(CAAC)Pd(py)催化剂歧化为Pd(CAAC)。
(CAAC)Pd(py) Catalysts Disproportionate to Pd(CAAC).
作者信息
Marigo Nicola, Morgenstern Bernd, Biffis Andrea, Munz Dominik
机构信息
Coordination Chemistry, Saarland University, Campus C4.1, Saarbrücken D-66123, Germany.
Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova I-35131, Italy.
出版信息
Organometallics. 2023 May 22;42(13):1567-1572. doi: 10.1021/acs.organomet.3c00150. eCollection 2023 Jul 10.
Palladium complexes with one -heterocyclic carbene (NHC) and a pyridine ancillary ligand are powerful cross-coupling precatalysts. Herein, we report such complexes with a cyclic (alkyl)(amino)carbene (CAAC) ligand replacing the NHC. We find that the alleged reduced form, (CAAC)Pd(py), disproportionates to the (CAAC)Pd complex and palladium nanoparticles. This notwithstanding, they are potent catalysts in the Buchwald-Hartwig amination with aryl chlorides under mild conditions (60 °C). In the presence of dioxygen, these complexes catalyze the formation of diazenes from anilines. The catalytic activities of the NHC- and CAAC-supported palladium(0) and palladium(II) complexes are similar in the cross-coupling reaction, yet the CAAC complexes are superior for diazene formation.
含有一个杂环卡宾（NHC）和一个吡啶辅助配体的钯配合物是强大的交叉偶联预催化剂。在此，我们报道了用环状（烷基）（氨基）卡宾（CAAC）配体取代NHC的此类配合物。我们发现所谓的还原形式（CAAC）Pd（py）会歧化为（CAAC）Pd配合物和钯纳米颗粒。尽管如此，它们在温和条件（60°C）下与芳基氯进行的布赫瓦尔德-哈特维希胺化反应中是有效的催化剂。在氧气存在下，这些配合物催化由苯胺形成重氮化合物。在交叉偶联反应中，NHC和CAAC负载的钯（0）和钯（II）配合物的催化活性相似，但CAAC配合物在重氮化合物形成方面更具优势。
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