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This thesis describes the synthesis and reactivity of α-diimine group 10 metal catalysts that contain hydrogen-bonding (H-bonding) groups in the second coordination sphere and the effect of H-bonding groups on the copolymerization of ethylene with polar monomers. Chapter One provides a brief introduction to ethylene polymerization and the copolymerization of ethylene with polar monomers using α-diimine Pd catalysts. The relationship between ligand structure and reactivity of ethylene/polar-monomer copolymerization was discussed, and the main challenges of (α-diimine)Pd-catalyzed ethylene/polar-monomer copolymerization were mentioned. This chapter includes a summary of the objectives of this thesis. Chapter Two describes the synthesis, coordination chemistry, and reactivity of a class of (Ar-N=CMeCMe=N-Ar’)Pd complexes that contain ortho-amide substituents on the N-aryl (Ar and Ar’) rings. H-bonding interactions involving the amide groups influence the structures, isomer distributions, and ligand coordination behavior of these compounds. Chapter Three describes the synthesis of second-generation amide-functionalized (α-diimine)Pd catalysts [{2,6-(CHPh2)2-4-Me-Ph}-N=CMeCMe=N-(2-CONHMe-6-iPr-Ph)]PdMeCl (1d,d’) and [{2,6-(CHPh2)2-4-Me-Ph}-N=CMeCMe=N-(2-CONMe2-6-iPr-Ph)]PdMeCl (1e,e’). Replacement of two isopropyl groups of the first-generation catalysts {(2,6-iPr2-Ph)-N=CMeCMe=N-(2-CONHMe-6-iPr-Ph)}PdMeCl (1a,a’) and {(2,6-iPr2-Ph)-N=CMeCMe=N-(2-CONMe2-6-iPr-Ph)}PdMeCl (1b,b’) with the more steric demanding benzhydryl (-CHPh2) groups in 1d,d’ and 1e,e’ was expected to significantly improve ethylene polymerization performance. Activation of 1d,d’ and 1e,e’ by NaB{3,5-(CF3)2C6H3}4 generates active ethylene polymerization catalysts that produce highly branched (77-81 br/1000C) polyethylenes with a moderate MW (Mn ca. 26-60 kDa). The replacement of two isopropyl units in the catalysts 1a,a’ and 1b,b’ with benzhydryl groups leads to a significant improvement on the overall homopolymerization performance. The H-bonding catalyst 1d,d’ is capable of incorporating ca. 2 times as much methyl acrylate and ca. 3 times as much acrylic acid as the non-H-bonding catalyst [{2,6-(CHPh2)2-4-Me-Ph}-N=CMeCMe=N-(2,6-iPr2-Ph)]PdMeCl (1f,f’) in the copolymerization with ethylene. The reactions of 1a,a’ and 1b,b’ with metal salts that contain weakly coordinating anions lead to extrusion of CH4 and the formation of μ-CH2 complexes, in which the amide carbonyl O-atoms coordinate to Pd centers. Chapter Four describes the coordination chemistry and ethylene polymerization behavior of amide-functionalized (α-diimine)Ni complexes. The α-diimine ligands (2,6-iPr2-Ph)-N=CMeCMe=N-(2-iPr-6-CONMe2-Ph) (L1) and (2,6-iPr2-Ph)-N=CMeCMe=N-[2,6-(CONMe2)2-Ph] (L2) react with (dme)NiBr2 to form the five-coordinate paramagnetic complexes (L1)NiBr2 (1) and (L2)NiBr2 (2), in which one amide oxygen atom and the two imine nitrogen atoms of L1 and L2 coordinate to the Ni center. L1 reacts with (py)2NiMe2 to form the diamagnetic, square planar 4-coordinate complex (L1)NiMe2 (3). Activation of 1 with Et2AlCl generates an ethylene polymerization catalyst that produces semicrystalline polyethylene with a broad molecular-weight (MW) distribution. Chapter Five describes the synthesis of 2,3-dihydroquinazolin-4(1H)-one compounds 4a, 5a and 6a, and their facile C-C cleavage reactions triggered by autoxidation. 2-Acyl-2,3-dihydroquinazolin-4(1H)-one compounds 4a and 5a undergo facile C-C cleavage reactions with O2 by a radical mechanism. The reaction pathway is dependent on the structure of substrate. The strained spirocyclic 4a undergoes ring expansion by 1,2-acyl migration to form a C-based radical followed by trapping with O2. Compound 5a, in which the 2-acetyl is not part of a cyclic structure, undergoes fragmentation to generate acetyl radical, which is trapped by O2 to form peracetic acid. Bis(dihydroquinazolinone) 6a undergoes C-C cleavage and formal dehydrogenation by O2. Chapter Six describes the synthesis and structure of an unusual Pd complex that contains the α-aminoimine ligand 6-Me-4-iPr-6-(dippN=C(Me))-6,11-dihydro-5H-indolo[3,2-c]quinoline (6). Ligand 6 coordinates in a κ2-C=N,NH fashion in the square planar complex (6)PdCl2. Chapter Seven describes the synthesis, coordination chemistry, and conformational isomerism and dynamics of chiral menthyl-substituted α-diimine ligands N,N’-(2-Men-4-Me-Ph)-BIAN (L1, BIAN = bis(imino)acenaphthene) and N,N’-(2-Men-4,6-Me2-Ph)-BIAN (L2). The syn conformation, in which the two menthyl groups face each other on the same side of N=C-C=N plane, is favored for L1, L2 and square planar complexes of these ligands, possibly due to attractive dispersion interactions between the two menthyl groups. In contrast, the anti conformation is favored for tetrahedral complexes of L1 and L2, and both menthyl iPr units point to the acenaphthene backbone. The anti,syn isomerization of square planar complexes (L1)Ni(acac)-anti,syn is facile at room temperature. Square planar complexes (L2)Ni(acac)-anti,syn are kinetically stable at room temperature, and the syn isomer produces polyethylene with a higher MW and branching level than the anti isomer. The syn isomer also produces poly(1-hexene) with less branches and a higher degree of chain-straightening compared to the anti isomer. These differences in polymerization behavior are attributed to the significantly different steric profiles of the two isomers.


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