UC Berkeley

Chapter 1. The amido ligand –N(SiiPr3)DIPP (DIPP = 2,6-diisopropylphenyl) was used to prepare two-coordinate complexes of CrI, CrII, and CrIII. The two-coordinate CrII complex was employed to prepare a three-coordinate CrIII iodide complex, which then afforded access to a stable CrIII methyl species.

Chapter 2. Products resulting from the reduction of various CrIII complexes supported by the silylarylamido ligand –N(SiMe3)DIPP (DIPP = 2,6-diisopropylphenyl) were synthesized and characterized. The solid state structure of a dimeric chromium species, in which the ligands have undergone C–H bond activation, is also reported.

Chapter 3. Products from reduction and attempted oxidations of low-coordinate manganese complexes supported by silylarylamido ligands –N(SiR3)DIPP2 (R = Me or iPr; DIPP = 2,6-diisopropylphenyl) were synthesized and characterized. Steric differences were found to have a noticeable effect on structure and even coordination number. In addition, the reduction of Mn[N(SiMe3)DIPP]2 under nitrogen afforded a dinitrogen-bound dimeric species.

Chapter 4. Divalent complexes of vanadium were synthesized employing bulky silyl(aryl)amido ligands –N(SiiPr3)DIPP and –N(SitBu2Me)DIPP (DIPP = 2,6-diisopropylphenyl). Solid-state structural characterization revealed that although the ligand –N(SiiPr3)DIPP supports a rare two-coordinate complex of vanadium, its constitutional isomer –N(SitBu2Me)DIPP affords a homoleptic complex in which the vanadium center is sandwiched between the arene rings, an unusual binding mode for arylamido ligands. Magnetometry studies indicate that V[N(SiiPr3)DIPP]2 and V[(η5-DIPP)N(SitBu2Me)]2 have similar high-spin d3 electron configurations. However, spectroscopic methods, including electron paramagnetic resonance, nuclear magnetic resonance, infrared, and UV-visible spectroscopies, suggest that V[N(SiiPr3)DIPP]2 is stereochemically nonrigid in solution while V[(η5-DIPP)N(SitBu2Me)]2 is not. This nonrigidity explicitly impacts the reactivity of V[N(SiiPr3)DIPP]2, which can be used to access both amido-bound and arene-bound complexes. In addition, these divalent complexes exhibit rich reduction and oxidation chemistry. Both vanadium(II) complexes can be reduced to anionic vanadium(I) species, {V[(η5-DIPP)N(SiiPr3)]2}− and {V[(η5-DIPP)N(SitBu2Me)]2}−. Moreover, treatment of V[N(SiiPr3)DIPP]2 with single and multi-electron oxidants reveals a range of transformations including an intramolecular C–H bond activation.