Synthesis and Spectroscopic Studies of some Divalent Metall Ion Complexes of 3-(4-hydroxyphenyl)-2-(3-(4-nitrobenzoyl) thioureido) propanoic acid

3-(4-hydroxyphenyl)-2-(3-(4-nitrobenzoyl) thioureido) propanoic acid (HNP) a new ligand was synthesized by reaction of Tyrosine with (4-Nitrobenzoyl isothiocyanate) by using acetone as a solvent. The prepared ligand (HNP) has been characterized by elemental analysis (CHNS), infrared (FT-IR), electronic spectral (Ultraviolet visible) and( 1 H, 13 C-Nuclear Magnetic Resonance) spectra. Some Divalent metal ion complexes of (HNP) were prepared and spectroscopic studies by Fourier transform infrared (FTIR), electronic spectral(UV-Vis), molar conductance, magnetic susceptibility and atomic absorption. The results measured showed the formula of six prepared complexes were [M (HNP)2] (M +2 = Manganese, Cobalt, Nickel, Znic, Cadmium and Mercury),from the obtained data tetrahedral structure suggested for all complexes, except Copper complex has a square planer geometry.


Introduction:
Both functional groups amine (-NH 2 ) and carboxyl (COOH), that amino acid contains, give the amino acid a biological important organic compounds , along with a side-chain(R group)specific to each amino acid, because of their biological importance. Amino acids are necessary in nutrition and commonly used in dietary supplements , compost and food technology. Industrial uses include the production of drugs, biodegradable plastics, and chiral catalysts [1]. Tyrosine is the one of standard amino acid; it is aromatic and anon-essential amino acid with a polar side group.
Tyrosine is a precursor to neurotransmitters and increases plasma neurotransmitter levels (particularly dopamine and norepinephrine) [2] but has little if any effect on mood [3]. The effect on mood is more eminent in humans subjected to stressful conditions ,L-tyrosine and its derivatives (L-DOPA, melanin, phenylpropanoids, and others) are used in pharmaceuticals, nutritional supplements , and food additives. Yang Z. and coworkers [4] was prepared a copper (II) complex with tyrosine of formulation[Cu-Phen-Tyr](H 2 O)](ClO 4 ) (Phen = 1,10-phenanthroline, L: -Tyr = Open Access L: -tyrosine) and also Each Abdul Wajid* and R. B. Mohod [5] • FT-IRspectra were recorded as FT-IR using 3800Shimadzu in the range of (4000-400) cm -1 by using (KBr) disc. •Electronic spectra were obtained using (UV-160 Shimadzu) spectrophotometer at 25 C for 10 -3 M solution DMSO. •Molar Conductivity was measured at 25 C for 10 -3 M by using PhilipsPW.
At room temperature, the mixture was stirred fore3hours. The precipitate was collected by filtration, washed with mixture of water: ethanol(1:1)then dried in an oven at(50˚C).

Fig(3): Infrared spectrum of ligand (HNP)
The (UV-Vis) spectrum of the free ligand(HNP), Figure(4) gives a high intense absorption peak at(36764) cm -1 which may be attributed to electronic transition type π→π* [11].The data of electronic spectrum of the free ligand (HNP)is registered in Table (3).

2-Complexes of the ligand (HNP)
The precipitate complexes soluble in some common solvents are "dimethyl formamide","dimethyl sulphoxide" and relatively thermally stable. The molar conductivity values of all complexes in DMSO solvent in 10 -3 M at 25˚C Table(1) indicated to be non-electrolytic nature [12].The atomic absorption measurements for all complexes gave approximated values when it is compared with theoretical values. Physical properties of the ligand(HNP) and its complexes shown in Table (1).

FT-IR Spectra
These spectra exhibited marked difference between bands Figure (5) shows Infrared spectrum of complex[Ni (HNP) 2 ]. The stretching vibration of υ(NH) between(3217-3116)cm -1 shifted higher frequencies by(175-50)cm -1 suggesting of the coordination of ligand through thee nitrogen atom from υ(N-H) group [13] while the band at(1701)cm -1 was assigned to the stretching of υ(COO) asym group, in the spectra of complexes. This band has been found in the range between(1666-1689)cm -1 ,so the band was shifted to lower frequencies by(35-11)cm -1 from the free ligand; the band at(1327)cm -1 was assigned to the stretching of υ(COO) sym group [14] in the spectra off complexes. This band has been found in the range between (1411-1435) cmm -1 shifted too higher frequencies by (84-108) [15]. Table (2) describes the important bands and assignment for all prepared complexes.

Conclusions:
As demonstrated by looking at the research and depending on the results obtained molar conductivity, magnetic moment, spectroscopic studies (FT-IR,UV-Vis and atomic absorption)for the ligand (HNP) and all prepared complexes add too( 1 H-13 CmNMR)only for ligand, the new prepared ligand (NHP) action as bi dentate on coordination with central ion Mn(II), Coo(II), Ni(II), Cu(II), Zn(II), Cd(II) & Hg(II) via oxygen atom of (COO) carboxylic group and nitrogen atom of (NH) group, So we propose Tetrahedral geometry around metal ions for all prepared complexes, except Copper complex that has a Square planer geometry as shown in Figure(