Hydrogen tetrachloroaurate 3 tetrahydrate

All reagents were used as received, without further purification. Hydrogen tetrachloroaurate(III) tetrahydrate (HAuCl₄·4H₂O, 99.0%) was purchased from Kanto Chemical Co., Inc. Silver(I) nitrate (AgNO₃, >99.9%) was purchased from Kojima Chemicals Co., Ltd. Tetrabutyl ammonium bromide {TBABr, [N(C₄H₉)₄]Br, >98.0%}, triethylamine [N(C₂H₅)₃, >99.0%], tetrakis(triphenylphosphine)palladium(0) [Pd(PPh₃)₄, >97.0%], and tetrakis(triphenylphosphine)platinum(0) [Pt(PPh₃)₄, >97.0%] were purchased from Tokyo Chemical Industry Co., Ltd. Sodium borohydride (NaBH₄, 95.0%), triphenylphosphine (PPh₃, 97.0%), 12 molybdo(VI) phosphoric acid n-hydrate [H₃(PMo₁₂O₄₀)·nH₂O, >95.0%], disodium molybdate(VI) dihydrate (Na₂MoO₄·2H₂O, >99.0%), disodium tungstate(VI) dihydrate (Na₂WO₄·2H₂O, 99.0%–100.5%), hydrochloric acid (HCl, 35.0%–37.0%), and acetic anhydride [(CH₃CO)₂O, >97.0%] were purchased from Wako Pure Chemical Industry.

Hydrogen tetrachloroaurate(III) tetrahydrate (HAuCl₄·4H₂O > 99%), urea (CH₄N₂O > 99.0%), benzylamine (C₇H₉N >98.0%), and 2-naphthol (C₁₀H₈O > 99.0%) were purchased from Kanto Chemical Co. Cinnamyl alcohol (C₉H₁₀O > 97.0%) was purchased from Tokyo Chemical Industry Co. Titanium bis(ammonium lactate) dihydroxide ([CH₃CH(O⁻)CO₂NH₄]₂Ti(OH)₂, 50 wt% in H₂O) solution was purchased from Sigma-Aldrich Co. Irregular-shaped anatase TiO₂ particles (mean particle size = 150 nm, specific surface area = 8.1 m² g⁻¹, A-100, Ishihara Sangyo) and rutile-TiO₂ particles (mean particle size = 80 nm, specific surface area = 18 m² g⁻¹, MT-700B, TAYCA) were used as the TiO₂ supports. All chemicals were used as received without further purification.