Entroduction IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Synthesis and Characterization of Novel Ligand Type N2O2 and it , s Complexes With Cu (п) Co (п) , Ni (п) , Zn (п) , and Cd (п) ions. A. Thabet, M. J.Al-jeboori, and E. I. Abdulkarim Department of Chemistry, College of Education Ibn Al-Haitham, University of Baghdad Abstract The reaction of ethylenediamine with [2,4,6-trihydroxyacetophenon] and KOH (Schiff Base) to gives the new tetradentate ligand 2-(1-{2-{1-2,6-Dihydroxy-4-methyl phenyl)- ethyliden amino}- ethylimino}-ethyl-benzene- 1,2,5-triol [HCl]. This ligand was reacted with some metal ions (Cu (II) , Co (II) , Ni (II) , Zn (II) , and Cd (II) ) in methanol with (1:1) metal : ligand ratio to give a series of new complexes of the general formula [M(H4L)], where: M= Cu (11) , Co (II) , Ni (II) , Zn (II) , and Cd (II) . All compounds were characterized by spectroscopic methods [I.R, U.V.-Vis, C.H.N., analysis H.P.L.C, atomic absorption, magnetic susceptibility, (EI-mass for the ligand)], and microanalysis along with conductivity measurements. From the obtained data the proposed molecular structure was suggested for [Co(H4L)], [Ni(H4L)], [Cu(H4L)], which are complexes adopting square planar structure, and [Zn(H4L) and [Cd(H4L)] which are complexes adopting a tetrahedral structure about the metal ions respectively. Introduction Chemists have reported on the chemical, structural and biological properties of Schiff bases. Schiff bases are characterized by the –N=CH-(imin) group which imports in elucidating the mechanism of transmaination rasemination reaction in biological system(1,2).The rapidly emerging field of heterobinucleating ligands and the coordination chemistry of the heteronuclear complexes were derived from such ligands(3,4), and have prompted an extension of our work on the synthesis and redox chemistry of nickel and copper Schiff base complexes(5,6) towards complexe functionalized with crown ether derivatives. During the past two decades, considerable attention has been paid to the chemistry of the metal complexes of Schiff basescontaining nitrogen and other donors (7). This may be attributed to their stability, biological activity(8) and Potential applications in many fields such as oxidation catalysis(9), electrochemistry(10). A series of cations of transitional metals, such as Fe (п) , Co (п) , Mn (п) , Cu (п) , etc., forms with Schiff bases, metallic complexes, with theoretical and practicl application of quite varied types. Some of them are capable of reversibly bnding molecular oxygen, being consequently employed as models in the study of oxygen , s reversible fixation such its natural carries (hemoglobns, hemocianines, etc. ) (11). The present study involves the synthesis and characterization of the complexes of copper (п) , Nichel (п) , cobalt (п) , Zinc (п) , and Cademeum (п) with Schiff bases optained from the condensation of [2,4,6-trihydroxy acetophenon] with Ethylenediamine and KOH (Schiff Base). . Experimental Reagents were purchased from Fluka and Rediel- Dehenge Chemical Co. .I.R spectra were recorded as(KBr) discs using a Shimadzu 8400S FTIR spectrophotometer in the range (4000- IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 