Preparation , Characterization and Radiolysis of Copper(II) Complexes Containing Mixed Ligand 

Z.F. DAWOOD*   and   Y.T. MAHMOOD
*Chemistry Department, Education College, Mosul University, Mosul-Iraq

( NJC)

           (Received on     26/4 /2006)	          (Accepted for publication on  5/7/2006)

Abstract
Complexes of the type  [Cu(B`SCH)(LH)]CO3 and [Cu(B`SC)(L)] have been prepared in neutral and basic medium, respectively {where B`SCH= benzoin semicarbazone, B`SC=deprotonated B`SCH ligand, AH= one of the substituted salicylic acid : salicylic acid (A1H),  2-acetylsalicylic acid (A2H), 3,5-dinitrosalicylic acid (A3H), 5-aminosalicylic acid (A4H) or 5-sulphosalicylic acid (A5H), A= deprotonated AH ligand}. The resulted complexes have been characterized physico-chemically.                                                                                                   
The effect of gamma rays have been studied on these complexes under conditions where the hydroxyl radicals were scavenged by sodium formate solution and in presence of nitrogen gas. The electronic spectral data and molar conductivities indicated that copper (II) ion may be reduced to copper (I) and presence of charge transfer between the metal ion and the ligands in some complexes. In addition some complexes have been completely decomposed and some of them polymerized while the others did not affected during the selected time of irradiation.
الخلاصة
حضرت معقدات ذات صيغ [Cu(B`SCH)(AH)]CO3  و [Cu(B`SC)(A)] في كل من الوسطين المتعادل والقاعدي على التوالي } حيث B`SCH = بنزوين سميكاربازون ، B`SC =الليكاند B`SCH مزال منه بروتون ، AH = أحد أحماض السالساليك المعوّضة : حامض السالساليك ((A1H أو 2-اسيتيل حامض السالساليك (A2H) أو 5،3-ثنائي نيترو حامض السالساليك ((A3H أو 5-أمينوحامض السالساليك ((A4H أو 5-سلفو حامض السالساليكA5H) ) ، A = الليكاند AH مزال منه بروتون{ . شخصت المعقدات الناتجة باستخدام تقنيات فيزيائية-كيميائية .                                                                                                                                  
درس تأثير أشعة كاما على هذه المعقدات تحت ظروف أكتسحت فيها جذور الهيدروكسيل باضافة فورمات الصوديوم وبوجود غاز النتروجين ، أوضحت نتائج الأطياف الالكترونية والتوصيلية المولارية بأن عملية إختزال للنحاس (II) الى نحاس (I) يمكن أن تحدث كما تم استنتاج وجود انتقال الشحنة بين الأيون الفلزي والليكاندات في بعض المعقدات . هذا اضافة الى أن بعض المعقدات تفككت تماما وبعضها قد تبلمر في حين بعضها الآخرلم يتأثر بالاشعاع .

