Photolytic Activation of Late-Transition-Metal–Carbon Bonds and Their Reactivity toward Oxygen

The photolytic activation of palladium(II) and platinum(II) complexes [M(BPI)(R)] (R = alkyl, aryl) featuring the 1,3-bis(2-pyridylimino)isoindole (BPI) ligand has been investigated in various solvents. In absence oxygen, formation chloro [M(BPI)Cl] is observed chlorinated solvents, most likely due to degradation solvent HCl. reactivity toward oxygen studied both experimentally computationally. Excitation by UV irradiation (365 nm) metal [Pt(BPI)Me] [Pd(BPI)Me] leads distortion square-planar coordination geometry excited triplet state a change electronic structure that allows interaction with oxygen. TD-DFT computational studies suggest that, case palladium, Pd(III) superoxide intermediate [Pd(BPI)(κ1-O2)Me] formed and, platinum, Pt(IV) peroxide [Pt(BPI)(κ2-O2)Me]. For alkyl where metal–carbon bonds are sufficiently weak, photoactivation insertion into bond generate alkylperoxo complexes: for example [Pd(BPI)OOMe], which isolated structurally characterized. stronger M–C(aryl) bonds, reaction [Pt(BPI)Ph] O2 light results complex, tentatively assigned as peroxo complex [Pt(BPI)(κ2-O2)Ph], solvents reacts further give [Pt(BPI)Cl2Ph], characterized scXRD. addition facilitation reactions, can also affect other components mixture, such or products, result reactions. Labeling using [Pt(BPI)(CD3)] chloroform have shown reactions involve solvent.