450) cm -1 . Electronic spectra of the prepared compound were measured in the region (200- 900) nm for10 -3 M solution in (DMF) at 25 0 C using a Shimadzu,160 spectrophotometer with 1.000+0.001 cm -1 matched quartz cells. Mass spectrum for the ligand was obtained by Electron-Impact (El) on a Shimadzu GCMSQPA 1000 spectrometer. Elemental microanalyses were preformed on a (C.H.N) analyzer, model 1106 (Carlo-Erba).While metal contents of the complexes were determined by atomic absorption (A.A) technique using a Shimadzu A.A 680G atomic absorption spectrophotometer.Electrical conductivity measurements of the complexes were rewcorded at 25 ° C for 10 -3 M solutions of the samples in (DMF) using a PW 9526 digital conductivity meter. Synthesis of the ligand (H6L): Synthesis of 2-(1-{2-{1-2,6-Dihydroxy-4-methyl phenyl) –ethyliden amino}-ethylimino}- ethyl-benzene-1,3,5-triol [H6L]. A solution of ethylenediamine (0.2g, 3.3 mmole ) in methanol (10 ml) was added slowly to [2,4,6- trihydroxyacetophenon] (1.15g, 6.8 mmole) dissolved in methanol (10ml). The reaction mixture was stirred at room temperature for a further (1 hr.), a brown solid was collected by filtration, recrystallised from a mixture of hot methanol /H2O and dried under vacuum for (24 hrs.) to give [H6L] as a pale brown solid. Yield1.5 g, (61%), m.p. (210 ° C) 1-Synthesis of [Co(H4L)]. CoCl2.6H2O (0.0669g, 0.27 mmole )was suspended in (10 ml) methanol. To this suspention, a mixture of (0.1g, 0.27 mmole) of [H4L] in (10 ml) methanol was added and allowed to stirred for (1 hrs.). a Brown precipitate formed, washed with (2 ml) ethylether to give 0.098 g (64 %) m.p (260 ° C) . . 2-Synthesis of [Ni(H4L)]. A similar procedure to that described for the complex [Cu(H4L)] but with NiCl2.6H2O (0.066g, 0.252 mmole) in place of CuCl2.2H2O, was mixed with (0.1g, 0.27 mmole)[H6L] to give a Brown precipitate , which was washed with (2 ml) ethylether to yield 0.068 g (59 %) m.p(180 ° C) dec. 3-Synthesis of [Cu(H4L)] In (50 ml) round bottom flask (0.037g, 0.288 mmole) of CuCl2.2H2O was suspended in (10 ml) methanol. A solution of(0.1g, 0.27 mmole) of [H6L] in (10 ml) methanol was added to the above mixture, the reaction was stirred at room temperature for a further (1 hr.). The pale Brown precipitate crystals which formed upon standing were collected, washed with (2 ml) ether, and dried to give 0.08 g (68 %) of the title compound, m.p (240 ° C) dec Synthesis of [Zn(H4L)]. 4- The method used to prepare [Zn(H4L)] was analogous to the procedure given for the complex [Co(H4L)] but with ZnCl2.2H2O (0.0342g, 0.27 mmole) instead of CoCl2.6H2O . The quantities of the other regents were adjusted accordingly and an identical work-up procedure gave a Brown precipitate 0.06 g (51 %),m.p(185 ° C). 5-Synthesis of [Cd(H4L)]. A (0.0634g, xx mmole) of CdCl2.2H2O was dissolved in (10 ml) methanol. A solution of (0.1g, 0.27 mmole) of [H4L] in (10ml) methanol was added to the above mixture. The reaction was allowed to stirred at room temperature for (1hrs.), during which time the colour of the mixture become pale Brown. The solution was allowed for a slow evaporation and pale brown precipitate was formed, yield 0.095 g (73%),m.p(220 ° C). IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Results and Discution Synyhesis of the ligand The [H6L] pro-ligand was prepared according to the general method shown in Scheme(1). The (I.R) spectrum for [H6L] Fig.