Graduation Semester and Year
Spring 2025
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Chemistry
Department
Chemistry and Biochemistry
First Advisor
Dr. Rasika Dias
Second Advisor
Dr. Frederick MacDonnell
Third Advisor
Dr. Krishnan Rajeshwar
Fourth Advisor
Dr. Subhrangsu Mandal
Abstract
This thesis explores the evolution and applications of diverse ligand systems and their coordination with coinage metals, emphasizing their roles in organometallic chemistry and catalysis. Ligand frameworks such as phenanthroline, poly(pyridyl)borate, and pyrazolate systems are highlighted in this work for their electronic and structural versatility, enabling advances in areas like coordination chemistry, catalysis and materials science. The ligand systems have been tuned sterically and electronically by incorporating electron-withdrawing groups like trifluoromethyl groups to synthesize and isolate coinage metal ethylene, carbonyl, triphenylphosphine, and t-butyl isocyanide complexes. These complexes showcase their unique coordination geometries, reactivities, and catalytic applications specifically, C–H bond activation and for sensing small anions. This work underlines the importance of ligand systems in shaping modern organometallic chemistry and their potential for future innovations.
Chapter 1 provides an overview of key ligand systems and metal-ligand interactions that have shaped modern organometallic chemistry. The discussion begins with the historical development and bonding principles of metal-olefin and metal-carbonyl complexes, highlighting their impact on catalysis and industrial applications. The chapter then explores poly(pyrazolyl)borate and poly(pyridyl)borate ligand systems, emphasizing their structural diversity, synthetic versatility, and utility in stabilizing transition metal complexes. Furthermore, the significance of phenanthroline ligands in coordination chemistry is examined, particularly in the context of catalysis, photochemistry, and electrochemical applications. Lastly, the structural and functional properties of coinage metal pyrazolates are reviewed, showcasing their relevance in gas separation, catalysis, and luminescent materials. Through this comprehensive analysis, the chapter establishes a foundational understanding of metal-ligand interactions, which is essential for subsequent discussions in this dissertation.
Chapter 2 contains the synthesis and application of phenanthroline-based ligand systems to support and isolate coinage metal ethylene and carbonyl complexes. This chapter explores the synthesis of sterically demanding, fluorinated, and nonfluorinated 1,10-phenanthroline ligand systems i.e. 2,9-bis(2,4,6-triisopropylphenyl)-1,10-phenanthroline and 2,9-bis(2,4,6- trifluoromethylphenyl)-1,10-phenanthroline. This chapter discusses the isolation of coinage metal-based ethylene complexes supported by both ligand systems. Preliminary catalytic investigations underscore the potential of copper complexes, particularly those with weakly coordinating supporting ligands, as effective catalysts for C(sp3)-H functionalization through trifluoromethyl carbene insertion. Complementary electrochemical studies on Cu–ethylene complexes further demonstrate the electron-deficient character imparted by fluorinated ligands. Together, these results provide valuable insights into the role of ligand design in tuning coinage metal carbonyl chemistry.
Chapter 3 reports the first structurally characterized isoleptic series of coinage metal carbonyl complexes supported by sterically demanding phenanthroline ligands: [{2,9-bis(2,4,6-triisopropylphenyl)-1,10- phenanthroline}M(CO)][SbF6] (M = Cu, Ag, Au). To probe electronic effects, fluorinated analogues [{2,9-bis(2,4,6-trifluoromethyl)-1,10- phenanthroline}M(CO)][SbF6] (M = Cu, Ag) were also synthesized. Infrared and 13C NMR spectroscopy reveals systematic trends in metal–CO bonding, with copper showing moderate back-donation, silver exhibiting weak back-donation, and gold displaying distinct electronic behavior.
Chapter 4 focuses on a B-vinylated tris(pyridyl)borate ligand synthesis and explores its coordination chemistry with Cu(I) in the presence of ethylene, carbonyl, tert-butyl isocyanide, and triphenylphosphine. Structural and spectroscopic studies revealed dynamic ligand coordination behavior, with the vinyl group participating in copper coordination under certain conditions. The ligand’s electronic influence was evident in modulating Cu-ethylene and Cu-CO interactions, demonstrating its potential for tuning the properties of copper complexes. These findings highlight the versatility of vinyl-functionalized scorpionate ligands for designing new ligand frameworks with applications in catalysis and small-molecule activation.
Chapter 5 discusses the synthesis of trinuclear dimesitylboronfunctionalized Ag(I) pyrazolate complexes and their structural analysis. The Cu(I) and Ag(I) complexes were investigaed for their ethylene-binding properties. The CF₃-substituted Cu(I) complex showed reversible ethylene coordination, while variations in pyrazole substituents influenced Ag–N bonding, Ag···Ag interactions, and photophysical behavior. The study highlights the role of ligand electronics and metallophilic interactions in tuning the properties of coinage metal pyrazolate complexes.
Disciplines
Inorganic Chemistry
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Karade, Deepika Virendra, "SYNTHESIS AND PROPERTIES OF COINAGE METAL COMPLEXES SUPPORTED BY BULKY PHENANTHROLINE AND OTHER N-BASED DONORS" (2025). Chemistry & Biochemistry Dissertations. 284.
https://mavmatrix.uta.edu/chemistry_dissertations/284