Effect of intermolecular anionic interactions on spin crossover of two triple-stranded dinuclear Fe(ii) complexes showing above room temperature spin transition

Abstract

Two new Fe(II)-based dinuclear triple helicates having the formula {[Fe2(L)3]·(CF3SO3)4]·6.5H2O·CH3OH}comple (complex 1) and {[Fe2(L)3]·(ClO4)4]·7H2O·1.35CH3OH} (complex 2), displaying near room temperature spin transition have been synthesized and the effect of intermolecular...

Pressure-Induced Hysteretic and Abrupt Spin Transition in Amine Functionalized Isoquinoline-Based Two-Dimensional FeII Hofmann Frameworks

“…The spin crossover (SCO) compounds undergo significant changes in various physical properties such as mechanical, magnetic, optical, and dielectric properties during the process of reversible spin-state switching. − They show potential application in the invention of switchable nanomaterials, − information storage devices, , microthermometers, chemical sensors, mechanical actuators, and display devices. − Among 3d transition metals (TM), Fe­(II) (d 6 ) octahedral compounds are the most widely studied as they show an abrupt interconversion between electronic configuration t 2g 4 e g 2 and t 2g 6 e g 0 which corresponds to the paramagnetic high spin (HS) and diamagnetic low spin (LS) state respectively, − under external stimuli such as heat, light irradiation, magnetic field, and pressure. − The applied external pressure is a useful tool for controlling the spin crossover temperature easily − and can be exploited to create switchable nanomaterials, − information storage devices, microthermometers, chemical sensors, mechanical actuators, and display devices, − leading to the growth of the SCO field in the past decade. In general, the LS condition is more stable when hydrostatic pressure is applied to the SCO materials, as it takes up less volume and modifies the various supramolecular interactions, resulting in a substantial impact on the cooperativity between SCO sites.…”

Reversible light-induced spin state switching in a dinuclear Fe(ii) spin crossover complex

“…[11][12][13] Spin crossover complexes present the ability to be controllably switched between the high spin (HS) and low spin (LS) states upon physical stimuli, and are the most investigated switchable molecular materials. [14][15][16][17][18] Up to now, most of the SCO complexes are still assemblies of monomeric units with through-space rather than through-bond interactions. Connecting SCO centers by suitable bridging ligands within a small cluster is an important strategy to enhance intracluster cooperativity because of the ability to efficiently transmit structural and electronic changes occurring at SCO centres.…”

Assessing the Performance of Approximate Density Functional Theory on 95 Experimentally Characterized Fe(II) Spin Crossover Complexes

“…The SCO behavior of a complex is influenced by its ligands, 60 crystal packing effects, 30,[61][62][63] and intermolecular interactions. [64][65][66][67] While a combination of experimental techniques can characterize SCO behavior through measurement of structural changes and T1/2, it is challenging to rationalize experimental trends to determine how T1/2 can be varied for use in molecular devices. 35 Empirical models proposed for predicting SCO behavior, e.g., based on N-N distances in tris-homoleptic bidentate ligands of Fe(II) complexes 68 , often lack transferability (e.g., to other denticities).…”