Tabone Roberta, Feser Dominik, Lemma Enrico D, Schepers Ute, Bizzarri Claudia
Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Institute of Functional Interfaces (IFG), KIT, Eggenstein-Leopoldshafen, Germany.
Front Chem. 2021 Sep 23;9:754420. doi: 10.3389/fchem.2021.754420. eCollection 2021.
Novel heteroleptic Zn bis(dipyrrinato) complexes were prepared as intriguing emitters. With our tailor-made design, we achieved far-red emissive complexes with a photoluminescence quantum yield up to 45% in dimethylsulfoxide and 70% in toluene. This means that heteroleptic Zn bis(dipyrrinato) complexes retain very intense emission also in polar solvents, in contrast to their homoleptic counterparts, which we prepared for comparing the photophysical properties. It is evident from the absorption and excitation spectra that heteroleptic complexes present the characteristic features of both ligands: the plain dipyrrin (L) and the π-extended dipyrrin (L). On the contrary, the emission comes exclusively from the π-extended dipyrrin L, suggesting an interligand nonradiative transition that causes a large -Stokes shift (up to 4,600 cm). The large -Stokes shifts and the emissive spectral region of these novel heteroleptic Zn bis(dipyrrinato) complexes are of great interest for bioimaging applications. Thus, their high biocompatibiliy with four different cell lines make them appealing as new fluorophores for cell imaging.
新型异质双（二吡咯）锌配合物被制备为引人注目的发光体。通过我们的定制设计，我们获得了远红光发射配合物，其在二甲基亚砜中的光致发光量子产率高达45%，在甲苯中为70%。这意味着与我们为比较光物理性质而制备的同配体对应物相比，异质双（二吡咯）锌配合物在极性溶剂中也能保持非常强烈的发射。从吸收光谱和激发光谱可以明显看出，异质配合物呈现出两种配体的特征：普通二吡咯（L）和π-扩展二吡咯（L）。相反，发射仅来自π-扩展二吡咯L，这表明配体间的非辐射跃迁导致了大的斯托克斯位移（高达4600 cm）。这些新型异质双（二吡咯）锌配合物的大斯托克斯位移和发射光谱区域在生物成像应用中具有很大的吸引力。因此，它们与四种不同细胞系的高生物相容性使其成为用于细胞成像的新型荧光团。
