Bhar, Kishalay published the artcileHigh temperature spin crossover behaviour of mononuclear bis-(thiocyanato)iron(II) complexes with judiciously designed bidentate N-donor Schiff bases with varying substituents, Safety of Phenyl(pyridin-2-yl)methanone, the publication is Dalton Transactions (2022), 51(24), 9302-9313, database is CAplus and MEDLINE.
THe authors present herein a family of mol. cis-[FeII(X-PPMA)2(NCS)2]·H2O [4-X-N-(phenyl(pyridin-2-yl)methylene)aniline; X-PPMA; X = Cl (1), Br (2), and CH3 (3)] complexes that exhibit spin crossover behavior above room temperature Judiciously designed bidentate N-donor Schiff bases of 2-benzoylpyridine and para-substituted anilines in combination with Fe(NCS)2 were used for the synthesis of complexes 1–3. The relatively strong ligand field of the Schiff bases stabilizes the low spin state of iron(II) up to 300 K which is evident from magnetic measurements, room temperature Mossbauer spectra and crystallog. bond/angle distortion parameters. Interestingly, complexes 1–3 crystallize in a tetragonal system with either a P43212 or P41212 chiral space group from achiral building units due to the supramol. helical arrangements of mols. through intermol. (pyridine)C-H···C(NCS) interactions in the crystalline state. Complexes 1 and 2 exhibit complete, gradual and slightly irreversible spin crossover behavior in the temperature range of 300-500 K with equilibrium temperatures (T1/2) 375 K (1) and 380 K (2). The spin state evolution of iron(II) in complexes 1 and 2 is monitored between 150 K and 450 K through variable temperature crystallog. studies in the warming mode. The structural data are in good agreement with the 94% (1) and 87% (2) high spin conversion of iron(II) at 450 K. At a high temperature (450 K), some minor irreversible ligand motion is noticed in complexes 1 and 2, in addition to a complete solvent loss that may induce the slight irreversibility of the spin crossover. On the other hand, complex 3 shows a complete and gradual spin crossover in the temperature range of 10-475 K with strong irreversible features. The equilibrium temperatures obtained upon first warming (T1/2↑) and second cooling (T1/2↓) are 375 K and 200 K, resp. In complex 3, the loss of a water mol. triggers strong deviations in the spin crossover behavior. Moreover, dehydrated complex 3 exhibits photoswitching LIESST effect with a relaxation temperature T(LIESST) = 60 K.
Dalton Transactions published new progress about 91-02-1. 91-02-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene,Ketone, name is Phenyl(pyridin-2-yl)methanone, and the molecular formula is C12H9NO, Safety of Phenyl(pyridin-2-yl)methanone.
Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem