4-Azomalononitrile Antipyrine Complexes of Some First Row Tran si tion Metals

Transcription

1 Pol ish J. Chem., 74, (2000) 4-Azomalononitrile Antipyrine Complexes of Some First Row Tran si tion Metals by F.A. El-Saied 1*, M.I. Ayad 1, R.M. Issa 2 and S.A. Aly 3 1 Department of Chem is try, Fac ulty of Sci ence, El-Menoufia Uni ver sity, Shebin El-Kom, Egypt 2 De part ment of Chem is try, Fac ulty of Sci ence, Tanta Uni ver sity, Tanta, Egypt 3 De part ment of Chem is try, Ge netic En gi neering and Bio tech nol ogy Re search In sti tute, El-Menoufia Uni ver sity, Sadat City, Egypt (Re ceived Jan u ary 25th, 2000; re vised manu script March 13th, 2000) Fe(III), Co(II), Ni(II) and Cu(II) com plexes of 4-azomalononitrile antipyrine (L) have been pre pared in eth a nol so lu tion and char ac ter ized by IR, elec tronic, and ESR spec tra as well as mag netic sus cep ti bil i ties and mo lar con duc tiv i ties. The ligand be haves as a neu - tral bidentate one and the co or di na tion takes place via the azomethine ni tro gen and the car bonyl ox y gen atom. Ligand field pa ram e ters have been cal cu lated and struc tures are pro posed. Key words: complexes, IR, ESR spectra, magnetic properties, conductivity, synthesis Antipyrine (2,3-dimethyl-1-phenyl-5-pyrazolone) and its de riv a tives pos sess a wide va ri ety of potentially use ful ap pli ca tions, in clud ing bi o log i cal [1], clin i cal [2] and phar ma co log i cal [3,4] ar eas. Among these we men tion their use as antipyretic, an al ge sic and anti-rheumatic ma te ri als [4]. Anti py rines have also been used as an a - lyt i cal re agents in the de ter mi na tion of some metal ions [5 9]. Con sid er able study has been de voted to Schiff bases and azo con tain ing lig ands de rived from ei ther 4-aminoor 4-formyl antipyrine [10]. We de scribe here the prep a ra tion and char ac ter iza tion of Fe(III), Co(II), Ni(II) and Cu(II) com plexes with 4-azomalononitrile antipyrine (L). EXPERIMENTAL Re agent grade chem i cals were used with out further pu ri fi ca tion. The ligand 4-azomalononitrile antipyrine was pre pared by cou pling the diazonium salt of 4-amino antipyrine with malononitrile (L) in so dium ac e tate so lu tion. The prod uct was recrystallized sev eral times from eth a nol. The metal com plexes were pre pared by stir ring mag net i cally at ca. 60 C the so lu tion of moles of a metal salt with 0.002, or moles of the 4-azomalononitrile antipyrine (L) in ca. 50 ml Et for pe ri ods of 6 h. The re - sult ing sol ids were fil tered off, washed sev eral times with Et and dried un der vac uum over P 4 O 10. El e - men tal anal y ses (C, H, Cl) were per formed by the microanalytical unit of the Uni ver sity of Cairo. Metal * Au thor to whom all cor re spon dence should be di rected.

