IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 Photodegredation of Schiff Bases Copper(II) Complexes in Dimethyl Sulphoxid (DMSO) A.J.AL-Lami Department of Chemistry, College of Science, University of AL-Mustansyriah Abstract Photodecomposition of dichlorobis N [4-Azo benzene aniline)2-hydroxy benzilidene] Copper (II) (Complexe A1) and dichloro N[2-Azo 3- sulphonic -2- naphthol) 6- carboxylic 2- hydroxy benzilidene] copper (II) (Complex A2).have been performed at λ = 373 nm for complex A1and at λ = 358 nm for complex A2 in dimethy l sulphoxide at 25C◦. the absorbance spectrum of these complexes have been recorded with time of irradiation in order to examine the kinetics of p hotodecay. The apparent rate constant (Kd) for the first order reaction has been calculated and found to be 1.1 ×10 -2 min -1 for complexe A1 and 2.34 × 10 -2 min -1 for camplexe A2. the primary quantum yields (Ø ) has also been calculated and found to be 2.810×10 -1 and 0.2765 ×10 -1 for complex A1 and A2 resp ectively . Introduction Copper is a metal that has a wide rang of app lications due to its good propert ies . It is used in electronics, for p roduction of wiers , sheets , tubes , and also to form alloys. The use of inorganic inhibitors as another native to organic compounds that are based on the possibility of degradation of organic compounds with time and temperature[1]. Long – lived , photochemically generated excited states of the second and third row transition metal complexes usually feature significant triplet character and often are based on internal charge transfer [2].Schiff bases form stable complexes with metals that perform important role in biological sy stems.They find also wide application in analytical chemistry since they allow simple and inexpensive determinations of several organic and inorganic substances.Some Schiff bases complexes were found to be very effective catalysts for hydrolyt ic cleavage or transesterification of RNA phosphate diester back bone.Therefore metal complexes of Schiff bases attained a prominent place in coordination chemistry[3,4].Photodecomposition of Schiff bases complexes are among the most known photoreactive metal complexes [5].Schiff bases are condensation products of an amine and a ketone or aldehyde, with R2C=NR as their general formula they, contain heteroatoms and π electrons that enable bonding with copper[1,5]. M arjorie and Joseph have studied toxicity 0f copper to larval p imephales promelas in the presence of p hotodegraded natural dissolved organic matter[6]. The photodegradation of copper complexes in (DM SO) solvent was perfomed. In this work, we used the following copper complexes as examples for study ing the photodegradation in DM SO solvent. IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 Complex(A1) dichloro bis N [ ( 4- Azo benzene 3- hydroxy Anilino ) 2- hydroxy benzilidene ] copper (II) . [ Cu (C19H15N3O)Cl2 ] Complex (A2) dichloro N [ ( 2-Azo – 3-sulphonic-2-naphthol) 6- carboxylic aniline -2-hy droxy benziliden ] copper(II). [ Cu (C24H17N3O7S)Cl2 ] Photodegredation of molybdeum(II) and tungesten(II) carbonyl complexes with triazole , benz – imidazole, and oxadiazole acetylinic derivatives have been studied previously[5]. In this departs the Kinetic and mechanism of degredation have been established. Copper is necessary for the formation of blood cells , connective tissue and it is also involved in producing the skin pigment melanin [7]. Experime ntals techniques Chemicals (a) potassium ferrioxalate hydrate K3[ Fe (C2O4)3] .3H2O actinometer was p erepared by the method reported by Hatchard and Parker[9]. (b) Two complexes (A1 and A 2 ) was p repared as reported earlier[8]. The ligand L1 (2 mmole,0.63 g) that was dissolved in ethanol (10 ml) was added to ethanolic solution (10 ml) of (1.05 mmole, 0.17 g) 0f CuCl2.2H2O with stirring the mixture was refluxed for 2 hr , the products was recrystallized from ethanol