Liu Yuan, Kean Zachary S, d'Aquino Andrea I, Manraj Yashin D, Mendez-Arroyo Jose, Mirkin Chad A
Department of Chemistry and International Institute for Nanotechnology, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Inorg Chem. 2017 May 15;56(10):5902-5910. doi: 10.1021/acs.inorgchem.7b00543. Epub 2017 May 4.
A new class of homoligated palladium(II) weak-link approach (WLA) complexes bearing hemilabile N-heterocyclic carbene (NHC)-thioether ligands is reported that, unlike previous tweezer-like WLA complexes, expand and contract in a linear fashion when switching between configurational states. These complexes can be chemically switched between a trans open state and a trans closed state via the addition or subsequent extraction of Cl. These bis(NHC) complexes also display unusual isomerization behavior. For example, an NMR spectroscopic investigation into the solution-state configuration of the open complex reveals the presence of interconverting syn,trans and anti,trans isomers, and a kinetic study shows that the barrier is large enough to isolate, store, and study the anti,trans isomer at room temperature. Notably, the linker length between the NHC and thioether moieties can be tailored with additional -CH- groups, which affords considerable control over the geometric changes imposed by switching. Therefore, this class of complexes may be useful in the construction of allosterically regulated supramolecular assemblies and materials.
报道了一类新型的带有半不稳定N-杂环卡宾（NHC）-硫醚配体的同配钯（II）弱连接方法（WLA）配合物，与之前类似镊子的WLA配合物不同，当在构型状态之间切换时，它们以线性方式扩展和收缩。这些配合物可以通过添加或随后萃取Cl在反式开放状态和反式封闭状态之间进行化学切换。这些双（NHC）配合物还表现出不寻常的异构化行为。例如，对开放配合物溶液态构型的核磁共振光谱研究揭示了顺式、反式和反式、反式异构体相互转化的存在，动力学研究表明，该势垒足够大，可以在室温下分离、储存和研究反式、反式异构体。值得注意的是，NHC和硫醚部分之间的连接长度可以用额外的-CH-基团进行调整，这可以对切换引起的几何变化进行相当程度的控制。因此，这类配合物可能在构建变构调节的超分子组装体和材料方面有用。
