The switchable phosphorescence and delayed fluorescence of a new rhodamine-like dye through allenylidene formation in a cyclometallated platinum(ii) system

Abstract

A new rhodamine-like alkyne substituted ligand (Rhodyne) was designed to coordinate the cyclometallated platinum(II) system. The chemo-induced “ON-OFF” switching capability on the spirolactone ring of Rhodyne ligand with end-capping platinum(II)...

Toward Near-Infrared Emission in Pt(II)-Cyclometallated Compounds: From Excimers’ Formation to Aggregation-Induced Emission

“…The d 8 platinum­(II) complexes are particularly relevant since they present unique supramolecular self-assembly properties that are not observable in the octahedral d 6 and tetrahedral d 10 metal complexes. They present square-planar geometries that can undergo face-to-face intermolecular interactions through ligand–ligand and Pt­(II)···Pt­(II) interactions, which can give rise to new electronic excited states that produce red-shifted emission from triplet metal–metal-to-ligand charge-transfer ( 3 MMLCT) or excimeric 3 IL excited states in addition to the one arising from the mononuclear Pt­(II) moiety. ,− These assemblies are of great relevance to modulate the resulting photophysical properties, both regarding their energy and emission intensity by subtle changes to their environment. It should be taken into consideration that aggregation can happen in the ground state (dimers) or the excited state (excimers).…”

Monoanionic C^N^N Luminophores and Monodentate C-Donor Co-Ligands for Phosphorescent Pt(II) Complexes: A Case Study Involving Their Photophysics and Cytotoxicity

“…Furthermore, we investigated the molecular structures of representative complexes as determined by single crystal X-ray diffractometric analysis. To the best of our knowledge, only two structures of Pt­(II) complexes with allenylidene ligands have been reported before. − A thorough photophysical and theoretical study of the complexes is also presented in this work, where a clear relationship between the photoluminescence parameters (such as quantum yields and deactivation rate constants) and molecular structure are confirmed by theoretical calculations. Finally, the cytotoxicity of the complexes was evaluated in vitro employing the sulforhodamine B assay and using the human liver carcinoma cell line HepG2.…”

“…In the case of (3) , the molecular structure in the solid state is quite interesting, as platinum complexes with an allenylidene ligand are extremely rare and, to date, only two structurally characterized precedents have been reported in the literature. − Since the monodentate ligand, the benzyl group, and the counterion are disordered in the structure of (3) , only one fragment is shown in Figure a for clarity. In the crystal structure, two molecules are stacked on top of each other with a Pt···Pt distance of 5.1612(3) Å, which is clearly beyond the ca.…”

“…With these scopes in mind, we designed new derivatives of our previously established C^N^N luminophores and combined them with different ancillary ligands to optimize the photophysical properties while controlling their aggregation, based on the bulk of the substituents and their protrusion out of the coordination plane. , It is worth mentioning at this point that Pt···Pt interactions can be diminished or even suppressed by the addition of bulky ligands in the coordination sphere, as observed previously in numerous related compounds. ,,, In this context, allenylidene-derived co-ligands can yield bright coordination compounds while being accessible from the corresponding acetylido complexes. , In addition, new species bearing a bulky out-of-plane-twisted N -heterocyclic carbene (NHC) co-ligand were explored to prevent aggregation while improving the photophysical properties. Furthermore, we investigated the molecular structures of representative complexes as determined by single crystal X-ray diffractometric analysis.…”

“…21,22,24,30 In this context, allenylidene-derived co-ligands can yield bright coordination compounds while being accessible from the corresponding acetylido complexes. 31,32 In addition, new species bearing a bulky out-of-plane-twisted Nheterocyclic carbene (NHC) co-ligand were explored to prevent aggregation while improving the photophysical properties. Furthermore, we investigated the molecular structures of representative complexes as determined by single crystal X-ray diffractometric analysis.…”