and dired under vacuum. (c) The DMSO used was of spectroscopic grade IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 Apparatus I) The photolysis apparatus consist of medium pressure mercury lamp 150w, λ=365 nm supplied by PHYWE ltd .was used as light source. II) UV-Vis sp ectral absorption bands were obtained using Pye-unicam(8800) spectrophotometer at 25 C°. using dimethel sulphoxide (DMSO) as a solvent in quartz photochemical cell. III) IR spectra were obtained using Pye-unicam SP3 -300 infrared spectrophotometer for the range (4000-200)cm -1 but for the ligands were recoded on KBr discs with a Pye- unicam SP3 -100 infrared spectrophotometer for the range 4000- 600 cm -1. IV) The acidity (pH) of the solution before and after irradiation was measured by (Multi 740/pH-meter ). procedures The photoexperiments wer carried out in (35 ml) pyrex cell with two holes in its upper section for the passage of gas and for sampling processes. 150W medium pressure mercury lamp was used as a radiation source. A known concentration (1.5x10 -6 M )of the complex was introduced into the cell after treatment with oxygen for 20 min. the cell was closed t ightly and the absorp tion spectra were recorded between 200-800 nm.The measurement of the incident light (I° ) was carried out by using standard method of potassium ferrioxalate actinometry[9]. A V1 I◦ = εØ λ V2 t where I◦ is the incident light intensity , A; the absorp tion at 510 nm . V1 the final volume (25 ml ); ε the extinction coefficient = slope of calibration curve , Ø λ the quantum yield = 1.21 at 365 nm , V 2 the volume taken from irradiation solution (1 ml) and t ; the time of irradiation of actinometer solution (s). Results and Discussion The sp ectra of cupper complexes . UV-Vis. spectra for the complexes have shown absorption bands around 373 nm(Fig 1) .The ε values are 0.043 ×10 6 and 0.009 × 10 6 mol -1 .L. cm -1 for the complexes A1and A2 resp ectively, the band at 34129 cm -1 is due to charge transfer(C.T) transition from (L M ) and at 23255 cm -1 is due to 2 Eg 2 T2g transition .Electronic absorption for complex (A2) shows band at 34482 cm-1 which is due to C.T transition from (L M) and at 24813 cm-1 which is due to 2 Eg 2 T2g transition ,Table (1) , which supports the squar p lanar structure. The changes in absorbance during photolysis were measured for different irradiation periods of time at 373 nm for complex A1 and 358 nm for the complex A2 in order to study the kinetics of the photodecay of complexes in solution (Fig .2). The specific decomposition rate constant of each complex (Kd) was determined after examining the order of reaction of these compounds. The sp ectra of the [Cu(C19 H15 N3 O ) Cl2 ] were treated kinetically by plotting the curve between(A∞ - A t ) and Ln(A∞ - A t ) versus irradiation time( Fig .3) . Only the plot of Ln (A∞ - A t ) with irradiation time gives st raight line which indicates that the reaction is first – order. The Kd of decomposition of this complex was determined by the following first – order equation , Ln (A∞ - A t ) = Ln (A° - A∞) – K d t. The value of Kd for this complex is 1.1 ×10 -2 min -1 ; photolysis of other complex( A2) has been performed in a similar manner . Fig 2(b) ) shows the change in Uv-Visb. Spectra with time of irradiation . On irradiation of the complex A1 in dimethyl sulphoxide, the color changes IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 gradually from pale yellow to coloress and the absorbance intensity of all bands increases with time of irradiation in the region 200-600 nm, all photochemical changes in these complexes are reactively similar and simple . Although we believe that the solvent(DMSO) undergoes photolysis during irradiation, but this fact does not affect the change in the sp ectra of the complex. Determination of appearant quantum yield (Ø ) The appearant quantum yield (Ø) for copper complexes was determined after the determination of