Here we describe detailed mechanistic analyses of the ruthenium-catalyzed synthesis of acrylate salt from ethylene and CO₂. All of the primary steps of the catalytic cycle, that is (i) oxidative cyclization of ethylene and CO₂ to give ruthenalactones, (ii) thermal β-H elimination of ruthenalactones to hydrido acrylato complexes, and (iii) base-mediated generation of ethylene-coordinated, zerovalent ruthenium complexes from hydrido acrylato complexes, are found to proceed more rapidly on the more electron rich complexes. These results suggest that the last two processes proceed through the cationic ruthenium complexes generated by dissociation of carboxylate anions. As another possible pathway for the catalytic acrylate synthesis, base-promoted cleavage of a ruthenalactone to an ethylene-coordinated, zerovalent ruthenium complex is also studied, and the reaction is found to proceed smoothly, where the rate of the reaction is dependent on the basicity of the base. In contrast to the stoichiometric reactivities, electron-deficient ruthenium complexes exhibited higher activity in the catalytic acrylate synthesis.

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钌催化乙烯和CO ₂合成丙烯酸盐的机理研究

在这里，我们描述了钌催化乙烯和CO ₂合成丙烯酸盐的详细机理分析。催化循环的所有主要步骤，即（i）乙烯和CO _2的氧化环化生成钌内酯，（ii）通过热β-H消除钌内酯成氢化丙烯酰基络合物，以及（iii）由氢化丙烯酰基络合物通过碱介导的乙烯配位的零价钌络合物的生成，随着电子的增多而加快丰富的情结。这些结果表明，最后两个过程是通过羧酸根阴离子离解生成的阳离子钌络合物进行的。作为丙烯酸酯催化合成的另一种可能途径，还研究了钌促进的内酯向乙烯配位的零价钌配合物的碱促进裂解，并且发现反应进行顺利，其中反应速率取决于碱性。基地。与化学计量反应性相比，