2 920 F.A. El-Saied, et al. anal y ses were car ried out by stan dard meth ods. IR spec tra were per formed as KBr discs us ing a Perkin-Elmer 1430 re cord ing spectrophotometer. 1 H NMR spec tra were re corded in d 6 - DMSO us ing a 300 MHz Varian NMR spec trom e ter. The elec tronic spec tra were car ried out in N,N-dimethylformamide (DMF) so lu tion us ing a Perkin-Elmer lambda 4B spectrophotometer. The mo lar con duc tiv ity mea sure - ments were made in DMF so lu tions (10 3 M) us ing a Tacussel conductometer type CD6N. Mag netic sus - cep ti bil i ties were mea sured at 27 C by the mod i fied Gouy method us ing Mag netic Sus cep ti bil ity John son Matthey Bal ance. Dia mag netic cor rec tions were ef fected by em ploy ing Pascal s con stants. The mag netic mo ments were cal cu lated from the equa tion µ eff = 2.84 χ M corr T. ESR spec tra were re corded with a Varian E 104 spec trom e ter and cal i brated with diphenylpicrylhydrazide. RE SULTS AND DIS CUS SION The ligand (L) was pre pared and char ac ter ized by el e men tal anal y ses, in fra red (Ta ble 2) and 1 H NMR spec tros copy. The 1 H NMR spec trum of L in DMSO re veals chem i cal shifts (δ/ppm) at 2.5 (t, 3H, N CH 3 ), 3.35 (t, 3H, C=C CH 3 ), (ar o - matic pro tons), and 8.8 (s,1 H, NH), where t = trip let and s = sin glet. The in fra red Fig ure 1. spec trum shows four bands at 3190, 2210,1630 and 1590 cm 1, as signed to ν(n H), ν(c N), ν(c=o) and ν(c=n), re spec tively. The el e men tal anal y ses, in fra red and 1 H NMR data are com pat i ble with the struc ture shown in Fig. 1. The re ac tions of the ligand (L) with dif fer ent salts of Fe(III), Co(II), Ni(II) and Cu(II) ions in ab sence or pres ence of ap pro pri ate amount of trihydrate so dium ac e tate gives two types: 1:1 and 1:2 metal com plexes. These air sta ble metal com plexes are non-hygroscopic, par tially sol u ble in most or ganic sol vent, ex cept in DMF and DMSO are freely sol u ble. The val ues of mo lar con duc tiv i ties in DMF (10 3 M) so lu - tion (Ta ble 1) show that only the com plex [FeL 2 CI 2 ]Cl 3H 2 O is 1:1 elec tro lyte, whereas the other com plexes are non-electrolytes [11,12]. The high val ues of mo lar con duc tiv i ties found for non-electrolytes are prob a bly due to par tial de com po si tion in so lu tions. Ta ble 2 lists the most useful infrared as sign ments for those bands most di ag nos tic of the mode of co or di na tion of 4-azomalononitrile antipyrine (L). The in fra red spec - tra of all metal com plexes show a de crease in the en ergy by cm 1 on complexation for ν(c=o) and ν(c=n) and are con sis tent with co or di na tion of the car -

3 4-Azomalononitrile antipyrine complexes bonyl ox y gen and azomethine ni tro gen at oms, as is the pres ence of bands at ca and cm 1 as signed to ν(mo) [13] and ν(mn) [13], re spec tively. Ta ble 1. Colors, mo lar con duc tiv i ties and mag netic sus cep ti bil i ties of 4-azomalononitrile antipyrine (L, C 21 H 19 N 7 O 2 ) ligand and its metal complexes. No. Com pound Color Λ M (ohm 1 cm 2 mol 1 ) µ eff (B.M) L or ange-yellow 1 [FeL 2Cl 2]Cl 3H 2O brown-red FeL() 2]Cl(H 