Synergistic photomagnetic effects in coordination polymer heterostructure particles of Hofmann-like Fe(4-phenylpyridine)₂[Ni(CN)₄]·0.5H₂O and K_0.4Ni[Cr(CN)₆]_0.8·nH₂O

Abstract

New nanometer scale heterostructure particles of the two-dimensional Hofmann-like Fe(ii) spin-crossover network, Fe(phpy)[Ni(CN)]·0.5HO {phpy = 4-phenylpyridine}, and the Prussian blue analogue KNi[Cr(CN)]·nHO (NiCr-PBA) have been developed, exhibiting synergistic photomagnetic effects, whereby the LIESST (light-induced electron spin-state trapping) effect in the Hofmann-like material induces a magnetization change in the NiCr-PBA. A variety of microscopic and spectroscopic techniques demonstrate the heterogeneous growth of the NiCr-PBA on the Hofmann seed particles and show the Hofmann compound retains its thermal and photoinduced spin transition properties in the heterostructure. The photoinduced magnetization change in the NiCr-PBA network arises from coupling of the two lattices despite dissimilar structure types. Isothermal magnetization minor hysteresis loop studies at 5 K show light absorption leads to changes in the local anisotropy of NiCr-PBA magnetic domains, providing direct evidence for a general magnetomechanical mechanism of light-switchable magnetism in coordination polymer heterostructures combining a photoactive material with a magnet.

Spin Crossover Nanomaterials: From Fundamental Concepts to Devices

“…Actually these latter can be seen also as core–shell systems with infinite shell thickness and therefore the theoretical analysis of core–shell particles can be often extended to composites in a straightforward way. Several core–shell SCO particles have been reported to date, but arguably the most advanced ones are Prussian blue analog (PBA) heterostructures. PBA compounds are cyanide‐bridged 3D coordination networks, which can exhibit very interesting magnetic properties—including SCO.…”

Pressure-tuning of the photomagnetic response of heterostructured CoFe@CrCr-PBA core@shell nanoparticles

“…The photo-CTIST establishs the PIM state in the CoFe-PBA core, and the thermal-CTIST strain, which formed while cooling, is relaxed as many of the CoFe pairs assume lattice dimensions close to those of the room temperature state [12]. The magnetic domains in the CrCr-PBA shells now experience a different magneto-crystalline anisotropy as long as the applied magnetic field is below nominally a few kG [18,40]. Furthermore, this new metastable magnetomechanical arrangement of the ferrimagnetic domains is maintained until the photo-CTIST is relaxed at T R ≈ 125 K.…”

“…On the other hand, the application of pressure does increase this magnetic transition temperature, at least for the CrCr-PBA shell used in this work. Ultimately, the next step to realizing persistent photocontrolled magnetic switching at higher temperatures may be to tune the chemical composition [17] or to explore options afforded by spin-crossover complexes [40][41][42][43][44]. Externally applied pressure applied to CoFe@CrCr Prussian blue analogue core@shell nanoparticles shifts the magnetic ordering temperatures of the CoFe-PBA core, the CrCr-PBA shell, and the photo-CTIST of the CoFe-PBA core.…”

Ionic Complexes [Ph3PBu-n][Au(CN)2Cl2] and [Ph3PCH2OMe][Au(CN)2Cl2]: Synthesis and Structure

“…Интерес к данному семейству комплексов вызван обилием различных практически применимых свойств, которые им можно придавать и модифицировать путём внедрения дополнительных лигандов или координационных центров. Среди таких свойств магнетизм [1][2][3][4][5][6][7], люминесценция [7][8][9][10][11][12], вапохромизм [11][12][13][14][15][16] Полученные комплексы представляют собой кристаллические, устойчивые на воздухе вещества с четко определенной температурой плавления.…”