A series of three dirhodium complexes cis-[Rh₂(DPhB)₂(bncn)₂](BF₄)₂ (1, DPhB = diphenylbenzamidine; bncn = benzocinnoline), cis-[Rh₂(DPhTA)₂(bncn)₂](BF₄)₂ (2, DPhTA = diphenyltriazenide), and cis-[Rh₂(DPhF)₂(bncn)₂](BF₄)₂ (3, DPhF = N,N′-diphenylformamidinate) shown to act as single-molecule photocatalysts for H₂ production was evaluated. Complexes 1–3 are able to generate H₂ in the absence of any other catalyst in homogenous acidic solution upon irradiation with red light in the presence of the sacrificial electron donor BNAH (1-benzyl-1,4-dihydronicotinamide). The excited state of each complex is reductively quenched by BNAH, producing the corresponding one-electron reduced complex. The latter is also able to absorb a photon and oxidize another BNAH molecule, producing the doubly-reduced, activated form of the catalyst that is able to generate H₂. The present work shows the effect of substitution on the bridging ligands on the driving force for reductive quenching and hydricity of the proposed active intermediate, both of which affect the efficiency of hydrogen production. Complexes 1–3 operate following a double reductive quenching mechanism and, importantly, are active with red light. This work lays the foundation for the design of single-molecule photocatalysts that operate from the ultraviolet to the near-infrared, such that solar photons throughout this entire range are harnessed and utilized for solar energy conversion.

中文翻译：

---

用于发红光双氢的全色dirhodium光催化剂

一系列三个dirhodium配合物顺-[Rh ₂（DPhB）₂（bncn）₂ ]（BF ₄）₂（1，DPhB =二苯基苯甲m; bncn =苯并肉桂碱），顺-[Rh ₂（DPhTA）₂（bncn）₂ ]（BF ₄）₂（2，DPhTA =二苯基三氮烯）和顺式-[Rh ₂（DPhF）₂（bncn）₂ ]（BF ₄）₂（3，DPhF = N，N评价了显示出用作H ₂产生的单分子光催化剂的'-二苯基甲酰胺基）。在牺牲电子供体BNAH（1-苄基-1,4-二氢烟碱酰胺）存在下，在红光照射下，在均相酸性溶液中不存在任何其他催化剂的情况下，配合物1-3能够生成H ₂。每个络合物的激发态被BNAH还原淬灭，产生相应的单电子还原的络合物。后者还能够吸收光子并氧化另一个BNAH分子，从而产生能够产生H ₂的催化剂的双还原活化形式。目前的工作表明，取代桥联配体对拟议的活性中间体的还原淬灭和水合作用的驱动力的影响，这两者都会影响制氢效率。配合物1–3遵循双重还原淬灭机制运行，重要的是在红光下具有活性。这项工作为设计从紫外光到近红外光的单分子光催化剂奠定了基础，从而可以利用整个范围内的太阳光子并将其用于太阳能转换。