IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 Pho todegredation of Schiff Bases Copper(II) Complexes in Dimethyl Sulphoxid (DMSO) A.J.AL-Lami De partment of Chemistry, College of Science, University of AL-Mus tansyriah Abstrac t Photodecomp osit ion of dichlorobis N [4-Azo benzene aniline)2-hydroxy benzilidene] Cop p er (II) (Comp lexe A1) and dichloro N[2-Azo 3- sulp honic -2- nap ht hol) 6- carboxy lic 2- hy droxy benzilidene] cop per (II) (Complex A2).have been p erformed at λ = 373 nm for comp lex A1and at λ = 358 nm for comp lex A2 in dimethy l sulp hoxide at 25C◦ . the absorbance spectrum of these complexes have been recorded with time of irradiation in order to examine the kinetics of p hot odecay. The ap p arent rate constant (Kd) for the first order reaction has been calculated and found to be 1.1 ×10 -2 min -1 for comp lexe A1 and 2.34 × 10 -2 min -1 for camp lexe A2. the p rimary quantum y ields (Ø ) has also been calculated and found t o be 2.810×10 -1 and 0.2765 ×10 -1 for complex A1 and A 2 resp ectively . Introductio n Cop p er is a metal that has a wide rang of app lications due to its good p ropert ies . It is used in electronics, for p roduction of w iers , sheets , tubes , and also to form alloys. The use of inorganic inhibitors as another native to organic comp ounds that are based on the possibility of degradation of organic comp ounds with time and t emp erature[1]. Long – lived , p hotochemically generated excited st ates of the second and third row transit ion metal comp lexes usually feature significant trip let character and oft en are based on internal charge transfer [2].Schiff bases form st able comp lexes with metals that p erform imp ort ant role in biological sy stems.They find also wide app lication in analytical chemistry since they allow simple and inexpensive determinations of several organic and inorganic substances.Some Schiff bases comp lexes were found to be very effective catalysts for hy drolyt ic cleavage or transesterification of RNA phos p hate diester back bone.Therefore metal complexes of Schiff bases attained a p rominent place in coordination chemist ry [3,4].Phot odecomp osit ion of Schiff bases comp lexes are among the most known p hotoreactive metal complexes [5].Schiff bases are condensation p roducts of an amine and a ketone or aldehy de, with R2C=NR as their general formula they , contain heteroatoms and π electrons that enable bonding with cop p er[1,5]. M arjorie and Josep h have st udied toxicity 0f cop p er to larval p imep hales p romelas in the presence of p hotodegraded natural dissolved organic matt er[6]. The p hot odegradation of cop p er complexes in (DM SO) solvent was p erfomed. In this work, we used the following cop per comp lexes as examp les for st udy ing the p hotodegradation in DM SO solvent. IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 Comp lex(A1) dichloro bis N [ ( 4- Azo benzene 3- hy droxy Anilino ) 2- hy droxy benz ilidene ] cop per (II) . [ Cu (C19H15N3O)Cl2 ] Comp lex (A2) dichloro N [ ( 2-Azo – 3-sulp honic-2-nap ht hol) 6- carboxy lic aniline -2-hy droxy benziliden ] cop p er(II). [ Cu (C24H17N3O7S)Cl2 ] Phot odegredation of moly bdeum(II) and tungesten(II) carbonyl complexes with triazole , benz – imidazole, and oxadiazole acety linic derivatives have been st udied p reviously [5]. In this dep arts the Kinetic and mechanism of degredation have been established. Cop per is necessary for the format ion of blood cells , connective tissue and it is also involved in producing the skin p igment melanin [7]. Experime ntals techniques Chemicals (a) p ot assium ferrioxalate hy drate K3[ Fe (C2O4)3] .3H 2O actinometer was p erep ared by t he method rep orted by H atchard and Parker[9]. (b) Tw o comp lexes (A 1 and A 2 ) was p rep ared as rep orted 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 CuCl2.2H 2O with stirring the mixture was refluxed for 2 hr , the p roducts was recryst allized from ethanol and dired under vacuum. (c) The DMSO used was of sp ectroscop ic grade IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 Apparatus I) T he p hot oly sis ap p aratus consist of medium p ressure mercury lamp 150w, λ=365 nm sup p lied by PHYWE ltd .was used as light source. II) UV-Vis sp ectral absorpt ion bands were obt ained using Py e-unicam(8800) spectrophotometer at 25 C°. using dimethel sulp hoxide (DMSO) as a solvent in quartz p hot ochemical cell. III) IR s pectra were obtained using Pye-unicam SP3 -300 infrared s p ectrop hotometer 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 (p H) of the solution before and after irradiation was measured by (Multi 740/p H-meter ). procedures The p hot oexp eriment s wer carried out in (35 ml) p y rex cell with t wo holes in its up per section for t he p assage of gas and for samp ling p rocesses. 150W medium pressure mercury lamp was used as a radiation source. A know n concentration (1.5x10 -6 M )of t he comp lex was introduced int o t he cell after treatment with oxygen for 20 min. t he cell was closed t ight ly and t he absorp tion sp ectra were recorded between 200-800 nm.T he measurement of the incident light (I° ) was carried out by using st andard method of pot assium ferrioxalate actinometry [9]. A V1 I◦ = εØ λ V2 t where I◦ is t he incident light intensit y , A; the absorp tion at 510 nm . V1 the final volume (25 ml ); ε t he extinction coefficient = slop e of calibration curve , Ø λ the quant um yield = 1.21 at 365 nm , V 2 the volume taken from irradiation solut ion (1 ml) and t ; the time of irradiation of actinometer solution (s). Results and Discussion The sp ectra of cup p er comp lexes . UV-Vis. spectra for the comp lexes have show n absorpt ion 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 t he comp lexes 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 T 2g transition .Electronic absorp tion for comp lex (A2) shows band at 34482 cm-1 which is due t o C.T transition from (L M ) and at 24813 cm-1 which is due t o 2 Eg 2 T 2g transit ion ,T able (1) , which supp ort s the squar p lanar structure. T he changes in absorbance during p hot olysis were measured for different irradiation periods of time at 373 nm for comp lex A1 and 358 nm for the comp lex A2 in order t o study the kinetics of t he photodecay of comp lexes in solut ion (Fig .2). The specific decomp osit ion rate constant of each comp lex (Kd) was determined after examining the order of reaction of these comp ounds . The sp ectra of t he [Cu(C19 H15 N3 O ) Cl2 ] were treated kinetically by p lot ting the curve between(A∞ - A t ) and Ln(A∞ - A t ) versus irradiation t ime( 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 decomp osition of this comp lex was determined by the following first – order equation , Ln (A∞ - A t ) = Ln (A° - A∞) – K d t. The value of Kd for this comp lex is 1.1 ×10 -2 min -1 ; p hot oly sis of ot her comp lex( A2) has been p erformed in a similar manner . Fig 2(b) ) show s the change in Uv-Visb. Spectra with time of irradiation . O n irradiation of the comp lex A1 in dimethy l sulphoxide, the color changes IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 gradually from p ale y ellow to coloress and the absorbance intensity of all bands increases with time of irradiation in the region 