Fujian Institute of photochromic materials made new progress

Photochromic materials have the characteristics of reversible changes in color and many kinds of physical properties. Among them, the compounds whose magnetic properties change with light stimulation (so-called magneto-optic effect), in addition to the functions of light protection and optical switch with general photochromic substances, It may also play an important role in magnetic resonance imaging, optical information storage and the like. Polycyano coordination complexes, which are considered to be the most promising materials of this kind, have attracted much attention for years, but their magneto-optic effect usually occurs below the liquid nitrogen temperature and rarely around room temperature. Therefore, it is of important scientific significance to develop photochromic polycyano complex with room temperature photomagnetic effect.

Chinese Academy of Sciences, Institute of 物理物, State Key Laboratory of Structural Chemistry, led by Guo Guo Cong research team has long been engaged in inorganic-organic hybrid functional chemical structural chemistry research. In 2003, they reported the synthesis and crystal structure of [Nd (DMF) 4 (H2O) 3 (μ-CN) FeIII (CN) 5] · H2O (NdFeDMF). Later, two research groups in Japan and Italy found that this compound and similar 3d 4f polycyano complex have novel magneto-optic effect, but the magneto-optic transition temperature is below 50 K, and the intrinsic mechanism remains controversial. Recently, the research team of Guo Guocong and Wang Mingsheng was found supported by the National Natural Science Foundation of China and the Natural Science Foundation of Fujian Province. EuIII (18-crown-6) (H2O) 3] FeIII (CN) After light or violet light irradiation, the lone pair of electrons on the crown ether oxygen is transferred to the ferric iron, resulting in stable crown ether radicals and ferrous iron. The color of the crystal changes from yellow-green to orange, and the discolored sample is dark-colored In the static or heating can fade, and then again light color, showing typical photochromism. Before and after discoloration, the magnetic properties of the compounds changed significantly. In this work, the value of? MT decreased by 33.5% at room temperature after being irradiated by a diode-pumped solid-state laser with a wavelength of 355 nm and a power density of 60 mW / cm2 for 10 minutes, which was lower than the reported value of NdFeDMF (<3% Much bigger.

This work first discovered the photochromism of 3d-4f polycyano complex and room temperature photomagnetic effect, not only successfully excavated a class of photochromic materials from known compounds, but also developed a class of room temperature Photo-induced photo-induced valence tautomeric compounds, recently published by the publication J. Am. Chem. Soc. 2015, 137, 10882-10885.

Previously, the team had made a series of advances in the structural chemistry of inorganic-organic hybrid photochromic materials (Angew. Chem. Int. Ed., 2007, 46, 3269, 2008, 47, 3565, 2008, 47 , 4149, 2012, 51, 3432, 2014, 53, 9298, 2014, 53, 11529; Chem. Commun. 2010, 46, 361, review).