Air-Stable Triazine-Based Ni(II) PNP Pincer Complexes As Catalysts for the Suzuki–Miyaura Cross-Coupling

Air-stable, thermally robust, and well-defined cationic Ni­(II) PNP pincer complexes based on the 2,4-diaminotriazine scaffold are described. These complexes are active catalysts for the Suzuki–Miyaura cross-coupling of a wide range of aryl, heteroaryl (including benzoxazole, thiazole, pyridine, pyrimidine, thiazole), primary and secondary alkyl halides, and pseudohalides with different organoboronate reagents giving excellent to good isolated yields. Neutral deprotonated complexes seem to play a key role in the catalytic process.本研究报道了一类基于2,4-二氨基三嗪骨架的空气稳定、热稳定性优异且结构明确的阳离子型二价镍（Ni(II)）PNP钳式配合物。该类配合物可作为高效催化剂，用于多种芳基、杂芳基（包括苯并恶唑、噻唑、吡啶、嘧啶）、一级及二级烷基卤化物与拟卤化物和不同有机硼酸酯试剂之间的铃木-宫村（Suzuki–Miyaura）交叉偶联反应，产物分离产率优异至良好。研究表明，中性去质子化配合物在该催化过程中发挥关键作用。