Chloride oxidation has tremendous utility in the burgeoning field of chlorine-mediated C–H activation, yet it remains a challenging process to initiate with light because exceedingly positive one-electron reduction potential, E° (Cl•/–), beyond most common transition-metal photooxidants. Herein, two photocatalytic chloride pathways that involve either one- or consecutive two-photon excitation N-phenylphenothiazine (PTH) are presented. The one-photon pathway generates PTH•+ by oxidative...

The synthesis and metalation of two bis(phosphine)/dihydrosilyl ligands at rhodium(I) sources is reported. Irrespective the substitution silicon (diaryl versus diamino), multiple Si–H activations chloride migration afford tridentate bis(phosphine)/chlorosilyl complexes Rh(I). For diarylsilyl ligand, reaction with a cationic triflate precursor gives analogous triflatosilyl complex. [P2Si]H2 proligands their Rh provide distinct opportunities for exploring metal/silicon cooperative reactivity.

A bis(phosphine)/triflatosilyl pincer-type Rh(i) complex can reversibly store one equivalent of H2 across the Si-Rh bond upon triflate migration from silicon to rhodium. The triflatosilyl serves as an effective precatalyst for norbornene hydrogenation, but Si-OTf cleavage is not implicated in major catalytic pathway. combined findings suggest possible strategies M/Si cooperation processes.

The standard one-electron reduction potentials of halogen atoms, E°'(X•/-), and many other radical or unstable species, are not accessible through electrochemical methods. Here, we report the use two Ir(III) photoredox catalysts to initiate chloride, bromide, iodide oxidation in organic solvents. kinetic rate constants were critically analyzed a derived diffusional model with Marcus theory estimate E°'(X•/-) propylene carbonate, acetonitrile, butyronitrile, dichloromethane. approximations...

Transition-metal photocatalysts capable of oxidizing chloride are rare yet serve as an attractive means to controllably generate chlorine atoms, which have continued garner the interest researchers for notable applications in photoredox catalysis and solar energy storage. Herein, a new series four Ir-photocatalysts with different dicationic chloride-sequestering ligands were synthesized characterized probe relationship between binding affinities, ion pair solution structures, rate constants...

Stabilization of ions and radicals often determines reaction kinetics thermodynamics, but experimental determination the stabilization magnitude remains difficult, especially when species is short-lived. Herein, a competitive kinetic approach to quantify halide ion toward oxidation imparted by specific stabilizing groups relative solvated reported. This provides increase in formal reduction potential, ΔE°'(Χ•/-), where X = Br I, that results from noncovalent interaction with groups. The...

The preassociation of reactants in a photoinitiated redox reaction through the use noncovalent interactions can have significant impact on excited state reactivity. As these render some stabilization to associated species, they kinetics and thermodynamics electron transfer. Reported herein is novel iridium(III) photocatalyst, equipped with an anion-sensitive, amide-substituted bipyridine ligand, its reactivity halides (X = I–, Br–, Cl–) acetonitrile dichloromethane. A noteworthy periodic...

A series of ruthenium polypyridyl photocatalysts bearing amide functional groups were designed that successfully promoted halide assembly in CH2Cl2 and CH3CN solution. In CH2Cl2, was accompanied by a visible color change, the spectral changes presented clear evidence for two binding events, yielding 1:2 ruthenium:halide assembly. more polar solvent CH3CN, structures also observed with chloride, bromide, iodide, large equilibrium constants measured association first second (K11 = 0.04 – 2 ×...