Process for photocatalysis and two-electron mixed-valence complexes

A process, comprising:

• providing a reaction medium comprising:
• a protic solution;
• a photocatalyst comprising a binuclear transition metal complex and a ligand capable of supporting the photocatalyst in a two electron mixed valence state;
• and
• a coproduct trap;
• and
• photoexciting the photocatalyst to produce hydrogen and eliminate halogen atoms.

A process, comprising:

• exciting at least two photocatalysts to an active state, wherein the photocatalysts comprises two rhodium atoms;
• contacting the photocatalysts with hydrogen ions and halogen ions of a hydrohalic acid solution, thereby producing hydrogen and a photocatalyst in a mixed valence state comprising halogen atoms;
• and
• irradiating the photocatalyst in a mixed valence state to eliminate at least a portion of the halogen atoms.

A process, comprising:

• irradiating a transition metal complex comprising:
• two rhodium atoms,
• three bis(difluorophosphine) methyl amine ligands, and triphenyl phosphine;
• in a solution comprising hydrohalic acid and a halogen trap.

A process, comprising:

• providing a reaction medium comprising:
• a protic solution;
• a photocatalyst capable of a two electron reduction of hydrogen ions, wherein the photocatalyst comprises:
• a binuclear transition metal core;
• and
• at least one chelating ligand coordinated to one transition metal of the binuclear transition metal core;
• and
• a coproduct trap;
• exposing the reaction medium to radiation capable of photoexciting the photocatalyst to produce hydrogen.