Introduction

206

A good deal of work has been reported on the preparation and structural investigation of semicarbazones and their complexes(1-3). This is due to their capability of acting as multidentate donor with the formation of either mono- or bi- or poly-nuclear complexes(4,5). In addition to their interesting ligational properties, semicarbazones and their complexes have important biological activities(6-8). A wide studies have been done on substituted salicylic acid complexes(9-11) due to their interesting ligational properties.
There has been growing interest in the formation of mixed ligands chelates involving  ligands containing different donation sites such as sulfur, oxygen and nitrogen of different functional groups(12-15). On the other hand, coordination compounds with mixed ligands are of considerable importance in the field of metalloenzymes and other biological activities(16,17). Hence a large body of the coordination chemistry of mixed ligands with transition and non-transition metal ions have been reported recently(12-20). Due to the importance of mixed ligands complexes, we took a humble part in the chemistry of mixed ligand complexes and some articles have been published so on their coordination chemistry with transi-tion and non-transition metal ions(21-24). 
Copper and it’s compounds have been used for the treatment of radiation sickness and more recently as an adjunct to radiotherapy for cancer patients(25). Since some complexes have been involved in biological system though some of these systems involved reducing free radicals. The hydrated electron and hydrogen atom have been capable to reduce the central metal ion(16). There has been considerable interest, recently, in the radiolysis of copper(II) complexes(26,27). 
In the present work, new copper (II) complexes containing mixed ligands {benzoin semicarbazone - B`SCH and substituted salicylic acids A1H, A2H, A3H, A4H or A5H} have been prepared and characterized physico-chemically. The effect of gamma irradiation on such complexes have not yet been reported, therefore, it is a matter of interest to determine the extent to which gamma irradiation for these new complexes would be affected. 
Experimental 
Synthetic Methods : 
Benzoin semicarbazone B`SCH has been prepared according to literature method(28). A general procedure has been adopted for the preparation of the complexes in neutral and basic medium.                                                                                                                                           
I- In neutral medium: A solution of 1g (8.1X10-3 mole) of copper carbonate in 5 ml. water has been added to the solution of 2.3968g (8.1X10-3 mole) of benzoin semicarbazone and 8.1X10-3 mole of one of the substituted salicylic acids in 15 ml. hot ethanol (the amounts in grams were listed in Table 1). The mixtures have been refluxed for three hours followed by evaporation to half their volumes then cooled. The products were filtered off, washed with petroleum ether (60ο, 80ο) and dried .                                                                                                                           
II- In basic medium: Complexes of the type [Cu(B`SC)(A)] have been prepared by applying same amounts used in neutral medium, after mixing the metal salts with the ligands and heating on a water bath, potassium hydroxide solution (1.0 M) has been added until pH of the solutions were 8-9. The mixtures have been heated on a water bath for half an hour then allowed to stand then cooled. The products were filtered off, washed with petroleum ether (60ο, 80ο) and dried. 
Analytical and physical measurements : 
Copper contents have been determined by applying precipitation method after the decomposition of the complexes with concentrated nitric acid (29). Relative molecular weights of the ligands and their complexes have been determined cryoscopically(30). 

207

Conductivity measurements have been carried out with Multiline F/SET-Z WTW Wissenschaf using 1.0x10-3 M dimethylformamide solution at 25 οC. The infrared spectra has been recorded on a Pye-Unicam 1100 Infrared Spectrophoto-meter in the range 400 - 4000 cm-1 using KBr pellets.  Electronic spectra has been recorded on Shimadzu UV-210A Spectro- photometer for 1.0x10-3 M solutions of the 
ligands and their complexes in dimethyl-formamide at 25oC, using a 1 cm cell. Magnetic susceptibility of the complexes have been measured by Bruker B.M6 . 
Radiolysis of the Complexes :
All the solutions of the copper (II) carbonate, ligands and complexes have been prepared using 1.0x10-3 M sodium formate solution in triply distilled water (neutral medium) or 1.0x10-3 M sodium formate and 1.0x10-1 M sodium hydroxide solution in triply distilled water (basic medium). The solutions were saturated with nitrogen gas. All gamma irradiations have been carried out using gamma cell-220 purchased from the Canadian Atomic Energy. The absorbed dose has been determined using Fricke dosimeter(31). The dose rate was 2.7x1016 eV.ml-1min-1. 
Results and Discussion
The reaction of copper (II) carbonate, benzoin semicarbezone and the substituted salicylic acids in 1:1:1 molar ratio in both neutral and basic medium can be represented by the following reactions : 
CuCO3 + B`SCH + AH → [Cu(B`SCH)(AH)]CO3 
CuCO3 + B`SCH + AH + 2KOH → [Cu(B`SC)(A)] +  K2CO3                                                   
(where AH=any one of the substituted salicylic acid A1H or A2H or A3H or A4H or A5H; A=deprotonated AH ligands; B`SCH =benzoin semicarbazone; B`SC-= deproto- nated B`SCH) .