2O) brown CoLCl 2 (H 2 O) 2 brown CoL()Cl brown CoL 2 (OAc) 2 H 2 O brown-green CoL 2() 2 H 2O brown-red CoL 2(NO 3) 2 H 2O green NiL()Cl H 2 O brown NiL 2 () 2 H 2 O brown NiL 2 (OAc) 2 2H 2 O green NiL 2()(ClO 4) 3H 2O brown CuL()Cl H 2O brown CuL(OAc) 2 H 2 O brown CuL()(ClO 4 ) green CuL 2 () 2 brown The spec tra of all com plexes show also that the bands cor re spond ing to ν(nh) and ν(c N) re main at the same fre quen cies or are slightly shifted to lower fre quen cies com pared to that of ligand, in di cat ing that the NH and C N groups do not par tic i pate in co or di na tion. The in fra red spec tra of hydroxo-complexes show one or two new bands at cm 1, as signed to ν(m ) [14]. The in fra red spec tra of the chloro-complexes show a new band at cm 1, as signed to ν(m Cl) [15]. The in fra red spec tra of acetato-complexes dis play two bands near 1605 and 1390 cm 1, as - signed to ν a (CO 2 ) and ν s (CO 2 ), re spec tively. This in di cates that the ac e tate ligand co - or di nates as a monodentate ligand [16]. Fur ther these com plexes ex hibit ν(coo) at ca. 630 cm 1, which is con sid ered di ag nos tic for monodentate lig ands [17]. The in - frared spectra of NiL 2 ()(ClO 4 ) 3H 2 O ex hib its a very strong split band (ν 3 ) at 1110 and 1070 cm 1 and a strong band at 625 cm 1 (ν 4 ), which are in dic a tive of a monodentate co or di nated per chlor ate [18]. The in fra red spec trum of CoL 2 (NO 3 ) 2 H 2 O shows a strong band at 1380 cm 1 and a weak band at 1310 cm 1, assigned to ν a (NO 3 ) and ν s (NO 3 ) re spec tively, in di cat ing that the group co or di nates as a monodentate ligand. The spec tra of com plexes, which con tain wa ter mol e cules, show two bands at cm 1 and 1610 (sh) as signed to ν() and δ(h 2 O), re spec tively, in di cat - ing hydration wa ter [19]. The in fra red spec trum of com plex 3 shows ad di tional two bands near 960 and 635 cm 1 ow ing to ρ rock (H 2 O) and ρ wagg (H 2 O) re spec tively, the appearance of the lat ter two modes in di cat ing co or di nated wa ter rather than hy drated wa ter [19]. The above ar gu ments in di cate that the ligand in all com plexes be haves as

4 922 F.A. El-Saied, et al.

5 4-Azomalononitrile antipyrine complexes a neu tral bidentate ligand and co or di na tion oc curs via the car bonyl ox y gen and azomethine ni tro gen at oms. Mag netic and elec tronic spec tral stud ies Iron(III) com plex: The mag netic mo ment (µ eff ) of the iron com plex, [FeL 2 Cl 2 ]Cl 3H 2 O, equal to 2.55 B.M., falls in the range re ported for low-spin (S = 1/2) oc ta he dral iron(iii) com plex [20]. The elec tronic spec trum of the iron(iii) com plex shows ab sorp tion bands be tween and cm 1, which can be ten ta tively as signed [21]. The bands above cm 1 can be as signed to ligand π π* tran si tions, those be tween and cm 1 to charge trans fer, prob a bly d π* tran si tions. The bands be tween and cm 1 can be as signed to d-d tran si tions [22]. Co balt(ii) com plexes: [Co(L) 2 (NO 3 ) 2 H 2 O] was found to be dia mag netic, which con firms that co balt is in the +3 ox i da tion state and has a low-spin, oc ta he dral struc ture as pre vi ously shown, when co balt(ii) salts were used for the prep a ra tions [23]. The octahedral com plex of co balt(ii) have ab sorp tion bands in the near in fra red, vis i ble and ul tra vi o let re gions and those com plex of ap prox i mate O h sym me try have the fol low ing as sign ments for their d d bands. 