(2-1), displayed band at (3128) cm -1 is attributed to the υ(O─H) stretching of the hydroxyl group. The band at (1631) cm 1- due to the υ(C=N)stretching frequency for the imine group (12). The sharp bands at (1283) and (1167 cm -1 ) are attributed to υ(C─O) and υ(C─N) stretching respectively. While (U.V-Vis): spectrum Fig (3-1) exhibits a high intense absorption peak at (301 nm) (33222 cm -1 ) (εmax=2126 molar -1 . cm -1 ) which assigned to overlap of (π→*π) and (n→*π) transitions(13). The EI (+) mass spectrum of the ligand Fig.(5) , shows the parent ion peak at (m/z =360) which corresponds to (M) + , and the fragments at, (330), (296), (188), (80), (54), (28), and (14), are assigned to [M-{CH3CH3-}] + , [M-{CH3CH3-(OH)2-}] + , [M-{CH3CH3-(OH)2- pH(OH)2-}] + , [M-CH3CH3-(OH)2-pH(OH)2-pH(OH)2-}] + , [M-{CH3CH3-(OH)2-pH(OH)2- pH(OH)2-C=N-}] + , [M-{CH3CH3-(OH)2-pH(OH)2-pH(OH)2-C=N-C=N-}] + ,[M-{CH3CH3- (OH)2-pH(OH)2-pH(OH)2-C=N-C=N-CH2-}] + , respectively Syntheses of the complexes The reaction of[N,Ń-bis(2,4,6-trihydroxy methyl ethel)] [H6L] with [Cu (II) , Co (II) , Ni (II) , Zn (II) , and Cd (II) ] was carried out in EtOH. These complexes are stable in solution. The analytical and physical data Table(1) and spectral data Table (2) and Table (3) are compatible with the suggested structure Fig.(1). The (I.R) spectral data of the complexes are presented in Table (2). In general the (I.R) spectra of the complexes showed a band at the range (1619- 1610) cm -1 assigned to the υ(C=N) stretching for the imine group. Which are shifted to lower frequency in comparison with that of the free ligand , this shifting due to the reduced bond order of (C=N). and can be attributed to the delocalisation of metal ion electronic density into the ligand (- system) (14,15). The υ(O─H) stretching band of the imin group in the free ligand at (3128) cm -1 is still present at the (3422-3411) cm -1 rang for these complexes. The bands at (617-570 cm -1 ) and (575-430 cm -1 ) were assigned to υ(M─N) and υ(M─O) stretching respectively, indicating that the imine nitrogens and the oxegen were involved in coordination with metal ion (16-18). Fig. (2-2), (2-3), (2-4) and (2-5 ) represented the I.R spectra for the complexes Co, Cd, Ni and Zn respectively.The molar conductance of the complexes in (DMF) lie in the (40-20cm -1 .mole -1 ) range Table (3), indicating their non electrolytic nature with neutral (19). The electronic spectral data of the complexes are summarized in Table (3). The (U.V-Vis.) spectra of the complexes displayed absorption at the range (302-299)nm assigned to the ligand field and charch transfer transtions (20). In the U.V- Vis pectrum of [Cu(H4L], In the (905) nm is attributed to (d-d) ( 2 E2 ← 2 B1) the [Co(H4L)] complex,Fig.(3-B) showed band at (840)nm attributed to (d-d) transition type ( 4 T2 ← 4 A2), and (864), Fig.(4-4) complexes are attributed to (d-d) electronic transition ( 1 T2g ← 1 A1g), The band at (730)nm is attributed to (d-d) transition of type ( 1 B2g← 1 A1g) of [Ni(H4L)] Fig.