the absorbed light intensity I abs. and incidence light intensity I◦ as follows :- I abs. = I◦ (1- e – ε c l ) = 9.40×10 -7 (1 – e – 0.043 × 10 6 x 1.5×10-6 ) = 0.5875×10 -7 Ein . L -1 .S -1 for complex A1 Rate K d [C ] Ø = = I abs I abs 1.1×10 -2 ×1.5×10 -6 = = 2.810 ×10 -1 , for complex A1 0.587×10 -7 The value of Ø for complex A2 = 0.2765 ×10 -1 Alias (10) found that appearent quantum yield for carbonyle complexes are in the range of 8.3 to 12.1 ×10 -4 . Luetal have invest igated several factors affecting the photocatalytic degradation of (DDVP) using a glass photo reactor coated with TiO2 and 2O W black –light tungsten fluorescent tube[11] . They found that the quantum yield for the destruction of DDVP was 2.67%. Qualitative Analysis of photolysis products It is essential to examine the final products of photolysis in order to set up the mechanism. Infrared (IR) sp ectra have been recorded for the final photoproducts of these reactions. Fig. 5 shows that there is only one peak appearing at 470 cm -1 due to M ―O band ,also the band at 247 , 1625 , 1560 cm -1 were disapp eared indicated to scission of Cu ―Cl , (C= N )and (N= N ) bands resp ectively , which clearly shows that the complex has photodecomposed to metal oxide( for complex A1). The difference between (Fig .4) before irradiation and (Fig.5) after irradiation, for example complex A1 indicates that there is a complete degredation of this complex metal oxide and stable ion via a series of secondary reactions , the following is a well known chemical reaction equation (6). h υ Complex (Complex) * Cux Oy +Cl - + other ions. IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 Analysis for NO3 - have also been done by using classical analytical method, p ositive (brow-ring ) has been detected depending on the number of nitrogen atom in the complex [12].The acidity (pH)of the final photoproduct also was measured by during the photolysis which was increased with time of irradiation. The initial pH=9.8 and the final pH was at 3.2, all these final photoreactions have been suggested without proposing the exact primary process. . Hussein [13] found that photodegradiation of dichlorovos (DDVP) under UV-150 W illumination in the presence of TiO2 in oxgen atmosphere ,gives an increase in the formation of Cl - ions and conductivity , but a decrease in pH.These types of reactions have an application in environmental degradation or mineralization of polluted water[14]. H υ Pollution molecule stable ions or molecule. TiO2/O2 Refrences 1.Antonijevic. M.M and Petrovic M .B. (2008) “ Copper Corrosin Inhibitors,a review”,Int .J.Electrochem.Sci. 3: 1-28 . 2.Walters Keith, A.; Kim Young – Jin and Joseph, T.Hupp , (2002) “ Experimental studies of Light – Induced charge transfer and charge redistribution in (X2- Bipy ridine ) Re′ (CO)3Cl Complexes ”, Inorg.Chem.41:2909-2919. 3.Hennig, H. ,(1999) "Homogeneous photocatalysis by transition metal complexes ", coord.chem.Rev.182:101-123. 4.Osman, A.H.; Aref, A.Aly and Gamal, A.H.Gouda, (2004) " Photoreactivity and Thermogravimetrof copper (II) complexes of N-salicyliden aniline and its derivatives .50- 45):1(25 .Soc..chem korean .Bull," 5.Naman, S. A.; Ayad, H.J.and Alias, M .F. (2002) “ Photodecomposition of Molybdenum (II) and Tungsten (II) carbony l complexes with triazole, benz-imidazole , and oxadiazole acety linic derivatives”, J.photochemistry and photobiology A: chemist ry 150, 41- 48 6.Marjorie, L.B.; Joseph, S. M . and Connie J.B. (2007) “ Toxicity of copper to Larvel pimephales promelas in the presence of photodegraded natural dissolved organic matter ” Can.J.Fish.Aquat.Sci, 64: 391-401. 7.Abid, F.M. ;Al-Dori ,K.M.; Hamad ,A.W.R. (2002) “ M easurement of Essential Trace Elements in blood serum of cardiovascular patients compared with normotensive control by atomic absorp tion spectrophotometry ” , National .Journal of chemistry , 6: 283-304. 