1 A 1g 3 T 1g (ν 3 ) and 1 A 1g 3 T 2g (ν 4 ). From solid state elec tronic spec trum of the com plex have as signed ν 1 at cm 1, ν 2 at cm 1, ν 3 ex pected to be at 6500 cm 1 and ν 4 was ob served at cm 1. As sign ment of the two higher en ergy bands is dif fi cult due to the over lap of intraligand and charge trans fer bands in this re gion of the spectrum, but ν 4 is most dif fi cult to as sign be cause this weak spin for bid den band is of ten at the on set of the higher en ergy, more in tense charge trans fer bands. Cal cu la tion of ligand field pa ram e ters [24] gives Dq = 1870, B = 782 and β = The lower value of the nephe loauxetic pa ram e ters β in the pres ent com plex in di cates a strong co va lent na ture of this metal ligand σ-bond. [Co(L) 2 (OAC) 2 ] H 2 O, [CoLCl 2 (H 2 O) 2 ] and [Co(L) 2 () 2 ] H 2 O: The co balt(ii) com plexes have mag netic mo ments of 4.9, 4.8 and 4.1 B.M re spec tively, in the range re ported for an oc ta he dral ge om e try around the Co(II) ion [25]. The elec tronic spec tra of these three co balt(ii) com plexes are char ac ter is tic of oc ta he dral stereochemistry around co balt(ii) [26]. The elec tronic spec trum of an oc ta he dral co balt(ii) com plex is ex pected to in volve three spin al lowed tran si tions [27]. 4 T 1g 4 T 2g (ν 1 ), 4 T 1g 4 A 2g (ν 2 ) and 4 T 1g 4 T 2g (F) (ν 3 ). These tran si tions are known to in volve en er gies around 9000 cm 1, cm 1 and cm 1 re spec tively. The spec tra of the com plexes un - der dis cus sion show bands in the re gion cm 1 and cm 1 as - sign able to ν 2 and ν 3 re spec tively. Var i ous ligand field pa ram e ters were cal cu lated for the com plexes and are listed in Ta ble 3. The val ues of the nepheloauxetic pa ram e ters β in di cate that the co va lent char ac ter of the metal ligand σ-band is low. [CoLCl()]: The mag netic mo ment value of the co balt(ii) com plex, [CoLCl()], is con sis tent with four-coordinate tet ra he dral ar range ment [28]. The value mea sured ( µ eff = 3.3 B.M) is near to spin only value, which shows no or bital con tri bu tion to the mag netic moment. The electronic spec trum of this com plex shows two bands at cm l and

6 924 F.A. El-Saied, et al cm 1 as sign able to 4 A 2 4 T 1 (F) (ν 3 ) and spin for bid den transition, re spec tively. The ν 3 is split into two bands in di cat ing tran si tions to 4 B 1 and 4 B 2 states [29]. Ta ble 3. Elec tronic spec tral bands (cm 1 ) and ligand field pa ram e ters for Co(II) and Ni(II) com plexes with 4-azomalononitrile antipyrine. Com plex 4 T 1g 4 T 2g (F) 4 A 2g (F) 4 T 1g (F) Dq B β [Co(L) 2 (OAc) 2 ] H 2 O [CoLCl 2(H 2O) 2] [Co(L) 2 () 2 ] H 2 O A 2g (F) 3 T 2g (F) 3 T 1g (F) 3 T 1g (F) NiL 2() 2 H 2O NiL 2 (OAc) 2 2H 2 O [NiL 2 ()(ClO 4 )] 3H 2 O Nickel com plexes: The mag netic