Structural and mechanistic aspects of copper catalyzed atom transfer radical processes

In this work, structural and mechanistic aspects of copper catalyzed atom transfer radical processes were discussed. Chapter 1 focused on the fundamentals of transition metal catalyzed atom transfer radical addition (TMC ATRA) and polymerization (ATRP) and extensively reviewed literature sources in both areas. In Chapters 2–6, various techniques used to study the structural features of copper(I) and copper(II) complexes employed in the ATRP were presented. The Electrospray Ionization Mass Spectrometric (ESI-MS) study of copper(I) and copper(II) complexes with bipyridine based ligands in polar and nonpolar medium were discussed in Chapter 2. In Chapter 3, the synthesis and characterization of novel CuII(dNbpy)Br₂ complex which is used in the reverse ATRP were presented. The molecular structures of [CuII(dNbpy) ₂Br]+[CuIBr₂]−, Cu II(PMDETA)Br₂, CuII(tNtpy)Br₂, [CuII(HMTETA)Br]+[Br]− and [CuII(Me₄CYCLAM)Br]+[Br] − isolated from ATRP solutions were reported in Chapter 4. Furthermore, in Chapter 5, the structural features of copper(I) and copper(II) complexes with nitrogen based ligands were studied in solution using Extended X-ray Absorption Fine Structure (EXAFS). In the last part of the structural studies, the role of monomer coordination to the copper(I) complexes was addressed and the isolation and characterization of novel copper(I) complexes with π-coordinated vinyl monomers, [Cu I(PMDETA)(π-CH₂CHR)]+[BPh₄] −− (R=COOCH₃ and C₆H ₅), were reported.; In Chapters 7–9, results of the mechanistic investigation of the ATRP systems were presented. In Chapter 7, the analytical solution of the persistent radical effect was used to determine the equilibrium constant for atom transfer for a series of alkyl bromides and copper(I) complexes that are commonly used in the ATRP. In Chapter 8, the equilibrium constant for atom transfer was correlated with the equilibrium constant for bromide dissociation from ATRP active copper(II) complexes and corresponding redox potentials. Lastly, a general method to determine the activation (k _a), deactivation (k_d) and initiation (k_i) rate constants by monomer trapping of the initiating radicals and the analytical solution of the persistent radical effect in ATR processes was reported ( Chapter 9).