Selective semihydrogenation of alkynes has been a long-term and significant target, yet it remains a great challenge. Herein, bimetallic nanoparticles in a metal–organic framework (MOF), i.e., CuPd@ZIF-8 composite, featuring a cubic CuPd core and a porous ZIF-8 shell, have been rationally fabricated for this end. Given the unique physicochemical properties, the Cu nanocubes can not only convert solar energy into heat to accelerate the reaction but also serve as the seed for in situ formation of Pd nanoparticles (NPs) on their external surface to regulate the chemoselectivity of Pd active sites. The additional growth of the MOF shell is helpful to stabilize the CuPd core and offer regioselectivity via the steric hindrance effect. Ammonia borane provides active hydrogen species to significantly boost the hydrogenation and ensure the high selectivity. As a result, the CuPd@MOF exhibits high efficiency, featuring a turnover frequency (TOF, 6799 min^–1) of 5–10⁵ times higher than that in previous reports, and high chemo- and regioselectivity toward the semihydrogenation of alkynes, in the presence of NH₃BH₃ as a hydrogen source, under visible-light irradiation at ambient temperature.

中文翻译：

---

金属-有机骨架中双金属纳米粒子上炔烃的化学和区域选择性加氢加速

炔烃的选择性半氢化反应是一个长期而重要的目标，但仍然是一个巨大的挑战。在此，为此目的，已经合理地制造了金属-有机骨架（MOF）中的双金属纳米粒子，即CuPd @ ZIF-8复合材料，具有立方CuPd核和多孔ZIF-8壳。鉴于其独特的理化特性，Cu纳米立方体不仅可以将太阳能转化为热量以加速反应，而且还可以作为原位种子在其外表面形成Pd纳米粒子（NPs），以调节Pd活性位点的化学选择性。MOF壳的额外生长有助于稳定CuPd核并通过空间位阻效应提供区域选择性。氨硼烷提供了活性氢物质，可显着促进氢化作用并确保高选择性。结果，CuPd @ MOF表现出很高的效率，其转换频率（TOF，6799 min ^–1）是以前报告的5-10倍，高⁵倍，并且对炔烃的半氢化反应具有较高的化学和区域选择性。在室温下可见光照射下，存在NH ₃ BH ₃作为氢源。