Solvent polarity and oxygen sensitivity, rather than viscosity, determine lifetimes of biaryl-sensitised terbium luminescence

Abstract

In a macrocyclic terbium complex incorporating a biaryl sensitiser, the observed variation of emission lifetime is shown to be determined by the solubility of oxygen in the solvent system and the relative energy of the chromophore excited state, rather than any dependence on solvent viscosity.

Twisted Charge‐Transfer Antennae for Ultra‐Bright Terbium(III) and Dysprosium(III) Bioprobes

“…The overall 1P‐brightness was thus acceptable (B 1 (311)=5900 m −1 cm −1 ) but could be significantly improved by increasing the luminescence quantum yield. We then hypothesized that the non‐radiative de‐excitation processes responsible for its low value were induced by the free rotation of the aryl–aryl moieties, and during the redaction of this article, the quenching by oxygen has been alternatively suggested . Herein we describe the new version of the prior charge‐transfer antenna featuring one or two bulky ortho ‐Me substituents ( no3A i Pa ) with i =4 and 5, respectively, depicted in Figure and called twisted antennae.…”

APTRA‐Based Luminescent Lanthanide Complexes Displaying Enhanced Selectivity for Mg2+

“…The absorption spectrumo fEuL 1 (Figure 2) displays three maxima; the bands at 270 nm and 315 nm are attributed to localised p-p*e xcited states, with the broad structurelessb and at 380 nm assigned to an intramolecular charge-transfer( ICT) transition within the pyridylalkynylaryl chromophore. [23] As with EuL 2 ,t he weak shoulder at lower energy (340 nm) is probably associatedw ith an ICT transition. Similarly, EuL 2 displays a [3,4] Chem.E ur.J.2018, 24,7724 -7733 www.chemeurj.org 2018 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim structured p-p*b and at 315 nm that sensitises europiumbased luminescence.…”

“…[23] Photophysical studies of EuL 1 ,EuL 2 and TbL 3 Compound 2 was formed in moderate yield, and the alcohol was converted to the benzylic bromide with phosphorust ribromide in dichloromethane to give 3 in quantitative yield.…”

“…The absorption spectrum of the bi-aryl complex TbL 3 has am aximum at 280 nm assigned to al ocalised p-p* excited state, and was previously shown to exhibit solvatochromic behaviour. [23] As with EuL 2 ,t he weak shoulder at lower energy (340 nm) is probably associatedw ith an ICT transition.…”

“…[23] Polar solvents such as water stabilised the excited state through dipolarinteractions,r educing its luminescence lifetime. [23] Polar solvents such as water stabilised the excited state through dipolarinteractions,r educing its luminescence lifetime.…”