29454-45-3Relevant academic research and scientific papers
Thermal and Light-Induced Spin Transitions of FeII Complexes with 4- and 5-(Phenylazo)-2,2′-bipyridine Ligands: Intra- vs. Intermolecular Effects
Schmidt, Sven Olaf,Naggert, Holger,Buchholz, Axel,Brandenburg, Hannah,Bannwarth, Alexander,Plass, Winfried,Tuczek, Felix
, p. 2175 - 2186 (2016)
Five new spin crossover complexes with 4- and 5-(phenylazo)-2,2-bipyridine (4-/5-PAbipy) ligands were synthesized and investigated with respect to their spin crossover (SCO) behavior. The results are compared to the thermal and light-induced spin transition properties of the parent SCO complexes [Fe(bpz)2(bipy)] (1) and [Fe(bipy)2(NCS)2] (2). [Fe(bpz)2(4-PAbipy)] (1a) undergoes a stepwise spin transition whereas [Fe(bpz)2(5-PAbipy)] (1b) exhibits a one-step transition with a 6 K-wide hysteresis. For [Fe(bpz)2(tBu5-PAbipy)] (1c) the spin transition to the low-spin state is incomplete. Qualitatively similar changes of the SCO behavior are observed for the complexes [Fe(4-PAbipy)2(NCS)2] (2a) and [Fe(5-PAbipy)2(NCS)2] (2b). In comparison to the parent system 2, a strengthening of intermolecular interactions leads to a stabilization of the low-spin state. Evidence for the LIESST behavior could be obtained for all new compounds by means of magnetic susceptibility measurements as well as UV/Vis and resonance Raman spectroscopy.