(3-C), suggesting square planar structure about Co, Ni and Cu ions respectively(21). The band at (380)nm in the spectrum of [Zn(H4L)] is assigned for a charge transfer, since Zn is (d 10 ) system, so that for [Cd(H4L) complex Fig.(3-D), suggesting a tetrahedral structure about Zn and Cd ions. The (H.P.L.C) results of the [Co(H4L)] complexe is presented in (Table-3). The chromatogram (Fig.4) of [Co(H4L)] complex shows one band at (tR= 2.62 min) indicating the purity of the complex. The magnetic moment for some complexes are shown in (Table-3), The Ni (II) (0.64 B.M) and Co (II) (4.15 B.M) consist with square planar geometry. . . IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 M= Cu, Co, Ni, Zn and Cd Fig. (1) The suggested structure for the complexes References 1.Lau, k.y. ; Mayr, A. andCheung, K.K (1999) Inorg. Chim. Acta, 285:223- 232 . 2.Shawali, A.S.; Harb ,N.M.S.and Badahdah K.O. (1985) J. Heterocylylic Chem., 22: 1397-1403 . 3.Veggel, F.C. ; Van, J.M.; Verboom, W. and Reinhoudt ,D.N. (199) Chem. Rev.,94: 279. 4.Beer ,P.D. (1992), Adv. Inorg. Chem., 39:79. 5.Santos, I.C.; Vilas-Boas, M.; Piedade, F.; Freire, C.; Duarte, M.T. and deCastro, B (2000). Polyhedron, 19, 655. 6.Freire C., de Castro, 1990 B.Inorg. Chem. 29:5113. 7.Wu ,J. C.; Tang, N.; Liu, W. S.; Tan, M. Y.; Chan, A. S. C.( 2001) Chin. Chem. Lett., 12: 757-760 8.Lu, C. M.; Xiong, R. G.; You, X. Z.; Lio, Y.J.; Cheung K. K. (1996) Polyhedron, 1996, 15: 4565-4571 9.Djebbar, S. S.;Benali, B. O.and Deloume, J. P. (1998) Transit. Metal. Chem., 23: 443-447 10.Hamada ,Y. J. (1997) IEEE Trans. Electron Devices, (1997), 44:1208-1217 11.Shkama, K. (1998) Chem. Rev., 98: 1357 12.Socrates G. (1980) “Infrared Characteristic Group Frequencies” Ed. Wiley-Interscience Publication. 13.W. Kemp, (1987) “Organic Spectroscopy” 2 nd . Ed.,144 14.Hadzi D. and Premru L., 1967 Spectrochim. Acta., 23A, 35. 15.Rahman A. A.Abdul-, Ph D.Thesis, collage Abn Al-Haetham University of Baghdad(2002) 16.Nakamoto, K. (1996) “Infrared Spectra of Inorganic and Coordination Compounds” 4th. Ed., J. Wiely and Sons, New York, 17.Ferraro,J. (1971) “Low Frequency Vibrations of Inorganic and Coordination Compounds” Ed. Plenum, New York, 18.Nanjappan P.; Ramalingam K.; Jurisson S.; Pirro J.; Diroxo R.; Narra R.K.; Nowotinik D.P. Nunn A.D., (1992)Abstracts of papers, Ninth International Symposium on Radiopharmaceutical Chem., Paris 6-10 April 19.Geary, W. J., (1971) Coord. Rev., , 7:81 20.Green, N. N. Wood and Earnshow ,A. (1998)., “Chemistry of the Elements”, Ed. J. Wiley and Sons Inc. New York, 21.Lever, A. B. P. (1968). “Inorganic Electronic Spectroscopy” Ed. New York, IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Tabl (1) Analytical and physical data of the ligand and it , s complexes Tabl (2) I.R. spectral data of the ligand and it , s complexes Additional peaks M─O M─N υ(C─N) υ(C=N) υ(C─O) υ(O─H) Complexes formation υ(C=C) ring 1459 CH3 1365 ─ ─ 1167 1631 1283 3128 [C18H20N2O6] [H6L] CH3 1325 442 614 1115 1610 1260 3422 [Cu( H4L)] υ(C=C) ring 1450 CH3 1390 430 570 1075 1616 1250 3411 [Ni( H4L)] υ(C─H)alph 2900 470 615 1025 1618 1150 