200-600 nm, all p hot ochemical changes in these comp lexes are reactively similar and simp le . Although we believe that the solvent (DM SO) undergoes p hotoly sis during irradiation, but this fact does not affect the change in the sp ectra of the comp lex. Determination of appearant quantum yield (Ø ) The ap pearant quant um y ield (Ø) for cop p er comp lexes 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 comp lex A1 Rate K d [C ] Ø = = I abs I abs 1.1×10 -2 ×1.5×10 -6 = = 2.810 ×10 -1 , for comp lex A 1 0.587×10 -7 The value of Ø for comp lex A 2 = 0.2765 ×10 -1 Alias (10) found that ap p earent quant um y ield for carbonyle comp lexes are in the range of 8.3 to 12.1 ×10 -4 . Luetal have invest igated several factors affecting the p hotocataly tic degradation of (DDVP) using a glass p hoto reactor coated with TiO2 and 2O W black –light tungsten fluorescent tube[11] . They found that the quant um y ield for the destruction of DDVP was 2.67%. Q ualitative Anal ysis of photolysis products It is essential to examine the final p roduct s of p hot oly sis in order to set up the mechanism. Infrared (IR) sp ectra have been recorded for the final p hot oproduct s of these reactions. Fig. 5 shows that there is only one p eak ap p earing at 470 cm -1 due t o 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 comp lex has photodecomp osed to metal oxide( for comp lex A1). T he difference between (Fig .4) before irradiation and (Fig.5) after irradiation, for examp le comp lex A1 indicates that there is a comp lete degredation of this comp lex metal oxide and stable ion via a series of secondary reactions , the following is a well known chemical reaction equation (6). h υ Comp lex (Comp lex) * Cux Oy +Cl - + other ions. IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 Analy sis for NO3 - have also been done by using class ical ana ly tical method, p osit ive (brow-ring ) has been detected dep ending on t he number of nitro gen atom in the co mp lex [12].T he acidity (p H)of the final p hotop roduct also was measured by during the photoly sis which was increased with time of irradiation. T he initial p H=9.8 and the final p H was at 3.2, all these final p hotoreactions have been suggest ed without p roposing the exact primary p rocess . . H ussein [13] found that photodegradiation of dichlorovos (DDVP) under UV-150 W illumination in the p resence of TiO2 in oxgen atmosp here ,gives an in crease in the formation of Cl - ions and conductivity , but a decrease in p H.These typ es of reactions have an ap plication in environmental degradation or min eralization of polluted water[14]. H υ Pollution molecule st able ions or molecule. TiO2/O2 Refrences 1.Antonijevic. M .M and Petrovic M .B. (2008) “ Cop p er Corrosin Inhibitors,a review”,Int .J.Electrochem.Sci. 3: 1-28 . 2.Walters Keith, A .; Kim Young – Jin and Josep h, T .Hupp , (2002) “ Exp erimental st udies of Light – Induced charge transfer and charge redist ribution in (X2- Bipy ridine ) Re′ (CO)3Cl Comp lexes ”, Inorg.Chem.41:2909-2919. 3.Hennig, H. ,(1999) "Homogeneous p hotocatalysis by transit ion metal comp lexes ", coord.chem.Rev.182:101-123. 4.Osman, A.H.; Aref, A.Aly and Gamal, A.H.Gouda, (2004) " Phot oreactivity and Thermograv imetrof copp er (II) complexes of N-salicy liden aniline and its derivatives .50- 45) :1(25 .Soc..chem korean .Bull," 5.Naman, S. A.; Ayad, H.J.and A lias, M .F. (2002) “ Photodecomp osition of Moly bdenum (II) and T ungst en (II) carbony l comp lexes with triazole, benz -imidazole , and oxad iazole acety linic deriv atives”, J .p hot ochemist ry and p hotobiology A: chemist ry 150, 41- 48 6.M arjorie, L.B.; Josep h, S. M . and Connie J.B. (2007) “ T oxicity of cop p er to Larvel pimep hales p romelas in the p resence of p hotodegraded 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 T race Elements in blood s erum of cardiovascular p atients comp ared with normot ensive cont rol by atomic absorp tion s p ectrop hotometry ” , N ational .Journal of chemist ry , 6: 283-304. 