期刊
NATURE CHEMISTRY
卷 14, 期 7, 页码 739-+出版社
NATURE PORTFOLIO
DOI: 10.1038/s41557-022-00933-0
关键词
-
资金
- Swiss National Science Foundation (SNSF) through the National Center of Competence in Research (NCCR) Molecular Ultrafast Science and Technology (MUST)
- postdoc programme of the German Academic Exchange Service (DAAD)
This study demonstrates trapping of the high-spin state in iron-based spin-crossover complexes by controlling the chiral configuration. The high-spin-state decay is found to be accompanied by changes in optical activity, reflecting coupling to a symmetry-breaking torsional mode. Diastereoselective ion pairing suppresses vibrational population and increases the high-spin-state lifetime. These findings motivate the synthetic control of torsional modes in iron(II) complexes to manipulate their spin-crossover dynamics as a complementary approach.
Iron-based spin-crossover complexes hold tremendous promise as multifunctional switches in molecular devices. However, real-world technological applications require the excited high-spin state to be kinetically stable-a feature that has been achieved only at cryogenic temperatures. Here we demonstrate high-spin-state trapping by controlling the chiral configuration of the prototypical iron(II)tris(4,4'-dimethyl-2,2'-bipyridine) in solution, associated for stereocontrol with the enantiopure Delta- or Lambda-enantiomer of tris(3,4,5,6-tetrachlorobenzene-1,2-diolato-(KO1)-O-2,O-2)phosphorus(V) (P(O2C6Cl4)(3)(-) or TRISPHAT) anions. We characterize the high-spin-state relaxation using broadband ultrafast circular dichroism spectroscopy in the deep ultraviolet in combination with transient absorption and anisotropy measurements. We find that the high-spin-state decay is accompanied by ultrafast changes of its optical activity, reflecting the coupling to a symmetry-breaking torsional twisting mode, contrary to the commonly assumed picture. The diastereoselective ion pairing suppresses the vibrational population of the identified reaction coordinate, thereby achieving a fourfold increase of the high-spin-state lifetime. More generally, our results motivate the synthetic control of the torsional modes of iron(II) complexes as a complementary route to manipulate their spin-crossover dynamics.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据