Browsing by Author "Ali Omer Elssmani Eltahir"

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    Antioxidant Activity Relationship Study of bichalcophenes Derivatives Using Density Functional Theory (DFT) B3LYP Method.
    (2008) Ali Omer Elssmani Eltahir
    abstract In spite of the large quantity of experimental work, the electronic and structural aspects of the bichalcophenes and aza-analogs namely 4-(2,2′-bifuran-5-yl)benzacyanide[1A], 4-(2,2′-bifuran-5-yl)benzamidine[1B],4-(2,2′-thiofuran-5-yl)benzacyanide[3A],4-(2,2′-thiofuran-5-yl)benzamidine [3B], 6-(2,2'-bithiophen-5yl)pyridine-3-carboximidamide [6B], respon- sible for free radical scavenging ability are theoretically analyzed in this work. Electronic parameters were calculated using the Density Functional Theory (DFT) methods in liqid phase to calculate a set of molecular properties of bichalcophenes derivatives. The electronic features found as being responsible for the antioxidant activity of the bichalcophenes derivatives compounds studied, are the Mullikan net charge of oxygen atom (-O), the energy of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), the energy gap (EL-EH ), ionization potential and dipole moment. These values are interpreted with Trolox equivalent antioxidant capacity (TEAC) value. The 13thO position in the bichalcophenes compounds have higher charges, hence chelation by metal occur in the 13th position oxygen group. The antioxidant activities increase with small the energy gap value (EL-EH) and high the net charge. The results of the antioxidant activity are in the following order 6B > 1B > 3B > 1A > 3A as can be obtained from experimental data. On the basis of these results we are able to design a novel antioxidant with enhanced activity.
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    Antioxidant Activity Relationship Study of bichalcophenes Derivatives Using Density Functional Theory (DFT) B3LYP Method.
    (AL-Neelain University, 2014-10) Ali Omer Elssmani Eltahir
    Abstract In spite of the large quantity of experimental work, the electronic and structural aspects of the bichalcophenes and aza-analogs namely 4-(2,2′-bifuran-5-yl)benzacyanide[1A], 4-(2,2′-bifuran-5-yl)benzamidine[1B],4-(2,2′-thiofuran-5-yl)benzacyanide[3A],4-(2,2′-thiofuran-5-yl)benzamidine [3B], 6-(2,2'-bithiophen-5yl)pyridine-3-carboximidamide [6B], respon- sible for free radical scavenging ability are theoretically analyzed in this work. Electronic parameters were calculated using the Density Functional Theory (DFT) methods in liqid phase to calculate a set of molecular properties of bichalcophenes derivatives. The electronic features found as being responsible for the antioxidant activity of the bichalcophenes derivatives compounds studied, are the Mullikan net charge of oxygen atom (-O), the energy of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), the energy gap (EL-EH ), ionization potential and dipole moment. These values are interpreted with Trolox equivalent antioxidant capacity (TEAC) value. The 13thO position in the bichalcophenes compounds have higher charges, hence chelation by metal occur in the 13th position oxygen group. The antioxidant activities increase with small the energy gap value (EL-EH) and high the net charge. The results of the antioxidant activity are in the following order 6B > 1B > 3B > 1A > 3A as can be obtained from experimental data. On the basis of these results we are able to design a novel antioxidant with enhanced activity. IX مستخلص البحث بالرغم مِ ن الكميةِ الكبيرة للعملِ التجريبي المعملي، فان دراسة السمات الإلكترونية والهيكلية لمشتقات bichalcophenes و -analogs aza المسؤولة عن الراديكالي الح ر تُحل لُ نظري ا في هذا العملِ . العوامل الإلكترونية حُسِب ت باستعمال نظريةِ الكثافة الوظيفية ) Density Functional Theory (DFT) methods في الطور المائي لحساب الخواص الجزيئية لمشتقات bichalcophenes . السمات الالكترونية المسؤولة عن النشاط المانع للتاكسد التي تمت دراستها لهذه المشتقات هي: Mullikan net charge لذرة الاكسجين (-O) ، طاقة HOMO وطاقة LUMO وفرق الطاقة بينهما (ΔE) والجهد الايوني وعزم ثنائي القطب. وقورنت هذه العوامل مع مقدار منع التاكسد التي تم الحصول عليها معمليا. وجد ان ذرة الاكسجين في الموقع الثالث عشر في هذه المشتقات تحتوي علي اكبرشحنة الكترونية مما يجعل إرتباط المعدن بالاكسجين في الموقع الثالث عشر. ووجد أن النشاط المانع للتاكسد يزيد بنقصان فرق الطاقة (ΔE) وزيادة الشحنة. ووجد ان ترتيب كفاءة منع التاكسد في هذه المركبات كما يلي:- 6B > 1B > 3B > 1A > 3A نفس النتيجة التي تم الحصول عليها عمليا. واعتمادا علي هذه النتائج يمكن نمذجة مركبات جديدة ذات نشاط مانع للتاكسد بدرجة عالية