208

The resulted complexes were colored solid, slightly soluble in water, ethanol and soluble in dimethylforma- mide. Copper contents and relative molecular weights revealed that the complexes had the composition [Cu(B`SCH)(AH)]CO3 and [Cu(B`SC)(A)] in neutral and basic medium , respectively (Table 1). The values of the molar conductivities (78-91 and 22-29 Ω-1 cm2 mol-1) approached those expected for 1:2 and non electrolytes(32) for complexes prepared in neutral and basic medium, respectively. The room temperature (25 οC) magnetic moments (1.3-2.2 B.M.) indicated the presence of one unpaired electron and assigned to a monomeric structure having distorted octahedral geometries(33). 
The infrared spectra of semicarbazone ligand showed a strong band at 1620 cm-1 attributed to C=N group was shifted towards a lower frequency on coordination due to the decrease of the bond order as a result of metal nitrogen bond formation(5,34). The next strong band at 1700 cm-1 which is attributed to C=O group shifted towards a lower frequency on coordination, in neutral medium, indicating the formation of chelation between the carbonyl oxygen and the metal ion(4,34). Whereas in basic medium, this band was disappeared in the complexes and a new band has been observed at 1430 cm-1 due to bending enolic OH thereby establishing the coordination of the ligand through the enolic oxygen atom(4,5.34) . The appearance of strong bands at 1635-1640 cm-1 and 1575-1585 cm-1 attributed to υC=N + υO-C=N and azine chromophore C=N-N=C, respectively, supported the formation of enolic structure in basic medium(4,5,34). The band observed at 3200-3300 cm-1 assigned to υNH remained unaltered in the complexes prepared in neutral medium indicating that there is no coordination through the NH group, Whereas this band was disappeared in the complexes prepared in basic medium due to the enolic form(4,5). The other bands observed at 3390, 3410 cm-1 and 1450 cm-1 assigned to υNH2 and δNH2 , respectively, remained unaltered on complexation indicated the absence of coordination of this group with the metal ion(4,5). 
Infrared spectra of substituted salicylic acids showed two bands at 1375-1390 cm-1 and 1575-1595 cm-1 assigned to the symmetric and asymmetric stretching frequency of carboxylic group, respective- ly. On complexation these bands shifted to lower frequencies (Table 2). The difference between the symmetry and asymmetry stretching vibration for CO2- group (Δυ = 110 or 170-180 cm-1) indicated that CO2- group coordinated to the central metal ion in bidentate or monodentate manner(34,35), respectively. The next bands observed at 3500-3600 cm-1 and 2900 cm-1 assigned to the stretching vibrations of carboxylic OH and phenolic OH, respectively. On complexation, a negative shift of the order 30-40 cm-1 were observed for these two bands in the complexes prepared in neutral medium, whereas for the complexes prepared in basic medium a negative shift were observed for only υOH(ph) and the disappearance of υOH(carb.) was observed due to the deprotonation of the acid and formation of ionic form (11,34,35). The band observed at 1730 cm-1 in A2H ligand due to υC=O was shifted to lower frequency in the order 35-40 cm-1 in the complexes (3, 4) indicating that there has been coordination through the carbonyl oxygen(34-36) with the metal ion .
The complexes in neutral medium showed a band at 1490 cm-1 due to the ionic bonding of carbonato group(34,35). Whereas, the complexes prepared in basic medium did not showed this band indicating the absence of   CO32-  group. 
On the other hand the spectra of all the complexes showed new bands at 500-550 and 600-720 cm-1 due to υCu-N and υCu-O, respectively(34-37). The presence of these bands supported the formation of the complexes under investigation.

