Resolving the ultrafast intersystem crossing in a bimetallic platinum complex

Andrew J S Valentine; Joseph J Radler; Alexis Mills; Pyosang Kim; Felix N Castellano; Lin X Chen; Xiaosong Li

doi:10.1063/1.5115169

Resolving the ultrafast intersystem crossing in a bimetallic platinum complex

J Chem Phys. 2019 Sep 21;151(11):114303. doi: 10.1063/1.5115169.

Authors

Andrew J S Valentine¹, Joseph J Radler¹, Alexis Mills¹, Pyosang Kim², Felix N Castellano³, Lin X Chen², Xiaosong Li¹

Affiliations

¹ Department of Chemistry, University of Washington, Seattle, Washington 98195, USA.
² Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA and Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
³ Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.

PMID: 31542032
DOI: 10.1063/1.5115169

Abstract

Bimetallic platinum complexes have interesting luminescent properties and feature long-lasting vibrational coherence and ultrafast intersystem crossing (ISC) after photoexcitation. Ultrafast triplet formation is driven by very strong spin-orbit coupling in these platinum (II) systems, where relativistic theoretical approaches beyond first-order perturbation theory are desirable. Using a fully variational relativistic theoretical method recently developed by the authors, we investigate the origins of ultrafast ISC in the [Pt(ppy) (μ-^tBu₂pz)]₂ complex (ppy = phenylpyridine, pz = pyrazolate). Spin-orbit coupling values, evaluated along a Born-Oppenheimer molecular dynamics trajectory, are used to propagate electronic populations in time. Using this technique, we estimate ultrafast ISC rates of 15-134 fs in this species for the possible ISC pathways into the three low-lying triplet states.