3416 [Co( H4L)] υ(C=C) ring 1425 CH3 1375 500 617 1110 1619 1300 3419 [Zn( H4L)] υ(C─H)alph 2920 575 609 1075 1619 1175 3413 [Cd( H4L)] Found , (Caled.) % Yield % M.P. ° C Colour Complexes formation Metal N H C ـــ 7.77 (7.65) 5.55 (5.40) 60 (58) 61 210 dce Pale Brown [C18H20N2O6] [H6L] 15.06 (14.88) 5.63 (5.50) 4.27 (4.01) 51.24 51.00)) 68 240 dce Pale Brown [Cu( H4L)] 22.95 (22.63) 6.71 (6.38) 4.31 (4.15) 51.80 (51.50) 59 180 dce Brown [Ni( H4L)] 14.14 (13,90) 6.71 (6.60) 4.31 (4.10) 51.80 (51.23) 64 260 dce Brown [Co( H4L)] 14.41 (13.92) 6.61 (6.43) 4.25 (4.02) 51.02 50.33)) 51 185 Brown [Zn( H4L)] 23.83 (23.77) 5.93 (5.77) 3.82 (3.50) 45.91 (4568) 73 220 dce Pale Brown [Cd( H4L)] IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Table (3): Electronic spectral data, and conductance measurements for the ligand [H6L] and it , s complexes Scheme (1) The synyhesis route of the ligand Ratio Medium eff (BM) eff (BM) Am S.cm 2 .) Mole -1 ) (HPLC) Min. εmax Molar Cm - 1 nm λ Compound - - 2126 301 [H6L] neutral DMF - 25 - 2201 301 [Cu( H4L)] 952 362 46 905 neutral DMF 1.7 20 2.62 1958 302 [Ni( H4L)] 196 730 neutral DMF - 30 - 1358 300 [Co( H4L)] 65 864 neutral DMF - 40 - 223 301 [Zn( H4L)] neutral DMF - 40 - 2271 299 [Cd( H4L)] 206 703 IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Fig. (2-A) The I.R. spectrum of The ligand [H6L] Fig. (2-B) The I.R. spectrum of [Co(H4L)] complexes IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Fig. (2-C) The I.R. spectrum of [Ni(H4L)] complexes Fig. (2-D) The I.R. spectrum of [Zn(H4L)] complexes IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Fig. (2-E) The I.R. spectrum of [Cd(H4L)] complexes Fig. (3-A) The U.V-Vis spectrum of The ligand [H6L] IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Fig. (3-B) The U.V-Vis spectrum of The ligand [Co(H4L)] complexes Fig. (3-C) The U.V-Vis spectrum of The ligand [Ni(H4L)] complexes Fig. (3-D) The U.V-Vis spectrum of The ligand [Cd(H4L)] complexes IBN AL- HAITHAM J. FOR PURE & APPL. SCI VOL.22 (2) 2009 Fig.(4) The H.P.L.C. chromatogram of the [Co( H4L)] complex Fig.(5) The mass spectrum of the ligand [H6L] 2002( 2) 22مجلة ابن الهيثم للعلوم الصرفة والتطبيقية المجلد وبعض معقداته N2O2نوع ليكند جديدتحضير وتشخيص مع العناصر الفلزية [Co (п) Cu (п) , Ni (п) , Zn (п) , and Cd (п) ] ايمان ابراهيم عبد الكريم ، ري محمد جابر الجبو ،احمد ثابت ابن الهيثم ،جامعة بغداد–قسم الكيمياء ،كليةالتربية الخالصة تضمن البحث تحضير الليكند [N,Ń-bis (2,4,6-trihydroxy methyl acetophnon)]ethyl [H6L]. ثم مفاعلة الليكاند مع بعض العناصر .[trihydroxyacetophenon-2,4,6]مع (اثيل داي امين مفاعلة) وذلك من د جديد تكون معق ، أذا قاعدة شف(بوجود هيدروكسيد البوتاسيوم ) (1:1ميثانول وسطا للتفاعل وبنسبة )ال باستعمالالفلزية [M(H4L)] العامة : ذا الصيغة M=Cu(II), Co(II), Ni(II), Zn(II), and Cd(II) :إذ المرئية –فوق البنفسجية االشعة تحت الحمراءواالشعة ) االتيةالطيفية بالطرائقشخصت جميع المركبات لليكند(،كذلك شخصت المركبات بوساطة ،التحليل EI) وطيف الكتلة بتقنية القصف االلكتروني H.P.L.Cو CHNو كان الشكل الفراغي البحث.من نتائج والحساسية المغناطيسيةالكمي الدقيق للعناصر مع التوصيلية الموالرية الكهربائية الخارصين والكادميوم رباعية السطوح ، بينما النحاس والنيكل والكوبلت فكان شكل معقداتها مربعًا مستويًا. اتالمقترح لمعقد