A family of Ru(cym)-type complexes bearing different pyridylideneamide (PYA) ligands has been prepared. Incorporation of diverse potentially coordinating sites afforded a series of different chelating hybrid ligands containing a PYA nitrogen as one donor site and a second variable donor site constituted of a cyclometalated aryl ring (complex 3a), a pyridine (3b), a pyridylidene (3c), another PYA unit (3d), or a triazolylidene ligand (3e). Structural and electrochemical analyses indicate considerable electronic variation in this series with decreasing donor ability from phenyl > PYA ≈ triazolylidene ≈ pyridylidene > pyridine. This trend allows the electronic properties of the metal center to be tailored and reveals the strong donor properties of PYA ligands, surpassing those of pyridine-derived N-heterocyclic carbenes. The effect of these tunable donor properties was demonstrated in transfer hydrogenation catalysis, for which a direct correlation between donor properties and catalytic activity was established.

中文翻译：

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螯合亚吡啶基钌（II）配合物的结构，电子和催化调节

已经制备了带有不同吡啶基亚酰胺（PYA）配体的Ru（cym）型复合物家族。纳入各种潜在的协调位点提供了一系列不同的螯合杂配体，包含PYA氮作为一个供体位和第二个可变的供体部位，其由环金属化的芳环（络合物3a），吡啶（3b），吡啶（3c）组成。 ，另一个PYA单元（3d）或三唑基亚配体（3e）。结构和电化学分析表明，该系列中大量电子变化，其供体能力从苯基> PYA≈三唑亚基≈吡啶亚基>吡啶而降低。这种趋势允许定制金属中心的电子性能，并揭示了PYA配体的强大供体性能，超过了吡啶衍生的N-杂环卡宾。在转移氢化催化中证明了这些可调的供体性质的影响，为此建立了供体性质与催化活性之间的直接关系。