Spin-Crossover Behaviors of Iron(II) Complexes Bearing Halogen Ligands in Solid State and Solution

Abstract

Numerous Fe(II) spin-crossover (SCO) compounds have been developed in the past decades, while the reports on the SCO materials with halogen atoms acting as coordinating ligands remain rare. In this study, we synthesize three iron(II) halide complexes with a general formula of [Fe II (Py5Me 2 )X] + (Py5Me 2 = 2,6bis[1,1-bis(2-pyridyl)ethyl]pyridine, X = Cl − or Br − ) that undergo complete SCO transitions at near room temperature. The SCO properties of these compounds are investigated in detail by magnetic measurements, variable-temperature single-crystal Xray diffractions, and Mossbauer spectra analyses. Because of the good stability of the coordination structures and suitable ligand-field strength, these compounds show robust spin transitions in both solid state and solution.

Significant differences in photophysical and photovoltaic properties of flexible chain terminated homoleptic tris-Ir(iii) complexes

“…S3, ESI †). The value is a little lower than 388 1C of the hexyl-terminated TBz3Ir, 32 indicating carboxylic ester terminal groups slightly reduced the thermal stability for the trishomoleptic Ir complexes.…”

“…However, research on Ir complex-based photovoltaic materials in organic solar cells (OSCs) lags far behind. [6][7][8] To date, the highest power conversion efficiency (PCE) for small-molecule Ir complexes as electron donor materials has been reported at approximately 12%, 9,10 which is significantly lower than the 19-20% achieved by pure organic/polymer materials. [11][12][13][14][15][16][17] To achieve a high PCE, a strong and broad optical absorption for light-harvesting ability is primarily required for the photoactive electron donor (D) and/or acceptor (A) materials.…”

Colour Tunability of Heteroleptic Ir(III) Complexes Through Second Sphere Coordination

“…Iridium complexes have catalyzed significant research interest due to their various applications such as bioimaging, [1][2][3][4][5][6] organic photovoltaic cells, [7][8][9][10] and catalysis. [11][12][13][14] Particularly, the implementation of iridium complexes as emitters in phosphorescent organic light-emitting diodes (PhOLEDs) has attracted great attention.…”

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

“…9,24,52 Other spectroscopic methods such as variable-temperature nuclear magnetic resonance (NMR), [53][54][55] infrared (IR), 49,53,56,57 Raman, 53,57,58 and UV/Vis 54,55,59 are also employed in the characterization of SCO behavior. 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.…”