Synthesis and Characterization of Some Metal Complexes of [4-Methoxy-N- (pyrimidine-2-ylcarbamothioyl)benzamide]

A new ligand [4-Methoxy -N-(pyrimidine-2-ylcarbamothioyl) benzamide] (MPB) was synthesized by reactioniofi(4-Methoxyibenzoyliisothiocyanate)withi(2-aminopyri-midine). The Ligand was characterized by elemental micro analysis (C.H.N.S),(FT-IR) (UVVis) and ( 1 Hi, 13 CNMR)spectra. Some transition metals complexes of this ligand were prepared and characterized by (FT-IR, UV-Vis) spectra conductivity measurements magnetic susceptibility and atomic absorption. From the obtained results the molecular formula of all complexes was suggested to be [M(MPB)2Cl2] (M +2i =Cu, Mn, Co ,Ni ,Zn ,Cd and Hg),the proposed geometrical structure for all complexes was an octahedral.


Introduction:
Nitrogen containing heterocycles act an important part in medicinal chemistry and also contribute to the society by helping as in different life processes [1]. Heterocyclic compounds are torrential in nature and are of great significance to life because their structural subunits exist in many natural products such as vitamins, hormones, antibiotics etc. A practical method for the synthesis of such compounds is of great interest in synthetic organic chemistry. Pyrimidine is a six-member heterocyclic compound that contains two nitrogen atoms at positionsi1 and 3. The structure of the pyrimidine ring is similar to benzene and pyridine The key role pyrimidines play in cellular processes has made them valuable leads for drug discovery. Pyrimidine derivatives are known to be biologically active compounds and substituted Pyrimidines have shown a wide range of biological activities like anti tubercular antibacterial, antioxidant, antiinflammatory activity [2]. The chemistry of pyrimidines and their derivatives have been studied since past centuryidue to their close pharma cological association with diverse pharmacological properties. Pyrimidine Scheme(1-a) was first isolated ini1899. Though pyrimidine itself does not exist in nature but substituted Pyrimidines moiety are found as part of more complex systems and are widely distributed. Pyrimidines [3]. 1 Department of Chemistry, College of Education for Pure Sciences, Ibn-AL-Haitham, University of Baghdad. 2 Ministry of Education. *E-mail: Salnkhyl 44@ gmail.com are considered to be important not only because they are an integral part of the genetic material DNA and RNA as nucleotides and nucleosides but they also impart numerous biological activities such as bactericides, fungicides, viricides, insecticides and meticides. They have also found applications in agricultural and industrial chemicals.

Instruments
1 H and 13 C-NMR spectra were recorded using Ultra Shield 300 MH z Switzerl and at University of Al al-Bayt, Jordan. Melting points were recorded by using Stuart-imelting point apparatus. FT-IR spectra were recorded as CsI disc usingi3800 Shimadzu in the range of (4000i-200)cm -. Electronic spectra were obtained using UV-160 Shimadzu spectro photometeriati25 Cifor10 -3 Mi solution DMSO with 1.000 ± 0.001icm matched quartz cell. Molar Conductivity was measured at 25 C fori10 -3 M solution of DMSO using Philips P W . Digital .micro elemental analysis (C.H.N.S) were performed using Acrlo Erba 1106 elemental analyzer. Magnetic susceptibility measurements were obtained magnetic susceptibility balance model MSB-MKI.
Metal contents of the complexes were determined by atomic absorption technique using Shimadzu (AA680G).

Synthesis of the ligand complexes Synthesis of the [Zn(MPB) 2 Cl 2 ] complex
A solution of (0.136 g, 1mmoli)iZnCl 2. in 10 ml ethanol was added to a solution of (0.576g,2mmoli) (MPB)in10 ml ethanol. The mixture was stirred under refluxed for 6 hrs at room temperature, the brown solid product was collected by filtration, washed with (1:1)imixture of water: ethanol, and dried in an oven at 50˚C.

Complexes of the ligand(MPB)
The solid complexes are soluble in some common solvents such as dimethyl form amide, dimethyl sulphoxide and relatively thermally stable. The molar conductivity values of all complexes in DMSOisolventiin10 -3 Miat 25˚C (Table-1 The atomic absorption measurements for all complexes gave approximated values when compared with theoretical values, Table(1) includes the physical properties for the ligand and its complexes.

FT-IR Spectra of complexes
These spectra exhibited marked differences between bands, Figure( irespectively.ithe spectra of complexes [14]. Table  (2) describe the important bands and assignment for free ligand (MPB) and its complexes.
-[ Cu (MPB) 2 Cl 2 ] d 9 The spectrum of Brown complex of Cu(II) shows two bands at (36630) cm -1 (11574)cm -1 refersito (L.F), 2 Egi 2 T 2 g (F) , electronic transition respectively which was in good agreement for distorted octahedral complex for Cu(II)iion [20]. The spectrum of these complexes displayed one peak at range(271-291)nm (36900-34364)cm -1 which attributed to L-F [21]. with their assignments are summarized in Table(3).Suggested structures for complexes on the basis of molar conductivity , magnetic moment ,spectroscopic studies (FT-IR, UV-Vis and atomic absorption) and 1 H- 13 CNMRifor ligand (MPB) only the ligand (MPB) behaves as bi dentate on coordination with Mn(II), Co(II), Ni(II), Cu(II), Zn(II),Cd(II) and Hg(II) ions via oxygen atom of (C=O) amido group and sulfur atom of (C=S) group, suggesting octahedral geometry around metal ions for all the prepared complexes.