Abstract：
The bis(azolium) salt [L1-H2 ]Br2 was found to serve as a suitable platform for accessing the heterobimetallic IrIII -M (M=PdII /AuI ) and PdII -IrIII complexes. Initially, selective mono-metalation of [L1-H2 ]Br2 yielded an orthometalated IrIII - or non-orthometalated PdII -complex. Sequential metalation of the mono-IrIII complex resulted in the formation of heterobimetallic IrIII -PdII /AuI complexes. Similarly, a distinct heterobimetallic PdII -IrIII complex was synthesized starting from the mono-PdII complex. Further, the corresponding homobimetallic IrIII -IrIII and PdII -PdII complexes were directly obtained from [L1-H2 ]Br2 . Additionally, monometallic PdII and IrIII analogues were synthesized from [L2-H]Br and [L3-H]Br, respectively. The heterobimetallic IrIII -PdII and PdII -IrIII complexes were then evaluated as catalysts in various one-pot tandem catalytic reactions in which they demonstrated superior activity than the mixtures of both their corresponding homobimetallic IrIII -IrIII /PdII -PdII and monometallic IrIII /PdII counterparts, under the constant concentrations of metal centers. Moreover, while comparing complexes IrIII -PdII and PdII -IrIII , the former exhibits higher activity in all the studied reactions. All these findings suggest the presence of some form of cooperativity between the two metal centers (Ir and Pd) connected by a single ligand framework in IrIII -PdII and PdII -IrIII complex, with IrIII -PdII displaying better cooperativity that has been validated by electrochemical, NMR, and DFT studies.
摘要：
发现双（唑盐）盐[L1-H2]Br2可作为获得异双金属IrIII-M（M=PdII/AuI）和PdII-IrIII络合物的合适平台。最初，[L1-H2]Br2的选择性单金属化产生了邻位金属化的IrIII-或非邻位金属化的PdII络合物。单-IrIII复合物的顺序金属化导致形成异双金属IrIII-PdII/AuI复合物。同样，从单-PdII复合物开始合成不同的异双金属PdII-IrIII复合物。Further,从[L1-H2]Br2直接获得相应的高双金属IrIII-IrIII和PdII-PdII络合物。此外,由[L2-H]Br和[L3-H]Br合成单金属PdII和IrIII类似物，分别。然后将异双金属IrIII-PdII和PdII-IrIII配合物在各种一锅串联催化反应中作为催化剂进行评估，在这些反应中，它们表现出比其相应的同双金属IrIII-IrIII/PdII-PdII混合物和单金属IrIII/PdII对应物，在金属中心的恒定浓度下。此外，在比较复合物IrIII-PdII和PdII-IrIII时，前者在所有研究的反应中表现出更高的活性。所有这些发现表明，在IrIII-PdII和PdII-IrIII络合物中通过单个配体骨架连接的两个金属中心（Ir和Pd）之间存在某种形式的协同作用，IrIII-PdII显示出更好的协同性，这已经被电化学验证了，NMR,和DFT研究。