mo ments ob served for the pres ent se ries of Ni(II) com plexes range from 3.0 to 3.4 B.M., which sug gests an oc ta he dral struc ture [30]. The spec tra of the nickel(ii) complexes show two ab sorp tion bands at ca cm 1 and ca cm 1, which are con sid ered to be due to ν 1 { 3 A 2g (F) 3 T 2g (F)} and ν 2 { 3 A 2g (F) 3 T 1g (F)} tran si tions [30] of six co or di nated nickel(ii) com plexes. The ν 3 { 3 A 2g (F) 3 T 1g (F)} band ex pected in the range of cm 1 was not de tected be cause of the in tense intraligand ab sorp tion bands in this re gion, the cal cu - la tions show this band at ca cm 1. The cal cu lated val ues of ν 2 /ν 1 (ca. 1.6) are con sis tent with an oc ta he dral con fig u ra tion [31]. Var i ous ligand field pa ram e ters were cal cu lated for the com plexes and are listed in Ta ble 3. The value of Dq has been cal cu lated from the tran si tion en ergy di a gram. The nepheloauxetic pa ram e ter β is readily ob tained us ing the re la tion β = B (com plex)/b (free ion), where B (free ion) is 1041 cm 1. β val ues for these com plexes in di cate that the co va lent char ac ter of the metal ligand σ-bond is low. Cop per(ii) com plexes: The cop per(ii) com plexes ex hibit mag netic mo ment val - ues close to spin only value (~ 1.73 B.M.) ex clud ing the pos si bil ity of spin-spin in ter - ac tion be tween the cop per(ii) cen ters. The elec tronic spec tra of the cop per(ii) com plexes show bands at ca cm 1 and cm 1. The po si tion of these bands sug gests that these com plexes are due to 2 B 1g 2 E 1g and 2 B 1g 2 A 1g tran si tions re spec tively and have a square pla nar ste reochem is try [28]. The ab sence of any bands be low cm 1 elim i nates the pos si bil - ity of a tet ra he dral or oc ta he dral environment in these cop per(ii) com plexes [32]. In - for ma tion about the sterochemistry of dif fer ent cop per(ii) com plexes was ob tained from the pow der and so lu tion ESR spec tra. Cop per(ii) com plexes gen er ally ex hibit three dif fer ent types of ESR spec tra: iso tro pic, anisotropic and rhombic [33]. The ESR spec tra of a solid sam ple at RT and 77 K show iso tro pic sig nal in the low field re gion with g iso = 2.11 and 2.12 char ac ter is tic of square pla nar ge om e try with d x 2 y2 ground state [35]. The ESR spec trum at 77 K seems al most iden ti cal at RT. Also the [CuL(OAc) 2 H 2 O] com plex in di cates a square pla nar en vi ron ment, Cu(II), d 9,

7 4-Azomalononitrile antipyrine complexes Cl 3H 2 O [FeL 2 Cl 2 ]Cl 3H 2 O (1) M X Y Z Com pound Fe(III) Cl H 2 O FeL() 2 Cl(H 2 O) (2) Co(II) Cl H 2 O H 2 O CoLCl 2 (H 2 O) 2 (3) M X Y Com pound Cu(II) Cl CuL()Cl (12) Cu(II) ClO 4 CuL()ClO 4 (14) Cu(II) OAc OAc CuL(OAc) 2 (13) Ni(II) Cl NiL()Cl (8) Co(II) Cl CoL()Cl (4) Fig ure 2. Chem i cal for mu lae of metal com plexes. M X Y Com pound Co(II) OAc OAc CoL 2 (OAc) 2 H 2 O (5) Co(II) Co(II) NO 3 NO 3 CoL 2() 2 H 2O CoL 2 (NO 3 ) 2 H 2 O (6) (7) Ni(II) Ni(II) OAc OAc NiL 2 () 2 2H 2 O NiL 2 (OAc) 2 2H 2 O (9) (10) Ni(II) Cu(II) ClO 4 NiL 2 ()(ClO 4 ) 3H 2 O CuL 2 () 2 (11) (15)

