美国普林斯顿大学Paul J. Chirik团队在研究中取得进展。他们提出了可见光实现和分子氢的弱化学键的催化形成。该研究于2021年7月12日发表于国际一流学术期刊《自然—化学》。

该课题组研究人员描述了极弱的金属复合物的元素-氢键以及极低化学键解离自由能（31 kcal/mol）的有机化合物的直接光催化合成。这种方法的关键是发色铱氢光催化剂的双官能行为。分子氢的活化发生在基态，产生的铱氢收集可见光使得在热动力势能附近自发形成弱化学键，且没有副产物。光物理和机械的研究证实了基于自由基的反应路线，并且强调了该光驱动方法在产生新催化化学中的独特性。

据介绍，在达到或接近热动力势能下合成弱化学键是化学中的一个基本挑战，在催化、生物和能源科学中都有应用。使用分子氢进行质子耦合电子转移是合成弱元素-氢键的一种吸引性策略，但其内在热动力学对于反应性是一个挑战。

附：英文原文

Title: Visible light enables catalytic formation of weak chemical bonds with molecular hydrogen

Author: Yoonsu Park, Sangmin Kim, Lei Tian, Hongyu Zhong, Gregory D. Scholes, Paul J. Chirik

Issue&Volume: 2021-07-12

Abstract: The synthesis of weak chemical bonds at or near thermodynamic potential is a fundamental challenge in chemistry, with applications ranging from catalysis to biology to energy science. Proton-coupled electron transfer using molecular hydrogen is an attractive strategy for synthesizing weak element–hydrogen bonds, but the intrinsic thermodynamics presents a challenge for reactivity. Here we describe the direct photocatalytic synthesis of extremely weak element–hydrogen bonds of metal amido and metal imido complexes, as well as organic compounds with bond dissociation free energies as low as 31kcal mol1. Key to this approach is the bifunctional behaviour of the chromophoric iridium hydride photocatalyst. Activation of molecular hydrogen occurs in the ground state and the resulting iridium hydride harvests visible light to enable spontaneous formation of weak chemical bonds near thermodynamic potential with no by-products. Photophysical and mechanistic studies corroborate radical-based reaction pathways and highlight the uniqueness of this photodriven approach in promoting new catalytic chemistry.

DOI: 10.1038/s41557-021-00732-z

Source: https://www.nature.com/articles/s41557-021-00732-z