Unusual near infrared (NIR) fluorescent palladium(ii) macrocyclic complexes containing M-C bonds with bioimaging capability.

ABSTRACT: Near infrared (NIR) luminescent metal complexes are promising probes in bioimaging and biosensing, however they generally suffer from oxygen interference arising from heavy metal effects. We designed new tetradentate macrocyclic benzitripyrrin (C^N^N^N) ligands by combination of M-C bond formation and reducing the π-conjugation to achieve NIR fluorescent Pd complexes (700-1000 nm) with quantum yields up to 14%. To understand the origin of NIR fluorescence, detailed analyses by density functional theory/time-dependent density functional theory (DFT/TDDFT) calculations together with femtosecond and nanosecond transient absorption spectroscopies suggest that M-C bond formation indeed leads to destabilization of the d-d excited state and less effective quenching of emission; and importantly, s

SUBMITTER: Yao Y 

PROVIDER: S-EPMC6979397 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature