Monitoring spin-crossover phenomena via Re(i) luminescence in hybrid Fe(ii) silica coated nanoparticles. Issue 44 (31st October 2021)

• Record Type: Journal Article
• Authors: Díaz-Ortega, Ismael Francisco; Fernández-Barbosa, Eva Luz; Titos-Padilla, Silvia; Pope, Simon J. A.; Jiménez, Juan-Ramón; Colacio, Enrique; Herrera, Juan Manuel
• Is Part Of: Dalton transactions. Volume 50:Issue 44(2021)
• Page Start: 16176
• Page End: 16184
• Publication Date: 2021-10-31
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d1dt03334d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Bifunctional Fe(ii )-SCO/Re(i )-luminescent nanocomposites were prepared, in which the Re(i ) 3 MLCT emission is regulated through the thermal switch of the Fe(ii ) t2g 6 eg 0 /t2g 4 eg 2 electronic configurations. Abstract : Bare (1 ) and silica coated (1@SiO2 ) spin crossover (SCO) nanoparticles based on the polymer {[Fe(NH2 Trz)3 ](BF4 )2 } n have been prepared following a water-in-oil synthetic procedure. For 1, the critical temperatures of the spin transition are T C ↓ = 214.6 K and T C ↑ = 220.9 K. For 1@SiO2, the abruptness of the transition is enhanced and the critical temperatures are centred at room temperature ( T C ↓ = 292.1 K and T C ↑ = 296.3 K). An inert Re(i ) complex of formula [Re(phen)(CO)3 (PETES)](PF6 ) (phen = 1, 10-phenanthroline; PETES = 2(4-pyridylethyl)triethoxysilane) (Re ) was also synthesized yielding intense green emission centred at λ em = 560 nm. The grafting of this complex on the silica shell of 1@SiO2 led to a bifunctional SCO-luminescence composite (1@SiO2 / Re ) whose luminescence properties were tuned by the spin state switching. Temperature-variable photophysical studies showed that luminescence and spin transition were synchronized through a radiative (trivial) energy transfer mechanism between the Re(i ) and the Fe(ii )-LS (LS, Low Spin) centres.