Guest‐Driven Light‐Induced Spin Change in an Azobenzene Loaded Metal–Organic Framework

Abstract

Stimuli-responsive materials that can be reversibly switched by light are of immense interest. Among them, photoresponsive spin crossover (SCO) complexes have great promises to combine the photoactive inputs with multifaceted outputs into switchable materials and devices.H owever,t he reversible control the spin-state change by photochromic guests is still challenging.H erein, we report an unprecedented guestdriven light-induced spin change (GD-LISC) in aH ofmanntype metal-organic framework (MOF), [Fe(bpn){Ag-(CN) 2 } 2 ]•azobenzene.( 1,b pn = 1,4-bis(4-pyridyl)naphthalene). The reversible trans-cis photoisomerization of azobenzeneguest upon UV/Vis irradiation in the solid-state results in the remarkable magnetic changes in awide temperature range of 10-180 K. This finding not only establishes anew switching mechanism for SCO complexes,but also paves the way toward the development of new generation of photo-responsive magnetic materials.

Spintronics on Demand: Optically Tunable Kondo-Type Phenomena in Germanene-Azobenzene Single-Molecule Junctions

“…These excess charges interact with existing unpaired electron densities on the surface, attempting to establish an antiferromagnetic coupling pattern. 71 Furthermore, we have depicted the partial contributions of trans and cis AZB to the composite system's overall band structure (found in Supporting Information S3). A significant contribution from cis-AZB, particularly near the Fermi level, stands out in the system's band structure�a striking contrast to trans-AZB, where its contribution is notably below the Fermi level.…”

“…Notably, structural changes in the AZB from trans to cis lead to a higher probability of directing excess electronic charges toward the germanene surface almost instantly. These excess charges interact with existing unpaired electron densities on the surface, attempting to establish an antiferromagnetic coupling pattern . Furthermore, we have depicted the partial contributions of trans and cis AZB to the composite system’s overall band structure (found in Supporting Information S3).…”

A water-tuned reversible spin transition with the largest hysteresis loop in 3D Hofmann frameworks pillared by flexible ligands

“…To date, most of the pillars used in 3D Hofmann SCO frameworks with a six-coordinate octahedral [FeN 6 ] configuration are rigid bidentate linkers. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Recently, a few flexible ligands have been adopted as linear pillars for constructing 3D Hofmann SCO frameworks. [29][30][31][32][33][34][35][36] These flexible pillars include di(4-pyridylthio)methane (dpsme), 29 1,2-di(4-pyridyl)ethane (dpa), 30 1,4-bis(4-pyridylmethyl)piperazine (bpmp), 31 di(4pyridyl)selenide (dpSe), 32 N-(4-pyridyl)isonicotinamide ( pina), 33 1,3-di(4-pyridyl)urea (dpyu), 34 1,2-dibromo-1,2-di(4pyridyl)ethane (dbdpe) 35 and N,N′-di(4-pyridyl)oxalamide (dpo) (Scheme 1).…”

Hysteretic Spin Crossover with High Transition Temperatures in Two Cobalt(II) Complexes

“…As one of the most important molecular magnetic materials with switchable magnetic properties, spin crossover (SCO) materials have been attracting intense attention. , The rearrangement of the electrons within the nonbonding t 2g and antibonding e g orbitals of the SCO materials can not only switch the spin state between the low spin (LS) and high spin (HS) states but also lead to modifications of physical properties through the application of external perturbations (such as pressure, magnetic and electric field, light irradiation, and guest molecules) and applications in areas such as display and memory, electrical, luminescent, and mechanical actuators. − …”