The photochemistry of chloro(triphenylphosphine)gold(I) and trichloro(triphenylphosphine)gold(III) in chloroform

AuCl(PPh3) in chloroform under 254 nm irradiation is converted to AuCl3(PPh3), which is itself converted photochemically to HAuCl4. The absorption of light by both AuCl(PPh3) and the solvent lead to oxidation to AuCl3(PPh3), but the photosubstitution of AuCl3(PPh3) is solely metal-initiated. The latter photoreaction frees up PPh3, which reacts thermally with HAuCl4 to yield AuCl3(PPh3) and with AuCl3(PPh3) to yield AuCl(PPh3) and PPh3Cl2.