209

The electronic spectra of the complexes (Table 3), showed one broad band centered at 13888-14084 cm-1 due to the transition 2Eg  2T2g of 2D state(38). This band has been comparable both in position and width with the earlier reported octahedral complexes. Since the eg state has been highly affected by Jahn Taller effect, therefore, copper(II) comp- lexes had distorted octahedral geometry (38,39). 10Dq and C.F.S.E have been determined(37) depending on the energy level diagram for d9 configuration (Figure 1)(40) . Since 10Dq= ∆o = υ(in cm-1). The value of C.F.S.E was determined by applying the following equation : 
C.F.S.E. = - ( 6x0.4xυ) – (-3x0.6xυ)

Figure 1: Energy level diagram  of  Cu(II)

Radiolysis of copper (II) carbonate in sodium formate solution and in presence of nitrogen gas for 5 min (Table 4) caused a decrease in the conductivity and a change in electronic spectra in neutral medium, this may be due to the following reaction : 
CO2.-/e-aq + Cu2+  Cu+1 + CO2
Increasing the time of irradiation, the conductivity was changed which may be due to the reaction of .OH, after the consumption of formate solution, with copper (I) and forming copper (II). Continuous irradiation caused reversible reaction. 
The results in basic medium (Table 4) indicated that .OH reacted with OH- forming O.-(41) which interacted with HCOO- as follows : 
.OH + OH-    O.- + H2O
O.- + HCOO-  OH- + CO2.- 
and hence CO2.- and e-aq reduced Cu (II) to Cu (I) leading to a decrease in conductivity and change in electronic spectra. Increasing time of irradiation Cu (I) oxidized to Cu (II) at 50 min. The results of gamma irradiation of the ligands (Tables 4, 5) in formate solution and in presence of nitrogen gas have been lead to a slight changes in conductivities and in absorbance but the wavelengths have been
not changed except the salicylic acid. The general reaction may be suggested as follows : 
L + CO2.-   L- + CO2
L + e-aq    L-
L-  decomposition (increase in conductivity)
L-+ L  (L-L-) association (decrease in conductivity
The reducing radicals CO2.- and   e-aq may have attacked the ligand and the reduced ligands may be either decompos- ed or associated leading to an increase or a decrease in the values of the  molar conductivities(41-43), respectively. In basic medium (Table 4, 5) the so formed O.- reacted with HCOO- as indicated before. CO2.- and e-aq may be reacted with the ligands forming either molecular association or decomposition of the ligands which caused either a decrease or increase in the values of the molar conductivities, respectively. 
Irradiation of the complexes in formate solution and in presence of nitrogen gas caused changes in conduc- tivity and electronic spectra for complex 1-4 . This may be  represented as follows : 
[Cu11(B`SCH)(AH)]2+ + CO2.-/ e-aq   [CuI(B`SCH)(AH)]+      +  CO2
[Cu11(B`SC)(A)]  +  CO2.-/ e-aq      [CuI(B`SC)(A)]-      +  CO2
When the irradiation continued the conductivity and electronic spectra have been changed supporting the formation of polymer(36,41-43). Irradiation of the comp- lexes 5 and 6 did not show any changes in the electronic spectra and only a very slight changes in conductivities which could be neglected. This supported the resistance of these complexes to the effect  of gamma radiation during the selected period time in the study. Irradiation of complexes 7-10 caused changes in conductivities only, indicating the decom- position of such complexes which may be represented by the following reactions : 
 [CuII(B`SCH)(AH)]2+ CuII+B`SCH+AH  
[CuII(B`SC)(A)] CuII+B`SC- +A-  
Conclusions
According to the analytical, physico-chemical studies, some observa- tions have been achieved that lead to establish the following points : 
1-Benzoin semicarbazone acted as triden- tate chelating ligand on coordination with copper(II) ion through the azomethine-nitrogen and the two oxygen atoms of the carbonyl and alcoholic groups . 
2-Substituted salicylic acids acted as tridentate chelating ligands . 
3-Carbonato group was presented in the complexes as counter ion . 
4- Copper (II) ion has been probably hexacoordinated, leading to distorted octahedral geometry (Figure 2) .
5-The effect of gamma rays could be summerised as follows :
I-Reduction of the complexes 1-4, leading to the formation of polymer .
II-Complex 5 and 6 were not affected.  III-Decomposition of the complexes 7-10. 

