A Near-Infrared-II Emissive Chromium(III) Complex

Narayan Sinha; Juan-Ramón Jiménez; Björn Pfund; Alessandro Prescimone; Claude Piguet; Oliver S Wenger

doi:10.1002/anie.202106398

A Near-Infrared-II Emissive Chromium(III) Complex

Angew Chem Int Ed Engl. 2021 Oct 25;60(44):23722-23728. doi: 10.1002/anie.202106398. Epub 2021 Jul 12.

Authors

Narayan Sinha¹, Juan-Ramón Jiménez², Björn Pfund¹, Alessandro Prescimone³, Claude Piguet², Oliver S Wenger¹

Affiliations

¹ Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland.
² Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai E. Ansermet, 1211, Geneva 4, Switzerland.
³ Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, 4058, Basel, Switzerland.

Abstract

The combination of π-donating amido with π-accepting pyridine coordination units in a tridentate chelate ligand causes a strong nephelauxetic effect in a homoleptic Cr^III complex, which shifts its luminescence to the NIR-II spectral range. Previously explored Cr^III polypyridine complexes typically emit between 727 and 778 nm (in the red to NIR-I spectral region), and ligand design strategies have so far concentrated on optimizing the ligand field strength. The present work takes a fundamentally different approach and focusses on increasing metal-ligand bond covalence to shift the ruby-like ² E emission of Cr^III to 1067 nm at 77 K.

Keywords: UV/Vis spectroscopy; chelates; chromium; luminescence; photophysics.

Publication types

Research Support, Non-U.S. Gov't