C,N-cyclopalladated complexes are among the most robust and widely used (pre)catalysts of cross-coupling reactions, combining long shelf life with high catalytic activity. In this report, we describe synthesis and properties of new Pd(II) complexes of a flexidentate ligand – 2,2-dimethyl-5-(2-pyridyl)pentane-3,5-dione (HL). Its coordinating properties resulted in the formation of two stereoisomeric cis- and trans-PdL₂ complexes each with one ligand in O,O- and the other in N,C(sp³)-coordination modes. The solid-state structures have been established by means of single-crystal X-ray diffraction methods and are retained in solution as indicated by NMR spectroscopy. Both these isomers proved to be efficient (pre)catalysts of phosphine-free Heck cross-coupling of iodoarenes with olefins.

C,N-环钯配合物是交叉偶联反应中最稳定和使用最广泛的（预）催化剂之一，结合了长保质期和高催化活性。在这份报告中，我们描述了合成和新的Pd（II）一flexidentate配体的配合物的性质- 2,2-二甲基-5-（2-吡啶基）戊烷-3,5-二酮（H大号）。其配位特性导致形成两种立体异构的顺式和反式Pd L ₂配合物，每个配合物在O , O - 中具有一个配体，另一个在N, C ( sp ³)-协调模式。固态结构已通过单晶 X 射线衍射方法建立，并如 NMR 光谱所示保留在溶液中。这两种异构体都被证明是碘芳烃与烯烃的无膦 Heck 交叉偶联的有效（预）催化剂。