Extrinsicvs.intrinsic luminescence and their interplay with spin crossover in 3D Hofmann-type coordination polymers

Abstract

Two series of coordination polymers have been synthesized to exhibit extrinsic or intrinsic luminescence modulated by spin crossover behavior. This study provides further insight into the features governing the synergy between both properties.

Bistable Hofmann-Type FeII Spin-Crossover Two-Dimensional Polymers of 4-Alkyldisulfanylpyridine for Prospective Grafting of Monolayers on Metallic Surfaces

“…This requires a rational design of the synthesis at macroscopic scale and precise control of essential elusive SCO parameters, such as critical temperature ( T 1/2 ), abruptness, hysteresis width, and completeness. Relevant achievements of this strategy include the combination of SCO and nonlinear optical properties, 4 electronic conduction, 5 electroluminescence, 6 fluorescence, 7 liquid-crystalline properties, 8 porosity, 2d , 2g molecular recognition, 9 photoswitchable magnets, 10 chirality, 11 room-temperature photoisomers and reactions, 12 etc. The ultimate goal is the construction of sensing materials capable of acting as switchers in response to changes of ambient conditions (temperature, humidity, chemical contaminants, etc.).…”

Acidity-Driven Bidirectional Room-Temperature Spin-State Switch and Fluorescence Modulation of a Mononuclear Fe(II) Complex

“…Synergetic effects of the two functions is a goal as it allows modulation of fluorescence emission upon spin state changes, and conversely, spin-state "read out" by monitoring the emission intensity. Coordination of SCO active metal ions with fluorescent ligands [17][18][19][20][21][22][23][24][25] and construction of fluorescent-SCO composite [24][25][26][27][28][29][30][31] are two well-developed strategies. Abnormal temperaturedependent fluorescence variations were observed in the SCO region due to different energy transfers in the two states and, in most cases, an enhanced fluorescence in the HS state was observed.…”

Monitoring spin-crossover phenomena via Re(i) luminescence in hybrid Fe(ii) silica coated nanoparticles

“…The emitter can be an organic fluorophore or luminescent complex which acts as: (i) ligand towards the Fe(II) centres; [8][9][10][11][12][13][14][15][16][17] (ii) counterion; 18 or (iii) guest molecules inserted within the cavities of three-dimensional SCO frameworks. 19,20 In these cases, the location of both components can be studied through structural elucidation techniques allowing the accurate determination of the nature of the correlation between the SCO and the lumine-scence phenomena. A second strategy deals with the synthesis of SCO composites doped or decorated with luminescence species.…”