Search or add a thesis

Advanced Search (Beta)
Home > Synthesis of Ag I -N-Heterocyclic Carbene and Cyclonickellated Complexes for Chemical and Biological Studies

Synthesis of Ag I -N-Heterocyclic Carbene and Cyclonickellated Complexes for Chemical and Biological Studies

Thesis Info

Access Option

External Link

Author

Habib, Aqsa

Program

PhD

Institute

University of Agriculture

City

Faisalabad

Province

Punjab

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11362/1/Thesis-Aqsa%20Habib-PhD%20chemistry%20%28UAF%29.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727477712

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


Metal complexes exhibit a wide variety of functional groups in drug designing and development due their vaious chemical properties, coordination modes, geometries and reactivities. Organonikellated and silver complexes have become attractive tool in the field of catalytic as well as medicinal chemistry. The present project was designed to synthesize new series of silver-N-Heterocyclic carbene (NHC) and cyclonickellated complexes. Various NHC based as well as phosphine/phosphinite based precursors were designed leading to the synthesis of target silver and nickel complexes, respectively. Three series (A-C) of novel mono- and bisimidazolium salts (1a-16a, 1b-12b, 1c-7c) as ligands and their mono, di, tri and polynuclear silver complexes (17a-20a, 13b-20b, 8c-12c) were synthesized. The corresponding silver(I) aducts were afforded by the in situ deprotonation of the NHC based ligands. Some of the NHC salts (7a-12a) of series A were found to be difficult to react with silver due to steric factor (bulky alkyl substituents attached to them), so their silver complexes could not be synthesized. The synthetic approaches of the ligands of series B were controlled by the methyl substituents attached to the backbone of benzimidazole imposing significant impact on the reactivity by the virtue of their aptitude to enhance sigma electron donating ability of ligands. The precursors and silver complexes were well characterized by FTIR, GC-MS, 1H, 13C (one and two dimensional), 31P and 19F NMR, elemental analysis, melting points, ESI-MS and single crystal X-ray crystallographic techniques. Adopting a different protocol of synthesis using excess of reactant, an interesting trinuclear silvercomplex (8c) was synthesized. After successful syntheses, the silver complexes were employed to study their redox potentials by cyclic voltammetry. The quasi reversibility and irreversibility of redox events in the electrochemical study of silver complexes indicated that the reduction event produces unstable decomposed species and oxidation event may be ascribed to decomposed species. Azolium salts and their Ag(I)-NHC complexes were tested in vitro against Bacillus subtillis, Macrococcus brunensis, and Bacillus cereus to study their antibacterial activity and against MDA-MB-231 and HCT116 cells to study their anticancer potential. All compounds were observed to pose potential antibacterial and anticancer activity, however, silver-NHC complexes were found relatively more potent compared to the corresponding NHC precursors (salts). Only few salts were found inactive, while their complexes were observed to be active concluding that the silver imparts greater anticancer potential to the compounds. Being air and moisture sensitive, cyclonickellated complexes could not be utilized for evaluation of their antimicrobial, anticancer or redox potential, however, the attempts were made to study their functionalization behaviour under inert atmosphere. It was observed that the coordination of PR2 moiety into CNi bond is apparent from the initial colour change and shift of 31P NMR and 19F NMR signals but final products of insertion remained difficult to be analyzed as they usually decomposed or appeared NMR silent after workup.In order to understand the feasibility of reaction and to evaluate the properties of product of insertion, further attempts were made to get target complexes via different way by synthesizing phosphine-phosphinite ligands and reacting them with nickel precursor. Appearance of specific signals in NMR spectra of few products provided some evidences of formation of the target products but later the products decomposed and signals disappeared. Thus the products of all reactions were very difficult to identify by NMR either due to paramagnetic nature or decomposition of products and crystallization attempts remained unsuccessful so their structures remained ambiguous as no other technique could help to study them due to their air/moisture sensitivity. On the whole the present project provided useful information for drug designing and chemical transformation studies.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

مو لانا فضل اﷲ رحمانی

مولانا فضل اﷲ مرحوم
معارف ابھی زیر ترتیب ہی تھا کہ مولانا فضل اﷲ صاحب رحمانی کے انتقال کی اطلاع ملی، مرحوم اپنے علم و فضل تقویٰ و طہارت، اور شرافت و حسن اخلاق میں سلف صالحین کا نمونہ تھے، راقم الحروف کو ان کی خدمت ایک عرصہ سے نیاز حاصل تھا، جب علی گڑھ جانا ہوتا تو ان کے یہاں ضرور حاضری دیتا، اور وہ بھی پیرانہ سالی اور ضعف جسمانی کے باوجود بازدید کے لیے تشریف لاتے اور دیر تک دینی و علمی گفتگو فرماتے میرا قیام سرسید نگر میں اپنے لڑکے ڈاکٹر محمد سالم قدوائی کے مکان بیت الفرح میں ہوتا ہے اور مولانا امیر نشان میں اپنی صاحبزادی روقہ بیگم کے یہاں رہتے تھے، امیر نشان سے سرسید نگر کا فاصلہ اچھا خاصا ہے، میں نے کئی بار عرض بھی کیا کہ آپ اتنی تکلیف گوارا نہ کیا کریں، میں جب تک علی گڑھ میں رہوں گا خود ہی حاضر ہوتا رہوں گا مگر انھوں نے اخلاق کریمانہ کی بنا پر میری اس درخواست کو کبھی قبول نہیں کیا، ایسی خورد نوازی کی مثالیں بہت کم ملتی ہیں، میں ان سے عمر میں بھی بہت چھوٹا تھا، اور علم و فضل میں تو ان سے کوئی نسبت ہی نہ تھی، میں ذرہ بے مقدار اور وہ آفتاب علم و کمال، یہ محض ان کی بزرگانہ شفقت تھی، اور اس تعلق خاطر کا اظہار تھا، جو انھیں ندوہ کے خادموں کے ساتھ تھا، دو ندوۃ العلماء کے بانی اور ناظم اول مولانا محمد علی مونگیری کے پوتے تھے، والد کا نام مولانا احمد علی تھا، وہ علم و فضل، صلاح و تقویٰ، محاسنِ اخلاق اور عقل و ذہانت میں بہت ممتاز تھے، ان کی نو عمری کے زمانہ میں ایک طرف مستشریوں کا بڑا زور تھا جو آئے دن اسلام کے خلاف کتابیں لکھتے...