8 926 F.A. El-Saied, et al. spe cies with d x 2 y2 ground state. The shift to slightly lower g iso value at 77 K in di cates stron ger metal ligand bond ing con sis tent with a flat ten ing of dis tor tion pres ent in this com plex at RT. Based on the above ar gu ments the sug gested chem i cal struc tures for the com - plexes are shown in Fig ure 2. REFERENCES l. Carciunescu D.G., An. R. Acad. Farm., 43, 265 (1977). 2. Hosler J., Tschanz C., Hignite C.E. and Azarnoff D.L., J. In vest. Dermatol., 74, 51 (1986). 3. Meffin P.J., Wil liams R.L., Blaschke T.F. and Rowland M., J. Pharm. Sci., 66, 135 (1977). 4. Schmidt E.V., Prishchep T.P. and Chernova N.A., Izv. Tomsk. Politekhn. Inst., 156 (1975); Shoukry M.M., Ghoneim A.Kh., Shoukry E.M. and El-Nagdi M.H., Synth. Re act. Inorg. Met. Org. Chem., 12, 815 (1982). 5. Olenovich N.L. and Kovalchuk L.I., Zh. Anal. Khim., 28, 2126 (1975). 6. Talipov Sh.T., Tashkhodzhaev A.T., Zeltser L.E. and Khikmatov Kh., Izv. Vyssh. Ucheb. Zaved. Khim. Tekhnol., 15, 1109 (1975). 7. Pilipenko A.T., Lisichenok S.L. and Volkova A.I., Ukr. Khim. Zh. (Russ. Ed), 42, 76 (1976). 8. Sa vant V.V., Ramamurthy P. and Patelec C., J. Less Comm. Met., 22, 479 (1970). 9. Janik B. and Sawicki S., Microchim. Acta, 1050 (1970). 10. El-Saied F.A., El-Bahnasaway R.M., Abdel Azzem M. and EI-Sawaf A.K., Poly he dron, 13, 1781 (1994) and ref er ences therein. 11. Ainscough A.W. and Plow man R.A., Aust. J. Chem., 23, 699 (1970). 12. Massacesi M., Pinna R. and Poticelli G., Spectrochim. Acta, Part A, 38, 725 (1982). 13. Aly F.A., Abu E1-Wafa S.M. and El-Ries M.A., Egypt. J. Chem., 28, 447 ( 1985). 14. Antholine W.E., Knight J.M. and Pe tering D.H., Inorg. Chem., 16, 569 ( 1977). 15. Ferrari M.B., Fara G.G., Lafranchi M., Pelizzi C. and Tarasconi M., Inorg. Chim. Acta, 181, 253 (1991). 16. Mikuriya M., Okawa H. and Kida S., Bull. Chem. Soc. Jpn., 53, 3717 (1980). 17. Nakamoto K., In fra red Spec tra of In or ganic and Co or di na tion Com pounds, Wiley Interscience, NY, p.173 (1965). 18. Hathaway B.J. and Underhill A.E., J. Chem. Soc., 3091 (1961). 19. Teotia M., Gurthu J.N and Rama V.B., J. Inorg. Nucl. Chem., 42, 821 (1980). 20. Raina R. and Srivastava T.S., Inorg. Chim. Acta, 67, 83 (1982). 21. Camp bell M.J.M., Coord Chem. Rev., 15, 309 (1975). 22. Raina R. and Srivastava T.S., Inorg. Chim. Acta, 91,137 (1984). 23. West D.X., Billeh I.S., Billch G.A., Valdes Mar ti nez J., Ebert K.H. and Ortega Hernandez S., Tran si tion Met. Chem., 21, 573 (1996). 24. Le ver A.B.P., J. Chem. Educ., 45, 711 (1968). 25. Yamada S., Coord Chem. Rev., 1, 415 (1966). 26. Fer gu son J., Wood D.L. and Knox K., J. Chem. Phys., 39, 881 (1963). 27. Barefield E.K., Busch D.H. and Nel son S.M., Quart. Rev., 22, 457 (1968). 28. Hathaway B.J. and Bill ing D.E., Coord. Chem. Rev., 5, 143 (1970). 29. Hathaway B.J. and Bill ing D.E., Coord. Chem. Rev., 37, 1 (1979). 30. Patel K.C. and Patel R.R., J. Inorg. Nucl. Chem., 39, 1325 (1977). 31. Graden J.P. and Mocklev M., Aust. J. Chem., 21, 617 (1968). 32. Ray R.K. and Kauffman G.B., Inorg. Chim. Acta, 174, 237 (1990). 33. Rich ard son H., Wasson J., Estes W. and Hat field W., Inorg. Chim. Acta, 23, 205 (1977).