Efficient Near‐Infrared‐Light‐Driven H₂ Production with Salts of a Diprotonated Saddle‐Distorted Porphyrin as Photosensitizers

Development of near‐infrared (NIR)‐light‐driven photocatalytic hydrogen (H 2 ) production is indispensable for an efficient use of solar energy in a sustainable society. Herein, a strategy is reported for achieving higher quantum yields of NIR‐light‐driven photocatalytic H 2 production using salts of diprotonated dodecaphenylporphyrin (H 4 DPP 2+ (X − ) 2 ), showing large saddle distortion as organic photosensitizers and platinum nanoparticles as catalysts. When a perchlorate ion (ClO 4 − ) is employed as a counter ion (X − ) of H 4 DPP 2+ (X − ) 2 , the quantum yield of the photocatalytic H 2 production reaches to 36% by excitation at 750 nm, which is the highest value among those of NIR‐light‐driven H 2 production reported so far. Such a drastic enhancement of the quantum yield is achieved by selection of X − as an appropriate counter anion of H 4 DPP 2+ , judging from second‐order rate constants of photoinduced electron transfer (ET) from electron donors to 3 (H 4 DPP 2+ (X − ) 2 )* and the reorganization energy of ET for H 4 DPP 2+ (X − ) 2 .