         A1                                         A2                               B1                               B2
Figure 2 : Model structure   of the complexes 

210

A1, A2 = in neutral medium , B1, B2 = in basic medium
Table 1 : Amounts , physical and analytical results
No	Complex	wt of AH  (g)	Medium	% yield ◘	Color	m.p or d* 0c	^M    **	Cu Calc./ (obs.)	M.Wt Cal./ (obs).	µeff    ●	
1	[Cu(B`SCH)(A1H)]CO3	1.1174	Neutral	98.14	Brown	109	82	11.97 (11.10)	530.5  (490.0)	2.1	
2	[Cu(B`SC)(A1)]	1.1174	Basic	97.52	Yellowish green	160	27	17.23  (16.50)	468.5  (453.0)	2.0	
3	[Cu(B`SCH)(A2H)]CO3	1.4575	Neutral	96.03	Olive	106	78	9.28  (8.90)	572.5  (533.0)	2.1	
4	[Cu(B`SC)(A2)]	1.4575	Basic	97.32	Yellowish brown	140 d	29	13.85  (13.100	510.5  (490.0)	2.2	
5	[Cu(B`SCH)(A3H)]CO3	1.8462	Neutral	95.78	Yellowish brown	110 d	91	10.23  (9.50)	620.5  (584.0)	1.3	
6	[Cu(B`SC)(A3)]	1.8462	Basic	96.11	Yellowish green	140 d	26	13.85  (13.30)	558.5  (533.0)	1.8	
7	[Cu(B`SCH)(A4H)]CO3	1.2389	Neutral	97.14	Brown	103 d	80	11.64  (11.20)	545.5  (533.0)	2.0	
8	[Cu(B`SC)(A4)]	1.2389	Basic	97.43	Black	124 d	22	16.56  (15.80)	383.5  (350.0)	1.4	
9	[Cu(B`SCH)(A5H)]CO3	1.7652	Neutral	96.89	Pale green	120 d	82	10.40  (9.80)	610.5  (584.0)	1.3	
10	[Cu(B`SC)(A5)]	1.7652	Basic	95.23	Yellowish green	178 d	23	11.16  (10.80)	448.5  (409 .0)	1.6	
◘ % yield = (experimental weight of the complex / theoritical weight of the complex) x 100
Theoretical weight of the complex =[(Molecular weight of complex)( weight of metal salt)] / (molecular weight of metal salt) 
* d = decomposition temperature 
**  ^M = molar conductivity in  ohm-1cm2 mol-1
● µeff = magnetic moment in Bohr magneton

Table 2 : IR spectral data of the ligands and their complexes (values in cm-1)
Comp.	υC=N
Semi	υNH2
Semi	υC=O
Semi	υC-O
Semi	υCOO-
(s)*	υCOO-
(as)**	Δυ	υNH
υO-H acid	υC-O (alc.)	υCu-O	υCu-O
	
B`SCH
AH	1620	1455	1700	-	1375-1390	1575-1595	200-205	3200-3300
3500-3600	1250	-	-	
1	1520	1455	1650	-	1410	1520	110	3200-3300
3500-3600	1300	550	650,  700	
2	1520	1455	-	1250	1420	1530	110	3500-3600	1300	550	650,  700	
3	1510	1455	1640	-	1420	1590	170	3200-3300
3500-3600	1300	500	650, 700	
4	1540	1455	-	1250	1410	1590	180	3500-3600	1300	500	625, 700	
5	1530	1455	1650	-	1410	1520	110	3200-3300
3500-3600	1280	500	600, 720	
6	1530	1455	-	1275	1400	1510	110	3500-3600	1300	500	650, 700	
7	1520	1455	1640	-	1420	1530	110	3200-3300
3500-3600	1300	500	650, 720	
8	1540	1455	-	1230	1400	1510	110	3500-3600	1300	525	675, 710	
9	1510	1455	1640	-	1420	1530	110	3200-3300	1300	500	650, 700	
10	1520	1455	-	1230	1410	1520	110	3500-3600	1300	500	600, 700	
•	s = symmetric ; ** as = asymmetric