برصغیر میں محدثین کی خدمات حدیث: تاریخی و تجزیاتی جائزہ

After the Prophet r the Muslims all over the world associate themselves with him by following his pious deeds and acting upon his sayings (Hadith). The Muslims of the sub-continent have been very zealous in this respect and have done great job in this regard. In the subcontinent, the sayings of the Holy Prophet reached with Islam during the era of pious caliphs. In those days, according to some traditions, 25 companions of the Holy Prophet ﷺ Sahaba (R. A) and 42 Tabe-ien (those who had seen the Sahaba R. A i-e their successors) came to India and preached Islam. This preaching was continued by later Muslims and the rulers like Mohammad Bin Qasim and Mehmood Ghaznavi. The services of great Muhaddeseen (narrators and illustrators of the sayings of the Holy Prophet r like Musa Bin Yaqoob, Yazid Bin Abi Kabsha, Abu Musa Israeel Bin Musa and Abu Hafs Rabi Bin Sabih are note worthy. They provided local people the knowledge of Hadith. These scholars earned fame and prestige by their great works in this field. Shah Waliuallah wrote Mussffa and Maswwa, in subcontinent there are great many institutions like Jamia Salfiya Faisalabad, Jamia Ashrafia Lahore, Jamia Naeemia Lahore, Khair- ul-Madaras Multan, Jamia Mohammadia Gujranwala, Dar-ul-Hadith Delhi and Jamia Salfiya Banaras to teach the knowledge of Hadith.

Social Capital As a Determinant of Individuals Entrepreneurial Engagement: A Moderated Mediation Model

Entrepreneurial activity is essential to ensure the economic stability of any country. The rate of entrepreneurial activity is high in developed countries, yet remains lower in developing nations. This research was conducted to examine the factors affecting the entrepreneurial behaviors of individuals in the developing country of Pakistan. Chapter 1 is an introductory chapter that presents an overview of this study, discusses the background of the research problem, and develops the research questions. Moreover, it highlights the ways in which this study enriches the existing literature. This study aimed to evaluate the direct effects of social capital on entrepreneurial attitude (EA) and the mediating effects of self-efficacy and social norms in this relationship. Moreover, this study examined the moderating effect of gender on entrepreneurial intention (EI) via self-efficacy and social norms. Chapter 2 reviews the existing literature, while highlighting the gap in the research. This study is unique in the way it analyzes the multi-mediation effect on EI, which further leads to entrepreneurial behavior. The literature affirms that EI followed by EA further leads toward entrepreneurial behavior. However, this study evaluates the direct and indirect effects of social capital on building both EA and EI. Moreover, the literature asserts that social norms are more associated with women, while self-efficacy is more associated with men. This study observes the effect of these associations on EI with the mediating role of EA. Further, this study is conducted in Pakistan, which represents the South Asian context. The hypothetical model presented in this study is tested in this developing country, which differentiates the results of this study from those found in developed country contexts. Moreover, this study exhibits the research model based on the hypotheses presented in this study. The theoretical model of this study is based on the theory of planned behavior with incorporation of gender schema theory. Moreover, it caters the existing literature on the behavioral determinants. This study posits that social capital affects the EA of individuals on the basis of role modeling and motivation, which causes individuals to believe in themselves and increases their self-efficacy. Thus, this study examines the moderation and mediation effects together. Chapter 3 presents the research methodology followed in this study. As a descriptive study, the data were collected through a questionnaire with graduate and undergraduate students of management and business studies from different universities in Pakistan. In this longitudinal study, a positivism paradigm was applied. Structural equation modeling (SEM) was used for the model testing. We used the test of moderation by applying the process (Bolin, 2014) to test the moderation effect of gender. Chapter 4 presents the data analysis. To validate the measurement tool in the South Asian context, we used confirmatory factor analysis in AMOS. The results depicted that all the variables were reliable, and established convergent and discriminant validity. Following this, to test the theoretical model of the study, the direct and indirect effects were examined through SEM. The findings of the study revealed that social capital affects EA and EI via the mediation of self-efficacy and social norms. EI leads toward entrepreneurial behavior. In addition, the findings indicate that gender moderates the effects of social norms and selfefficacy on both EA and EI. Chapter 5 presents the conclusion and recommendations, which comprises the discussion, research implications, research limitations, and conclusion. The results demonstrate that social capital more significantly affects EA when it is linked with the social norms and selfefficacy of individuals. In addition, social norms are more associated with female individuals, while self-efficacy affects both genders equally. Moreover, EA moderates the effect of social capital on EI in such a way that it is higher among male individuals. These findings offer practical implications to policymakers.