6533b871fe1ef96bd12d1160
RESEARCH PRODUCT
[Cr(ddpd) 2 ] 3+ : A Molecular, Water‐Soluble, Highly NIR‐Emissive Ruby Analogue
Christoph KreitnerUte Resch-gengerKatja HeinzeMarkus GrabolleSven OttoChristoph Förstersubject
ChromiumSubstitution reactionSpectroscopy Near-InfraredWaterchemistry.chemical_elementGeneral ChemistryBite anglePhotochemistryCatalysisMetalFluorescence intensityChromiumWater solubleIntersystem crossingSolubilityX-Ray DiffractionchemistryCoordination Complexesvisual_artvisual_art.visual_art_mediumPhosphorescencedescription
Bright, long-lived emission from first-row transition-metal complexes is very challenging to achieve. Herein, we present a new strategy relying on the rational tuning of energy levels. With the aid of the large N-Cr-N bite angle of the tridentate ligand ddpd (N,N'-dimethyl-N,N'-dipyridine-2-ylpyridine-2,6-diamine) and its strong σ-donating capabilities, a very large ligand-field splitting could be introduced in the chromium(III) complex [Cr(ddpd)2](3+), that shifts the deactivating and photoreactive (4)T2 state well above the emitting (2)E state. Prevention of back-intersystem crossing from the (2)E to the (4)T2 state enables exceptionally high near-infrared phosphorescence quantum yields and lifetimes for this 3d metal complex. The complex [Cr(ddpd)2](BF4)3 is highly water-soluble and very stable towards thermal and photo-induced substitution reactions and can be used for fluorescence intensity- and lifetime-based oxygen sensing in the NIR.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-08-12 | Angewandte Chemie International Edition |