8.Ayal, A.K. (2005 ). “ Synthesis and spectrophotometric study of some metal ions complexes with some Schiff bases”,M .Sc.Thesis ,M ustansiriyah Univ., 9.Hatchard, C.G. and Porker ,C.A. (1956) “ A new sensitive chemical actinometer II. Potassium ferrioxalate as astandard chemical actinometer ”, Proc.Roy .Soc., page 235 . 10.Alias, M.F. (2000).Ph.D.Thesis,Baghdad Univ. , Baghdad 11.Lu, M .C.; Roam, G.D. (1993) J.N.chem,J.photochem.photobiol.76:103. 12.Hahn, R.B. (1987)Semimicro Qualitative Analysis.VanNostrand.New york. 13.Naman ,S.A.; Khammas,Z.A.A. Hussein, F.M. (2002) Photochem.PhotobiologyA:chemist ry,6100:1-8 . 14.Bahnemann, D. (1999). in:p. Boule, (Ed.),The Handbook of Environmental chemistry,2(L-) Environmental photochemistry, soringer,Bertin, IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 Table (1): UV-Visible bands of copper complexes in DMS O complex Absorbance band cm -1 Transition Geometry [Cu(C19 H15 N3O ) Cl2 ] 34129 23255 C.T 2 Eg 2 T2g Squar planar [Cu(C24 H17 N3O7S ) Cl2 ] 34482 24813 C.T 2 Eg 2 T2g Squar planar Table(2): Absorbance of complex [Cu(C19 H15 N3O)Cl2 ] versus irradiation time Time (sec.) Abs. 373nm (A∞ - A t ) Ln (A∞ - A t ) 0 0.062 0.013 - 4.342 1800 0.066 0.009 - 4.710 3600 0.069 0.006 - 5.11 5400 0.0672 0.007 - 4.853 7200 0.071 0.004 - 5.52 9000 0.073 0.002 - 6.214 10800 0.075 0 ------ Table (3): IR ban ds of the Ligand and complexes cm -1 No.Comp lex compound υ(C=N) υ(N=N), C=C υ(OH) M -Cl M -N M -O υ (CO) L1 C19H15N3O 1600 1560 3200 _ _ _ _ L2 C24H17N3O7S 1610 1532 3300 _ _ _ 1720 A1 [Cu(L1) Cl2] 1625 1560 _ 247- 271 334- 364 470 _ A2 [Cu(L2) Cl2] 1618 1533 3242 235- 260 322- 340 470- 520 1720 IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 Fig (1): Electronic spectra of (a) [Cu(C19 H15 N3 O ) Cl2 ] . (b) [Cu(C24 H17 N3 O7S ) Cl2 ] . a b Fig. (2): Electronic spectra of (a) complex A1 (b) complex A2 changes at 373 nm accompany change in irradiation time in dimethyl sulphoxide solvent at 298 K° (1) 0 , (2) 3 hr. a b IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 -6.5 -6 -5.5 -5 -4.5 -4 0 50 100 150 200 ti me(mi n.) L n (A -A t) -10 -9 -8 -7 -6 -5 -4 0 50 100 150 200 time( mi n.) L n (A t- A ) a b Fig.(3): Variation of nautral logarithm of absorbance with irradiation time of (a) complex A1 and (b) complex A2 in dimethey sulphoxide solvent at 373 nm (complex A1) and 358nm (complexA2), using MPML Lamp at 298 k°. Fig .(4): IR spectrum of [Cu(C19 H15 N3 O ) Cl2 ] at 289 k° before photolysis. IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 cm -1 Fig.(5): IR spectrum of [Cu(C19 H15 N3 O ) Cl2 ] at 289 k° after photolysis. cm -1 Fig.(6): a IR spectrum of L1= C19H15N3O IBN AL- HAITHAM J. FO R PURE & APPL. SCI VOL. 22 (4) 2009 cm -1 Fig.( 6): b IR spectrum of L2= C24H17N3O7S الصرفة والتطبیقیة 200) 4(22المجلد مجلة ابن الھیثم للعلوم 9 مع قواعد شف في مذیب ثنائي مثیل ) (IIالتجزئة الضوئیة لمعقدي النحاس (DMAO)سلفوكساید اسماء جمیل علي الالمي الجامعة المستنصریة،كلیة العلوم،قسم الكیمیاء الخالصة ــــث ـــ ـــذا البحــ ـــ ـــي هــ ـــ ـم فـــ ـــ ـــ ـــــاستـ ــــدي النحـــ ـــ معقــ ـــضوئیة ل ـــ ـــة الــ ـــ ـــة التجزئـــ ـــ ـــورو )II(دراســ ـــ ـــ ـــائي كل ـــ ـــع ثنــ ـــ آزو -N]4مـــ عقـد]) هیدروكسي بنزیلیدین -2نیلین بنزین ا ائي كلـورو )A1( الم -6) نفثـول -2- سـلفونك -3 آزو بنـزین -N ])2 وثنـ زیلیـدین-2كربوكـسیلك عـقـد] هیدروكــسي بن ة ین المعقـدین شـخص هــذ ) .A2( الم االشــعة تحــت مثـل بأســتخدام الطرائـق الطیفیــ ثنائي مثیل في مذیب C25° ضوئیا في درجة حرارة ین المعقدیندرست حركیة تفكك هذ. المرئیة–الحمراء والفوق البنفسجیة بـت ى ومن ذلك قیس ثا ة النـوعيسلفوكساید ووجد أن تفاعل التجزئة الضوئیة هو من المرتبة االول ) Kd( الـضوئي للتفكـك الـسرع ـعة فـوق البنفـسجیة المرئیــة وبطـول مـوجي ة التغیــر فـي امتـصاصیة االشـ ـد nm 373مـن خـالل متابعـ عقـ nm 358 و A1 للم ـم عــی. علــى التـواليA2 و A1 ین للمعقـدmin-1 2- 10 ×1.1 ، 2 - 10× 2.34كانـت تــساوي ف ، A2للمعقـد ن نـاتج الكـ 10 لتفاعل التجزئة الضوئیة وكانت تساوي -1 و 2.810 × 1- . على التواليA2 و A1 للمعقدین 0.2765× 10