Preparation and Characterization of Cu (II), Mn(II) and Zn(II)complexes with new sulfamethoxazole Compounds

Acetophenone sulfamethoxazole and 3-Nitrobenzophenone sulfamethoxazole were prepared from the reaction of sulfamethoxazole with two ketones. The prepared ligands were identified by (C.H.N) analysis and UV-VIS, FT-IR spectroscopic techniques. Metal complexes of the two ligands were prepared in an aqueous alcohol with Zn (II) , Mn (II) and Cu (II) ions with a molar ratio1:1. The proposed general formula for the resulting complexes was [ML.CL2.H2O]H2O .The complexes were characterized by (C.H.N) technique , spectroscopic methods ,conductivity, atomic absorption ,magnetic susceptibility measurements and melting point. According to the results obtained, the suggested geometry is to be octahedral for all the complexes.


Introduction:
Sulfonamides are structural analogs and competitive antagonists of paraamino benzoic acid (PABA). Sulfamethoxazole derivatives are widely used in the medicine and pharmaceutical industry because of their extensive biological effectiveness [1]. Sulfamethoxazole prevents the formation of dihydrofolic acid, a compound which makes the bacteria able to survive. It has been reacted with selected ketons and aldehydes to give Schiff bases [2].Schiff bases play an important role in the coordination chemistry and are used as chelating agents with transition elements [3]. Schiff base metal complexes have a wide interest in clinical, biological and analytical applications [4].They show biological activities including anti bacterial, anti fungal, anti cancer and herbicidal activities, anti-tubercular activities [5]. Moreover, some metal complexes of these ligands have been found to promote rapid healing of burns in humans and animals [6]. The current study investigated the preparation and properties of some metal ion complexes with sulfamethoxazole derivatives.

Materials and Methods:
All the chemicals used in this work are of high purity. The electronic spectra were measured on (Shimadzu UV -160 A) Ultra Violet-Visible Spectrophotometer. The infrared spectra were measured using (Shimadzu FTIR-

Open Access
Baghdad Science Journal Vol.14(3)2017 576 8600 S) Fourier Transform Infrared, Spectrophotometer (4000-400) cm -1 with samples prepared as KBr discs. Metal analysis was determined by using (A.A-680) Shimadzu atomic absorption spectrophotometer. The conductivity measurements were obtained using conduct meter WTW; the complexes were dissolved in DMF, element microanalyses were recorded by microanalysis (C.H.N) in Al-Albaite University in Jordan, the magnetic susceptibility values of the prepared complexes were obtained by using magnetic susceptibility balance Johnosn Matthey. The melting points of the prepared ligands and the complexes were measured by using melting point apparatus Gallenkamp M.F.B-60.

Synthesis of Schiff bases (L1, L2)
Schiff bases L1and L2 were prepared from reaction of sulfamethoxazol (0.01mole) with two different ketones (aceto phenone and4nitro benzo phenone) (0.01mole in 25 ml absolute ethanol and drops of glacial acetic acide).The mixture was heated under reflux for 5 hrs Precipitates were flittered and recrystalliz ed from ethanol .The synthesis route is shown in Scheme (1).

Preparation of Metal Complexes
An aqueous solution containing 0.17g, 0.136g and 0.197g (1mmole) of CuCl 2 .2H 2 O,ZnCl 2 and MnCl 2 .4H 2 O respectively was added gradually with stirring to ethanolic solution (1mmole) of the ligand (L1). The reaction mixture was heated under reflux for 3 hours, keeping the reaction mixture over night to give solid products and recrystallization from ethanol. The complexes of L2 were prepared by the same method.

Results and Discussion:
The ligands were prepared by condensation reaction between sulfamethoxazol with two different ketones .All prepared complexes were colored, soluble in organic solvent such as EtOH, DMSO and DMF and stable toward air. (Table1) includes some physical properties and elemental analysis, of prepared ligands and their complexes.
Comparing the IR spectra of the complexes and free ligands, the following differences were observed: I. A strong band at ( 3387)cm -1 in the ligands assigned to (NH) group was shifted to lower frequency on chelating with metal ion indicating the (NH) group acting as a coordinating site [8] .  [11,12]. VI. The appearance of a band at (1685, 1620) cm -1 in the ligands assigned to ν(C=N) azomethine, this band remains almost at the same position in the complexes and hence suggests that the azomethine nitrogen is not taking part in coordination [7].

The Electronic Spectral Studies
The free ligand solution display high intensity peaks in the UVregions at 248 and 311 nm, which are assigned to (π→π*) electronic transitions for functional groups, C=N and S=O respectively [13]. The absorption band appeared at (291nm) which can be attributed to (π→π*) transition for the aromatic system [14].
The spectra of copper complexes exhibit a broad band around (600-755nm) described by the 2 Eg → 2 T 2 g electronic transition [15]. These transitions indicated the copper complexes to be distorted octahedral, the magnetic moment values of Cu complexes are (1.85-1.86 [18]. The electronic spectrum of manganese complexes showed three peaks : the first peak at( 257 , 247) nm was attributed to ( 6 A 1 g→ 4 A 1 g ),the second peak at( 301 , 297)nm was attributed to ( 6 A 1 g→ 4 T 1 g ) and the third peak at (302 , 303) nm which was assigned to ( 6 A 1 g→ 4 T 2 g). These transitions indicated these complexes to be octahedral [18]. The molar conductances of the complexes (10 -3 M) in DMF refer to their non-electrolytic nature. The data are listed in Table 3. The suggested geometry of the complexes can be shown in Figures (1) and( 2).

Conclusions:
Tow schiff bases were synthesized from sulfamethoxazole derivatives and characterized .The ligands were treated with metal ions salts to afford corresponding complexes. The complexes showed octahedral geometry around the metal.