8.Ayal, A.K. (2005 ). “ Synthesis and sp ectrop hotometric st udy of some metal ions comp lexes with some Schiff bases”,M .Sc.T hesis ,M ustansiriyah Univ., 9.Hatchard, C.G . and Porker ,C.A. (1956) “ A new sensitive chemical actinometer II. Potassium ferrioxalate as ast andard chemical actinometer ”, Proc.Roy .Soc., p age 235 . 10.Alias, M.F. (2000).P h.D.Thesis,Baghdad Univ. , Baghdad 11.Lu, M .C.; Roam, G.D. (1993) J.N.chem,J.p hotochem.p hot obiol.76:103. 12.Hahn, R.B. (1987)Semimicro Qualitative Analysis.VanNostrand.N ew y ork. 13.Naman ,S.A.; Khammas,Z .A.A. Huss ein, F.M. (2002) Photochem.Phot obiology A:chemist ry,6100:1-8 . 14.Bahnemann, D . (1999). in:p. Boule, (Ed.),T he Handbook of Environmental chemist ry ,2(L-) Environmental p hot ochemist ry , soringer,Bertin, IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 Table (1): UV-Visible bands of copper com ple xes in DMS O comp lex Absorbance band cm -1 Transit ion Geometry [Cu(C19 H15 N3O ) Cl2 ] 34129 23255 C.T 2 Eg 2 T2 g Squar p lanar [Cu(C24 H17 N3O7S ) Cl2 ] 34482 24813 C.T 2 Eg 2 T 2g Squar p lanar Table(2): Absorbance of com plex [C u(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 th e Ligand and complexes cm -1 No.Comp lex comp ound υ(C=N) υ(N=N ), C=C υ(O H) 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 & APP L. SC I VO L. 22 (4) 2009 Fig (1): Electronic spectra of (a) [C u(C19 H15 N3 O ) Cl2 ] . (b) [C u(C24 H17 N3 O 7S ) Cl 2 ] . a b Fig. (2): Electronic spectra of (a) complex A1 (b) complex A2 changes at 373 nm accompany chan ge in irradiation time in dimethyl sulphoxide solvent at 298 K° (1) 0 , (2) 3 hr. a b IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 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 ti me( mi n.) L n (A t- A ) a b Fig.(3): Variati on of nautral logarithm of absorbance with irradiation time of (a) complex A1 and (b) com plex A2 in dimethey sulphoxi de solvent at 373 nm (complex A1) an d 358nm (complexA2), usi ng MPML Lamp at 298 k°. Fig .(4): IR spectrum of [Cu(C19 H15 N3 O ) Cl2 ] at 289 k° before photol ysis. IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 cm -1 Fig.(5): IR spectrum of [Cu(C 19 H15 N3 O ) Cl2 ] at 289 k° after photolysis. cm -1 Fig.(6): a IR spectrum of L1= C 19H15N3O IBN AL- HAITHAM J. FO R PURE & APP L. SC I VO L. 22 (4) 2009 cm -1 Fig.( 6): b IR spectrum of L2= C24H17N3O 7S 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 ــــــي هــ ــــم فـــ ـــ ـــــاستـ ـــــــدي النحـــ معقــ ــــــضوئیة ل ـــة الــ ـــ ـــة التجزئـــ ـــ ــــــورو )II(دراســ ــــــائي كلـــ 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 االشــعة تحــت مثـل بأســتخدام الطرائـق الطیفیــة ین المعقـدین شـخص هــذ ) .A2( الم ثنائي مثیل في مذیب C25° ضوئیا في درجة حرارة ین المعقدیندرست حركیة تفكك هذ. المرئیة–الحمراء والفوق البنفسجیة بـت ك قیس ثا ى ومن ذل هو من المرتبة االول ل التجزئة الضوئیة د أن تفاع ة النـوعيسلفوكساید ووج ) Kd( الـضوئي للتفكـك الـسرع عقــد nm 373مـن خـالل متابعـة التغیــر فـي امتـصاصیة االشــعة فـوق البنفـسجیة المرئیــة وبطـول مـوجي nm 358 و A1 للم minكانـت تــساوي ف ، A2للمعقـد ن نـاتج الكــم عــی. علــى التـواليA2 و A1 ین للمعقـد2.34 ×10 - 2 ، 1.1× 10 -2 1- ت تساوي 10 لتفاعل التجزئة الضوئیة وكان -1 و 2.810 × 1- . على التواليA2 و A1 للمعقدین 0.2765× 10