Direct Determination of the Rate of Intersystem Crossing in a NIR Luminescent Cr(III) Triazolyl Complex

Description

A detailed understanding of the dynamics of photoinduced processes occurring within the electronic excited state is essential for the design of new and efficient photoactive coordination complexes. In this contribution we demonstrate the use of fluorescence upconversion spectroscopy (FLUPS) in the direct determination of the rate of intersystem crossing (ISC) in a Cr(III)-centered spin-flip emitter.
Photoactive complexes of Cr(III) have recently undergone somewhat of a renaissance, driven through impressive advancements in both molecular design and photophysical performance. Consequently, Cr(III) systems can now begin to be considered as credible Earth-abundant and sustainable alternatives to photoactive complexes of the rare and expensive late transition metal elements commonly employed in applications such as photocatalysis, luminescence sensing and biological imaging.
Here we present the first example of a Cr(III) 1,2,3-triazolyl complex which displays long-lived near-IR photoluminescence (λem = 760, τ = 14 µs). Whilst ultrafast transient absorption spectroscopy allows us to observe the evolution of phosphorescent doublet states, we utilise FLUPS to capture the short-lived fluorescence from initially populated quartet states immediately prior to ISC. We are thus able to disentangle the process of intersystem crossing from other closely associated excited state events and will present a detailed picture of the excited state behaviour and dynamics of this system. The talk will conclude with a discussion of the tuning of NIR phosphorescence in our most recent organometallic complexes of Cr(III).

Period	26 Jul 2023
Event title	25th International Symposium on the Photochemistry and Photophysics of Coordination Compounds
Event type	Conference
Conference number	25
Location	Ulm, Germany, Baden-WürttembergShow on map
Degree of Recognition	International