211

Table 3 : Electronic spectral data of the complexes
No.
	C.T         (cm-1)	υ            (cm-1)	10Dq         (cm-1)	C.F.S.E        *	
1	32000	13888	13888	8332.8	
2	31950	13888	13888	8332.8	
3	32100	14084	14084	8450.4	
4	32000	14084	14084	8450.4	
5	34100	13888	13888	8332.8	
6	34000	13888	13888	8332.8	
7	29000	13888	13888	8332.8	
8	28800	13888	13888	8332.8	
9	31500	13888	13888	8332.8	
10	31450	13888	13888	8332.8	
*C.F.S.E = (6x 0.4x13888) – (3x 0.6x13888)  = 8332.4 ; C.F.S.E = (6x 0.4x14084) – (3x 0.6x14084) = 8450.4

Table 4 : Radiolytical results of CuCO3 and B`SCH in formate solution (N2  gas)  

	CuCO3 Neutral	CuCO3 Basic	B`SCH Neutral	B`SCH  Basic	
T	 ^M 	l
(nm)	A	^ M	l
(nm)	A	 ^M	l
(nm)	A	 ^ M	l
(nm)	A	
0	3.2 	820, 710, 270	0.03, 0.05, 0.61	9.8	295	0.88	3.3	325	0.96	2.0	275	0.81	
5	3.0	308	0.54	9.8	295	0.88	3.2	325	0.95	2.1	275	0.81	
10	3.1	308	0.55	7.9	305	0.76	3.9	325	0.95	2.6	275	0.82	
15	2.1	310	0.50	8.8	260, 305	0.68, 0.80	3.8	325	0.96	2.6	275	0.80	
20	3.0	650, 310	0.04, 0.52	9.8	295	0.86	3.8	325	0.94	2.6	275	0.80	
30	2.5	310	0.55	8.2	295	0.85	1.6	305	0.85	1.1	275	0.70	
40	3.1	310	0.50	9.4	295	0.86	3.0	305	0.85	1.5	275	0.72	
50	3.3	310	0.53	9.2	610, 300	0.075. 0.70	3.1	305	0.85	1.5	275	0.72	
60	3.2	310	0.54	9.2	300	0.70	3.1	305	0.85	1.6	275	0.71	
T = Time of radiation , ^M   = molar conductivity *104 in ohm-1 Cm2 mol-1 , l=wave length , A= absorbence 

Table 5 : Radiolytical results of A1H and A2H ; formate solution (N2 gas)

	A1H Neutral	A1H Basic	A2H Neutral	A2H Basic	
T	  ^M	l
(nm)	A	 ^M	l
(nm)	A	 ^M	l
(nm)	A	 ^M	l
(nm)	A	
0	1.30	270	0.63	1.10	230	0.72	1.60	280	0.62	1.00	220	0.90	
5	1.20	270	0.63	1.00	230	0.72	1.50	280	0.60	1.00	220	0.88	
10	1.00	275	0.60	1.00	230	0.71	1.30	280	0.61	0.80	220	0.90	
15	0.90	275	0.61	0.80	230	0.7	1.00	280	0.61	0.70	220	0.89	
20	0.90	310
270	0.51
0.60	0.70	290
230	0.42
0.70	1.90	280	0.60	0.70	220	0.89	
30	0.75	310
270	0.50
0.60	0.65	290
230	0.42
0.70	0.75	280	0.62	0.50	220	0.90	
40	0.50	310
270	0.50
0.60	0.40	290
230	0.42
0.70	0.60	280	0.62	0.40	220	0.90	
50	0.40	310
270	0.50
0.60	0.30	290
230	0.42
0.70	0.50	280	0.62	0.20	220	0.90	
60	0.20	310
270	0.50
0.60	0.20	290
230	0.42
0.70	
212

0.40	280	0.62	0.20	220	0.90	

Table 6 : Radiolytical results of A3H, A4H and A5H ; formate solution (N2 gas) 

