Correlations between ligand field Δ_o, spin crossover T_1/2 and redox potential E_pa in a family of five dinuclear helicates

Abstract

A family of five new bis-bidentate azole-triazole Rat ligands (1,3-bis(5-azole)-4-isobutyl-4H-1,2,4-triazol-3-yl)benzene), varying in choice of azole (2-imidazole, 4-imidazole, 1-methyl-4-imidazole, 4-oxazole and 4-thiazole), and the corresponding family of spin-crossover (SCO) and redox...

Unique Spin Crossover Pathways Differentiated by Scan Rate in a New Dinuclear Fe(II) Triple Helicate: Mechanistic Deductions Enabled by Synchrotron Radiation Studies

“…To date, most of the Fe(II) helicate structures exhibiting SCO properties involve an imidazolimine-based coordination environment. [20][21][22][23][24][25][26][27][28][29] Manipulation of the SCO properties in these dinuclear systems relies on the design of ligand structure(s) so as to induce a suitbale ligand field. Several distinct dinuclear triple helicates have been shown to exhibit spin switching, with different structures from those conjoining metal cations via ligand bridging.…”

Thermosalience coupled to abrupt spin crossover with dynamic ligand motion in an iron(ii) molecular crystal

“…29 SCO complexes have d 4 -d 7 electron configuration-the most typical case is the 3d 6 iron(II) system 5,[30][31][32][33][34][35][36][37] -and can interconvert their high-spin (HS) and low-spin (LS) states accompanied by color change via external stimuli such as temperature, light, pressure, and guest molecules. 38 SCO profiles including transition temperature (T 1/2 ), gradualness or abruptness, stepwise nature, and with or without hysteresis are strongly affected by not only ligand field strength 39 and the structure of the individual SCO molecule 40 but also the cooperative effect between the SCO metal sites through bridging ligands 37,41 or intermolecular interactions. 31,34,42,43 Furthermore, molecular motions, 35 order-disorder transitions, 5,44 and symmetry breaking 45 in the crystal lattice also complicatedly affect the SCO properties.…”

The substituent effect on the spin-crossover behaviour in a series of mononuclear Fe(ii) complexes from thio-pybox ligands

“…20 Similarly, the observation and discussion of ligand substituent effects on SCO were conducted for some family complexes. 19,[21][22][23][24][25][26][27][28][29][30] An in-depth understanding of the structural influence on the spin state properties will be useful guidance for the structural design of SCO complexes.…”