Cowley Ryan E, Bontchev Ranko P, Duesler Eileen N, Smith Jeremy M
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, USA.
Inorg Chem. 2006 Nov 27;45(24):9771-9. doi: 10.1021/ic061299a.
Low-temperature deprotonation of the phenylborane dications, PhB(RIm)3OTf2 (R = tBu, Mes), followed by in situ reaction with CoCl2(thf)1.5, results in the formation of the four-coordinate complexes, kappa3-PhB(RIm)3CoCl, in which the metal is supported by tripodal N-heterocyclic carbene-based ligands. The chloride complexes are exceptionally sensitive to acid and can be reversibly protonated to form the zwitterions kappa2-{PhB(RIm)2(RIm.H)}CoCl2. This unexpected reactivity is attributed to the highly basic nature of the tris(carbene)borate ligands. Reaction of the chloride complexes with methylating reagents results in products that depend on the N-heterocyclic carbene substituent. For R = tBu, the four-coordinate high-spin complex, kappa3-PhB(tBuIm)3CoMe, is formed, while for R = Mes, reduction to a multitude of complexes occurs.
苯基硼双阳离子PhB(RIm)₃OTf₂（R = tBu、Mes）进行低温去质子化，随后与CoCl₂(thf)₁.₅原位反应，生成四配位配合物κ³-PhB(RIm)₃CoCl，其中金属由三脚架型基于N-杂环卡宾的配体支撑。氯化物配合物对酸异常敏感，可被可逆质子化形成两性离子κ²-{PhB(RIm)₂(RIm.H)}CoCl₂。这种意外的反应性归因于三（卡宾）硼酸酯配体的高碱性。氯化物配合物与甲基化试剂反应生成的产物取决于N-杂环卡宾取代基。当R = tBu时，形成四配位高自旋配合物κ³-PhB(tBuIm)₃CoMe，而当R = Mes时，则会还原为多种配合物。
