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

This work reports on the combination between photochromic complexes (Na-2[Fe(CN)(5)(NO)]center dot 2H2O and K-2[RuCl5(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)]center dot solvent, [Fe(salEen)(2)](2)[Fe(CN)(5)(NO)] and [Fe(qsal)(2)](2)[Ru(CN)(5)(NO)]center dot 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)]center dot 2.5H(2)O also exhibits a reverse-LIESST effect. Regardless of the complex, no photochromic effect from the nitroprusside units was detected.