Photomagnetic Studies of Spin‐Crossover‐ and Photochromic‐Based Complexes

Abstract

Abstract This work reports on the combination between photochromic complexes (Na 2 [Fe(CN) 5 (NO)] · 2H 2 O and K 2 [RuCl 5 (NO)]) with spin‐crossover compounds derived from Fe III complexes {[Fe(qsal) 2 ] + and [Fe(salEen) 2 ] + ; Hqsal = N ‐(8‐quinolyl)salicylaldimine; HsalEen = N ‐[(2‐ethylamino)ethyl]salicylaldimine}. These associations have resulted in the synthesis of new materials that contain a spin‐crossover unit and a photochromic unit, as evidenced by their X‐ray structure. Spectroscopic, magnetic and photomagnetic properties of these complexes were studied, with or without light irradiation, to evaluate the possible influence of the photochromic group on the spin transition. [Fe(qsal) 2 ] 2 [Fe(CN) 5 (NO)] · solvent, [Fe(salEen) 2 ] 2 [Fe(CN) 5 (NO)] and [Fe(qsal) 2 ] 2 [Ru(CN) 5 (NO)] · 2.5H 2 O all exhibit a spin transition. The light‐induced excited spin‐state trapping (LIESST) effect was detected in the (Fe‐qsal)‐based complexes. [Fe(qsal) 2 ] 2 [Ru(CN) 5 (NO)] · 2.5H 2 O also exhibits a reverse‐LIESST effect. Regardless of the complex, no photochromic effect from the nitroprusside units was detected.