Thermal and Light‐Induced Spin Transitions of FeII Complexes with 4‐ and 5‐(Phenylazo)‐2, 2′‐bipyridine Ligands: Intra‐ vs. Intermolecular Effects1. Issue 13 (23rd December 2015)

• Record Type: Journal Article
• Authors: Schmidt, Sven Olaf; Naggert, Holger; Buchholz, Axel; Brandenburg, Hannah; Bannwarth, Alexander; Plass, Winfried; Tuczek, Felix
• Other Names: Garcia Yann sponsoringEditor.; Su Bao‐Lian sponsoringEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 13/14(2016)
• Page Start: 2175
• Page End: 2186
• Publication Date: 2015-12-23
• Subjects: Iron -- Spin crossover -- Magnetic properties -- Moessbauer spectroscopy -- Resonance Raman spectroscopy -- LIESST; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201501252
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: 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 ( t Bu 5‐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 system2, 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. Abstract : Attachment of a phenylazo unit in 4‐ and 5‐position to 2, 2′‐bipyridine leads to characteristic changes in the spin crossover properties of Fe II complexes with bipy ligands