High Quantum Yields from Perfluorinated Binolate Erbium Complexes and Their Circularly Polarized Luminescence

Abstract

High quantum yield and circularly polarized luminescence (CPL) brightness values are reported from Shibasaki-type erbium complexes supported by a perfluorinated Binol ligand (F12Binol). The total fluorination of the ligand circumvents nonradiative quenching from Csp2-H vibrations and leads to quantum yields of up to 11% and CPL brightness values of up to 317 M–1 cm–1 (a 19- and 6-fold increase, respectively, compared to (Binol)3ErNa3). These values are the highest values for any molecular erbium complex to date, making them comparable to Yb emitters. A series of fluorinated Shibasaki-type complexes are synthesized by varying the alkali metal (K, Na, Li) in the secondary coordination sphere, leading to unexpected structural differences. NMR (19F, 7Li) and chiroptical spectroscopy analyses provide insights into their structural geometry. With much improved quantum yields and CPL brightness values, we provide synthetic design principles toward other practical candidates for use in quantum communication technologies.

Variable Peripheral Ligand Donation Tunes Electronic Structure and NIR II Emission in Tetrathiafulvalene Tetrathiolate Diradicaloids

“…Leading NIR II-emitting lumiphores rely on complex scaffolds with large, conjugated motifs to shift absorption and emission energies into this low-energy region; ,, however, these complex scaffolds prevent facile synthetic tuning of photophysical properties. Scaffolds with tunable NIR absorption/emission would be valuable as they would also allow for targeted and multicolor imaging. , Furthermore, multicolor imaging can additionally be enhanced and leveraged with dyes that are responsive to various environments; this approach can give additional environmental information as a result of emission or absorption shifts. − In addition to NIR II bioimaging, complexes that emit in the low attenuation telecom bands (∼1260–1550 nm) are of special interest for communication-related applications. , In particular, open-shell complexes that emit in this region would be ideal candidates for sensing and transmitting quantum information.…”