - O R G . C H E M , , 32(3), 509-527 (2002)
SYNTHESIS AND CHARACTERIZATION OF MONONUCLEAR AND BINUCLEAR CHROMIUM(III) COMPLEXES OF a-BENZOIN OXIME A. S. Attia,* S. F. El-Mashtouly, and M. F. El-Shahat
?
12. 13. 14. 15. 16.
17. 18.
19.
:
20.
Received M a y 23, 2001 Accepted December 5, 2001
Referee I: D. P. Rillema Referee II: D. T. Haworth
Chemistry Department, Faculty of Science, U A E University, Al-Ain, P. O. Box 17551, U A E
ABSTRACT Irradiation of a T H F solution containing C r ( C O ) and a-benzoin oxime ( H B N O ) under various atmospheric conditions, of cither argon or vacuum, gave two dichromium(III) complexes of the formulae [ C r ( u - O H ) ( B N l M ) ( H B N O ) ] (1) and [ C r ( B N I M ) ( H B N O ) ( T H F ) ] 0 (2) where B N I M is the a-benzoin imine radical anion formed as a result of homolytic cleavage of the oxime N - O H bond. When a related reaction of a-benzoin oxime was carried out with C r ( N O ) in open atmosphere, C r ( H B N O ) 3 (3) was obtained. Variable-temperature magnetic susceptibility measurements show a magnetic moment of 8.12 B.M. for the u.-dihydroxo complex (1) at room temperature. This high magnetic m o m e n t value strongly confirms the formulation of a dimer consisting of two benzoin imine radicals (S = 1 /2 coordinated to bridged dichromiu6
2
2
2
3
•Corresponding author. Present temporary address: Chemistry Department, Faculty of Science, Ain Shams'University, Cairo, Egypt. E-mail:
[email protected] 509
MAHFOUZ, ET AL. 0 r^>
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Hinton agar (Merck) plates at 37 °C for 18 h, and then were diluted to a final concentration of approximately I 0 C F U / m L . 0.1 mL of each bacterial suspension was spread over the surface of the Mueller-Hinton agar plates. 10 uL of l O m g / m L of each compound, H T T A and the investigated complexes, was absorbed onto a sterilized filter paper disk of 6 mm diameter. The sterilized filter paper disks were dried under sterile condition and then immediately placed on the surface of Mueller-Hinton agar plates after their inoculation with the test bacterium. T h e plates were incubated at 37 °C for 24 h and the diameter (mm) of the inhibition zone was recorded. The results presented in Table IX show that the free ligand showed higher toxicity towards the growth of gram-negative bacteria, more than gram-positive bacteria. U p o n complexation with In(III), Re(III) and Re(V) metal ions a reduction in inhibitory power towards Y. Pseudetuberculosis and Y. enterocolitica was observed. This reduction in inhibitory power also appeared towards S. aureus upon, complexation with In(III). Salmonella typhi (gram negative) is the most resistant bacteria towards complexation with Re(III) as [Re(TTA)(H20) ]Cl . The effect of the ligand and its complexes on S. aureus, S. epidermidis and streptococcus faceless is equal and nearly negligible.
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In(III), Re(HI), AND Re(V) COMPLEXES
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ACKNOWLEDGMENTS
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This research was. supported by King Abdulaziz City for Science and Technology (K.ACST), project N o . (At-19-43). The authors would like to thank Mr. Mohscn H. Mukhalalati and Mr. Nasser M. Abd El-Salam for technical help and assistance throughout the whole work. REFERENCES
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