Oxidation is an important tool for imparting value to carbon-based feedstocks derived from natural gas and petroleum refining. For its large-scale implementation, the oxidant employed in oxidation reactions must be cost effective and environmentally friendly. Molecular oxygen or O2 is thus highly attractive as an oxidant. Achieving high selectivity in aerobic transformations, specifically in oxygen atom transfer from O2 to the substrate (oxygenase type oxidation), however, is often challenging. This thesis aims to address this problem of selectivity via the development of new homogenous Platinum Group Metal (PGM) complexes for oxygen activation and oxygen atom transfer. The designs of these complexes bearing protic ligands are inspired from both synthetic and biological examples. Chapter 2 and 3 outline the syntheses, characterization, and oxygenation of Ir, Rh, and Pd complexes bearing protic PN ligands. The synthetic aprotic variants of all these complexes have been previously shown to react productively with O2. Chapter 4 describes the synthesis of a novel bioinspired protic ONN ligand and the O2 reactivity of its Ir-complex. Chapter 5 attempts to deconvolute the role of protons in those systems where their involvement is suspected.