Single-chromophore single-molecule photocatalysts for the conversion and storage of solar energy into chemical bonds are rare, inefficient and do not use significant portions of the visible spectrum. Here we show a new, air-stable bimetallic scaffold that acts as a single-chromophore photocatalyst for hydrogen-gas generation and operates with irradiation wavelengths that span the ultraviolet to the red/near-infrared. Irradiation in acidic solutions that contain an electron donor results in the catalytic production of hydrogen with 170 ± 5 turnovers in 24 hours and an initial rate of 28 turnovers per hour. The catalysis proceeds through two stepwise excited-state redox events—atypical of the currently known homogeneous photocatalysis—and features the storage of multiple redox equivalents on a dirhodium catalyst enabled by low-energy light.

用于将太阳能转化和储存成化学键的单发色团单分子光催化剂是稀有的、低效的并且不使用大部分可见光谱。在这里，我们展示了一种新的、空气稳定的双金属支架，它充当用于产生氢气的单发色团光催化剂，并在从紫外到红/近红外的辐照波长下工作。在含有电子供体的酸性溶液中进行辐照会导致在 24 小时内催化产生 170 ± 5 次循环，初始速率为每小时 28 次。催化通过两个逐步激发态的氧化还原事件进行——这不是目前已知的均相光催化的典型特征——其特点是在低能光的二铑催化剂上存储多个氧化还原当量。