Zatsikha Yuriy V, Shamova Liliya I, Shepit Michael, Berry Steven M, Thomas Fabrice, Herbert David E, van Lierop Johan, Nemykin Victor N
Department of Chemistry, University of Manitoba, Winnipeg MB, R3T 2 N2, Canada.
Enamine Ltd., Chervonotkatska Street 78, Kyiv, 02094, Ukraine.
Chemistry. 2022 Jul 20;28(41):e202201181. doi: 10.1002/chem.202201181. Epub 2022 Jun 24.
The preparation of radicals with intense and redox-switchable absorption beyond 1000 nm is a long-standing challenge in the chemistry of functional dyes. Here we report the preparation of a series of unprecedented stable neutral nickel(II) and copper(II) complexes of "Manitoba dipyrromethenes" (MB-DIPYs) in which the organic chromophore is present in the radical-anion state. The new stable radicals have an intense absorption at λ ∼1300 nm and can be either oxidized to regular [M (MB-DIPY)] (M=Cu or Ni) or reduced to [M (MB-DIPY)] compounds. The radical nature of the stable [M (MB-DIPY)] complexes was confirmed by EPR spectroscopy with additional insight into their electronic structure obtained by UV-Vis spectroscopy, electro- and spectroelectrochemistry, magnetic measurements, and X-ray crystallography. The electronic structures and spectroscopic properties of the radical-based chromophores were also probed by density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. These nickel(II) and copper(II) complexes represent the first stable radical compounds with a MB-DIPY ligand.
制备具有超过1000 nm的强烈且可氧化还原切换吸收的自由基是功能染料化学领域长期存在的挑战。在此，我们报道了一系列前所未有的稳定的“马尼托巴二吡咯亚甲基”（MB-DIPYs）中性镍（II）和铜（II）配合物的制备，其中有机发色团以自由基阴离子状态存在。这些新的稳定自由基在λ ∼1300 nm处有强烈吸收，并且可以被氧化为常规的[M (MB-DIPY)]（M = Cu或Ni）或还原为[M (MB-DIPY)]化合物。通过电子顺磁共振光谱（EPR）证实了稳定的[M (MB-DIPY)]配合物的自由基性质，并通过紫外可见光谱、电化学和光谱电化学、磁性测量以及X射线晶体学对其电子结构有了进一步了解。基于自由基的发色团的电子结构和光谱性质也通过密度泛函理论（DFT）和含时密度泛函理论（TDDFT）计算进行了探究。这些镍（II）和铜（II）配合物代表了首批具有MB-DIPY配体的稳定自由基化合物。
