Mörtel Max, Witt Alexander, Heinemann Frank W, Bochmann Sebastian, Bachmann Julien, Khusniyarov Marat M
Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nürnberg , Egerlandstrasse 1, 91058 Erlangen, Germany.
Inorg Chem. 2017 Nov 6;56(21):13174-13186. doi: 10.1021/acs.inorgchem.7b01952.
Spin-crossover molecular switches [Fe(HB(pz))L] (L = novel phenanthroline-based ligands featuring photochromic diarylethene units; pz = 1-pyrazolyl) were synthesized and thoroughly characterized by variable-temperature X-ray crystallography, Mössbauer spectroscopy, and magnetic measurements. The effect of substituents introduced into the phenanthroline backbone (L2) and into the photochromic diarylethene unit (L3) on photophysical properties of metal-free ligands and spin-crossover iron(II) complexes 2 and 3, respectively, were investigated in detail. Both ligands and complexes could be switched with light in solution at room temperature. The photocyclization of 2 was accompanied by a high-spin to low-spin photoconversion determined at 19%. The closed-ring isomers of L3 and 3 reveal the lifetimes in the range of minutes, whereas those of L2 and 2 are thermally stable for days in solutions at room temperature. The reversibility of the photoswitching can be improved by avoiding the photostationary states. Prospective introduction of anchoring groups to the phenanthroline backbone might allow the construction of chemisorbed self-assembled monolayers of spin-crossover species switchable with light at room temperature.
合成了自旋交叉分子开关[Fe(HB(pz))L]（L = 具有光致变色二芳基乙烯单元的新型菲咯啉基配体；pz = 1-吡唑基），并通过变温X射线晶体学、穆斯堡尔光谱和磁性测量对其进行了全面表征。详细研究了引入菲咯啉主链（L2）和光致变色二芳基乙烯单元（L3）中的取代基分别对无金属配体以及自旋交叉铁（II）配合物2和3的光物理性质的影响。配体和配合物在室温下的溶液中均可通过光照进行切换。2的光环化伴随着19%的高自旋到低自旋光转换。L3和3的闭环异构体的寿命在几分钟范围内，而L2和2的闭环异构体在室温下的溶液中可热稳定存在数天。通过避免光稳态可以提高光开关的可逆性。在菲咯啉主链上引入锚定基团有望构建在室温下可通过光照切换的自旋交叉物种的化学吸附自组装单分子层。