	A3H Neutral	A3H Basic	A4H Neutral	A4H Basic	A5H Neutral	A5H Basic	
T	 ^M	l
(nm)	A	 ^M	l
(nm)	A	 ^M	l
(nm)	A	  ^M	l
(nm)	A	^M	l
(nm)	A	^M	l
(nm)	A	
0	2.50	300	0.60	1.10	240	0.85	2.10	270	0.8	1.7	290	0.65	1.1	210	0.45	1.0	230	0.3	
5	2.50	300	0.60	1.00	240	0.85	2.00	270	0.8	1.5	290	0.65	1.3	210	0.45	1.2	230	0.3	
10	2.30	300	0.60	1.00	240	0.85	2.00	270	0.8	1.2	290	0.65	1.3	210	0.45	1.2	230	0.3	
15	2.50	300	0.60	1.20	240	0.85	1.80	270	0.8	1.2	290	0.65	1.6	210	0.45	1.2	230	0.3	
20	2.40	300	0.60	1.10	240	0.85	1.70	270	0.8	1.0	290	0.65	1.8	210	0.45	1.3	230	0.3	
30	2.40	300	0.60	1.10	240	0.85	1.70	270	0.8	0.9	290	0.65	1.9	210	0.45	1.5	230	0.3	
40	2.50	300	0.60	1.00	240	0.85	1.50	270	0.8	0.6	290	0.65	2.1	210	0.45	1.9	230	0.3	
50	2.50	300	0.60	1.10	240	0.85	1.20	270	0.8	0.4	290	0.65	2.5	210	0.45	2.2	230	0.3	
60	2.50	300	0.60	1.10	240	0.85	1.20	270	0.8	0.2	290	0.65	3.0	210	0.45	2.4	230	0.3	

Table 7 : Radiolytical results of complex 1 -4 ; formate solution (N2 gas) 

	Complex 1	Complex 2	Complex 3 	Complex 4	
T	  ^M	l
(nm)	A	 ^M	l
(nm)	A	 ^M	l
(nm)	A	  ^M	l
(nm)	A	
0	4.1	790, 300	0.082, 0.75	3.0	880, 210	0.065, 0.90	6.3	610, 290	0.07, 0.70	4.5	700, 250	0.04, 0.85	
5	3.6	300	0.75	2.7	880, 210	0.064, 0.91	5.5	290	0.71	4.1	700, 250	0.04, 0.83	
10	3.3	300	0.74	2.3	880, 210	0.065, 0.90	5.0	290	0.69	3.8	700, 250	0.04, 0.86	
15	2.9	300	0.74	2.0	880, 210	0.065, 0.92	4.3	290	0.70	3.3	250	0.84	
20	2.4	300, 345	0.75, 0.51	1.8	210, 320	0.95, 0.78	3.5	290	0.70	2.8	250	0.85	
30	1.8	300, 345	0.75, 0.51	1.4	210, 320	 0.91, 0.77	2.9	290	0.70	2.2	250	0.85	
40	1.2	300, 345	0.74, 0.52	1.1	210, 320	 0.91, 0.78	2.4	290, 320	0.70, 0.58	1.9	250, 305	0.85, 0.91	
50	0.8	300, 345	0.74, 0.52	0.6	210, 320	 0.91, 0.78	1.8	290, 320	0.70, 0.56	1.4	250, 305	0.84, 0.90	
60	0.3	300, 345	0.75, 0.51	0.2	210, 320	 0.90, 0.78	1.2	290, 320	0.70, 0.58	0.6	250, 305	0.85, 0.90	

