This work explores avenues toward PCP pincer complexes with acyclic diaminocarbene central moieties that are suitable for ligand-assisted reactivity involving the carbene carbon. For this purpose, diphosphine chelating ligands 1 and 2, with bis(imidazolyl)methyl and bis(pyrazolyl)methyl backbones, respectively, were prepared in two high-yield synthetic steps. Nickel(II) and platinum(II) dihalide complexes 3 and 6, incorporating 1, were prepared and converted into PCP pincer ligands 5 and 7 upon deprotonation with KHMDS. Chelated nickel(I) complex 4 was obtained as a byproduct to 3. Although the solid-state structures of 5 and 7 presented geometric strain at the diaminomethyl carbon, this moiety could not be converted into a diaminocarbene by proton or hydride abstraction. 7 could be converted into platinum(IV) analog 8 by oxidation with PhICl₂. Ligand 2 proved more versatile than 1, or less dependable in its behavior, generating P,N-chelating cobalt(II) dibromide complex 9. Easily accessible ligands 1 and 2 provide a new and versatile PCP pincer platform.

中文翻译：

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结合无环二氨基烷基中心部分连接咪唑或吡唑环的镍和铂PCP钳形配合物

这项工作探索了具有无环二氨基卡宾中心部分的PCP夹杂物复合物的途径，该化合物适合于涉及卡宾碳的配体辅助反应性。为此，在两个高产率合成步骤中分别制备了具有双（咪唑基）甲基和双（吡唑基）甲基骨架的二膦螯合配体1和2。镍（II）和铂（II）配合物的二卤化3和6，结合1，制备并转化成PCP钳配体5和7与KHMDS时去质子化。获得了螯合的镍（I）配合物4作为3的副产品。尽管5和7的固态结构在二氨基甲基碳上表现出几何应变，但该部分无法通过质子或氢化物提取转化为二氨基卡宾。7可以通过用PhICl ₂氧化而转化为铂（IV）类似物8。配体2被证明比1具有更多的通用性，或在行为上不太可靠，从而生成了P，N-螯合钴（II）二溴化物络合物9。容易获得的配体1和2提供了一个新的多功能PCP钳夹平台。