Heteronuclear PtII–PdII dimers formation through ligands subtle tailoring†

The synthesis of heteronuclear Pt–Pd complexes has long presented a significant challenge, hindering both scientific exploration and industrial applications in electroluminescence and catalysis. This study reports the successful preparation and isolation of two Pt–Pd complexes, designated as 1 and 2, achieved by utilizing distinct cyclometallating C^N ligands. Both complexes were comprehensively characterized, with single crystal X-ray diffraction confirming Pt–Pd distances of 2.8557(5) Å and 2.8548(6) Å for 1 and 2, respectively. Furthermore, these complexes exhibited strong triplet emission at wavelengths of 656 nm and 669 nm, with photoluminescence quantum yields of 40.5% and 48.1% for 1 and 2, respectively. The potential of these complexes in electroluminescent applications was also explored, achieving maximum external quantum efficiencies (EQE_max) of 10.9% for 2 and 10.5% for 1. This inaugural synthesis of phosphorescent heteronuclear Pt–Pd complexes, featuring pronounced metal–metal interactions, not only provides a new synthetic strategy but also paves the way for further application-based studies of heteronuclear Pt–Pd complexes in OLEDs and photocatalysis.