Table 8 : Radiolytical results of the complexes 5, 6; formate solution (N2 gas) 
	Complex 5	Complex 6	
T	 ^M	^M*	l
(nm)	l*
(nm)	A	A*	 ^M	^M*	l
(nm)	l*
(nm)	A	A*	
0	2.1	2.1	700, 220	700, 220	0.05, 0.91	0.05, 0.90	0.9	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
5	2.1	2.0	700, 220	700, 220	0.05, 0.91	0.05, 0.90	0.9	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
10	2.1	2.1	700, 220	700, 220	0.05, 0.91	0.05, 0.90	1.0	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
15	2.0	2.0	700, 220	700, 220	0.05, 0.91	0.05, 0.90	0.9	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
20	2.0	2.0	700, 220	700, 220	0.05, 0.91	0.05, 0.90	1.0	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
30	2.2	2.1	700, 220	700, 220	0.05, 0.91	0.05, 0.90	0.8	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
40	2.2	2.0	700, 220	700, 220	0.05, 0.90	0.05, 0.90	0.8	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
50	2.0	2.0	700, 220	700, 220	0.05, 0.90	0.05, 0.90	1.0	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
60	2.1	2.0	700, 220	700, 220	0.05, 0.90	0.05, 0.90	1.0	0.9	640, 210	640, 210	0.08,  0.70	0.08,  0.70	
•	= Data after one hour of irradiation

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Table 9 : Radiolytical results of the complexes 7, 8 ; formate solution (N2 gas)  

	Complex 7	Complex 8	
T	^M	l
(nm)	A	^M	l
(nm)	A	
0	4.6	675, 325
	0.06, 0.77
	2.0	600, 300	0.07, 0.60	
5	5.0	675, 325
	0.05, 0.76
	2.3	600, 300	0.07, 0.60	
10	5.4	675, 325
	0.06, 0.76
	3.0	600, 300	0.071, 0.60	
15	6.1	675, 325
	0.065, 0.78
	3.4	600, 300	0.072, 0.62	
20	6.8	675, 325
	0.058, 0.77
	4.0	600, 300	0.07, 0.61	
30	7.5	675, 325
	0.06, 0.79
	4.5	600, 300	0.07, 0.60	
40	8.1	675, 325
	0.06, 0.77
	4.9	600, 300	0.07, 0.60	
50	8.8	675, 325
	0.062, 0.77
	5.2	600, 300	0.07, 0.61	
60	9.3	675, 325
	0.06, 0.77
	6.0	600, 300	0.072, 0.61	

Table 10 : Radiolytical results of the complexes 9, 10; formate solution (N2 gas) 

	Complex 9	Complex 10	
T*	 ^M	^M*	l
(nm)	l*
(nm)	A	A*	 ^M	^M*	l
(nm)	l*
(nm)	A	A*	
0	2.5	2.5	700, 250	700, 250	0.035, 0.80	0.035, 0.80	1.0	1.0	790, 290	790, 290	0.02,  0.62	0.02,  0.60	
5	3.1	3.0	700, 250	700, 250	0.034, 0.80	0.035, 0.80	1.6	1.5	790, 290	790, 290	0.02,  0.62	0.02,  0.60	
10	3.5	3.5	700, 250	700, 250	0.035, 0.81	0.035, 0.80	2.3	2.5	790, 290	790, 290	0.02,  0.61	0.02,  0.60	
15	4.1	4.0	700, 250	700, 250	0.035, 0.80	0.035, 0.80	3.0	3.0	790, 290	790, 290	0.02,  0.60	0.02,  0.60	
20	4.8	4.5	700, 250	700, 250	0.035, 0.81	0.035, 0.80	3.5	3.5	790, 290	790, 290	0.02,  0.60	0.02,  0.60	
30	5.4	4.5	700, 250	700, 250	0.035, 0.82	0.035, 0.80	3.9	4.0	790, 290	790, 290	0.02,  0.61	0.02,  0.60	
40	6.2	6.0	700, 250	700, 250	0.035, 0.80	0.035, 0.80	4.5	4.5	790, 290	790, 290	0.02,  0.60	0.02,  0.60	
50	7.1	7.0	700, 250	700, 250	0.035, 0.80	0.035, 0.80	5.2	5.2	790, 290	790, 290	0.02,  0.60	0.02,  0.60	
60	8.0	8.0	700, 250	700, 250	0.035, 0.80	0.035, 0.80	6.5	6.5	790, 290	790, 290	0.02,  0.60	0.02,  0.60	

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