الفهرس 
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Abstract
The present work comprises a study of electron transfer reaction of CrIII-mefenamic acid binary complex by NBS.
CHAPTER I, Introduction.
The electron transfer, outer- sphere and inner- sphere mechanisms have been discussed. The beneficial actions of CrIII were summarized and oxidation of Cr from trivalent (CrIII) to hexavalent (CrVI) was discussed, biological importance of Cr, Cr toxicity, environmental issues of Cr and uses of Cr in industry.
The uses of NBS as brominating agent, oxidizing agent for organic and miscellaneous inorganic compounds were reported with concerning on the oxidation of CrIII - complexes by NBS.
The biological important of mefenamic acid as analgisic, anti-inflammatory and anti-pyretic drug was illustrated and its mechanism of action, absorption, distribution, metabolism and excretion.
CHAPTER II, Experimental.
Chemicals, Solutions and Preparation of the ligand CrIII - complex was illustrated. The different instruments were used in this study were described. Kinetics procedures for the kinetic studies and method for the data were determined.
CHAPTER III, Results and discussion.
This part includes the layout of the results obtained and their discussion. The effects of various parameters on the rate of the reaction have been discussed. This chapter consists of two parts as follows;
Part (I)
The binary complex, [CrIII(MF)(H2O)5](OH)2.8H2O (MF = Mefenamic acid) was prepared and characterized. Kinetics of oxidation of [CrIII(MF)(H2O)5+2] with N-bromosuccinimide (NBS) in an aqueous solution was studied spectrophotometrically, over (1.0 - 4.0) × 10-4 mol dm-3 complex, (0.5- 5.0) ×10-2 mol dm-3 NBS, (0.2- 0.8) mol dm-3 Ionic strength (I) and (25- 45)oC. The reaction is first order with respect to [CrIII] and [NBS], decreases as pH increases in range (8.20- 9.10). Thermodynamic activation parameters including enthalpy; ΔH*, and entropy, ΔS*, were calculated. The experimental rate law is consistent with a mechanism in which the protonated species is considered to be the most reactive species compared to its conjugate base. It is assumed that two steps one-electron transfer takes place via an inner-sphere mechanism.
Part (II)
Kinetics of oxidation of [CrIII(MF)(H2O)5+2] with N-bromosuccinimide (NBS) in an organic solvent-water mixture was studied spectrophotometrically, over (0.5- 2.0) ml of organic solvent (petroleum ether, cyclohexane, benzene and ethanol), (2.5) ×10-2 mol dm-3 NBS, (0.2) mol dm-3 Ionic strength (I) and (25- 45)oC. The reaction is first order with respect to [CrIII] and [NBS], increases as organic solvent content increases. Thermodynamic activation parameters including enthalpy; ΔH*, and entropy, ΔS*, and free energy, ΔG* were calculated. The experimental results are consistent with a mechanism.