Reversible Photo- and Thermo-Induced Spin-State Switching in a Heterometallic {5d-3d} W₂Fe₂ Molecular Square Complex

Abstract

Following the complex-as-a-ligand strategy, selfassembly of [W(CN) 8 ] 3− and iron(II) with bidentate nitrogen donor ligand bik (bik = bis(1-methyl-1H-imidazol-2-yl)ketone) ligand affords a cyanide-bridged [W 2 Fe 2 ] molecular square complexThe complex was characterized by single-crystal X-ray diffraction analyses, (photo)magnetic studies, optical reflectivity, electrochemical studies, and spectroscopic studies. Structural analyses revealed that in the [W 2 Fe 2 ] square motif tungsten(V) and iron(II) centers reside in an alternate corner of the square and are bridged by the cyanide ligands. Complex 1 exhibits thermoinduced spin crossover (SCO) between {W V (S = 1/2) − Fe II LS (S = 0)} and {W V (S = 1/2) − Fe II HS (S = 2)} pairs near room temperature and photoinduced spin-state switching with T LIESST = 70 K under light irradiation at low temperature. To the best of our knowledge, 1 represents the first complex containing iron(II) and [W V (CN) 8 ] 3− units exhibiting both SCO and photomagnetic effect.

Molecular Magnetic Materials Based on {CoIII(Tp*)(CN)3}− Cyanidometallate: Combined Magnetic, Structural and 59Co NMR Study

“…ca 292 ca 55 405, 532, 635 or 900 532) [22] [a] only 808, 405 and 532 nm wavelengths were tested in that case.…”

Construction of Magneto‐Fluorescent Bifunctional Spin‐Crossover Fe(II) Complex from Pyrene‐Decorated Pybox Ligand

“…Among this type of multifunctional materials, the SCO-fluorescence bifunctional molecules are more attractive because it can achieve multiple input or output signals through the means of light, thermal and magnetic moment. [14][15][16][17][18][19][20] Impressively, some cases in these bifunctional complexes display strong synergy between SCO and fluorescence emission. [21][22][23][24][25][26][27][28][29][30][31][32][33] The research on these bifunctional complexes will create numerous molecule-based functional materials that display potential applications in biosensors, thermometry, optical memory devices, and biological imaging, etc.…”

Impact of counter anions on spin-state switching of manganese(iii) complexes containing an azobenzene ligand

“…[36][37][38][39][40] Various external stimuli, including temperature, light, and pressure, have been applied to tune their bistability precisely with significant alteration in photophysical properties (magnetic, conductive, optical, etc.). [41][42][43][44][45] It is important to mention that SCO occurrence near or at room temperature is necessary to develop SCO-based devices with potential for practical uses. [46][47][48][49] In this regard, apart from well-studied thermo-induced SCO, the photo-switched SCO phenomenon, particularly ligand-driven light-induced spin change (LDLISC), has recently offered an excellent opportunity to study SCO under ambient conditions.…”

“…). 41–45 It is important to mention that SCO occurrence near or at room temperature is necessary to develop SCO-based devices with potential for practical uses. 46–49 In this regard, apart from well-studied thermo-induced SCO, the photo-switched SCO phenomenon, particularly ligand-driven light-induced spin change (LDLISC), has recently offered an excellent opportunity to study SCO under ambient conditions.…”