Visible‐light Homogeneous Photocatalytic Conversion of CO 2 into CO in Aqueous Solutions with an Iron Catalyst

An iron‐substituted tetraphenyl porphyrin bearing positively charged trimethylammonio groups at the para position of each phenyl ring catalyzes the photoinduced conversion of CO 2 . This complex is water soluble and acts as a molecular catalyst to selectively reduce CO 2 into CO under visible‐light irradiation in aqueous solutions (acetonitrile/water=1:9  v / v ) with the assistance of purpurin, a simple organic photosensitizer. CO is produced with a catalytic selectivity of 95 % and turnover number up to 120, illustrating the possibility of photocatalyzing the reduction of CO 2 in aqueous solution by using visible light, a simple organic sensitizer coupled to an amine as a sacrificial electron donor, and an earth‐abundant metal‐based molecular catalyst.